text: /*
   * Copyright (c) 2004-2009 Sergey Lyubka
   * Portions Copyright (c) 2009 Gilbert Wellisch
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   *
   * $Id: mongoose.c 446 2009-07-08 21:06:56Z valenok $
   */
  
  #if defined(_WIN32)
  #define _CRT_SECURE_NO_WARNINGS	/* Disable deprecation warning in VS2005 */
  #endif /* _WIN32 */
  
  #ifndef _WIN32_WCE /* Some ANSI #includes are not available on Windows CE */
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <errno.h>
  #include <signal.h>
  #include <fcntl.h>
  #endif /* !_WIN32_WCE */
  
  #include <time.h>
  #include <stdlib.h>
  #include <stdarg.h>
  #include <assert.h>
  #include <string.h>
  #include <ctype.h>
  #include <limits.h>
  #include <stddef.h>
  #include <stdio.h>
  
  #if defined(_WIN32)		/* Windows specific #includes and #defines */
  #define	_WIN32_WINNT	0x0400	/* To make it link in VS2005 */
  #include <windows.h>
  
  #ifndef _WIN32_WCE
  #include <process.h>
  #include <direct.h>
  #include <io.h>
  #else /* _WIN32_WCE */
  /* Windows CE-specific definitions */
  #include <winsock2.h>
  #define NO_CGI	/* WinCE has no pipes */
  #define NO_SSI	/* WinCE has no pipes */
  
  #define FILENAME_MAX	MAX_PATH
  #define BUFSIZ		4096
  typedef long off_t;
  
  #define errno			GetLastError()
  #define strerror(x)		_ultoa(x, (char *) _alloca(sizeof(x) *3 ), 10)
  #endif /* _WIN32_WCE */
  
  #define EPOCH_DIFF	0x019DB1DED53E8000 /* 116444736000000000 nsecs */
  #define RATE_DIFF	10000000 /* 100 nsecs */
  #define MAKEUQUAD(lo, hi)	((uint64_t)(((uint32_t)(lo)) | \
  				((uint64_t)((uint32_t)(hi))) << 32))
  #define	SYS2UNIX_TIME(lo, hi) \
  	(time_t) ((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF)
  
  /*
   * Visual Studio 6 does not know __func__ or __FUNCTION__
   * The rest of MS compilers use __FUNCTION__, not C99 __func__
   */
  #if defined(_MSC_VER) && _MSC_VER < 1300
  #define	STRX(x)			#x
  #define	STR(x)			STRX(x)
  #define	__func__		"line " STR(__LINE__)
  #else
  #define	__func__		__FUNCTION__
  #endif /* _MSC_VER */
  
  #define	ERRNO			GetLastError()
  #define	NO_SOCKLEN_T
  #define	SSL_LIB			"ssleay32.dll"
  #define	CRYPTO_LIB		"libeay32.dll"
  #define	DIRSEP			'\\'
  #define	IS_DIRSEP_CHAR(c)	((c) == '/' || (c) == '\\')
  #define	O_NONBLOCK		0
  #define	EWOULDBLOCK		WSAEWOULDBLOCK
  #define	_POSIX_
  #define UINT64_FMT		"I64"
  
  #define	SHUT_WR			1
  #define	snprintf		_snprintf
  #define	vsnprintf		_vsnprintf
  #define	sleep(x)		Sleep((x) * 1000)
  
  #define	popen(x, y)		_popen(x, y)
  #define	pclose(x)		_pclose(x)
  #define	close(x)		_close(x)
  #define	dlsym(x,y)		GetProcAddress((HINSTANCE) (x), (y))
  #define	RTLD_LAZY		0
  #define	fseeko(x, y, z)		fseek((x), (y), (z))
  #define	write(x, y, z)		_write((x), (y), (unsigned) z)
  #define	read(x, y, z)		_read((x), (y), (unsigned) z)
  #define	flockfile(x)		(void) 0
  #define	funlockfile(x)		(void) 0
  
  #ifdef HAVE_STRTOUI64
  #define	strtoull(x, y, z)	_strtoui64(x, y, z)
  #else
  #define	strtoull(x, y, z)	strtoul(x, y, z)
  #endif /* HAVE_STRTOUI64 */
  
  #if !defined(fileno)
  #define	fileno(x)		_fileno(x)
  #endif /* !fileno MINGW #defines fileno */
  
  typedef HANDLE pthread_mutex_t;
  typedef HANDLE pthread_cond_t;
  typedef DWORD pthread_t;
  typedef HANDLE pid_t;
  
  struct timespec {
  	long tv_nsec;
  	long tv_sec;
  };
  
  static int pthread_mutex_lock(pthread_mutex_t *);
  static int pthread_mutex_unlock(pthread_mutex_t *);
  
  #if defined(HAVE_STDINT)
  #include <stdint.h>
  #else
  typedef unsigned int		uint32_t;
  typedef unsigned short		uint16_t;
  #if _MSC_VER > 1200
  typedef unsigned __int64	uint64_t;
  #else
  /* VC6 cannot cast double to unsigned __int64, needed by print_dir_entry() */
  typedef __int64	uint64_t;
  #endif /* _MSC_VER */
  #endif /* HAVE_STDINT */
  
  /*
   * POSIX dirent interface
   */
  struct dirent {
  	char	d_name[FILENAME_MAX];
  };
  
  typedef struct DIR {
  	HANDLE			handle;
  	WIN32_FIND_DATAW	info;
  	struct dirent		result;
  } DIR;
  
  #else				/* UNIX  specific	*/
  #include <sys/wait.h>
  #include <sys/socket.h>
  #include <sys/select.h>
  #include <sys/mman.h>
  #include <netinet/in.h>
  #include <arpa/inet.h>
  #include <sys/time.h>
  
  #include <pwd.h>
  #include <unistd.h>
  #include <dirent.h>
  #include <dlfcn.h>
  #include <pthread.h>
  #define	SSL_LIB			"libssl.so"
  #define	CRYPTO_LIB		"libcrypto.so"
  #define	DIRSEP			'/'
  #define	IS_DIRSEP_CHAR(c)	((c) == '/')
  #define	O_BINARY		0
  #define	closesocket(a)		close(a)
  #define	mg_fopen(x, y)		fopen(x, y)
  #define	mg_mkdir(x, y)		mkdir(x, y)
  #define	mg_remove(x)		remove(x)
  #define	mg_rename(x, y)		rename(x, y)
  #define	mg_getcwd(x, y)		getcwd(x, y)
  #define	ERRNO			errno
  #define	INVALID_SOCKET		(-1)
  #ifdef __LP64__
  #define UINT64_FMT		"l"
  #else
  #define UINT64_FMT		"ll"
  #endif
  typedef int SOCKET;
  
  #endif /* End of Windows and UNIX specific includes */
  
  #include "mongoose.h"
  
  #define	MONGOOSE_VERSION	"2.8"
  #define	PASSWORDS_FILE_NAME	".htpasswd"
  #define	CGI_ENVIRONMENT_SIZE	4096
  #define	MAX_CGI_ENVIR_VARS	64
  #define	MAX_REQUEST_SIZE	8192
  #define	MAX_LISTENING_SOCKETS	10
  #define	MAX_CALLBACKS		20
  #define	ARRAY_SIZE(array)	(sizeof(array) / sizeof(array[0]))
  #define	UNKNOWN_CONTENT_LENGTH	((uint64_t) ~0)
  #define	DEBUG_MGS_PREFIX	"*** Mongoose debug *** "
  
  #if defined(DEBUG)
  #define	DEBUG_TRACE(x) do {printf x; putchar('\n'); fflush(stdout);} while (0)
  #else
  #define DEBUG_TRACE(x)
  #endif /* DEBUG */
  
  /*
   * Darwin prior to 7.0 and Win32 do not have socklen_t
   */
  #ifdef NO_SOCKLEN_T
  typedef int socklen_t;
  #endif /* NO_SOCKLEN_T */
  
  #if !defined(FALSE)
  enum {FALSE, TRUE};
  #endif /* !FALSE */
  
  typedef int bool_t;
  typedef void * (*mg_thread_func_t)(void *);
  
  static const char *http_500_error = "Internal Server Error";
  
  /*
   * Snatched from OpenSSL includes. I put the prototypes here to be independent
   * from the OpenSSL source installation. Having this, mongoose + SSL can be
   * built on any system with binary SSL libraries installed.
   */
  typedef struct ssl_st SSL;
  typedef struct ssl_method_st SSL_METHOD;
  typedef struct ssl_ctx_st SSL_CTX;
  
  #define	SSL_ERROR_WANT_READ	2
  #define	SSL_ERROR_WANT_WRITE	3
  #define SSL_FILETYPE_PEM	1
  #define	CRYPTO_LOCK		1
  
  /*
   * Dynamically loaded SSL functionality
   */
  struct ssl_func {
  	const char	*name;		/* SSL function name	*/
  	void		(*ptr)(void);	/* Function pointer	*/
  };
  
  #define	SSL_free(x)	(* (void (*)(SSL *)) ssl_sw[0].ptr)(x)
  #define	SSL_accept(x)	(* (int (*)(SSL *)) ssl_sw[1].ptr)(x)
  #define	SSL_connect(x)	(* (int (*)(SSL *)) ssl_sw[2].ptr)(x)
  #define	SSL_read(x,y,z)	(* (int (*)(SSL *, void *, int)) 		\
  				ssl_sw[3].ptr)((x),(y),(z))
  #define	SSL_write(x,y,z) (* (int (*)(SSL *, const void *,int))		\
  				ssl_sw[4].ptr)((x), (y), (z))
  #define	SSL_get_error(x,y)(* (int (*)(SSL *, int)) ssl_sw[5])((x), (y))
  #define	SSL_set_fd(x,y)	(* (int (*)(SSL *, SOCKET)) ssl_sw[6].ptr)((x), (y))
  #define	SSL_new(x)	(* (SSL * (*)(SSL_CTX *)) ssl_sw[7].ptr)(x)
  #define	SSL_CTX_new(x)	(* (SSL_CTX * (*)(SSL_METHOD *)) ssl_sw[8].ptr)(x)
  #define	SSLv23_server_method()	(* (SSL_METHOD * (*)(void)) ssl_sw[9].ptr)()
  #define	SSL_library_init() (* (int (*)(void)) ssl_sw[10].ptr)()
  #define	SSL_CTX_use_PrivateKey_file(x,y,z)	(* (int (*)(SSL_CTX *, \
  		const char *, int)) ssl_sw[11].ptr)((x), (y), (z))
  #define	SSL_CTX_use_certificate_file(x,y,z)	(* (int (*)(SSL_CTX *, \
  		const char *, int)) ssl_sw[12].ptr)((x), (y), (z))
  #define SSL_CTX_set_default_passwd_cb(x,y) \
  	(* (void (*)(SSL_CTX *, mg_spcb_t)) ssl_sw[13].ptr)((x),(y))
  #define SSL_CTX_free(x) (* (void (*)(SSL_CTX *)) ssl_sw[14].ptr)(x)
  
  #define CRYPTO_num_locks() (* (int (*)(void)) crypto_sw[0].ptr)()
  #define CRYPTO_set_locking_callback(x)					\
  		(* (void (*)(void (*)(int, int, const char *, int)))	\
  	 	crypto_sw[1].ptr)(x)
  #define CRYPTO_set_id_callback(x)					\
  	(* (void (*)(unsigned long (*)(void))) crypto_sw[2].ptr)(x)
  
  /*
   * set_ssl_option() function when called, updates this array.
   * It loads SSL library dynamically and changes NULLs to the actual addresses
   * of respective functions. The macros above (like SSL_connect()) are really
   * just calling these functions indirectly via the pointer.
   */
  static struct ssl_func	ssl_sw[] = {
  	{"SSL_free",			NULL},
  	{"SSL_accept",			NULL},
  	{"SSL_connect",			NULL},
  	{"SSL_read",			NULL},
  	{"SSL_write",			NULL},
  	{"SSL_get_error",		NULL},
  	{"SSL_set_fd",			NULL},
  	{"SSL_new",			NULL},
  	{"SSL_CTX_new",			NULL},
  	{"SSLv23_server_method",	NULL},
  	{"SSL_library_init",		NULL},
  	{"SSL_CTX_use_PrivateKey_file",	NULL},
  	{"SSL_CTX_use_certificate_file",NULL},
  	{"SSL_CTX_set_default_passwd_cb",NULL},
  	{"SSL_CTX_free",		NULL},
  	{NULL,				NULL}
  };
  
  /*
   * Similar array as ssl_sw. These functions are located in different lib.
   */
  static struct ssl_func	crypto_sw[] = {
  	{"CRYPTO_num_locks",		NULL},
  	{"CRYPTO_set_locking_callback",	NULL},
  	{"CRYPTO_set_id_callback",	NULL},
  	{NULL,				NULL}
  };
  
  /*
   * Month names
   */
  static const char *month_names[] = {
  	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
  	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  };
  
  /*
   * Unified socket address. For IPv6 support, add IPv6 address structure
   * in the union u.
   */
  struct usa {
  	socklen_t len;
  	union {
  		struct sockaddr	sa;
  		struct sockaddr_in sin;
  	} u;
  };
  
  /*
   * Specifies a string (chunk of memory).
   * Used to traverse comma separated lists of options.
   */
  struct vec {
  	const char	*ptr;
  	size_t		len;
  };
  
  /*
   * Structure used by mg_stat() function. Uses 64 bit file length.
   */
  struct mgstat {
  	bool_t		is_directory;	/* Directory marker		*/
  	uint64_t	size;		/* File size			*/
  	time_t		mtime;		/* Modification time		*/
  };
  
  struct mg_option {
  	const char	*name;
  	const char	*description;
  	const char	*default_value;
  	int		index;
  	bool_t (*setter)(struct mg_context *, const char *);
  };
  
  /*
   * Numeric indexes for the option values in context, ctx->options
   */
  enum mg_option_index {
  	OPT_ROOT, OPT_INDEX_FILES, OPT_PORTS, OPT_DIR_LIST, OPT_CGI_EXTENSIONS,
  	OPT_CGI_INTERPRETER, OPT_CGI_ENV, OPT_SSI_EXTENSIONS, OPT_AUTH_DOMAIN,
  	OPT_AUTH_GPASSWD, OPT_AUTH_PUT, OPT_ACCESS_LOG, OPT_ERROR_LOG,
  	OPT_SSL_CERTIFICATE, OPT_ALIASES, OPT_ACL, OPT_UID, OPT_PROTECT,
  	OPT_SERVICE, OPT_HIDE, OPT_ADMIN_URI, OPT_MAX_THREADS, OPT_IDLE_TIME,
  	OPT_MIME_TYPES,
  	NUM_OPTIONS
  };
  
  /*
   * Structure used to describe listening socket, or socket which was
   * accept()-ed by the master thread and queued for future handling
   * by the worker thread.
   */
  struct socket {
  	SOCKET		sock;		/* Listening socket		*/
  	struct usa	lsa;		/* Local socket address		*/
  	struct usa	rsa;		/* Remote socket address	*/
  	bool_t		is_ssl;		/* Is socket SSL-ed		*/
  };
  
  /*
   * Callback function, and where it is bound to
   */
  struct callback {
  	char		*uri_regex;	/* URI regex to handle		*/
  	mg_callback_t	func;		/* user callback		*/
  	bool_t		is_auth;	/* func is auth checker		*/
  	int		status_code;	/* error code to handle		*/
  	void		*user_data;	/* opaque user data		*/
  };
  
  /*
   * Mongoose context
   */
  struct mg_context {
  	int		stop_flag;	/* Should we stop event loop	*/
  	SSL_CTX		*ssl_ctx;	/* SSL context			*/
  
  	FILE		*access_log;	/* Opened access log		*/
  	FILE		*error_log;	/* Opened error log		*/
  
  	struct socket	listeners[MAX_LISTENING_SOCKETS];
  	int		num_listeners;
  
  	struct callback	callbacks[MAX_CALLBACKS];
  	int		num_callbacks;
  
  	char		*options[NUM_OPTIONS];	/* Configured opions	*/
  	pthread_mutex_t	opt_mutex[NUM_OPTIONS];	/* Option protector	*/
  
  	int		max_threads;	/* Maximum number of threads	*/
  	int		num_threads;	/* Number of threads		*/
  	int		num_idle;	/* Number of idle threads	*/
  	pthread_mutex_t	thr_mutex;	/* Protects (max|num)_threads	*/
  	pthread_cond_t	thr_cond;
  	pthread_mutex_t	bind_mutex;	/* Protects bind operations	*/
  
  	struct socket	queue[20];	/* Accepted sockets		*/
  	int		sq_head;	/* Head of the socket queue	*/
  	int		sq_tail;	/* Tail of the socket queue	*/
  	pthread_cond_t	empty_cond;	/* Socket queue empty condvar	*/
  	pthread_cond_t	full_cond;	/* Socket queue full condvar	*/
  
  	mg_spcb_t	ssl_password_callback;
  	mg_callback_t	log_callback;
  };
  
  /*
   * Client connection.
   */
  struct mg_connection {
  	struct mg_request_info	request_info;
  	struct mg_context *ctx;		/* Mongoose context we belong to*/
  	SSL		*ssl;		/* SSL descriptor		*/
  	struct socket	client;		/* Connected client		*/
  	time_t		birth_time;	/* Time connection was accepted	*/
  	bool_t		free_post_data;	/* post_data was malloc-ed	*/
  	bool_t		embedded_auth;	/* Used for authorization	*/
  	uint64_t	num_bytes_sent;	/* Total bytes sent to client	*/
  };
  
  /*
   * Print error message to the opened error log stream.
   */
  static void
  cry(struct mg_connection *conn, const char *fmt, ...)
  {
  	char	buf[BUFSIZ];
  	va_list	ap;
  
  	va_start(ap, fmt);
  	(void) vsnprintf(buf, sizeof(buf), fmt, ap);
  	conn->ctx->log_callback(conn, &conn->request_info, buf);
  	va_end(ap);
  }
  
  /*
   * Return fake connection structure. Used for logging, if connection
   * is not applicable at the moment of logging.
   */
  static struct mg_connection *
  fc(struct mg_context *ctx)
  {
  	static struct mg_connection fake_connection;
  	fake_connection.ctx = ctx;
  	return (&fake_connection);
  }
  
  /*
   * If an embedded code does not intercept logging by calling
   * mg_set_log_callback(), this function is used for logging. It prints
   * stuff to the conn->error_log, which is stderr unless "error_log"
   * option was set.
   */
  static void
  builtin_error_log(struct mg_connection *conn,
  		const struct mg_request_info *request_info, void *message)
  {
  	FILE	*fp;
  	time_t	timestamp;
  
  	fp = conn->ctx->error_log;
  	flockfile(fp);
  
  	timestamp = time(NULL);
  
  	(void) fprintf(fp,
  	    "[%010lu] [error] [client %s] ",
  	    (unsigned long) timestamp,
  	    inet_ntoa(conn->client.rsa.u.sin.sin_addr));
  
  	if (request_info->request_method != NULL)
  		(void) fprintf(fp, "%s %s: ",
  		    request_info->request_method,
  		    request_info->uri);
  
  	(void) fprintf(fp, "%s", (char *) message);
  
  	fputc('\n', fp);
  
  	funlockfile(fp);
  }
  
  const char *
  mg_version(void)
  {
  	return (MONGOOSE_VERSION);
  }
  
  static void
  mg_strlcpy(register char *dst, register const char *src, size_t n)
  {
  	for (; *src != '\0' && n > 1; n--)
  		*dst++ = *src++;
  	*dst = '\0';
  }
  
  static int
  lowercase(const char *s)
  {
  	return (tolower(* (unsigned char *) s));
  }
  
  static int
  mg_strncasecmp(const char *s1, const char *s2, size_t len)
  {
  	int	diff = 0;
  
  	if (len > 0)
  		do {
  			diff = lowercase(s1++) - lowercase(s2++);
  		} while (diff == 0 && s1[-1] != '\0' && --len > 0);
  
  	return (diff);
  }
  
  static int
  mg_strcasecmp(const char *s1, const char *s2)
  {
  	int	diff;
  
  	do {
  		diff = lowercase(s1++) - lowercase(s2++);
  	} while (diff == 0 && s1[-1] != '\0');
  
  	return (diff);
  }
  
  static char *
  mg_strndup(const char *ptr, size_t len)
  {
  	char	*p;
  
  	if ((p = (char *) malloc(len + 1)) != NULL)
  		mg_strlcpy(p, ptr, len + 1);
  
  	return (p);
  
  }
  
  static char *
  mg_strdup(const char *str)
  {
  	return (mg_strndup(str, strlen(str)));
  }
  
  /*
   * Like snprintf(), but never returns negative value, or the value
   * that is larger than a supplied buffer.
   * Thanks to Adam Zeldis to pointing snprintf()-caused vulnerability
   * in his audit report.
   */
  static int
  mg_vsnprintf(struct mg_connection *conn,
  		char *buf, size_t buflen, const char *fmt, va_list ap)
  {
  	int	n;
  
  	if (buflen == 0)
  		return (0);
  
  	n = vsnprintf(buf, buflen, fmt, ap);
  
  	if (n < 0) {
  		cry(conn, "vsnprintf error");
  		n = 0;
  	} else if (n >= (int) buflen) {
  		cry(conn, "truncating vsnprintf buffer: [%.*s]",
  		    n > 200 ? 200 : n, buf);
  		n = (int) buflen - 1;
  	}
  	buf[n] = '\0';
  
  	return (n);
  }
  
  static int
  mg_snprintf(struct mg_connection *conn,
  		char *buf, size_t buflen, const char *fmt, ...)
  {
  	va_list	ap;
  	int	n;
  
  	va_start(ap, fmt);
  	n = mg_vsnprintf(conn, buf, buflen, fmt, ap);
  	va_end(ap);
  
  	return (n);
  }
  
  /*
   * Convert string representing a boolean value to a boolean value
   */
  static bool_t
  is_true(const char *str)
  {
  	static const char	*trues[] = {"1", "yes", "true", "ja", NULL};
  	int			i;
  
  	for (i = 0; trues[i] != NULL; i++)
  		if (str != NULL && mg_strcasecmp(str, trues[i]) == 0)
  			return (TRUE);
  
  	return (FALSE);
  }
  
  /*
   * Skip the characters until one of the delimiters characters found.
   * 0-terminate resulting word. Skip the rest of the delimiters if any.
   * Advance pointer to buffer to the next word. Return found 0-terminated word.
   */
  static char *
  skip(char **buf, const char *delimiters)
  {
  	char	*p, *begin_word, *end_word, *end_delimiters;
  
  	begin_word = *buf;
  	end_word = begin_word + strcspn(begin_word, delimiters);
  	end_delimiters = end_word + strspn(end_word, delimiters);
  
  	for (p = end_word; p < end_delimiters; p++)
  		*p = '\0';
  
  	*buf = end_delimiters;
  
  	return (begin_word);
  }
  
  /*
   * Return HTTP header value, or NULL if not found.
   */
  static const char *
  get_header(const struct mg_request_info *ri, const char *name)
  {
  	int	i;
  
  	for (i = 0; i < ri->num_headers; i++)
  		if (!mg_strcasecmp(name, ri->http_headers[i].name))
  			return (ri->http_headers[i].value);
  
  	return (NULL);
  }
  
  const char *
  mg_get_header(const struct mg_connection *conn, const char *name)
  {
  	return (get_header(&conn->request_info, name));
  }
  
  /*
   * A helper function for traversing comma separated list of values.
   * It returns a list pointer shifted to the next value, of NULL if the end
   * of the list found.
   * Value is stored in val vector. If value has form "x=y", then eq_val
   * vector is initialized to point to the "y" part, and val vector length
   * is adjusted to point only to "x".
   */
  static const char *
  next_option(const char *list, struct vec *val, struct vec *eq_val)
  {
  	if (list == NULL || *list == '\0') {
  		/* End of the list */
  		list = NULL;
  	} else {
  		val->ptr = list;
  		if ((list = strchr(val->ptr, ',')) != NULL) {
  			/* Comma found. Store length and shift the list ptr */
  			val->len = list - val->ptr;
  			list++;
  		} else {
  			/* This value is the last one */
  			list = val->ptr + strlen(val->ptr);
  			val->len = list - val->ptr;
  		}
  
  		if (eq_val != NULL) {
  			/*
  			 * Value has form "x=y", adjust pointers and lengths
  			 * so that val points to "x", and eq_val points to "y".
  			 */
  			eq_val->len = 0;
  			eq_val->ptr = memchr(val->ptr, '=', val->len);
  			if (eq_val->ptr != NULL) {
  				eq_val->ptr++;  /* Skip over '=' character */
  				eq_val->len = val->ptr + val->len - eq_val->ptr;
  				val->len = (eq_val->ptr - val->ptr) - 1;
  			}
  		}
  	}
  
  	return (list);
  }
  
  #if !(defined(NO_CGI) && defined(NO_SSI))
  /*
   * Verify that given file has certain extension
   */
  static bool_t
  match_extension(const char *path, const char *ext_list)
  {
  	struct vec	ext_vec;
  	size_t		path_len;
  
  	path_len = strlen(path);
  
  	while ((ext_list = next_option(ext_list, &ext_vec, NULL)) != NULL)
  		if (ext_vec.len < path_len &&
  		    mg_strncasecmp(path + path_len - ext_vec.len,
  			    ext_vec.ptr, ext_vec.len) == 0)
  			return (TRUE);
  
  	return (FALSE);
  }
  #endif /* !(NO_CGI && NO_SSI) */
  
  /*
   * Return TRUE if "uri" matches "regexp".
   * '*' in the regexp means zero or more characters.
   */
  static bool_t
  match_regex(const char *uri, const char *regexp)
  {
  	if (*regexp == '\0')
  		return (*uri == '\0');
  
  	if (*regexp == '*')
  		do {
  			if (match_regex(uri, regexp + 1))
  				return (TRUE);
  		} while (*uri++ != '\0');
  
  	if (*uri != '\0' && *regexp == *uri)
  		return (match_regex(uri + 1, regexp + 1));
  
  	return (FALSE);
  }
  
  static const struct callback *
  find_callback(struct mg_context *ctx, bool_t is_auth,
  		const char *uri, int status_code)
  {
  	const struct callback	*cb, *found;
  	int			i;
  
  	found = NULL;
  	pthread_mutex_lock(&ctx->bind_mutex);
  	for (i = 0; i < ctx->num_callbacks; i++) {
  		cb = ctx->callbacks + i;
  		if ((uri != NULL && cb->uri_regex != NULL &&
  		    ((is_auth && cb->is_auth) || (!is_auth && !cb->is_auth)) &&
  		    match_regex(uri, cb->uri_regex)) || (uri == NULL &&
  		     (cb->status_code == 0 ||
  		      cb->status_code == status_code))) {
  			found = cb;
  			break;
  		}
  	}
  	pthread_mutex_unlock(&ctx->bind_mutex);
  
  	return (found);
  }
  
  /*
   * For use by external application. This sets custom logging function.
   */
  void
  mg_set_log_callback(struct mg_context *ctx, mg_callback_t log_callback)
  {
  	/* If NULL is specified as a callback, revert back to the default */
  	if (log_callback == NULL)
  		ctx->log_callback = &builtin_error_log;
  	else
  		ctx->log_callback = log_callback;
  }
  
  /*
   * Send error message back to the client.
   */
  static void
  send_error(struct mg_connection *conn, int status, const char *reason,
  		const char *fmt, ...)
  {
  	const struct callback	*cb;
  	char		buf[BUFSIZ];
  	va_list		ap;
  	int		len;
  
  	conn->request_info.status_code = status;
  
  	/* If error handler is set, call it. Otherwise, send error message */
  	if ((cb = find_callback(conn->ctx, FALSE, NULL, status)) != NULL) {
  		cb->func(conn, &conn->request_info, cb->user_data);
  	} else {
  		buf[0] = '\0';
  		len = 0;
  
  		/* Errors 1xx, 204 and 304 MUST NOT send a body */
  		if (status > 199 && status != 204 && status != 304) {
  			len = mg_snprintf(conn, buf, sizeof(buf),
  			    "Error %d: %s\n", status, reason);
  			cry(conn, "%s", buf);
  
  			va_start(ap, fmt);
  			len += mg_vsnprintf(conn, buf + len, sizeof(buf) - len,
  			    fmt, ap);
  			va_end(ap);
  			conn->num_bytes_sent = len;
  		}
  
  		(void) mg_printf(conn,
  		    "HTTP/1.1 %d %s\r\n"
  		    "Content-Type: text/plain\r\n"
  		    "Content-Length: %d\r\n"
  		    "Connection: close\r\n"
  		    "\r\n%s", status, reason, len, buf);
  	}
  }
  
  #ifdef _WIN32
  static int
  pthread_mutex_init(pthread_mutex_t *mutex, void *unused)
  {
  	unused = NULL;
  	*mutex = CreateMutex(NULL, FALSE, NULL);
  	return (*mutex == NULL ? -1 : 0);
  }
  
  static int
  pthread_mutex_destroy(pthread_mutex_t *mutex)
  {
  	return (CloseHandle(*mutex) == 0 ? -1 : 0);
  }
  
  static int
  pthread_mutex_lock(pthread_mutex_t *mutex)
  {
  	return (WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1);
  }
  
  static int
  pthread_mutex_unlock(pthread_mutex_t *mutex)
  {
  	return (ReleaseMutex(*mutex) == 0 ? -1 : 0);
  }
  
  static int
  pthread_cond_init(pthread_cond_t *cv, const void *unused)
  {
  	unused = NULL;
  	*cv = CreateEvent(NULL, FALSE, FALSE, NULL);
  	return (*cv == NULL ? -1 : 0);
  }
  
  static int
  pthread_cond_timedwait(pthread_cond_t *cv, pthread_mutex_t *mutex,
  	const struct timespec *ts)
  {
  	DWORD	status;
  	DWORD	msec = INFINITE;
  	time_t	now;
  	
  	if (ts != NULL) {
  		now = time(NULL);
  		msec = 1000 * (now > ts->tv_sec ? 0 : ts->tv_sec - now);
  	}
  
  	(void) ReleaseMutex(*mutex);
  	status = WaitForSingleObject(*cv, msec);
  	(void) WaitForSingleObject(*mutex, INFINITE);
  	
  	return (status == WAIT_OBJECT_0 ? 0 : -1);
  }
  
  static int
  pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex)
  {
  	return (pthread_cond_timedwait(cv, mutex, NULL));
  }
  
  static int
  pthread_cond_signal(pthread_cond_t *cv)
  {
  	return (SetEvent(*cv) == 0 ? -1 : 0);
  }
  
  static int
  pthread_cond_destroy(pthread_cond_t *cv)
  {
  	return (CloseHandle(*cv) == 0 ? -1 : 0);
  }
  
  static pthread_t
  pthread_self(void)
  {
  	return (GetCurrentThreadId());
  }
  
  /*
   * Change all slashes to backslashes. It is Windows.
   */
  static void
  fix_directory_separators(char *path)
  {
  	int	i;
  
  	for (i = 0; path[i] != '\0'; i++) {
  		if (path[i] == '/')
  			path[i] = '\\';
  		/* i > 0 check is to preserve UNC paths, \\server\file.txt */
  		if (path[i] == '\\' && i > 0)
  			while (path[i + 1] == '\\' || path[i + 1] == '/')
  				(void) memmove(path + i + 1,
  				    path + i + 2, strlen(path + i + 1));
  	}
  }
  
  /*
   * Encode 'path' which is assumed UTF-8 string, into UNICODE string.
   * wbuf and wbuf_len is a target buffer and its length.
   */
  static void
  to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len)
  {
  	char	buf[FILENAME_MAX], *p;
  
  	mg_strlcpy(buf, path, sizeof(buf));
  	fix_directory_separators(buf);
  
  	/* Point p to the end of the file name */
  	p = buf + strlen(buf) - 1;
  
  	/* Trim trailing backslash character */
  	while (p > buf && *p == '\\' && p[-1] != ':')
  		*p-- = '\0';
  
  	/*
  	 * Protect from CGI code disclosure.
  	 * This is very nasty hole. Windows happily opens files with
  	 * some garbage in the end of file name. So fopen("a.cgi    ", "r")
  	 * actually opens "a.cgi", and does not return an error!
  	 */
  	if (*p == 0x20 || *p == 0x2e || *p == 0x2b || (*p & ~0x7f)) {
  		(void) fprintf(stderr, "Rejecting suspicious path: [%s]", buf);
  		buf[0] = '\0';
  	}
  
  	(void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
  }
  
  #if defined(_WIN32_WCE)
  
  static time_t
  time(time_t *ptime)
  {
  	time_t		t;
  	SYSTEMTIME	st;
  	FILETIME	ft;
  
  	GetSystemTime(&st);
  	SystemTimeToFileTime(&st, &ft);
  	t = SYS2UNIX_TIME(ft.dwLowDateTime, ft.dwHighDateTime);
  
  	if (ptime != NULL)
  		*ptime = t;
  
  	return (t);
  }
  
  static time_t
  mktime(struct tm *ptm)
  {
  	SYSTEMTIME	st;
  	FILETIME	ft, lft;
  
  	st.wYear = ptm->tm_year + 1900;
  	st.wMonth = ptm->tm_mon + 1;
  	st.wDay = ptm->tm_mday;
  	st.wHour = ptm->tm_hour;
  	st.wMinute = ptm->tm_min;
  	st.wSecond = ptm->tm_sec;
  	st.wMilliseconds = 0;
  
  	SystemTimeToFileTime(&st, &ft);
  	LocalFileTimeToFileTime(&ft, &lft);
  	return (time_t)((MAKEUQUAD(lft.dwLowDateTime, lft.dwHighDateTime) -
  	    EPOCH_DIFF) / RATE_DIFF);
  }
  
  static struct tm *
  localtime(const time_t *ptime, struct tm *ptm)
  {
  	uint64_t	t = ((uint64_t)*ptime) * RATE_DIFF + EPOCH_DIFF;
  	FILETIME	ft, lft;
  	SYSTEMTIME	st;
  	TIME_ZONE_INFORMATION	tzinfo;
  
  	if (ptm == NULL)
  		return NULL;
  
  	* (uint64_t *) &ft = t;
  	FileTimeToLocalFileTime(&ft, &lft);
  	FileTimeToSystemTime(&lft, &st);
  	ptm->tm_year = st.wYear - 1900;
  	ptm->tm_mon = st.wMonth - 1;
  	ptm->tm_wday = st.wDayOfWeek;
  	ptm->tm_mday = st.wDay;
  	ptm->tm_hour = st.wHour;
  	ptm->tm_min = st.wMinute;
  	ptm->tm_sec = st.wSecond;
  	ptm->tm_yday = 0; // hope nobody uses this
  	ptm->tm_isdst = ((GetTimeZoneInformation(&tzinfo) ==
  	    TIME_ZONE_ID_DAYLIGHT) ? 1 : 0);
  
  	return ptm;
  }
  
  static size_t
  strftime(char *dst, size_t dst_size, const char *fmt, const struct tm *tm)
  {
  	(void) snprintf(dst, dst_size, "implement strftime() for WinCE");
  	return (0);
  }	
  #endif
  
  static int
  mg_rename(const char* oldname, const char* newname)
  {
  	wchar_t	woldbuf[FILENAME_MAX];
  	wchar_t	wnewbuf[FILENAME_MAX];
  
  	to_unicode(oldname, woldbuf, ARRAY_SIZE(woldbuf));
  	to_unicode(newname, wnewbuf, ARRAY_SIZE(wnewbuf));
  
  	return (MoveFileW(woldbuf, wnewbuf) ? 0 : -1);
  }
  
  
  static FILE *
  mg_fopen(const char *path, const char *mode)
  {
  	wchar_t	wbuf[FILENAME_MAX], wmode[20];
  
  	to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
  	MultiByteToWideChar(CP_UTF8, 0, mode, -1, wmode, ARRAY_SIZE(wmode));
  
  	return (_wfopen(wbuf, wmode));
  }
  
  static int
  mg_stat(const char *path, struct mgstat *stp)
  {
  	int				ok = -1; /* Error */
  	wchar_t				wbuf[FILENAME_MAX];
  	WIN32_FILE_ATTRIBUTE_DATA	info;
  
  	to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
  
  	if (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0) {
  		stp->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
  		stp->mtime = SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
  		    info.ftLastWriteTime.dwHighDateTime);
  		stp->is_directory =
  		    info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
  		ok = 0;  /* Success */
  	}
  
  	return (ok);
  }
  
  static int
  mg_remove(const char *path)
  {
  	wchar_t	wbuf[FILENAME_MAX];
  
  	to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
  
  	return (DeleteFileW(wbuf) ? 0 : -1);
  }
  
  static int
  mg_mkdir(const char *path, int mode)
  {
  	char	buf[FILENAME_MAX];
  	wchar_t	wbuf[FILENAME_MAX];
  
  	mode = 0; /* Unused */
  	mg_strlcpy(buf, path, sizeof(buf));
  	fix_directory_separators(buf);
  
  	(void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, sizeof(wbuf));
  
  	return (CreateDirectoryW(wbuf, NULL) ? 0 : -1);
  }
  
  static char *
  mg_getcwd(char *buf, int buf_len)
  {
  	wchar_t		wbuf[FILENAME_MAX], *basename;
  
  	if (GetModuleFileNameW(NULL, wbuf, ARRAY_SIZE(wbuf))) {
  		if ((basename = wcsrchr(wbuf, DIRSEP)) != NULL) {
  			*basename = L'\0';
  			if (WideCharToMultiByte(CP_UTF8, 0, wbuf, -1, buf,
  			    buf_len, NULL, NULL) > 0)
  				return (buf);
  		}
  	}
  
  	return (NULL);
  }
  
  /*
   * Implementation of POSIX opendir/closedir/readdir for Windows.
   */
  static DIR *
  opendir(const char *name)
  {
  	DIR	*dir = NULL;
  	wchar_t	wpath[FILENAME_MAX];
  	DWORD attrs;
  
  	if (name == NULL) {
  		SetLastError(ERROR_BAD_ARGUMENTS);
  	} else if ((dir = (DIR *) malloc(sizeof(*dir))) == NULL) {
  		SetLastError(ERROR_NOT_ENOUGH_MEMORY);
  	} else {
  		to_unicode(name, wpath, ARRAY_SIZE(wpath));
  		attrs = GetFileAttributesW(wpath);
  		if (attrs != 0xFFFFFFFF &&
  		    ((attrs & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY)) {
  			(void) wcscat(wpath, L"\\*");
  			dir->handle = FindFirstFileW(wpath, &dir->info);
  			dir->result.d_name[0] = '\0';
  		} else {
  			free(dir);
  			dir = NULL;
  		}
  	}
  
  	return (dir);
  }
  
  static int
  closedir(DIR *dir)
  {
  	int result = 0;
  
  	if (dir != NULL) {
  		if (dir->handle != INVALID_HANDLE_VALUE)
  			result = FindClose(dir->handle) ? 0 : -1;
  
  		free(dir);
  	} else {
  		result = -1;
  		SetLastError(ERROR_BAD_ARGUMENTS);
  	}
  
  	return (result);
  }
  
  struct dirent *
  readdir(DIR *dir)
  {
  	struct dirent *result = 0;
  
  	if (dir) {
  		if (dir->handle != INVALID_HANDLE_VALUE) {
  			result = &dir->result;
  			(void) WideCharToMultiByte(CP_UTF8, 0,
  			    dir->info.cFileName, -1, result->d_name,
  			    sizeof(result->d_name), NULL, NULL);
  
  			if (!FindNextFileW(dir->handle, &dir->info)) {
  				(void) FindClose(dir->handle);
  				dir->handle = INVALID_HANDLE_VALUE;
  			}
  
  		} else {
  			SetLastError(ERROR_FILE_NOT_FOUND);
  		}
  	} else {
  		SetLastError(ERROR_BAD_ARGUMENTS);
  	}
  
  	return (result);
  }
  
  #define	set_close_on_exec(fd)	/* No FD_CLOEXEC on Windows */
  
  static int
  start_thread(struct mg_context *ctx, mg_thread_func_t func, void *param)
  {
  	HANDLE	hThread;
  
  	ctx = NULL;	/* Unused */
  	
  	hThread = CreateThread(NULL, 0,
  	    (LPTHREAD_START_ROUTINE) func, param, 0, NULL);
  
  	if (hThread != NULL)
  		(void) CloseHandle(hThread);
  
  	return (hThread == NULL ? -1 : 0);
  }
  
  static HANDLE
  dlopen(const char *dll_name, int flags)
  {
  	wchar_t	wbuf[FILENAME_MAX];
  
  	flags = 0; /* Unused */
  	to_unicode(dll_name, wbuf, ARRAY_SIZE(wbuf));
  
  	return (LoadLibraryW(wbuf));
  }
  
  #if !defined(NO_CGI)
  static int
  kill(pid_t pid, int sig_num)
  {
  	(void) TerminateProcess(pid, sig_num);
  	(void) CloseHandle(pid);
  	return (0);
  }
  
  static pid_t
  spawn_process(struct mg_connection *conn, const char *prog, char *envblk,
  		char *envp[], int fd_stdin, int fd_stdout, const char *dir)
  {
  	HANDLE	me;
  	char	*p, *interp, cmdline[FILENAME_MAX], line[FILENAME_MAX];
  	FILE	*fp;
  	STARTUPINFOA		si;
  	PROCESS_INFORMATION	pi;
  
  	envp = NULL; /* Unused */
  
  	(void) memset(&si, 0, sizeof(si));
  	(void) memset(&pi, 0, sizeof(pi));
  
  	/* XXX redirect CGI errors to the error log file */
  	si.cb		= sizeof(si);
  	si.dwFlags	= STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  	si.wShowWindow	= SW_HIDE;
  
  	me = GetCurrentProcess();
  	(void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdin), me,
  	    &si.hStdInput, 0, TRUE, DUPLICATE_SAME_ACCESS);
  	(void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdout), me,
  	    &si.hStdOutput, 0, TRUE, DUPLICATE_SAME_ACCESS);
  
  	/* If CGI file is a script, try to read the interpreter line */
  	interp = conn->ctx->options[OPT_CGI_INTERPRETER];
  	if (interp == NULL) {
  		line[2] = '\0';
  		(void) mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%c%s",
  		    dir, DIRSEP, prog);
  		if ((fp = fopen(cmdline, "r")) != NULL) {
  			(void) fgets(line, sizeof(line), fp);
  			if (memcmp(line, "#!", 2) != 0)
  				line[2] = '\0';
  			/* Trim whitespaces from interpreter name */
  			for (p = &line[strlen(line) - 1]; p > line &&
  			    isspace(*p); p--)
  				*p = '\0';
  			(void) fclose(fp);
  		}
  		interp = line + 2;
  	}
  
  	if ((p = (char *) strrchr(prog, '/')) != NULL)
  		prog = p + 1;
  
  	(void) mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%s%s",
  	    interp, interp[0] == '\0' ? "" : " ", prog);
  
  	(void) mg_snprintf(conn, line, sizeof(line), "%s", dir);
  	fix_directory_separators(line);
  
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: Running [%s]", __func__, cmdline));
  	if (CreateProcessA(NULL, cmdline, NULL, NULL, TRUE,
  	    CREATE_NEW_PROCESS_GROUP, envblk, line, &si, &pi) == 0) {
  		cry(conn, "%s: CreateProcess(%s): %d",
  		    __func__, cmdline, ERRNO);
  		pi.hProcess = (pid_t) -1;
  	} else {
  		(void) close(fd_stdin);
  		(void) close(fd_stdout);
  	}
  
  	(void) CloseHandle(si.hStdOutput);
  	(void) CloseHandle(si.hStdInput);
  	(void) CloseHandle(pi.hThread);
  
  	return ((pid_t) pi.hProcess);
  }
  
  static int
  pipe(int *fds)
  {
  	return (_pipe(fds, BUFSIZ, _O_BINARY));
  }
  #endif /* !NO_CGI */
  
  static int
  set_non_blocking_mode(struct mg_connection *conn, SOCKET sock)
  {
  	unsigned long	on = 1;
  
  	conn = NULL; /* unused */
  	return (ioctlsocket(sock, FIONBIO, &on));
  }
  
  #else
  
  static int
  mg_stat(const char *path, struct mgstat *stp)
  {
  	struct stat	st;
  	int		ok;
  
  	if (stat(path, &st) == 0) {
  		ok = 0;
  		stp->size = st.st_size;
  		stp->mtime = st.st_mtime;
  		stp->is_directory = S_ISDIR(st.st_mode);
  	} else {
  		ok = -1;
  	}
  
  	return (ok);
  }
  
  static void
  set_close_on_exec(int fd)
  {
  	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
  }
  
  static int
  start_thread(struct mg_context *ctx, mg_thread_func_t func, void *param)
  {
  	pthread_t	thread_id;
  	pthread_attr_t	attr;
  	int		retval;
  
  	(void) pthread_attr_init(&attr);
  	(void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  
  	if ((retval = pthread_create(&thread_id, &attr, func, param)) != 0)
  		cry(fc(ctx), "%s: %s", __func__, strerror(retval));
  
  	return (retval);
  }
  
  #ifndef NO_CGI
  static pid_t
  spawn_process(struct mg_connection *conn, const char *prog, char *envblk,
  		char *envp[], int fd_stdin, int fd_stdout, const char *dir)
  {
  	pid_t		pid;
  	const char	*interp;
  
  	envblk = NULL;	/* unused */
  
  	if ((pid = fork()) == -1) {
  		/* Parent */
  		send_error(conn, 500, http_500_error,
  		    "fork(): %s", strerror(ERRNO));
  	} else if (pid == 0) {
  		/* Child */
  		if (chdir(dir) != 0) {
  			cry(conn, "%s: chdir(%s): %s",
  			    __func__, dir, strerror(ERRNO));
  		} else if (dup2(fd_stdin, 0) == -1) {
  			cry(conn, "%s: dup2(stdin, %d): %s",
  			    __func__, fd_stdin, strerror(ERRNO));
  		} else if (dup2(fd_stdout, 1) == -1) {
  			cry(conn, "%s: dup2(stdout, %d): %s",
  			    __func__, fd_stdout, strerror(ERRNO));
  		} else {
  			/* If error file is specified, send errors there */
  			if (conn->ctx->error_log != NULL)
  				(void) dup2(fileno(conn->ctx->error_log), 2);
  
  			(void) close(fd_stdin);
  			(void) close(fd_stdout);
  
  			/* Execute CGI program */
  			interp = conn->ctx->options[OPT_CGI_INTERPRETER];
  			if (interp == NULL) {
  				(void) execle(prog, prog, NULL, envp);
  				cry(conn, "%s: execle(%s): %s",
  				    __func__, prog, strerror(ERRNO));
  			} else {
  				(void) execle(interp, interp, prog, NULL, envp);
  				cry(conn, "%s: execle(%s %s): %s",
  				    __func__, interp, prog, strerror(ERRNO));
  			}
  		}
  		exit(EXIT_FAILURE);
  	} else {
  		/* Parent. Close stdio descriptors */
  		(void) close(fd_stdin);
  		(void) close(fd_stdout);
  	}
  
  	return (pid);
  }
  #endif /* !NO_CGI */
  
  static int
  set_non_blocking_mode(struct mg_connection *conn, SOCKET sock)
  {
  	int	flags, ok = -1;
  
  	if ((flags = fcntl(sock, F_GETFL, 0)) == -1) {
  		cry(conn, "%s: fcntl(F_GETFL): %d", __func__, ERRNO);
  	} else if (fcntl(sock, F_SETFL, flags | O_NONBLOCK) != 0) {
  		cry(conn, "%s: fcntl(F_SETFL): %d", __func__, ERRNO);
  	} else {
  		ok = 0;	/* Success */
  	}
  
  	return (ok);
  }
  #endif /* _WIN32 */
  
  static void
  lock_option(struct mg_context *ctx, int opt_index)
  {
  	if (pthread_mutex_lock(&ctx->opt_mutex[opt_index]) != 0)
  		cry(fc(ctx), "pthread_mutex_lock: %s", strerror(ERRNO));
  }
  
  static void
  unlock_option(struct mg_context *ctx, int opt_index)
  {
  	if (pthread_mutex_unlock(&ctx->opt_mutex[opt_index]) != 0)
  		cry(fc(ctx), "pthread_mutex_unlock: %s", strerror(ERRNO));
  }
  
  /*
   * Write data to the IO channel - opened file descriptor, socket or SSL
   * descriptor. Return number of bytes written.
   */
  static uint64_t
  push(FILE *fp, SOCKET sock, SSL *ssl, const char *buf, uint64_t len)
  {
  	uint64_t	sent;
  	int		n, k;
  
  	sent = 0;
  	while (sent < len) {
  
  		/* How many bytes we send in this iteration */
  		k = len - sent > INT_MAX ? INT_MAX : (int) (len - sent);
  
  		if (ssl != NULL) {
  			n = SSL_write(ssl, buf + sent, k);
  		} else if (fp != NULL) {
  			n = fwrite(buf + sent, 1, k, fp);
  			if (ferror(fp))
  				n = -1;
  		} else {
  			n = send(sock, buf + sent, k, 0);
  		}
  
  		if (n < 0)
  			break;
  
  		sent += n;
  	}
  
  	return (sent);
  }
  
  /*
   * Read from IO channel - opened file descriptor, socket, or SSL descriptor.
   * Return number of bytes read.
   */
  static int
  pull(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int len)
  {
  	int	nread;
  
  	if (ssl != NULL) {
  		nread = SSL_read(ssl, buf, len);
  	} else if (fp != NULL) {
  		nread = fread(buf, 1, (size_t) len, fp);
  		if (ferror(fp))
  			nread = -1;
  	} else {
  		nread = recv(sock, buf, (size_t) len, 0);
  	}
  
  	return (nread);
  }
  
  int
  mg_write(struct mg_connection *conn, const void *buf, int len)
  {
  	assert(len >= 0);
  	return ((int) push(NULL, conn->client.sock, conn->ssl,
  				(const char *) buf, (uint64_t) len));
  }
  
  int
  mg_printf(struct mg_connection *conn, const char *fmt, ...)
  {
  	char	buf[MAX_REQUEST_SIZE];
  	int	len;
  	va_list	ap;
  
  	va_start(ap, fmt);
  	len = mg_vsnprintf(conn, buf, sizeof(buf), fmt, ap);
  	va_end(ap);
  
  	return (mg_write(conn, buf, len));
  }
  
  /*
   * Return content length of the request, or UNKNOWN_CONTENT_LENGTH constant if
   * Content-Length header is not set.
   */
  static uint64_t
  get_content_length(const struct mg_connection *conn)
  {
  	const char *cl = mg_get_header(conn, "Content-Length");
  	return (cl == NULL ? UNKNOWN_CONTENT_LENGTH : strtoull(cl, NULL, 10));
  }
  
  /*
   * URL-decode input buffer into destination buffer.
   * 0-terminate the destination buffer. Return the length of decoded data.
   * form-url-encoded data differs from URI encoding in a way that it
   * uses '+' as character for space, see RFC 1866 section 8.2.1
   * http://ftp.ics.uci.edu/pub/ietf/html/rfc1866.txt
   */
  static size_t
  url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
  		bool_t is_form_url_encoded)
  {
  	size_t	i, j;
  	int	a, b;
  #define	HEXTOI(x)	(isdigit(x) ? x - '0' : x - 'W')
  
  	for (i = j = 0; i < src_len && j < dst_len - 1; i++, j++) {
  		if (src[i] == '%' &&
  		    isxdigit(* (unsigned char *) (src + i + 1)) &&
  		    isxdigit(* (unsigned char *) (src + i + 2))) {
  			a = tolower(* (unsigned char *) (src + i + 1));
  			b = tolower(* (unsigned char *) (src + i + 2));
  			dst[j] = ((HEXTOI(a) << 4) | HEXTOI(b)) & 0xff;
  			i += 2;
  		} else if (is_form_url_encoded && src[i] == '+') {
  			dst[j] = ' ';
  		} else {
  			dst[j] = src[i];
  		}
  	}
  
  	dst[j] = '\0';	/* Null-terminate the destination */
  
  	return (j);
  }
  
  /*
   * Search for a form variable in a given buffer.
   * Semantic is the same as for mg_get_var().
   */
  static char *
  get_var(const char *name, const char *buf, size_t buf_len)
  {
  	const char	*p, *e, *s;
  	char		*val;
  	size_t		var_len, len;
  
  	var_len = strlen(name);
  	e = buf + buf_len;
  	val = NULL;
  
  	/* buf is "var1=val1&var2=val2...". Find variable first */
  	for (p = buf; p + var_len < e; p++)
  		if ((p == buf || p[-1] == '&') && p[var_len] == '=' &&
  		    !mg_strncasecmp(name, p, var_len)) {
  
  			/* Point p to variable value */
  			p += var_len + 1;
  
  			/* Point s to the end of the value */
  			s = (const char *) memchr(p, '&', e - p);
  			if (s == NULL)
  				s = e;
  
  			/* Try to allocate the buffer */
  			len = s - p;
  			if ((val = (char *) malloc(len + 1)) != NULL)
  				(void) url_decode(p, len, val, len + 1, TRUE);
  			break;
  		}
  
  	return (val);
  }
  
  /*
   * Free the pointer returned by mg_get_var(). This is needed for languages
   * like python, to have an ability to free allocated data without
   * loading C runtime library and calling free().
   */
  void
  mg_free(char *data)
  {
  	free(data);
  }
  
  /*
   * Return form data variable.
   * It can be specified in query string, or in the POST data.
   * Return NULL if the variable not found, or allocated 0-terminated value.
   * It is caller's responsibility to free the returned value.
   */
  char *
  mg_get_var(const struct mg_connection *conn, const char *name)
  {
  	const struct mg_request_info	*ri = &conn->request_info;
  	char				*v1, *v2;
  
  	v1 = v2 = NULL;
  
  	/* Look in both query_string and POST data */
  	if (ri->query_string != NULL)
  		v1 = get_var(name, ri->query_string, strlen(ri->query_string));
  	if (ri->post_data_len > 0)
  		v2 = get_var(name, ri->post_data, ri->post_data_len);
  
  	/* If they both have queried variable, POST data wins */
  	if (v1 != NULL && v2 != NULL)
  		free(v1);
  
  	return (v2 == NULL ? v1 : v2);
  }
  
  /*
   * Transform URI to the file name.
   */
  static void
  convert_uri_to_file_name(struct mg_connection *conn, const char *uri,
  		char *buf, size_t buf_len)
  {
  	struct mg_context	*ctx = conn->ctx;
  	struct vec		uri_vec, path_vec;
  	const char		*list;
  
  	lock_option(ctx, OPT_ROOT);
  	mg_snprintf(conn, buf, buf_len, "%s%s", ctx->options[OPT_ROOT], uri);
  	unlock_option(ctx, OPT_ROOT);
  
  	/* If requested URI has aliased prefix, use alternate root */
  	lock_option(ctx, OPT_ALIASES);
  	list = ctx->options[OPT_ALIASES];
  
  	while ((list = next_option(list, &uri_vec, &path_vec)) != NULL) {
  		if (memcmp(uri, uri_vec.ptr, uri_vec.len) == 0) {
  			(void) mg_snprintf(conn, buf, buf_len, "%.*s%s",
  			    path_vec.len, path_vec.ptr, uri + uri_vec.len);
  			break;
  		}
  	}
  	unlock_option(ctx, OPT_ALIASES);
  
  #ifdef _WIN32
  	fix_directory_separators(buf);
  #endif /* _WIN32 */
  }
  
  /*
   * Setup listening socket on given address, return socket.
   * Address format: [local_ip_address:]port_number
   */
  static SOCKET
  mg_open_listening_port(struct mg_context *ctx, const char *str, struct usa *usa)
  {
  	SOCKET		sock;
  	int		on = 1, a, b, c, d, port;
  
  	/* MacOS needs that. If we do not zero it, bind() will fail. */
  	(void) memset(usa, 0, sizeof(*usa));
  
  	if (sscanf(str, "%d.%d.%d.%d:%d", &a, &b, &c, &d, &port) == 5) {
  		/* IP address to bind to is specified */
  		usa->u.sin.sin_addr.s_addr =
  		    htonl((a << 24) | (b << 16) | (c << 8) | d);
  	} else if (sscanf(str, "%d", &port) == 1) {
  		/* Only port number is specified. Bind to all addresses */
  		usa->u.sin.sin_addr.s_addr = htonl(INADDR_ANY);
  	} else {
  		return (INVALID_SOCKET);
  	}
  
  	usa->len			= sizeof(usa->u.sin);
  	usa->u.sin.sin_family		= AF_INET;
  	usa->u.sin.sin_port		= htons((uint16_t) port);
  
  	if ((sock = socket(PF_INET, SOCK_STREAM, 6)) != INVALID_SOCKET &&
  	    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
  	    (char *) &on, sizeof(on)) == 0 &&
  	    bind(sock, &usa->u.sa, usa->len) == 0 &&
  	    listen(sock, 128) == 0) {
  		/* Success */
  		set_close_on_exec(sock);
  	} else {
  		/* Error */
  		cry(fc(ctx), "%s(%d): %s", __func__, port, strerror(ERRNO));
  		if (sock != INVALID_SOCKET)
  			(void) closesocket(sock);
  		sock = INVALID_SOCKET;
  	}
  
  	return (sock);
  }
  
  /*
   * Check whether full request is buffered. Return:
   *   -1         if request is malformed
   *    0         if request is not yet fully buffered
   *   >0         actual request length, including last \r\n\r\n
   */
  static int
  get_request_len(const char *buf, size_t buflen)
  {
  	const char	*s, *e;
  	int		len = 0;
  
  	for (s = buf, e = s + buflen - 1; len <= 0 && s < e; s++)
  		/* Control characters are not allowed but >=128 is. */
  		if (!isprint(* (unsigned char *) s) && *s != '\r' &&
  		    *s != '\n' && * (unsigned char *) s < 128)
  			len = -1;
  		else if (s[0] == '\n' && s[1] == '\n')
  			len = (int) (s - buf) + 2;
  		else if (s[0] == '\n' && &s[1] < e &&
  		    s[1] == '\r' && s[2] == '\n')
  			len = (int) (s - buf) + 3;
  
  	return (len);
  }
  
  /*
   * Convert month to the month number. Return -1 on error, or month number
   */
  static int
  montoi(const char *s)
  {
  	size_t	i;
  
  	for (i = 0; i < sizeof(month_names) / sizeof(month_names[0]); i++)
  		if (!strcmp(s, month_names[i]))
  			return ((int) i);
  
  	return (-1);
  }
  
  /*
   * Parse date-time string, and return the corresponding time_t value
   */
  static time_t
  date_to_epoch(const char *s)
  {
  	time_t		current_time;
  	struct tm	tm, *tmp;
  	char		mon[32];
  	int		sec, min, hour, mday, month, year;
  
  	(void) memset(&tm, 0, sizeof(tm));
  	sec = min = hour = mday = month = year = 0;
  
  	if (((sscanf(s, "%d/%3s/%d %d:%d:%d",
  	    &mday, mon, &year, &hour, &min, &sec) == 6) ||
  	    (sscanf(s, "%d %3s %d %d:%d:%d",
  	    &mday, mon, &year, &hour, &min, &sec) == 6) ||
  	    (sscanf(s, "%*3s, %d %3s %d %d:%d:%d",
  	    &mday, mon, &year, &hour, &min, &sec) == 6) ||
  	    (sscanf(s, "%d-%3s-%d %d:%d:%d",
  	    &mday, mon, &year, &hour, &min, &sec) == 6)) &&
  	    (month = montoi(mon)) != -1) {
  		tm.tm_mday	= mday;
  		tm.tm_mon	= month;
  		tm.tm_year	= year;
  		tm.tm_hour	= hour;
  		tm.tm_min	= min;
  		tm.tm_sec	= sec;
  	}
  
  	if (tm.tm_year > 1900)
  		tm.tm_year -= 1900;
  	else if (tm.tm_year < 70)
  		tm.tm_year += 100;
  
  	/* Set Daylight Saving Time field */
  	current_time = time(NULL);
  	tmp = localtime(&current_time);
  	tm.tm_isdst = tmp->tm_isdst;
  
  	return (mktime(&tm));
  }
  
  /*
   * Protect against directory disclosure attack by removing '..',
   * excessive '/' and '\' characters
   */
  static void
  remove_double_dots_and_double_slashes(char *s)
  {
  	char	*p = s;
  
  	while (*s != '\0') {
  		*p++ = *s++;
  		if (s[-1] == '/' || s[-1] == '\\') {
  			/* Skip all following slashes and backslashes */
  			while (*s == '/' || *s == '\\')
  				s++;
  
  			/* Skip all double-dots */
  			while (*s == '.' && s[1] == '.')
  				s += 2;
  		}
  	}
  	*p = '\0';
  }
  
  /*
   * Built-in mime types
   */
  static const struct {
  	const char	*extension;
  	size_t		ext_len;
  	const char	*mime_type;
  	size_t		mime_type_len;
  } mime_types[] = {
  	{".html",	5,	"text/html",			9},
  	{".htm",	4,	"text/html",			9},
  	{".shtm",	5,	"text/html",			9},
  	{".shtml",	6,	"text/html",			9},
  	{".css",	4,	"text/css",			8},
  	{".js",		3,	"application/x-javascript",	24},
  	{".ico",	4,	"image/x-icon",			12},
  	{".gif",	4,	"image/gif",			9},
  	{".jpg",	4,	"image/jpeg",			10},
  	{".jpeg",	5,	"image/jpeg",			10},
  	{".png",	4,	"image/png",			9},
  	{".svg",	4,	"image/svg+xml",		13},
  	{".torrent",	8,	"application/x-bittorrent",	24},
  	{".wav",	4,	"audio/x-wav",			11},
  	{".mp3",	4,	"audio/x-mp3",			11},
  	{".mid",	4,	"audio/mid",			9},
  	{".m3u",	4,	"audio/x-mpegurl",		15},
  	{".ram",	4,	"audio/x-pn-realaudio",		20},
  	{".ra",		3,	"audio/x-pn-realaudio",		20},
  	{".doc",	4,	"application/msword",		19},
  	{".exe",	4,	"application/octet-stream",	24},
  	{".zip",	4,	"application/x-zip-compressed",	28},
  	{".xls",	4,	"application/excel",		17},
  	{".tgz",	4,	"application/x-tar-gz",		20},
  	{".tar",	4,	"application/x-tar",		17},
  	{".gz",		3,	"application/x-gunzip",		20},
  	{".arj",	4,	"application/x-arj-compressed",	28},
  	{".rar",	4,	"application/x-arj-compressed",	28},
  	{".rtf",	4,	"application/rtf",		15},
  	{".pdf",	4,	"application/pdf",		15},
  	{".swf",	4,	"application/x-shockwave-flash",29},
  	{".mpg",	4,	"video/mpeg",			10},
  	{".mpeg",	5,	"video/mpeg",			10},
  	{".asf",	4,	"video/x-ms-asf",		14},
  	{".avi",	4,	"video/x-msvideo",		15},
  	{".bmp",	4,	"image/bmp",			9},
  	{NULL,		0,	NULL,				0}
  };
  
  /*
   * Look at the "path" extension and figure what mime type it has.
   * Store mime type in the vector.
   */
  static void
  get_mime_type(struct mg_context *ctx, const char *path, struct vec *vec)
  {
  	struct vec	ext_vec, mime_vec;
  	const char	*list, *ext;
  	size_t		i, path_len;
  
  	path_len = strlen(path);
  
  	/*
  	 * Scan user-defined mime types first, in case user wants to
  	 * override default mime types.
  	 */
  	lock_option(ctx, OPT_MIME_TYPES);
  	list = ctx->options[OPT_MIME_TYPES];
  	while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL) {
  		/* ext now points to the path suffix */
  		ext = path + path_len - ext_vec.len;
  		if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0) {
  			*vec = mime_vec;
  			unlock_option(ctx, OPT_MIME_TYPES);
  			return;
  		}
  	}
  	unlock_option(ctx, OPT_MIME_TYPES);
  
  	/* Now scan built-in mime types */
  	for (i = 0; mime_types[i].extension != NULL; i++) {
  		ext = path + (path_len - mime_types[i].ext_len);
  		if (path_len > mime_types[i].ext_len &&
  		    mg_strcasecmp(ext, mime_types[i].extension) == 0) {
  			vec->ptr = mime_types[i].mime_type;
  			vec->len = mime_types[i].mime_type_len;
  			return;
  		}
  	}
  
  	/* Nothing found. Fall back to text/plain */
  	vec->ptr = "text/plain";
  	vec->len = 10;
  }
  
  #ifndef HAVE_MD5
  typedef struct MD5Context {
  	uint32_t	buf[4];
  	uint32_t	bits[2];
  	unsigned char	in[64];
  } MD5_CTX;
  
  #if __BYTE_ORDER == 1234
  #define byteReverse(buf, len)	/* Nothing */
  #else
  /*
   * Note: this code is harmless on little-endian machines.
   */
  static void
  byteReverse(unsigned char *buf, unsigned longs)
  {
  	uint32_t t;
  	do {
  		t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  			((unsigned) buf[1] << 8 | buf[0]);
  		*(uint32_t *) buf = t;
  		buf += 4;
  	} while (--longs);
  }
  #endif /* __BYTE_ORDER */
  
  /* The four core functions - F1 is optimized somewhat */
  
  /* #define F1(x, y, z) (x & y | ~x & z) */
  #define F1(x, y, z) (z ^ (x & (y ^ z)))
  #define F2(x, y, z) F1(z, x, y)
  #define F3(x, y, z) (x ^ y ^ z)
  #define F4(x, y, z) (y ^ (x | ~z))
  
  /* This is the central step in the MD5 algorithm. */
  #define MD5STEP(f, w, x, y, z, data, s) \
  ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
  
  /*
   * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
   * initialization constants.
   */
  static void
  MD5Init(MD5_CTX *ctx)
  {
  	ctx->buf[0] = 0x67452301;
  	ctx->buf[1] = 0xefcdab89;
  	ctx->buf[2] = 0x98badcfe;
  	ctx->buf[3] = 0x10325476;
  
  	ctx->bits[0] = 0;
  	ctx->bits[1] = 0;
  }
  
  /*
   * The core of the MD5 algorithm, this alters an existing MD5 hash to
   * reflect the addition of 16 longwords of new data.  MD5Update blocks
   * the data and converts bytes into longwords for this routine.
   */
  static void
  MD5Transform(uint32_t buf[4], uint32_t const in[16])
  {
  	register uint32_t a, b, c, d;
  
  	a = buf[0];
  	b = buf[1];
  	c = buf[2];
  	d = buf[3];
  
  	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  
  	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
  
  	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
  	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
  	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
  	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
  
  	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
  	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
  	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
  	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
  	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
  	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
  	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
  	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
  	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
  	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
  	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
  	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
  	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
  	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
  	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
  	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
  
  	buf[0] += a;
  	buf[1] += b;
  	buf[2] += c;
  	buf[3] += d;
  }
  
  /*
   * Update context to reflect the concatenation of another buffer full
   * of bytes.
   */
  static void
  MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len)
  {
  	uint32_t t;
  
  	/* Update bitcount */
  
  	t = ctx->bits[0];
  	if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  		ctx->bits[1]++;		/* Carry from low to high */
  	ctx->bits[1] += len >> 29;
  
  	t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */
  
  	/* Handle any leading odd-sized chunks */
  
  	if (t) {
  		unsigned char *p = (unsigned char *) ctx->in + t;
  
  		t = 64 - t;
  		if (len < t) {
  			memcpy(p, buf, len);
  			return;
  		}
  		memcpy(p, buf, t);
  		byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  		buf += t;
  		len -= t;
  	}
  	/* Process data in 64-byte chunks */
  
  	while (len >= 64) {
  		memcpy(ctx->in, buf, 64);
  		byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  		buf += 64;
  		len -= 64;
  	}
  
  	/* Handle any remaining bytes of data. */
  
  	memcpy(ctx->in, buf, len);
  }
  
  /*
   * Final wrapup - pad to 64-byte boundary with the bit pattern
   * 1 0* (64-bit count of bits processed, MSB-first)
   */
  static void
  MD5Final(unsigned char digest[16], MD5_CTX *ctx)
  {
  	unsigned count;
  	unsigned char *p;
  
  	/* Compute number of bytes mod 64 */
  	count = (ctx->bits[0] >> 3) & 0x3F;
  
  	/* Set the first char of padding to 0x80.  This is safe since there is
  	   always at least one byte free */
  	p = ctx->in + count;
  	*p++ = 0x80;
  
  	/* Bytes of padding needed to make 64 bytes */
  	count = 64 - 1 - count;
  
  	/* Pad out to 56 mod 64 */
  	if (count < 8) {
  		/* Two lots of padding:  Pad the first block to 64 bytes */
  		memset(p, 0, count);
  		byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  
  		/* Now fill the next block with 56 bytes */
  		memset(ctx->in, 0, 56);
  	} else {
  		/* Pad block to 56 bytes */
  		memset(p, 0, count - 8);
  	}
  	byteReverse(ctx->in, 14);
  
  	/* Append length in bits and transform */
  	((uint32_t *) ctx->in)[14] = ctx->bits[0];
  	((uint32_t *) ctx->in)[15] = ctx->bits[1];
  
  	MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  	byteReverse((unsigned char *) ctx->buf, 4);
  	memcpy(digest, ctx->buf, 16);
  	memset((char *) ctx, 0, sizeof(ctx));	/* In case it's sensitive */
  }
  #endif /* !HAVE_MD5 */
  
  /*
   * Stringify binary data. Output buffer must be twice as big as input,
   * because each byte takes 2 bytes in string representation
   */
  static void
  bin2str(char *to, const unsigned char *p, size_t len)
  {
  	static const char *hex = "0123456789abcdef";
  
  	for (; len--; p++) {
  		*to++ = hex[p[0] >> 4];
  		*to++ = hex[p[0] & 0x0f];
  	}
  	*to = '\0';
  }
  
  /*
   * Return stringified MD5 hash for list of vectors.
   * buf must point to 33-bytes long buffer
   */
  static void
  mg_md5(char *buf, ...)
  {
  	unsigned char	hash[16];
  	const char	*p;
  	va_list		ap;
  	MD5_CTX		ctx;
  
  	MD5Init(&ctx);
  
  	va_start(ap, buf);
  	while ((p = va_arg(ap, const char *)) != NULL)
  		MD5Update(&ctx, (unsigned char *) p, (int) strlen(p));
  	va_end(ap);
  
  	MD5Final(hash, &ctx);
  	bin2str(buf, hash, sizeof(hash));
  }
  
  /*
   * Check the user's password, return 1 if OK
   */
  static bool_t
  check_password(const char *method, const char *ha1, const char *uri,
  		const char *nonce, const char *nc, const char *cnonce,
  		const char *qop, const char *response)
  {
  	char	ha2[32 + 1], expected_response[32 + 1];
  
  	/* XXX  Due to a bug in MSIE, we do not compare the URI	 */
  	/* Also, we do not check for authentication timeout */
  	if (/*strcmp(dig->uri, c->ouri) != 0 || */
  	    strlen(response) != 32 /*||
  	    now - strtoul(dig->nonce, NULL, 10) > 3600 */)
  		return (FALSE);
  
  	mg_md5(ha2, method, ":", uri, NULL);
  	mg_md5(expected_response, ha1, ":", nonce, ":", nc,
  	    ":", cnonce, ":", qop, ":", ha2, NULL);
  
  	return (!mg_strcasecmp(response, expected_response));
  }
  
  /*
   * Use the global passwords file, if specified by auth_gpass option,
   * or search for .htpasswd in the requested directory.
   */
  static FILE *
  open_auth_file(struct mg_connection *conn, const char *path)
  {
  	struct mg_context	*ctx = conn->ctx;
  	char 			name[FILENAME_MAX];
  	const char		*p, *e;
  	struct mgstat		st;
  	FILE			*fp;
  
  	if (ctx->options[OPT_AUTH_GPASSWD] != NULL) {
  		/* Use global passwords file */
  		fp =  mg_fopen(ctx->options[OPT_AUTH_GPASSWD], "r");
  		if (fp == NULL)
  			cry(fc(ctx), "fopen(%s): %s",
  			    ctx->options[OPT_AUTH_GPASSWD], strerror(ERRNO));
  	} else if (!mg_stat(path, &st) && st.is_directory) {
  		(void) mg_snprintf(conn, name, sizeof(name), "%s%c%s",
  		    path, DIRSEP, PASSWORDS_FILE_NAME);
  		fp = mg_fopen(name, "r");
  	} else {
  		/*
  		 * Try to find .htpasswd in requested directory.
  		 * Given the path, create the path to .htpasswd file
  		 * in the same directory. Find the right-most
  		 * directory separator character first. That would be the
  		 * directory name. If directory separator character is not
  		 * found, 'e' will point to 'p'.
  		 */
  		for (p = path, e = p + strlen(p) - 1; e > p; e--)
  			if (IS_DIRSEP_CHAR(*e))
  				break;
  
  		/*
  		 * Make up the path by concatenating directory name and
  		 * .htpasswd file name.
  		 */
  		(void) mg_snprintf(conn, name, sizeof(name), "%.*s%c%s",
  		    (int) (e - p), p, DIRSEP, PASSWORDS_FILE_NAME);
  		fp = mg_fopen(name, "r");
  	}
  
  	return (fp);
  }
  
  /*
   * Parsed Authorization: header
   */
  struct ah {
  	char	*user, *uri, *cnonce, *response, *qop, *nc, *nonce;
  };
  
  static bool_t
  parse_auth_header(struct mg_connection *conn, char *buf, size_t buf_size,
  		struct ah *ah)
  {
  	char		*name, *value, *s;
  	const char	*auth_header;
  
  	if ((auth_header = mg_get_header(conn, "Authorization")) == NULL ||
  	    mg_strncasecmp(auth_header, "Digest ", 7) != 0)
  		return (FALSE);
  
  	/* Make modifiable copy of the auth header */
  	(void) mg_strlcpy(buf, auth_header + 7, buf_size);
  
  	s = buf;
  	(void) memset(ah, 0, sizeof(*ah));
  
  	/* Gobble initial spaces */
  	while (isspace(* (unsigned char *) s))
  		s++;
  
  	/* Parse authorization header */
  	for (;;) {
  		name = skip(&s, "=");
  		value = skip(&s, ", ");
  
  		if (*value == '"') {
  			value++;
  			value[strlen(value) - 1] = '\0';
  		} else if (*value == '\0') {
  			break;
  		}
  
  		if (!strcmp(name, "username")) {
  			ah->user = value;
  		} else if (!strcmp(name, "cnonce")) {
  			ah->cnonce = value;
  		} else if (!strcmp(name, "response")) {
  			ah->response = value;
  		} else if (!strcmp(name, "uri")) {
  			ah->uri = value;
  		} else if (!strcmp(name, "qop")) {
  			ah->qop = value;
  		} else if (!strcmp(name, "nc")) {
  			ah->nc = value;
  		} else if (!strcmp(name, "nonce")) {
  			ah->nonce = value;
  		}
  	}
  
  	/* CGI needs it as REMOTE_USER */
  	if (ah->user != NULL)
  		conn->request_info.remote_user = mg_strdup(ah->user);
  
  	return (TRUE);
  }
  
  /*
   * Authorize against the opened passwords file. Return 1 if authorized.
   */
  static bool_t
  authorize(struct mg_connection *conn, FILE *fp)
  {
  	struct ah	ah;
  	char		line[256], f_user[256], domain[256], ha1[256],
  			buf[MAX_REQUEST_SIZE];
  
  	if (!parse_auth_header(conn, buf, sizeof(buf), &ah))
  		return (FALSE);
  
  	/* Loop over passwords file */
  	while (fgets(line, sizeof(line), fp) != NULL) {
  
  		if (sscanf(line, "%[^:]:%[^:]:%s", f_user, domain, ha1) != 3)
  			continue;
  
  		if (!strcmp(ah.user, f_user) &&
  		    !strcmp(domain, conn->ctx->options[OPT_AUTH_DOMAIN]))
  			return (check_password(
  			    conn->request_info.request_method, ha1,
  			    ah.uri, ah.nonce, ah.nc, ah.cnonce,
  			    ah.qop, ah.response));
  	}
  
  	return (FALSE);
  }
  
  /*
   * Return TRUE if request is authorised, FALSE otherwise.
   */
  static bool_t
  check_authorization(struct mg_connection *conn, const char *path)
  {
  	FILE		*fp;
  	char		fname[FILENAME_MAX];
  	struct vec	uri_vec, filename_vec;
  	const char	*list;
  	bool_t		authorized;
  
  	fp = NULL;
  	authorized = TRUE;
  
  	lock_option(conn->ctx, OPT_PROTECT);
  	list = conn->ctx->options[OPT_PROTECT];
  	while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
  		if (!memcmp(conn->request_info.uri, uri_vec.ptr, uri_vec.len)) {
  			(void) mg_snprintf(conn, fname, sizeof(fname), "%.*s",
  			    filename_vec.len, filename_vec.ptr);
  			if ((fp = mg_fopen(fname, "r")) == NULL)
  				cry(conn, "%s: cannot open %s: %s",
  				    __func__, fname, strerror(errno));
  			break;
  		}
  	}
  	unlock_option(conn->ctx, OPT_PROTECT);
  
  	if (fp == NULL)
  		fp = open_auth_file(conn, path);
  
  	if (fp != NULL) {
  		authorized = authorize(conn, fp);
  		(void) fclose(fp);
  	}
  
  	return (authorized);
  }
  
  static void
  send_authorization_request(struct mg_connection *conn)
  {
  	conn->request_info.status_code = 401;
  	(void) mg_printf(conn,
  	    "HTTP/1.1 401 Unauthorized\r\n"
  	    "WWW-Authenticate: Digest qop=\"auth\", "
  	    "realm=\"%s\", nonce=\"%lu\"\r\n\r\n",
  	    conn->ctx->options[OPT_AUTH_DOMAIN], (unsigned long) time(NULL));
  }
  
  static bool_t
  is_authorized_for_put(struct mg_connection *conn)
  {
  	FILE	*fp;
  	int	ret = FALSE;
  
  	if ((fp = mg_fopen(conn->ctx->options[OPT_AUTH_PUT], "r")) != NULL) {
  		set_close_on_exec(fileno(fp));
  		ret = authorize(conn, fp);
  		(void) fclose(fp);
  	}
  
  	return (ret);
  }
  
  int
  mg_modify_passwords_file(struct mg_context *ctx, const char *fname,
  		const char *user, const char *pass)
  {
  	int		found;
  	char		line[512], u[512], d[512], ha1[33], tmp[FILENAME_MAX];
  	const char	*domain;
  	FILE		*fp, *fp2;
  
  	found = 0;
  	fp = fp2 = NULL;
  	domain = ctx->options[OPT_AUTH_DOMAIN];
  
  	/* Regard empty password as no password - remove user record. */
  	if (pass[0] == '\0')
  		pass = NULL;
  
  	(void) snprintf(tmp, sizeof(tmp), "%s.tmp", fname);
  
  	/* Create the file if does not exist */
  	if ((fp = mg_fopen(fname, "a+")) != NULL)
  		(void) fclose(fp);
  
  	/* Open the given file and temporary file */
  	if ((fp = mg_fopen(fname, "r")) == NULL) {
  		cry(fc(ctx), "Cannot open %s: %s", fname, strerror(errno));
  		return (0);
  	} else if ((fp2 = mg_fopen(tmp, "w+")) == NULL) {
  		cry(fc(ctx), "Cannot open %s: %s", tmp, strerror(errno));
  		return (0);
  	}
  
  	/* Copy the stuff to temporary file */
  	while (fgets(line, sizeof(line), fp) != NULL) {
  
  		if (sscanf(line, "%[^:]:%[^:]:%*s", u, d) != 2)
  			continue;
  
  		if (!strcmp(u, user) && !strcmp(d, domain)) {
  			found++;
  			if (pass != NULL) {
  				mg_md5(ha1, user, ":", domain, ":", pass, NULL);
  				fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
  			}
  		} else {
  			(void) fprintf(fp2, "%s", line);
  		}
  	}
  
  	/* If new user, just add it */
  	if (!found && pass != NULL) {
  		mg_md5(ha1, user, ":", domain, ":", pass, NULL);
  		(void) fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
  	}
  
  	/* Close files */
  	(void) fclose(fp);
  	(void) fclose(fp2);
  
  	/* Put the temp file in place of real file */
  	(void) mg_remove(fname);
  	(void) mg_rename(tmp, fname);
  
  	return (0);
  }
  
  struct de {
  	struct mg_connection	*conn;
  	char			*file_name;
  	struct mgstat		st;
  };
  
  /*
   * This function is called from send_directory() and prints out
   * single directory entry.
   */
  static void
  print_dir_entry(struct de *de)
  {
  	char		size[64], mod[64];
  
  	if (de->st.is_directory) {
  		(void) mg_snprintf(de->conn,
  		    size, sizeof(size), "%s", "[DIRECTORY]");
  	} else {
  		/*
  		 * We use (signed) cast below because MSVC 6 compiler cannot
  		 * convert unsigned __int64 to double. Sigh.
  		 */
  		if (de->st.size < 1024)
  			(void) mg_snprintf(de->conn, size, sizeof(size),
  			    "%lu", (unsigned long) de->st.size);
  		else if (de->st.size < 1024 * 1024)
  			(void) mg_snprintf(de->conn, size, sizeof(size),
  			    "%.1fk", (double) de->st.size / 1024.0);
  		else if (de->st.size < 1024 * 1024 * 1024)
  			(void) mg_snprintf(de->conn, size, sizeof(size),
  			    "%.1fM", (double) de->st.size / 1048576);
  		else
  			(void) mg_snprintf(de->conn, size, sizeof(size),
  			  "%.1fG", (double) de->st.size / 1073741824);
  	}
  	(void) strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M",
  		localtime(&de->st.mtime));
  	de->conn->num_bytes_sent += mg_printf(de->conn,
  	    "<tr><td><a href=\"%s%s\">%s%s</a></td>"
  	    "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
  	    de->conn->request_info.uri, de->file_name, de->file_name,
  	    de->st.is_directory ? "/" : "", mod, size);
  }
  
  /*
   * This function is called from send_directory() and used for
   * sorting direcotory entries by size, or name, or modification time.
   */
  static int
  compare_dir_entries(const void *p1, const void *p2)
  {
  	const struct de	*a = (struct de *) p1, *b = (struct de *) p2;
  	const char	*query_string = a->conn->request_info.query_string;
  	int		cmp_result = 0;
  
  	if (query_string == NULL)
  		query_string = "na";
  
  	if (a->st.is_directory && !b->st.is_directory) {
  		return (-1);  /* Always put directories on top */
  	} else if (!a->st.is_directory && b->st.is_directory) {
  		return (1);   /* Always put directories on top */
  	} else if (*query_string == 'n') {
  		cmp_result = strcmp(a->file_name, b->file_name);
  	} else if (*query_string == 's') {
  		cmp_result = a->st.size == b->st.size ? 0 :
  			a->st.size > b->st.size ? 1 : -1;
  	} else if (*query_string == 'd') {
  		cmp_result = a->st.mtime == b->st.mtime ? 0 :
  			a->st.mtime > b->st.mtime ? 1 : -1;
  	}
  
  	return (query_string[1] == 'd' ? -cmp_result : cmp_result);
  }
  
  /*
   * Send directory contents.
   */
  static void
  send_directory(struct mg_connection *conn, const char *dir)
  {
  	struct dirent	*dp;
  	DIR		*dirp;
  	struct de	*entries = NULL;
  	char		path[FILENAME_MAX];
  	int		i, sort_direction, num_entries = 0, arr_size = 128;
  
  	if ((dirp = opendir(dir)) == NULL) {
  		send_error(conn, 500, "Cannot open directory",
  		    "Error: opendir(%s): %s", path, strerror(ERRNO));
  		return;
  	}
  
  	(void) mg_printf(conn, "%s",
  	    "HTTP/1.1 200 OK\r\n"
  	    "Connection: close\r\n"
  	    "Content-Type: text/html; charset=utf-8\r\n\r\n");
  
  	sort_direction = conn->request_info.query_string != NULL &&
  	    conn->request_info.query_string[1] == 'd' ? 'a' : 'd';
  
  	while ((dp = readdir(dirp)) != NULL) {
  
  		/* Do not show current dir and passwords file */
  		if (!strcmp(dp->d_name, ".") ||
  		    !strcmp(dp->d_name, "..") ||
  		    !strcmp(dp->d_name, PASSWORDS_FILE_NAME))
  			continue;
  
  		if (entries == NULL || num_entries >= arr_size) {
  			arr_size *= 2;
  			entries = (struct de *) realloc(entries,
  			    arr_size * sizeof(entries[0]));
  		}
  
  		if (entries == NULL) {
  			send_error(conn, 500, "Cannot open directory",
  			    "%s", "Error: cannot allocate memory");
  			return;
  		}
  
  		(void) mg_snprintf(conn, path, sizeof(path), "%s%c%s",
  		    dir, DIRSEP, dp->d_name);
  
  		(void) mg_stat(path, &entries[num_entries].st);
  		entries[num_entries].conn = conn;
  		entries[num_entries].file_name = mg_strdup(dp->d_name);
  		num_entries++;
  	}
  	(void) closedir(dirp);
  
  	conn->num_bytes_sent += mg_printf(conn,
  	    "<html><head><title>Index of %s</title>"
  	    "<style>th {text-align: left;}</style></head>"
  	    "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
  	    "<tr><th><a href=\"?n%c\">Name</a></th>"
  	    "<th><a href=\"?d%c\">Modified</a></th>"
  	    "<th><a href=\"?s%c\">Size</a></th></tr>"
  	    "<tr><td colspan=\"3\"><hr></td></tr>",
  	    conn->request_info.uri, conn->request_info.uri,
  	    sort_direction, sort_direction, sort_direction);
  
  	/* Print first entry - link to a parent directory */
  	conn->num_bytes_sent += mg_printf(conn,
  	    "<tr><td><a href=\"%s%s\">%s</a></td>"
  	    "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
  	    conn->request_info.uri, "..", "Parent directory", "-", "-");
  
  	/* Sort and print directory entries */
  	qsort(entries, num_entries, sizeof(entries[0]), compare_dir_entries);
  	for (i = 0; i < num_entries; i++) {
  		print_dir_entry(&entries[i]);
  		free(entries[i].file_name);
  	}
  	free(entries);
  
  	conn->num_bytes_sent += mg_printf(conn, "%s", "</table></body></html>");
  	conn->request_info.status_code = 200;
  }
  
  /*
   * Send len bytes from the opened file to the client.
   */
  static void
  send_opened_file_stream(struct mg_connection *conn, FILE *fp, uint64_t len)
  {
  	char	buf[BUFSIZ];
  	int	to_read, num_read, num_written;
  
  	while (len > 0) {
  		/* Calculate how much to read from the file in the buffer */
  		to_read = sizeof(buf);
  		if ((uint64_t) to_read > len)
  			to_read = (int) len;
  
  		/* Read from file, exit the loop on error */
  		if ((num_read = fread(buf, 1, to_read, fp)) == 0)
  			break;
  
  		/* Send read bytes to the client, exit the loop on error */
  		if ((num_written = mg_write(conn, buf, num_read)) != num_read)
  			break;
  
  		/* Both read and were successful, adjust counters */
  		conn->num_bytes_sent += num_written;
  		len -= num_written;
  	}
  }
  
  /*
   * Send regular file contents.
   */
  static void
  send_file(struct mg_connection *conn, const char *path, struct mgstat *stp)
  {
  	char		date[64], lm[64], etag[64], range[64];
  	const char	*fmt = "%a, %d %b %Y %H:%M:%S %Z", *msg = "OK", *hdr;
  	time_t		curtime = time(NULL);
  	uint64_t	cl, r1, r2;
  	struct vec	mime_vec;
  	FILE		*fp;
  	int		n;
  
  	get_mime_type(conn->ctx, path, &mime_vec);
  	cl = stp->size;
  	conn->request_info.status_code = 200;
  	range[0] = '\0';
  
  	if ((fp = mg_fopen(path, "rb")) == NULL) {
  		send_error(conn, 500, http_500_error,
  		    "fopen(%s): %s", path, strerror(ERRNO));
  		return;
  	}
  	set_close_on_exec(fileno(fp));
  
  	/* If Range: header specified, act accordingly */
  	r1 = r2 = 0;
  	hdr = mg_get_header(conn, "Range");
  	if (hdr != NULL && (n = sscanf(hdr,
  	    "bytes=%" UINT64_FMT "u-%" UINT64_FMT "u", &r1, &r2)) > 0) {
  		conn->request_info.status_code = 206;
  		(void) fseeko(fp, (off_t) r1, SEEK_SET);
  		cl = n == 2 ? r2 - r1 + 1: cl - r1;
  		(void) mg_snprintf(conn, range, sizeof(range),
  		    "Content-Range: bytes "
  		    "%" UINT64_FMT "u-%"
  		    UINT64_FMT "u/%" UINT64_FMT "u\r\n",
  		    r1, r1 + cl - 1, stp->size);
  		msg = "Partial Content";
  	}
  
  	/* Prepare Etag, Date, Last-Modified headers */
  	(void) strftime(date, sizeof(date), fmt, localtime(&curtime));
  	(void) strftime(lm, sizeof(lm), fmt, localtime(&stp->mtime));
  	(void) mg_snprintf(conn, etag, sizeof(etag), "%lx.%lx",
  	    (unsigned long) stp->mtime, (unsigned long) stp->size);
  
  	(void) mg_printf(conn,
  	    "HTTP/1.1 %d %s\r\n"
  	    "Date: %s\r\n"
  	    "Last-Modified: %s\r\n"
  	    "Etag: \"%s\"\r\n"
  	    "Content-Type: %.*s\r\n"
  	    "Content-Length: %" UINT64_FMT "u\r\n"
  	    "Connection: close\r\n"
  	    "Accept-Ranges: bytes\r\n"
  	    "%s\r\n",
  	    conn->request_info.status_code, msg, date, lm, etag,
  	    mime_vec.len, mime_vec.ptr, cl, range);
  
  	if (strcmp(conn->request_info.request_method, "HEAD") != 0)
  		send_opened_file_stream(conn, fp, cl);
  	(void) fclose(fp);
  }
  
  /*
   * Parse HTTP headers from the given buffer, advance buffer to the point
   * where parsing stopped.
   */
  static void
  parse_http_headers(char **buf, struct mg_request_info *ri)
  {
  	int	i;
  
  	for (i = 0; i < (int) ARRAY_SIZE(ri->http_headers); i++) {
  		ri->http_headers[i].name = skip(buf, ": ");
  		ri->http_headers[i].value = skip(buf, "\r\n");
  		if (ri->http_headers[i].name[0] == '\0')
  			break;
  		ri->num_headers = i + 1;
  	}
  }
  
  static bool_t
  is_known_http_method(const char *method)
  {
  	return (!strcmp(method, "GET") ||
  	    !strcmp(method, "POST") ||
  	    !strcmp(method, "HEAD") ||
  	    !strcmp(method, "PUT") ||
  	    !strcmp(method, "DELETE"));
  }
  
  /*
   * Parse HTTP request, fill in mg_request_info structure.
   */
  static bool_t
  parse_http_request(char *buf, struct mg_request_info *ri, const struct usa *usa)
  {
  	char	*http_version;
  	int	n, success_code = FALSE;
  
  	ri->request_method = skip(&buf, " ");
  	ri->uri = skip(&buf, " ");
  	http_version = skip(&buf, "\r\n");
  
  	if (is_known_http_method(ri->request_method) &&
  	    ri->uri[0] == '/' &&
  	    sscanf(http_version, "HTTP/%d.%d%n",
  	    &ri->http_version_major, &ri->http_version_minor, &n) == 2 &&
  	    http_version[n] == '\0') {
  		parse_http_headers(&buf, ri);
  		ri->remote_port = ntohs(usa->u.sin.sin_port);
  		(void) memcpy(&ri->remote_ip, &usa->u.sin.sin_addr.s_addr, 4);
  		ri->remote_ip = ntohl(ri->remote_ip);
  		success_code = TRUE;
  	}
  
  	return (success_code);
  }
  
  /*
   * Keep reading the input (either opened file descriptor fd, or socket sock,
   * or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
   * buffer (which marks the end of HTTP request). Buffer buf may already
   * have some data. The length of the data is stored in nread.
   * Upon every read operation, increase nread by the number of bytes read.
   */
  static int
  read_request(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int bufsiz, int *nread)
  {
  	int	n, request_len;
  
  	request_len = 0;
  	while (*nread < bufsiz && request_len == 0) {
  		n = pull(fp, sock, ssl, buf + *nread, bufsiz - *nread);
  		if (n <= 0) {
  			break;
  		} else {
  			*nread += n;
  			request_len = get_request_len(buf, (size_t) *nread);
  		}
  	}
  
  	return (request_len);
  }
  
  /*
   * For given directory path, substitute it to valid index file.
   * Return 0 if index file has been found, -1 if not found.
   * If the file is found, it's stats is returned in stp.
   */
  static bool_t
  substitute_index_file(struct mg_connection *conn,
  		char *path, size_t path_len, struct mgstat *stp)
  {
  	const char	*list;
  	struct mgstat	st;
  	struct vec	filename_vec;
  	size_t		n;
  	bool_t		found;
  
  	n = strlen(path);
  
  	/*
  	 * The 'path' given to us points to the directory. Remove all trailing
  	 * directory separator characters from the end of the path, and
  	 * then append single directory separator character.
  	 */
  	while (n > 0 && IS_DIRSEP_CHAR(path[n - 1]))
  		n--;
  	path[n] = DIRSEP;
  
  	/*
  	 * Traverse index files list. For each entry, append it to the given
  	 * path and see if the file exists. If it exists, break the loop
  	 */
  	lock_option(conn->ctx, OPT_INDEX_FILES);
  	list = conn->ctx->options[OPT_INDEX_FILES];
  	found = FALSE;
  
  	while ((list = next_option(list, &filename_vec, NULL)) != NULL) {
  
  		/* Ignore too long entries that may overflow path buffer */
  		if (filename_vec.len > path_len - n)
  			continue;
  
  		/* Prepare full path to the index file  */
  		(void) mg_strlcpy(path + n + 1,
  		    filename_vec.ptr, filename_vec.len + 1);
  
  		/* Does it exist ? */
  		if (mg_stat(path, &st) == 0) {
  			/* Yes it does, break the loop */
  			*stp = st;
  			found = TRUE;
  			break;
  		}
  	}
  	unlock_option(conn->ctx, OPT_INDEX_FILES);
  
  	/* If no index file exists, restore directory path */
  	if (found == FALSE)
  		path[n] = '\0';
  
  	return (found);
  }
  
  static void
  remove_callback(struct mg_context *ctx,
  		const char *uri_regex, int status_code, bool_t is_auth)
  {
  	struct callback	*cb;
  	int		i;
  
  	for (i = 0; i < ctx->num_callbacks; i++) {
  		cb = ctx->callbacks + i;
  		if ((uri_regex != NULL && cb->uri_regex != NULL &&
  		    ((is_auth && cb->is_auth) || (!is_auth && !cb->is_auth)) &&
  		    !strcmp(uri_regex, cb->uri_regex)) || (uri_regex == NULL &&
  		     (cb->status_code == 0 ||
  		      cb->status_code == status_code))) {
  			(void) memmove(cb, cb + 1,
  			    (char *) (ctx->callbacks + ctx->num_callbacks) -
  			    (char *) (cb + 1));
  			break;
  		}
  	}
  }
  
  static void
  add_callback(struct mg_context *ctx, const char *uri_regex, int status_code,
  		mg_callback_t func, bool_t is_auth, void *user_data)
  {
  	struct callback	*cb;
  
  	pthread_mutex_lock(&ctx->bind_mutex);
  	if (func == NULL) {
  		remove_callback(ctx, uri_regex, status_code, is_auth);
  	} else if (ctx->num_callbacks >= (int) ARRAY_SIZE(ctx->callbacks) - 1) {
  		cry(fc(ctx), "Too many callbacks! Increase MAX_CALLBACKS.");
  	} else {
  		cb = &ctx->callbacks[ctx->num_callbacks];
  		cb->uri_regex = uri_regex ? mg_strdup(uri_regex) : NULL;
  		cb->func = func;
  		cb->is_auth = is_auth;
  		cb->status_code = status_code;
  		cb->user_data = user_data;
  		ctx->num_callbacks++;
  		DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: uri %s code %d",
  		    __func__, uri_regex ? uri_regex : "NULL", status_code));
  	}
  	pthread_mutex_unlock(&ctx->bind_mutex);
  }
  
  void
  mg_set_uri_callback(struct mg_context *ctx, const char *uri_regex,
  		mg_callback_t func, void *user_data)
  {
  	assert(uri_regex != NULL);
  	add_callback(ctx, uri_regex, -1, func, FALSE, user_data);
  }
  
  void
  mg_set_error_callback(struct mg_context *ctx, int error_code,
  		mg_callback_t func, void *user_data)
  {
  	assert(error_code >= 0 && error_code < 1000);
  	add_callback(ctx, NULL, error_code, func, FALSE, user_data);
  }
  
  void
  mg_set_auth_callback(struct mg_context *ctx, const char *uri_regex,
  		mg_callback_t func, void *user_data)
  {
  	assert(uri_regex != NULL);
  	add_callback(ctx, uri_regex, -1, func, TRUE, user_data);
  }
  
  /*
   * Return True if we should reply 304 Not Modified.
   */
  static bool_t
  is_not_modified(const struct mg_connection *conn, const struct mgstat *stp)
  {
  	const char *ims = mg_get_header(conn, "If-Modified-Since");
  	return (ims != NULL && stp->mtime < date_to_epoch(ims));
  }
  
  static bool_t
  append_chunk(struct mg_request_info *ri, FILE *fp, const char *buf, int len)
  {
  	bool_t	ret_code = TRUE;
  
  	if (fp == NULL) {
  		/* TODO: check for NULL here */
  		ri->post_data = (char *) realloc(ri->post_data,
  		    ri->post_data_len + len);
  		(void) memcpy(ri->post_data + ri->post_data_len, buf, len);
  		ri->post_data_len += len;
  	} else if (push(fp, INVALID_SOCKET,
  	    NULL, buf, (uint64_t) len) != (uint64_t) len) {
  		ret_code = FALSE;
  	}
  
  	return (ret_code);
  }
  
  static bool_t
  handle_request_body(struct mg_connection *conn, FILE *fp)
  {
  	struct mg_request_info	*ri = &conn->request_info;
  	const char	*expect, *tmp;
  	uint64_t	content_len;
  	char		buf[BUFSIZ];
  	int		to_read, nread, already_read;
  	bool_t		success_code = FALSE;
  
  	content_len = get_content_length(conn);
  	expect = mg_get_header(conn, "Expect");
  
  	if (content_len == UNKNOWN_CONTENT_LENGTH) {
  		send_error(conn, 411, "Length Required", "");
  	} else if (expect != NULL && mg_strcasecmp(expect, "100-continue")) {
  		send_error(conn, 417, "Expectation Failed", "");
  	} else {
  		if (expect != NULL)
  			(void) mg_printf(conn, "HTTP/1.1 100 Continue\r\n\r\n");
  
  		already_read = ri->post_data_len;
  		assert(already_read >= 0);
  
  		if (content_len <= (uint64_t) already_read) {
  			ri->post_data_len = (int) content_len;
  			/*
  			 * If fp is NULL, this is embedded mode, and we do not
  			 * have to do anything: POST data is already there,
  			 * no need to allocate a buffer and copy it in.
  			 * If fp != NULL, we need to write the data.
  			 */
  			success_code = fp == NULL || (push(fp, INVALID_SOCKET,
  			    NULL, ri->post_data, content_len) == content_len) ?
  			    TRUE : FALSE;
  		} else {
  
  			if (fp == NULL) {
  				conn->free_post_data = TRUE;
  				tmp = ri->post_data;
  				/* +1 in case if already_read == 0 */
  				ri->post_data = (char*)malloc(already_read + 1);
  				(void) memcpy(ri->post_data, tmp, already_read);
  			} else {
  				(void) push(fp, INVALID_SOCKET, NULL,
  				    ri->post_data, (uint64_t) already_read);
  			}
  
  			content_len -= already_read;
  
  			while (content_len > 0) {
  				to_read = sizeof(buf);
  				if ((uint64_t) to_read > content_len)
  					to_read = (int) content_len;
  				nread = pull(NULL, conn->client.sock,
  				    conn->ssl, buf, to_read);
  				if (nread <= 0)
  					break;
  				if (!append_chunk(ri, fp, buf, nread))
  					break;
  				content_len -= nread;
  			}
  			success_code = content_len == 0 ? TRUE : FALSE;
  		}
  
  		/* Each error code path in this function must send an error */
  		if (success_code != TRUE)
  			send_error(conn, 577, http_500_error,
  			    "%s", "Error handling body data");
  	}
  
  	return (success_code);
  }
  
  #if !defined(NO_CGI)
  
  /*
   * This structure helps to create an environment for the spawned CGI program.
   * Environment is an array of "VARIABLE=VALUE\0" ASCIIZ strings,
   * last element must be NULL.
   * However, on Windows there is a requirement that all these VARIABLE=VALUE\0
   * strings must reside in a contiguous buffer. The end of the buffer is
   * marked by two '\0' characters.
   * We satisfy both worlds: we create an envp array (which is vars), all
   * entries are actually pointers inside buf.
   */
  struct cgi_env_block {
  	struct mg_connection *conn;
  	char	buf[CGI_ENVIRONMENT_SIZE];	/* Environment buffer	*/
  	int	len;				/* Space taken		*/
  	char	*vars[MAX_CGI_ENVIR_VARS];	/* char **envp		*/
  	int	nvars;				/* Number of variables	*/
  };
  
  /*
   * Append VARIABLE=VALUE\0 string to the buffer, and add a respective
   * pointer into the vars array.
   */
  static char *
  addenv(struct cgi_env_block *block, const char *fmt, ...)
  {
  	int	n, space;
  	char	*added;
  	va_list	ap;
  
  	/* Calculate how much space is left in the buffer */
  	space = sizeof(block->buf) - block->len - 2;
  	assert(space >= 0);
  
  	/* Make a pointer to the free space int the buffer */
  	added = block->buf + block->len;
  
  	/* Copy VARIABLE=VALUE\0 string into the free space */
  	va_start(ap, fmt);
  	n = mg_vsnprintf(block->conn, added, (size_t) space, fmt, ap);
  	va_end(ap);
  
  	/* Make sure we do not overflow buffer and the envp array */
  	if (n > 0 && n < space &&
  	    block->nvars < (int) ARRAY_SIZE(block->vars) - 2) {
  		/* Append a pointer to the added string into the envp array */
  		block->vars[block->nvars++] = block->buf + block->len;
  		/* Bump up used length counter. Include \0 terminator */
  		block->len += n + 1;
  	}
  
  	return (added);
  }
  
  static void
  prepare_cgi_environment(struct mg_connection *conn, const char *prog,
  		struct cgi_env_block *blk)
  {
  	const char	*s, *script_filename, *root;
  	struct vec	var_vec;
  	char		*p;
  	int		i;
  
  	blk->len = blk->nvars = 0;
  	blk->conn = conn;
  
  	/* SCRIPT_FILENAME */
  	script_filename = prog;
  	if ((s = strrchr(prog, '/')) != NULL)
  		script_filename = s + 1;
  
  	lock_option(conn->ctx, OPT_ROOT);
  	root = conn->ctx->options[OPT_ROOT];
  	addenv(blk, "SERVER_NAME=%s", conn->ctx->options[OPT_AUTH_DOMAIN]);
  	unlock_option(conn->ctx, OPT_ROOT);
  
  	/* Prepare the environment block */
  	addenv(blk, "%s", "GATEWAY_INTERFACE=CGI/1.1");
  	addenv(blk, "%s", "SERVER_PROTOCOL=HTTP/1.1");
  	addenv(blk, "%s", "REDIRECT_STATUS=200");	/* PHP */
  	addenv(blk, "SERVER_PORT=%d", ntohs(conn->client.lsa.u.sin.sin_port));
  	addenv(blk, "SERVER_ROOT=%s", root);
  	addenv(blk, "DOCUMENT_ROOT=%s", root);
  	addenv(blk, "REQUEST_METHOD=%s", conn->request_info.request_method);
  	addenv(blk, "REMOTE_ADDR=%s",
  	    inet_ntoa(conn->client.rsa.u.sin.sin_addr));
  	addenv(blk, "REMOTE_PORT=%d", conn->request_info.remote_port);
  	addenv(blk, "REQUEST_URI=%s", conn->request_info.uri);
  	addenv(blk, "SCRIPT_NAME=%s", prog + strlen(root));
  	addenv(blk, "SCRIPT_FILENAME=%s", script_filename);	/* PHP */
  	addenv(blk, "PATH_TRANSLATED=%s", prog);
  	addenv(blk, "HTTPS=%s", conn->ssl == NULL ? "off" : "on");
  
  	if ((s = mg_get_header(conn, "Content-Type")) != NULL)
  		addenv(blk, "CONTENT_TYPE=%s", s);
  
  	if (conn->request_info.query_string != NULL)
  		addenv(blk, "QUERY_STRING=%s", conn->request_info.query_string);
  
  	if ((s = mg_get_header(conn, "Content-Length")) != NULL)
  		addenv(blk, "CONTENT_LENGTH=%s", s);
  
  	if ((s = getenv("PATH")) != NULL)
  		addenv(blk, "PATH=%s", s);
  
  #if defined(_WIN32)
  	if ((s = getenv("COMSPEC")) != NULL)
  		addenv(blk, "COMSPEC=%s", s);
  	if ((s = getenv("SYSTEMROOT")) != NULL)
  		addenv(blk, "SYSTEMROOT=%s", s);
  #else
  	if ((s = getenv("LD_LIBRARY_PATH")) != NULL)
  		addenv(blk, "LD_LIBRARY_PATH=%s", s);
  #endif /* _WIN32 */
  
  	if ((s = getenv("PERLLIB")) != NULL)
  		addenv(blk, "PERLLIB=%s", s);
  
  	if (conn->request_info.remote_user != NULL) {
  		addenv(blk, "REMOTE_USER=%s", conn->request_info.remote_user);
  		addenv(blk, "%s", "AUTH_TYPE=Digest");
  	}
  
  	/* Add all headers as HTTP_* variables */
  	for (i = 0; i < conn->request_info.num_headers; i++) {
  		p = addenv(blk, "HTTP_%s=%s",
  		    conn->request_info.http_headers[i].name,
  		    conn->request_info.http_headers[i].value);
  
  		/* Convert variable name into uppercase, and change - to _ */
  		for (; *p != '=' && *p != '\0'; p++) {
  			if (*p == '-')
  				*p = '_';
  			*p = (char) toupper(* (unsigned char *) p);
  		}
  	}
  
  	/* Add user-specified variables */
  	lock_option(conn->ctx, OPT_CGI_ENV);
  	s = conn->ctx->options[OPT_CGI_ENV];
  	while ((s = next_option(s, &var_vec, NULL)) != NULL)
  		addenv(blk, "%.*s", var_vec.len, var_vec.ptr);
  	unlock_option(conn->ctx, OPT_CGI_ENV);
  
  	blk->vars[blk->nvars++] = NULL;
  	blk->buf[blk->len++] = '\0';
  
  	assert(blk->nvars < (int) ARRAY_SIZE(blk->vars));
  	assert(blk->len > 0);
  	assert(blk->len < (int) sizeof(blk->buf));
  }
  
  static void
  send_cgi(struct mg_connection *conn, const char *prog)
  {
  	int			headers_len, data_len, i, n;
  	const char		*status;
  	char			buf[MAX_REQUEST_SIZE], *pbuf;
  	struct mg_request_info	ri;
  	struct cgi_env_block	blk;
  	char			dir[FILENAME_MAX], *p;
  	int			fd_stdin[2], fd_stdout[2];
  	FILE			*in, *out;
  	pid_t			pid;
  
  	prepare_cgi_environment(conn, prog, &blk);
  
  	/* CGI must be executed in its own directory */
  	(void) mg_snprintf(conn, dir, sizeof(dir), "%s", prog);
  	if ((p = strrchr(dir, DIRSEP)) != NULL)
  		*p++ = '\0';
  
  	pid = (pid_t) -1;
  	fd_stdin[0] = fd_stdin[1] = fd_stdout[0] = fd_stdout[1] = -1;
  	in = out = NULL;
  
  	if (pipe(fd_stdin) != 0 || pipe(fd_stdout) != 0) {
  		send_error(conn, 500, http_500_error,
  		    "Cannot create CGI pipe: %s", strerror(ERRNO));
  		goto done;
  	} else if ((pid = spawn_process(conn, p, blk.buf, blk.vars,
  	    fd_stdin[0], fd_stdout[1], dir)) == (pid_t) -1) {
  		goto done;
  	} else if ((in = fdopen(fd_stdin[1], "wb")) == NULL ||
  	    (out = fdopen(fd_stdout[0], "rb")) == NULL) {
  		send_error(conn, 500, http_500_error,
  		    "fopen: %s", strerror(ERRNO));
  		goto done;
  	}
  
  	setbuf(in, NULL);
  	setbuf(out, NULL);
  
  	/*
  	 * spawn_process() must close those!
  	 * If we don't mark them as closed, close() attempt before
  	 * return from this function throws an exception on Windows.
  	 * Windows does not like when closed descriptor is closed again.
  	 */
  	fd_stdin[0] = fd_stdout[1] = -1;
  
  	/* Send POST data to the CGI process if needed */
  	if (!strcmp(conn->request_info.request_method, "POST") &&
  	    !handle_request_body(conn, in)) {
  		goto done;
  	}
  
  	/*
  	 * Now read CGI reply into a buffer. We need to set correct
  	 * status code, thus we need to see all HTTP headers first.
  	 * Do not send anything back to client, until we buffer in all
  	 * HTTP headers.
  	 */
  	data_len = 0;
  	headers_len = read_request(out, INVALID_SOCKET, NULL,
  	    buf, sizeof(buf), &data_len);
  	if (headers_len <= 0) {
  		send_error(conn, 500, http_500_error,
  		    "CGI program sent malformed HTTP headers: [%.*s]",
  		    data_len, buf);
  		goto done;
  	}
  	pbuf = buf;
  	buf[headers_len - 1] = '\0';
  	parse_http_headers(&pbuf, &ri);
  
  	/* Make up and send the status line */
  	status = get_header(&ri, "Status");
  	conn->request_info.status_code = status == NULL ? 200 : atoi(status);
  	(void) mg_printf(conn, "HTTP/1.1 %d OK\r\n",
  	    conn->request_info.status_code);
  
  	/* Send headers */
  	for (i = 0; i < ri.num_headers; i++)
  		(void) mg_printf(conn, "%s: %s\r\n",
  		    ri.http_headers[i].name,
  		    ri.http_headers[i].value);
  	(void) mg_write(conn, "\r\n", 2);
  
  	/* Send chunk of data that may be read after the headers */
  	conn->num_bytes_sent += mg_write(conn,
  	    buf + headers_len, data_len - headers_len);
  
  	/*
  	 * Read the rest of CGI output and send to the client. If read from
  	 * CGI returns 0, CGI has finished output. If it returns < 0,
  	 * some read error occured (CGI process terminated unexpectedly?)
  	 * If write to the client fails, the means client has disconnected
  	 * unexpectedly.
  	 * In all such cases, stop data exchange and do cleanup.
  	 */
  	do {
  		n = pull(out, INVALID_SOCKET, NULL, buf, sizeof(buf));
  		if (n > 0)
  			n = mg_write(conn, buf, n);
  		if (n > 0)
  			conn->num_bytes_sent += n;
  	} while (n > 0);
  
  done:
  	if (pid != (pid_t) -1)
  		kill(pid, SIGTERM);
  	if (fd_stdin[0] != -1)
  		(void) close(fd_stdin[0]);
  	if (fd_stdout[1] != -1)
  		(void) close(fd_stdout[1]);
  
  	if (in != NULL)
  		(void) fclose(in);
  	else if (fd_stdin[1] != -1)
  		(void) close(fd_stdin[1]);
  
  	if (out != NULL)
  		(void) fclose(out);
  	else if (fd_stdout[0] != -1)
  		(void) close(fd_stdout[0]);
  }
  #endif /* !NO_CGI */
  
  /*
   * For a given PUT path, create all intermediate subdirectories
   * for given path. Return 0 if the path itself is a directory,
   * or -1 on error, 1 if OK.
   */
  static int
  put_dir(const char *path)
  {
  	char		buf[FILENAME_MAX];
  	const char	*s, *p;
  	struct mgstat	st;
  	size_t		len;
  
  	for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
  		len = p - path;
  		assert(len < sizeof(buf));
  		(void) memcpy(buf, path, len);
  		buf[len] = '\0';
  
  		/* Try to create intermediate directory */
  		if (mg_stat(buf, &st) == -1 && mg_mkdir(buf, 0755) != 0)
  			return (-1);
  
  		/* Is path itself a directory ? */
  		if (p[1] == '\0')
  			return (0);
  	}
  
  	return (1);
  }
  
  static void
  put_file(struct mg_connection *conn, const char *path)
  {
  	struct mgstat	st;
  	FILE		*fp;
  	int		rc;
  
  	conn->request_info.status_code = mg_stat(path, &st) == 0 ? 200 : 201;
  
  	if (mg_get_header(conn, "Range")) {
  		send_error(conn, 501, "Not Implemented",
  		    "%s", "Range support for PUT requests is not implemented");
  	} else if ((rc = put_dir(path)) == 0) {
  		(void) mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n",
  		    conn->request_info.status_code);
  	} else if (rc == -1) {
  		send_error(conn, 500, http_500_error,
  		    "put_dir(%s): %s", path, strerror(ERRNO));
  	} else if ((fp = mg_fopen(path, "wb+")) == NULL) {
  		send_error(conn, 500, http_500_error,
  		    "fopen(%s): %s", path, strerror(ERRNO));
  	} else {
  		set_close_on_exec(fileno(fp));
  		if (handle_request_body(conn, fp))
  			(void) mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n",
  			    conn->request_info.status_code);
  		(void) fclose(fp);
  	}
  }
  
  #if !defined(NO_SSI)
  static void send_ssi_file(struct mg_connection *, const char *, FILE *, int);
  
  static void
  do_ssi_include(struct mg_connection *conn, const char *ssi, char *tag,
  		int include_level)
  {
  	char	file_name[BUFSIZ], path[FILENAME_MAX], *p;
  	FILE	*fp;
  
  	/*
  	 * sscanf() is safe here, since send_ssi_file() also uses buffer
  	 * of size BUFSIZ to get the tag. So strlen(tag) is always < BUFSIZ.
  	 */
  	if (sscanf(tag, " virtual=\"%[^\"]\"", file_name) == 1) {
  		/* File name is relative to the webserver root */
  		lock_option(conn->ctx, OPT_ROOT);
  		(void) mg_snprintf(conn, path, sizeof(path), "%s%c%s",
  		    conn->ctx->options[OPT_ROOT], DIRSEP, file_name);
  		unlock_option(conn->ctx, OPT_ROOT);
  	} else if (sscanf(tag, " file=\"%[^\"]\"", file_name) == 1) {
  		/*
  		 * File name is relative to the webserver working directory
  		 * or it is absolute system path
  		 */
  		(void) mg_snprintf(conn, path, sizeof(path), "%s", file_name);
  	} else if (sscanf(tag, " \"%[^\"]\"", file_name) == 1) {
  		/* File name is relative to the currect document */
  		(void) mg_snprintf(conn, path, sizeof(path), "%s", ssi);
  		if ((p = strrchr(path, DIRSEP)) != NULL)
  			p[1] = '\0';
  		(void) mg_snprintf(conn, path + strlen(path),
  		    sizeof(path) - strlen(path), "%s", file_name);
  	} else {
  		cry(conn, "Bad SSI #include: [%s]", tag);
  		return;
  	}
  
  	if ((fp = mg_fopen(path, "rb")) == NULL) {
  		cry(conn, "Cannot open SSI #include: [%s]: fopen(%s): %s",
  		    tag, path, strerror(ERRNO));
  	} else {
  		set_close_on_exec(fileno(fp));
  		if (match_extension(path,
  		    conn->ctx->options[OPT_SSI_EXTENSIONS])) {
  			send_ssi_file(conn, path, fp, include_level + 1);
  		} else {
  			send_opened_file_stream(conn, fp,
  			    UNKNOWN_CONTENT_LENGTH);
  		}
  		(void) fclose(fp);
  	}
  }
  
  static void
  do_ssi_exec(struct mg_connection *conn, char *tag)
  {
  	char	cmd[BUFSIZ];
  	FILE	*fp;
  
  	if (sscanf(tag, " \"%[^\"]\"", cmd) != 1) {
  		cry(conn, "Bad SSI #exec: [%s]", tag);
  	} else if ((fp = popen(cmd, "r")) == NULL) {
  		cry(conn, "Cannot SSI #exec: [%s]: %s", cmd, strerror(ERRNO));
  	} else {
  		send_opened_file_stream(conn, fp, UNKNOWN_CONTENT_LENGTH);
  		(void) pclose(fp);
  	}
  }
  
  static void
  send_ssi_file(struct mg_connection *conn, const char *path, FILE *fp,
  		int include_level)
  {
  	char	buf[BUFSIZ];
  	int	ch, len, in_ssi_tag;
  
  	if (include_level > 10) {
  		cry(conn, "SSI #include level is too deep (%s)", path);
  		return;
  	}
  
  	in_ssi_tag = FALSE;
  	len = 0;
  
  	while ((ch = fgetc(fp)) != EOF) {
  		if (in_ssi_tag && ch == '>') {
  			in_ssi_tag = FALSE;
  			buf[len++] = ch & 0xff;
  			buf[len] = '\0';
  			assert(len <= (int) sizeof(buf));
  			if (len < 6 || memcmp(buf, "<!--#", 5) != 0) {
  				/* Not an SSI tag, pass it */
  				(void) mg_write(conn, buf, len);
  			} else {
  				if (!memcmp(buf + 5, "include", 7)) {
  					do_ssi_include(conn, path, buf + 12,
  					    include_level);
  				} else if (!memcmp(buf + 5, "exec", 4)) {
  					do_ssi_exec(conn, buf + 9);
  				} else {
  					cry(conn, "%s: unknown SSI "
  					    "command: \"%s\"", path, buf);
  				}
  			}
  			len = 0;
  		} else if (in_ssi_tag) {
  			if (len == 5 && memcmp(buf, "<!--#", 5) != 0) {
  				/* Not an SSI tag */
  				in_ssi_tag = FALSE;
  			} else if (len == (int) sizeof(buf) - 2) {
  				cry(conn, "%s: SSI tag is too large", path);
  				len = 0;
  			}
  			buf[len++] = ch & 0xff;
  		} else if (ch == '<') {
  			in_ssi_tag = TRUE;
  			if (len > 0)
  				(void) mg_write(conn, buf, len);
  			len = 0;
  			buf[len++] = ch & 0xff;
  		} else {
  			buf[len++] = ch & 0xff;
  			if (len == (int) sizeof(buf)) {
  				(void) mg_write(conn, buf, len);
  				len = 0;
  			}
  		}
  	}
  
  	/* Send the rest of buffered data */
  	if (len > 0)
  		(void) mg_write(conn, buf, len);
  
  }
  
  static void
  send_ssi(struct mg_connection *conn, const char *path)
  {
  	FILE	*fp;
  
  	if ((fp = mg_fopen(path, "rb")) == NULL) {
  		send_error(conn, 500, http_500_error,
  		    "fopen(%s): %s", path, strerror(ERRNO));
  	} else {
  		set_close_on_exec(fileno(fp));
  		(void) mg_printf(conn, "%s", "HTTP/1.1 200 OK\r\n"
  		    "Content-Type: text/html\r\nConnection: close\r\n\r\n");
  		send_ssi_file(conn, path, fp, 0);
  		(void) fclose(fp);
  	}
  }
  #endif /* !NO_SSI */
  
  void
  mg_authorize(struct mg_connection *conn)
  {
  	conn->embedded_auth = TRUE;
  }
  
  static bool_t
  check_embedded_authorization(struct mg_connection *conn)
  {
  	const struct callback	*cb;
  	bool_t			authorized;
  
  	authorized = TRUE;
  	cb = find_callback(conn->ctx, TRUE, conn->request_info.uri, -1);
  
  	if (cb != NULL) {
  		cb->func(conn, &conn->request_info, cb->user_data);
  		authorized = conn->embedded_auth;
  	}
  
  	return (authorized);
  }
  
  /*
   * This is the heart of the Mongoose's logic.
   * This function is called when the request is read, parsed and validated,
   * and Mongoose must decide what action to take: serve a file, or
   * a directory, or call embedded function, etcetera.
   */
  static void
  analyze_request(struct mg_connection *conn)
  {
  	struct mg_request_info *ri = &conn->request_info;
  	char			path[FILENAME_MAX], *uri = ri->uri;
  	struct mgstat		st;
  	const struct callback	*cb;
  
  	if ((conn->request_info.query_string = strchr(uri, '?')) != NULL)
  		* conn->request_info.query_string++ = '\0';
  
  	(void) url_decode(uri, (int) strlen(uri), uri, strlen(uri) + 1, FALSE);
  	remove_double_dots_and_double_slashes(uri);
  	convert_uri_to_file_name(conn, uri, path, sizeof(path));
  
  	if (!check_authorization(conn, path)) {
  		send_authorization_request(conn);
  	} else if (check_embedded_authorization(conn) == FALSE) {
  		/*
  		 * Embedded code failed authorization. Do nothing here, since
  		 * an embedded code must handle this itself by either
  		 * showing proper error message, or redirecting to some
  		 * sort of login page, or something else.
  		 */
  	} else if ((cb = find_callback(conn->ctx, FALSE, uri, -1)) != NULL) {
  		if ((strcmp(ri->request_method, "POST") != 0 &&
  		    strcmp(ri->request_method, "PUT") != 0) ||
  		    handle_request_body(conn, NULL))
  			cb->func(conn, &conn->request_info, cb->user_data);
  	} else if (strstr(path, PASSWORDS_FILE_NAME)) {
  		/* Do not allow to view passwords files */
  		send_error(conn, 403, "Forbidden", "Access Forbidden");
  	} else if ((!strcmp(ri->request_method, "PUT") ||
  	    !strcmp(ri->request_method, "DELETE")) &&
  	    (conn->ctx->options[OPT_AUTH_PUT] == NULL ||
  	     !is_authorized_for_put(conn))) {
  		send_authorization_request(conn);
  	} else if (!strcmp(ri->request_method, "PUT")) {
  		put_file(conn, path);
  	} else if (!strcmp(ri->request_method, "DELETE")) {
  		if (mg_remove(path) == 0)
  			send_error(conn, 200, "OK", "");
  		else
  			send_error(conn, 500, http_500_error,
  			    "remove(%s): %s", path, strerror(ERRNO));
  	} else if (mg_stat(path, &st) != 0) {
  		send_error(conn, 404, "Not Found", "%s", "File not found");
  	} else if (st.is_directory && uri[strlen(uri) - 1] != '/') {
  		(void) mg_printf(conn,
  		    "HTTP/1.1 301 Moved Permanently\r\n"
  		    "Location: %s/\r\n\r\n", uri);
  	} else if (st.is_directory &&
  	    substitute_index_file(conn, path, sizeof(path), &st) == FALSE) {
  		if (is_true(conn->ctx->options[OPT_DIR_LIST])) {
  			send_directory(conn, path);
  		} else {
  			send_error(conn, 403, "Directory Listing Denied",
  			    "Directory listing denied");
  		}
  #if !defined(NO_CGI)
  	} else if (match_extension(path,
  	    conn->ctx->options[OPT_CGI_EXTENSIONS])) {
  		if (strcmp(ri->request_method, "POST") &&
  		    strcmp(ri->request_method, "GET")) {
  			send_error(conn, 501, "Not Implemented",
  			    "Method %s is not implemented", ri->request_method);
  		} else {
  			send_cgi(conn, path);
  		}
  #endif /* NO_CGI */
  #if !defined(NO_SSI)
  	} else if (match_extension(path,
  	    conn->ctx->options[OPT_SSI_EXTENSIONS])) {
  		send_ssi(conn, path);
  #endif /* NO_SSI */
  	} else if (is_not_modified(conn, &st)) {
  		send_error(conn, 304, "Not Modified", "");
  	} else {
  		send_file(conn, path, &st);
  	}
  }
  
  static void
  close_all_listening_sockets(struct mg_context *ctx)
  {
  	int	i;
  
  	for (i = 0; i < ctx->num_listeners; i++)
  		(void) closesocket(ctx->listeners[i].sock);
  	ctx->num_listeners = 0;
  }
  
  static bool_t
  set_ports_option(struct mg_context *ctx, const char *list)
  {
  	SOCKET		sock;
  	int		is_ssl;
  	struct vec	vec;
  	struct socket	*listener;
  
  	close_all_listening_sockets(ctx);
  	assert(ctx->num_listeners == 0);
  
  	while ((list = next_option(list, &vec, NULL)) != NULL) {
  
  		is_ssl	= vec.ptr[vec.len - 1] == 's' ? TRUE : FALSE;
  		listener = ctx->listeners + ctx->num_listeners;
  
  		if (ctx->num_listeners >=
  		    (int) (ARRAY_SIZE(ctx->listeners) - 1)) {
  			cry(fc(ctx), "%s", "Too many listeninig sockets");
  			return (FALSE);
  		} else if ((sock = mg_open_listening_port(ctx,
  		    vec.ptr, &listener->lsa)) == INVALID_SOCKET) {
  			cry(fc(ctx), "cannot bind to %.*s", vec.len, vec.ptr);
  			return (FALSE);
  		} else if (is_ssl == TRUE && ctx->ssl_ctx == NULL) {
  			(void) closesocket(sock);
  			cry(fc(ctx), "cannot add SSL socket, please specify "
  			    "-ssl_cert option BEFORE -ports option");
  			return (FALSE);
  		} else {
  			listener->sock = sock;
  			listener->is_ssl = is_ssl;
  			ctx->num_listeners++;
  		}
  	}
  
  	return (TRUE);
  }
  
  static void
  log_header(const struct mg_connection *conn, const char *header, FILE *fp)
  {
  	const char	*header_value;
  
  	if ((header_value = mg_get_header(conn, header)) == NULL) {
  		(void) fprintf(fp, "%s", " -");
  	} else {
  		(void) fprintf(fp, " \"%s\"", header_value);
  	}
  }
  
  static void
  log_access(const struct mg_connection *conn)
  {
  	const struct mg_request_info *ri;
  	char		date[64];
  
  	if (conn->ctx->access_log == NULL)
  		return;
  
  	(void) strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z",
  	    localtime(&conn->birth_time));
  
  	ri = &conn->request_info;
  
  	flockfile(conn->ctx->access_log);
  
  	(void) fprintf(conn->ctx->access_log,
  	    "%s - %s [%s] \"%s %s HTTP/%d.%d\" %d %" UINT64_FMT "u",
  	    inet_ntoa(conn->client.rsa.u.sin.sin_addr),
  	    ri->remote_user == NULL ? "-" : ri->remote_user,
  	    date,
  	    ri->request_method ? ri->request_method : "-",
  	    ri->uri ? ri->uri : "-",
  	    ri->http_version_major, ri->http_version_minor,
  	    conn->request_info.status_code, conn->num_bytes_sent);
  	log_header(conn, "Referer", conn->ctx->access_log);
  	log_header(conn, "User-Agent", conn->ctx->access_log);
  	(void) fputc('\n', conn->ctx->access_log);
  	(void) fflush(conn->ctx->access_log);
  
  	funlockfile(conn->ctx->access_log);
  }
  
  static bool_t
  isbyte(int n) {
  	return (n >= 0 && n <= 255);
  }
  
  /*
   * Verify given socket address against the ACL.
   * Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
   */
  static int
  check_acl(struct mg_context *ctx, const char *list, const struct usa *usa)
  {
  	int		a, b, c, d, n, mask, allowed;
  	char		flag;
  	uint32_t	acl_subnet, acl_mask, remote_ip;
  	struct vec	vec;
  
  	(void) memcpy(&remote_ip, &usa->u.sin.sin_addr, sizeof(remote_ip));
  
  	/* If any ACL is set, deny by default */
  	allowed = '-';
  
  	while ((list = next_option(list, &vec, NULL)) != NULL) {
  
  		mask = 32;
  
  		if (sscanf(vec.ptr, "%c%d.%d.%d.%d%n",
  		    &flag, &a, &b, &c, &d, &n) != 5) {
  			cry(fc(ctx),
  			    "%s: subnet must be [+|-]x.x.x.x[/x]", __func__);
  			return (-1);
  		} else if (flag != '+' && flag != '-') {
  			cry(fc(ctx), "%s: flag must be + or -: [%s]",
  			    __func__, vec.ptr);
  			return (-1);
  		} else if (!isbyte(a)||!isbyte(b)||!isbyte(c)||!isbyte(d)) {
  			cry(fc(ctx),
  			    "%s: bad ip address: [%s]", __func__, vec.ptr);
  			return (-1);
  		} else if (sscanf(vec.ptr + n, "/%d", &mask) == 0) {
  			/* Do nothing, no mask specified */
  		} else if (mask < 0 || mask > 32) {
  			cry(fc(ctx), "%s: bad subnet mask: %d [%s]",
  			    __func__, n, vec.ptr);
  			return (-1);
  		}
  
  		acl_subnet = (a << 24) | (b << 16) | (c << 8) | d;
  		acl_mask = mask ? 0xffffffffU << (32 - mask) : 0;
  
  		if (acl_subnet == (ntohl(remote_ip) & acl_mask))
  			allowed = flag;
  	}
  
  	return (allowed == '+' ? 1 : 0);
  }
  
  static void
  add_to_set(SOCKET fd, fd_set *set, int *max_fd)
  {
  	FD_SET(fd, set);
  	if (fd > (SOCKET) *max_fd)
  		*max_fd = (int) fd;
  }
  
  /*
   * Deallocate mongoose context, free up the resources
   */
  static void
  mg_fini(struct mg_context *ctx)
  {
  	int	i;
  
  	close_all_listening_sockets(ctx);
  
  	/* Wait until all threads finish */
  	(void) pthread_mutex_lock(&ctx->thr_mutex);
  	while (ctx->num_threads > 0)
  		(void) pthread_cond_wait(&ctx->thr_cond, &ctx->thr_mutex);
  	(void) pthread_mutex_unlock(&ctx->thr_mutex);
  
  	/* Deallocate all registered callbacks */
  	for (i = 0; i < ctx->num_callbacks; i++)
  		if (ctx->callbacks[i].uri_regex != NULL)
  			free(ctx->callbacks[i].uri_regex);
  
  	/* Deallocate all options */
  	for (i = 0; i < NUM_OPTIONS; i++)
  		if (ctx->options[i] != NULL)
  			free(ctx->options[i]);
  
  	/* Close log files */
  	if (ctx->access_log)
  		(void) fclose(ctx->access_log);
  	if (ctx->error_log)
  		(void) fclose(ctx->error_log);
  
  	/* Deallocate SSL context */
  	if (ctx->ssl_ctx)
  		SSL_CTX_free(ctx->ssl_ctx);
  
  	/* Deallocate mutexes and condvars */
  	for (i = 0; i < NUM_OPTIONS; i++)
  		(void) pthread_mutex_destroy(&ctx->opt_mutex[i]);
  
  	(void) pthread_mutex_destroy(&ctx->thr_mutex);
  	(void) pthread_mutex_destroy(&ctx->bind_mutex);
  	(void) pthread_cond_destroy(&ctx->thr_cond);
  	(void) pthread_cond_destroy(&ctx->empty_cond);
  	(void) pthread_cond_destroy(&ctx->full_cond);
  
  	/* Signal mg_stop() that we're done */
  	ctx->stop_flag = 2;
  }
  
  #if !defined(_WIN32)
  static bool_t
  set_uid_option(struct mg_context *ctx, const char *uid)
  {
  	struct passwd	*pw;
  	int		retval = FALSE;
  
  	if ((pw = getpwnam(uid)) == NULL)
  		cry(fc(ctx), "%s: unknown user [%s]", __func__, uid);
  	else if (setgid(pw->pw_gid) == -1)
  		cry(fc(ctx), "%s: setgid(%s): %s",
  		    __func__, uid, strerror(errno));
  	else if (setuid(pw->pw_uid) == -1)
  		cry(fc(ctx), "%s: setuid(%s): %s",
  		    __func__, uid, strerror(errno));
  	else
  		retval = TRUE;
  
  	return (retval);
  }
  #endif /* !_WIN32 */
  
  #if !defined(NO_SSL)
  void
  mg_set_ssl_password_callback(struct mg_context *ctx, mg_spcb_t func)
  {
  	ctx->ssl_password_callback = func;
  }
  
  static pthread_mutex_t *ssl_mutexes;
  
  static void
  ssl_locking_callback(int mode, int mutex_num, const char *file, int line)
  {
  	line = 0;	/* Unused */
  	file = NULL;	/* Unused */
  
  	if (mode & CRYPTO_LOCK)
  		(void) pthread_mutex_lock(&ssl_mutexes[mutex_num]);
  	else
  		(void) pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
  }
  
  static unsigned long
  ssl_id_callback(void)
  {
  	return ((unsigned long) pthread_self());
  }
  
  static bool_t
  load_dll(struct mg_context *ctx, const char *dll_name, struct ssl_func *sw)
  {
  	union {void *p; void (*fp)(void);} u;
  	void		*dll_handle;
  	struct ssl_func	*fp;
  
  	if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
  		cry(fc(ctx), "%s: cannot load %s", __func__, dll_name);
  		return (FALSE);
  	}
  
  	for (fp = sw; fp->name != NULL; fp++) {
  #ifdef _WIN32
  		/* GetProcAddress() returns pointer to function */
  		u.fp = (void (*)(void)) dlsym(dll_handle, fp->name);
  #else
  		/*
  		 * dlsym() on UNIX returns void *.
  		 * ISO C forbids casts of data pointers to function
  		 * pointers. We need to use a union to make a cast.
  		 */
  		u.p = dlsym(dll_handle, fp->name);
  #endif /* _WIN32 */
  		if (u.fp == NULL) {
  			cry(fc(ctx), "%s: cannot find %s", __func__, fp->name);
  			return (FALSE);
  		} else {
  			fp->ptr = u.fp;
  		}
  	}
  
  	return (TRUE);
  }
  
  /*
   * Dynamically load SSL library. Set up ctx->ssl_ctx pointer.
   */
  static bool_t
  set_ssl_option(struct mg_context *ctx, const char *pem)
  {
  	SSL_CTX		*CTX;
  	int		i, size, retval = FALSE;
  
  	if (load_dll(ctx, SSL_LIB, ssl_sw) == FALSE ||
  	    load_dll(ctx, CRYPTO_LIB, crypto_sw) == FALSE)
  		return (FALSE);
  
  	/* Initialize SSL crap */
  	SSL_library_init();
  
  	if ((CTX = SSL_CTX_new(SSLv23_server_method())) == NULL)
  		cry(fc(ctx), "SSL_CTX_new error");
  	else if (ctx->ssl_password_callback != NULL)
  		SSL_CTX_set_default_passwd_cb(CTX, ctx->ssl_password_callback);
  
  	if (CTX != NULL && SSL_CTX_use_certificate_file(
  	    CTX, pem, SSL_FILETYPE_PEM) == 0)
  		cry(fc(ctx), "%s: cannot open %s", __func__, pem);
  	else if (CTX != NULL && SSL_CTX_use_PrivateKey_file(
  	    CTX, pem, SSL_FILETYPE_PEM) == 0)
  		cry(fc(ctx), "%s: cannot open %s", NULL, pem);
  	else
  		retval = TRUE;
  
  	/*
  	 * Initialize locking callbacks, needed for thread safety.
  	 * http://www.openssl.org/support/faq.html#PROG1
  	 */
  	size = sizeof(pthread_mutex_t) * CRYPTO_num_locks();
  	if ((ssl_mutexes = (pthread_mutex_t *) malloc(size)) == NULL) {
  		cry(fc(ctx), "%s: cannot allocate mutexes", __func__);
  		return (FALSE);
  	}
  
  	for (i = 0; i < CRYPTO_num_locks(); i++)
  		pthread_mutex_init(&ssl_mutexes[i], NULL);
  
  	CRYPTO_set_locking_callback(&ssl_locking_callback);
  	CRYPTO_set_id_callback(&ssl_id_callback);
  
  	/* Done with everything. Save the context. */
  	ctx->ssl_ctx = CTX;
  
  	return (retval);
  }
  #endif /* !NO_SSL */
  
  static bool_t
  open_log_file(struct mg_context *ctx, FILE **fpp, const char *path)
  {
  	bool_t	retval = TRUE;
  
  	if (*fpp != NULL)
  		(void) fclose(*fpp);
  
  	if (path == NULL) {
  		*fpp = NULL;
  	} else if ((*fpp = mg_fopen(path, "a")) == NULL) {
  		cry(fc(ctx), "%s(%s): %s", __func__, path, strerror(errno));
  		retval = FALSE;
  	} else {
  		set_close_on_exec(fileno(*fpp));
  	}
  
  	return (retval);
  }
  
  static bool_t
  set_alog_option(struct mg_context *ctx, const char *path)
  {
  	return (open_log_file(ctx, &ctx->access_log, path));
  }
  
  static bool_t
  set_elog_option(struct mg_context *ctx, const char *path)
  {
  	return (open_log_file(ctx, &ctx->error_log, path));
  }
  
  static bool_t
  set_gpass_option(struct mg_context *ctx, const char *path)
  {
  	struct mgstat	mgstat;
  	ctx = NULL;
  	return (mg_stat(path, &mgstat) == 0);
  }
  
  static bool_t
  set_max_threads_option(struct mg_context *ctx, const char *str)
  {
  	ctx->max_threads = atoi(str);
  	return (TRUE);
  }
  
  static bool_t
  set_acl_option(struct mg_context *ctx, const char *acl)
  {
  	struct usa	fake;
  
  	return (check_acl(ctx, acl, &fake) != -1);
  }
  
  static void admin_page(struct mg_connection *,
  		const struct mg_request_info *, void *);
  static bool_t
  set_admin_uri_option(struct mg_context *ctx, const char *uri)
  {
  	mg_set_uri_callback(ctx, uri, &admin_page, NULL);
  	return (TRUE);
  }
  
  /*
   * Check if the comma-separated list of options has a format of key-value
   * pairs: "k1=v1,k2=v2". Return FALSE if any entry has invalid key or value.
   */
  static bool_t
  set_kv_list_option(struct mg_context *ctx, const char *str)
  {
  	const char	*list;
  	struct vec	key, value;
  
  	list = str;
  	while ((list = next_option(list, &key, &value)) != NULL)
  		if (key.len == 0 || value.len == 0) {
  			cry(fc(ctx), "Invalid list specified: [%s], "
  			    "expecting key1=value1,key2=value2,...", str);
  			return (FALSE);
  		}
  
  	return (TRUE);
  }
  
  static const struct mg_option known_options[] = {
  	{"root", "\tWeb root directory", NULL, OPT_ROOT, NULL},
  	{"index_files",	"Index files", "index.html,index.htm,index.cgi",
  		OPT_INDEX_FILES, NULL},
  #if !defined(NO_SSL)
  	{"ssl_cert", "SSL certificate file", NULL,
  		OPT_SSL_CERTIFICATE, &set_ssl_option},
  #endif /* !NO_SSL */
  	{"ports", "Listening ports", NULL,
  		OPT_PORTS, &set_ports_option},
  	{"dir_list", "Directory listing", "yes",
  		OPT_DIR_LIST, NULL},
  	{"protect", "URI to htpasswd mapping", NULL,
  		OPT_PROTECT, &set_kv_list_option},
  #if !defined(NO_CGI)
  	{"cgi_ext", "CGI extensions", ".cgi,.pl,.php",
  		OPT_CGI_EXTENSIONS, NULL},
  	{"cgi_interp", "CGI interpreter to use with all CGI scripts", NULL,
  		OPT_CGI_INTERPRETER, NULL},
  	{"cgi_env", "Custom CGI enviroment variables", NULL,
  		OPT_CGI_ENV, &set_kv_list_option},
  #endif /* NO_CGI */
  	{"ssi_ext", "SSI extensions", ".shtml,.shtm",
  		OPT_SSI_EXTENSIONS, NULL},
  	{"auth_realm", "Authentication domain name", "mydomain.com",
  		OPT_AUTH_DOMAIN, NULL},
  	{"auth_gpass", "Global passwords file", NULL,
  		OPT_AUTH_GPASSWD, &set_gpass_option},
  	{"auth_PUT", "PUT,DELETE auth file", NULL,
  		OPT_AUTH_PUT, NULL},
  #if !defined(_WIN32)
  	{"uid", "\tRun as user", NULL, OPT_UID, &set_uid_option},
  #endif /* !_WIN32 */
  	{"access_log", "Access log file", NULL,
  		OPT_ACCESS_LOG, &set_alog_option},
  	{"error_log", "Error log file", NULL,
  		OPT_ERROR_LOG, &set_elog_option},
  	{"aliases", "Path=URI mappings", NULL,
  		OPT_ALIASES, &set_kv_list_option},
  	{"admin_uri", "Administration page URI", NULL,
  		OPT_ADMIN_URI, &set_admin_uri_option},
  	{"acl", "\tAllow/deny IP addresses/subnets", NULL,
  		OPT_ACL, &set_acl_option},
  	{"max_threads", "Maximum simultaneous threads to spawn", "100",
  		OPT_MAX_THREADS, &set_max_threads_option},
  	{"idle_time", "Time in seconds connection stays idle", "10",
  		OPT_IDLE_TIME, NULL},
  	{"mime_types", "Comma separated list of ext=mime_type pairs", NULL,
  		OPT_MIME_TYPES, &set_kv_list_option},
  	{NULL, NULL, NULL, 0, NULL}
  };
  
  static const struct mg_option *
  find_opt(const char *opt_name)
  {
  	int	i;
  
  	for (i = 0; known_options[i].name != NULL; i++)
  		if (!strcmp(opt_name, known_options[i].name))
  			return (known_options + i);
  
  	return (NULL);
  }
  
  int
  mg_set_option(struct mg_context *ctx, const char *opt, const char *val)
  {
  	const struct mg_option	*option;
  	int			i, retval;
  
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: [%s]->[%s]", __func__, opt, val));
  	if (opt != NULL && (option = find_opt(opt)) != NULL) {
  		i = (int) (option - known_options);
  		lock_option(ctx, i);
  
  		if (option->setter != NULL)
  			retval = option->setter(ctx, val);
  		else
  			retval = TRUE;
  
  		/* Free old value if any */
  		if (ctx->options[option->index] != NULL)
  			free(ctx->options[option->index]);
  
  		/* Set new option value */
  		ctx->options[option->index] = val ? mg_strdup(val) : NULL;
  		unlock_option(ctx, i);
  
  		if (retval == FALSE)
  			cry(fc(ctx), "%s(%s): failure", __func__, opt);
  	} else {
  		cry(fc(ctx), "%s: No such option: [%s]", __func__, opt);
  		retval = -1;
  	}
  
  	return (retval);
  }
  
  void
  mg_show_usage_string(FILE *fp)
  {
  	const struct mg_option	*o;
  
  	(void) fprintf(stderr,
  	    "Mongoose version %s (c) Sergey Lyubka\n"
  	    "usage: mongoose [options] [config_file]\n", mg_version());
  
  	fprintf(fp, "  -A <htpasswd_file> <realm> <user> <passwd>\n");
  
  	for (o = known_options; o->name != NULL; o++) {
  		(void) fprintf(fp, "  -%s\t%s", o->name, o->description);
  		if (o->default_value != NULL)
  			fprintf(fp, " (default: \"%s\")", o->default_value);
  		fputc('\n', fp);
  	}
  }
  
  const char *
  mg_get_option(const struct mg_context *ctx, const char *option_name)
  {
  	const struct mg_option	*option;
  
  	if ((option = find_opt(option_name)) != NULL)
  		return (ctx->options[option->index]);
  	else
  		return (NULL);
  }
  
  static void
  admin_page(struct mg_connection *conn, const struct mg_request_info *ri,
  			   void *user_data)
  {
  	const struct mg_option	*option;
  	const char		*option_name, *option_value;
  
  	user_data = NULL; /* Unused */
  
  	(void) mg_printf(conn,
  	"HTTP/1.1 200 OK\r\n"
  			"Content-Type: text/html\r\n\r\n"
  			"<html><body><h1>Mongoose v. %s</h1>", mg_version());
  
  	if (!strcmp(ri->request_method, "POST")) {
  		option_name = mg_get_var(conn, "o");
  		option_value = mg_get_var(conn, "v");
  		if (mg_set_option(conn->ctx,
  		    option_name, option_value) == -1) {
  			(void) mg_printf(conn,
  			    "<p style=\"background: red\">Error setting "
  			    "option \"%s\"</p>",
  			    option_name ? option_name : "(null)");
  		} else {
  			(void) mg_printf(conn,
  			    "<p style=\"color: green\">Saved: %s=%s</p>",
  			    option_name, option_value ? option_value : "NULL");
  		}
  	}
  
  	/* Print table with all options */
  	(void) mg_printf(conn, "%s", "<table border=\"1\""
  			"<tr><th>Option</th><th>Description</th>"
  					"<th colspan=2>Value</th></tr>");
  
  	for (option = known_options; option->name != NULL; option++) {
  		option_value = mg_get_option(conn->ctx, option->name);
  		if (option_value == NULL)
  			option_value = "";
  		(void) mg_printf(conn,
  		    "<form method=post><tr><td>%s</td><td>%s</td>"
  		    "<input type=hidden name=o value='%s'>"
  		    "<td><input type=text name=v value='%s'></td>"
  		    "<td><input type=submit value=save></td></form></tr>",
  		    option->name, option->description,
  		    option->name, option_value);
  	}
  
  	(void) mg_printf(conn, "%s", "</table></body></html>");
  }
  
  static void
  reset_per_request_attributes(struct mg_connection *conn)
  {
  	if (conn->request_info.remote_user != NULL) {
  		free((void *) conn->request_info.remote_user);
  		conn->request_info.remote_user = NULL;
  	}
  	if (conn->free_post_data && conn->request_info.post_data != NULL) {
  		free((void *) conn->request_info.post_data);
  		conn->request_info.post_data = NULL;
  	}
  }
  
  static void
  close_socket_gracefully(struct mg_connection *conn, SOCKET sock)
  {
  	char	buf[BUFSIZ];
  	int	n;
  
  	/* Send FIN to the client */
  	(void) shutdown(sock, SHUT_WR);
  	set_non_blocking_mode(conn, sock);
  
  	/*
  	 * Read and discard pending data. If we do not do that and close the
  	 * socket, the data in the send buffer may be discarded. This
  	 * behaviour is seen on Windows, when client keeps sending data
  	 * when server decide to close the connection; then when client
  	 * does recv() it gets no data back.
  	 */
  	do {
  		n = pull(NULL, sock, NULL, buf, sizeof(buf));
  	} while (n > 0);
  
  	/* Now we know that our FIN is ACK-ed, safe to close */
  	(void) closesocket(sock);
  }
  
  static void
  close_connection(struct mg_connection *conn)
  {
  	reset_per_request_attributes(conn);
  
  	if (conn->ssl)
  		SSL_free(conn->ssl);
  
  	if (conn->client.sock != INVALID_SOCKET)
  		close_socket_gracefully(conn, conn->client.sock);
  }
  
  static void
  reset_connection_attributes(struct mg_connection *conn)
  {
  	reset_per_request_attributes(conn);
  	conn->free_post_data = FALSE;
  	conn->request_info.status_code = -1;
  	conn->num_bytes_sent = 0;
  	(void) memset(&conn->request_info, 0, sizeof(conn->request_info));
  }
  
  static void
  shift_to_next(struct mg_connection *conn, char *buf, int req_len, int *nread)
  {
  	uint64_t	cl;
  	int		over_len, body_len;
  
  	cl = get_content_length(conn);
  	over_len = *nread - req_len;
  	assert(over_len >= 0);
  
  	if (cl == UNKNOWN_CONTENT_LENGTH) {
  		body_len = 0;
  	} else if (cl < (uint64_t) over_len) {
  		body_len = (int) cl;
  	} else {
  		body_len = over_len;
  	}
  
  	*nread -= req_len + body_len;
  	(void) memmove(buf, buf + req_len + body_len, *nread);
  }
  
  static void
  process_new_connection(struct mg_connection *conn)
  {
  	struct mg_request_info *ri = &conn->request_info;
  	char	buf[MAX_REQUEST_SIZE];
  	int	request_len, nread;
  
  	nread = 0;
  	reset_connection_attributes(conn);
  
  	/* If next request is not pipelined, read it in */
  	if ((request_len = get_request_len(buf, (size_t) nread)) == 0)
  		request_len = read_request(NULL, conn->client.sock,
  		    conn->ssl, buf, sizeof(buf), &nread);
  	assert(nread >= request_len);
  
  	if (request_len <= 0)
  		return;	/* Remote end closed the connection */
  
  	/* 0-terminate the request: parse_request uses sscanf */
  	buf[request_len - 1] = '\0';
  
  	if (parse_http_request(buf, ri, &conn->client.rsa)) {
  		if (ri->http_version_major != 1 ||
  		    (ri->http_version_major == 1 &&
  		    (ri->http_version_minor < 0 ||
  		    ri->http_version_minor > 1))) {
  			send_error(conn, 505,
  			    "HTTP version not supported",
  			    "%s", "Weird HTTP version");
  			log_access(conn);
  		} else {
  			ri->post_data = buf + request_len;
  			ri->post_data_len = nread - request_len;
  			conn->birth_time = time(NULL);
  			analyze_request(conn);
  			log_access(conn);
  			shift_to_next(conn, buf, request_len, &nread);
  		}
  	} else {
  		/* Do not put garbage in the access log */
  		send_error(conn, 400, "Bad Request",
  		    "Can not parse request: [%.*s]", nread, buf);
  	}
  
  }
  
  /*
   * Worker threads take accepted socket from the queue
   */
  static bool_t
  get_socket(struct mg_context *ctx, struct socket *sp)
  {
  	struct timespec	ts;
  
  	(void) pthread_mutex_lock(&ctx->thr_mutex);
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p: going idle",
  	    __func__, (void *) pthread_self()));
  
  	/* If the queue is empty, wait. We're idle at this point. */
  	ctx->num_idle++;
  	while (ctx->sq_head == ctx->sq_tail) {
  		ts.tv_nsec = 0;
  		ts.tv_sec = time(NULL) + atoi(ctx->options[OPT_IDLE_TIME]) + 1;
  		if (pthread_cond_timedwait(&ctx->empty_cond,
  		    &ctx->thr_mutex, &ts) != 0) {
  			/* Timeout! release the mutex and return */
  			(void) pthread_mutex_unlock(&ctx->thr_mutex);
  			return (FALSE);
  		}
  	}
  	assert(ctx->sq_head > ctx->sq_tail);
  
  	/* We're going busy now: got a socket to process! */
  	ctx->num_idle--;
  
  	/* Copy socket from the queue and increment tail */
  	*sp = ctx->queue[ctx->sq_tail % ARRAY_SIZE(ctx->queue)];
  	ctx->sq_tail++;
  	DEBUG_TRACE((DEBUG_MGS_PREFIX
  	    "%s: thread %p grabbed socket %d, going busy",
  	    __func__, (void *) pthread_self(), sp->sock));
  
  	/* Wrap pointers if needed */
  	while (ctx->sq_tail > (int) ARRAY_SIZE(ctx->queue)) {
  		ctx->sq_tail -= ARRAY_SIZE(ctx->queue);
  		ctx->sq_head -= ARRAY_SIZE(ctx->queue);
  	}
  
  	pthread_cond_signal(&ctx->full_cond);
  	(void) pthread_mutex_unlock(&ctx->thr_mutex);
  
  	return (TRUE);
  }
  
  static void
  worker_thread(struct mg_context *ctx)
  {
  	struct mg_connection	conn;
  
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p starting",
  	    __func__, (void *) pthread_self()));
  
  	(void) memset(&conn, 0, sizeof(conn));
  
  	while (get_socket(ctx, &conn.client) == TRUE) {
  		conn.birth_time = time(NULL);
  		conn.ctx = ctx;
  
  		if (conn.client.is_ssl &&
  		    (conn.ssl = SSL_new(conn.ctx->ssl_ctx)) == NULL) {
  			cry(&conn, "%s: SSL_new: %d", __func__, ERRNO);
  		} else if (conn.client.is_ssl &&
  		    SSL_set_fd(conn.ssl, conn.client.sock) != 1) {
  			cry(&conn, "%s: SSL_set_fd: %d", __func__, ERRNO);
  		} else if (conn.client.is_ssl && SSL_accept(conn.ssl) != 1) {
  			cry(&conn, "%s: SSL handshake error", __func__);
  		} else {
  			process_new_connection(&conn);
  		}
  
  		close_connection(&conn);
  	}
  
  	/* Signal master that we're done with connection and exiting */
  	pthread_mutex_lock(&conn.ctx->thr_mutex);
  	conn.ctx->num_threads--;
  	conn.ctx->num_idle--;
  	pthread_cond_signal(&conn.ctx->thr_cond);
  	assert(conn.ctx->num_threads >= 0);
  	pthread_mutex_unlock(&conn.ctx->thr_mutex);
  
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p exiting",
  	    __func__, (void *) pthread_self()));
  }
  
  /*
   * Master thread adds accepted socket to a queue
   */
  static void
  put_socket(struct mg_context *ctx, const struct socket *sp)
  {
  	(void) pthread_mutex_lock(&ctx->thr_mutex);
  
  	/* If the queue is full, wait */
  	while (ctx->sq_head - ctx->sq_tail >= (int) ARRAY_SIZE(ctx->queue))
  		(void) pthread_cond_wait(&ctx->full_cond, &ctx->thr_mutex);
  	assert(ctx->sq_head - ctx->sq_tail < (int) ARRAY_SIZE(ctx->queue));
  
  	/* Copy socket to the queue and increment head */
  	ctx->queue[ctx->sq_head % ARRAY_SIZE(ctx->queue)] = *sp;
  	ctx->sq_head++;
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: queued socket %d",
  	    __func__, sp->sock));
  
  	/* If there are no idle threads, start one */
  	if (ctx->num_idle == 0 && ctx->num_threads < ctx->max_threads) {
  		if (start_thread(ctx,
  		    (mg_thread_func_t) worker_thread, ctx) != 0)
  			cry(fc(ctx), "Cannot start thread: %d", ERRNO);
  		else
  			ctx->num_threads++;
  	}
  
  	pthread_cond_signal(&ctx->empty_cond);
  	(void) pthread_mutex_unlock(&ctx->thr_mutex);
  }
  
  static void
  accept_new_connection(const struct socket *listener, struct mg_context *ctx)
  {
  	struct socket		accepted;
  
  	accepted.rsa.len = sizeof(accepted.rsa.u.sin);
  	accepted.lsa = listener->lsa;
  	if ((accepted.sock = accept(listener->sock,
  	    &accepted.rsa.u.sa, &accepted.rsa.len)) == INVALID_SOCKET)
  		return;
  
  	lock_option(ctx, OPT_ACL);
  	if (ctx->options[OPT_ACL] != NULL &&
  	    !check_acl(ctx, ctx->options[OPT_ACL], &accepted.rsa)) {
  		cry(fc(ctx), "%s: %s is not allowed to connect",
  		    __func__, inet_ntoa(accepted.rsa.u.sin.sin_addr));
  		(void) closesocket(accepted.sock);
  		unlock_option(ctx, OPT_ACL);
  		return;
  	}
  	unlock_option(ctx, OPT_ACL);
  
  	/* Put accepted socket structure into the queue */
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: accepted socket %d",
  	    __func__, accepted.sock));
  	accepted.is_ssl = listener->is_ssl;
  	put_socket(ctx, &accepted);
  }
  
  static void
  master_thread(struct mg_context *ctx)
  {
  	fd_set		read_set;
  	struct timeval	tv;
  	int		i, max_fd;
  
  	while (ctx->stop_flag == 0) {
  		FD_ZERO(&read_set);
  		max_fd = -1;
  
  		/* Add listening sockets to the read set */
  		lock_option(ctx, OPT_PORTS);
  		for (i = 0; i < ctx->num_listeners; i++)
  			add_to_set(ctx->listeners[i].sock, &read_set, &max_fd);
  		unlock_option(ctx, OPT_PORTS);
  
  		tv.tv_sec = 1;
  		tv.tv_usec = 0;
  
  		if (select(max_fd + 1, &read_set, NULL, NULL, &tv) < 0) {
  #ifdef _WIN32
  			/*
  			 * On windows, if read_set and write_set are empty,
  			 * select() returns "Invalid parameter" error
  			 * (at least on my Windows XP Pro). So in this case,
  			 * we sleep here.
  			 */
  			sleep(1);
  #endif /* _WIN32 */
  		} else {
  			lock_option(ctx, OPT_PORTS);
  			for (i = 0; i < ctx->num_listeners; i++)
  				if (FD_ISSET(ctx->listeners[i].sock, &read_set))
  					accept_new_connection(
  					    ctx->listeners + i, ctx);
  			unlock_option(ctx, OPT_PORTS);
  		}
  	}
  
  	/* Stop signal received: somebody called mg_stop. Quit. */
  	mg_fini(ctx);
  }
  
  void
  mg_stop(struct mg_context *ctx)
  {
  	ctx->stop_flag = 1;
  
  	/* Wait until mg_fini() stops */
  	while (ctx->stop_flag != 2)
  		(void) sleep(1);
  
  	assert(ctx->num_threads == 0);
  	free(ctx);
  
  #if defined(_WIN32)
  	(void) WSACleanup();
  #endif /* _WIN32 */
  }
  
  struct mg_context *
  mg_start(void)
  {
  	struct mg_context	*ctx;
  	const struct mg_option	*option;
  	char			web_root[FILENAME_MAX];
  	int			i;
  
  #if defined(_WIN32)
  	WSADATA data;
  	WSAStartup(MAKEWORD(2,2), &data);
  #endif /* _WIN32 */
  
  	if ((ctx = (struct mg_context *) calloc(1, sizeof(*ctx))) == NULL) {
  		cry(fc(ctx), "cannot allocate mongoose context");
  		return (NULL);
  	}
  
  	ctx->error_log = stderr;
  	mg_set_log_callback(ctx, builtin_error_log);
  
  	/* Initialize options. First pass: set default option values */
  	for (option = known_options; option->name != NULL; option++)
  		ctx->options[option->index] = option->default_value == NULL ?
  			NULL : mg_strdup(option->default_value);
  
  	/* Call setter functions */
  	for (option = known_options; option->name != NULL; option++)
  		if (option->setter != NULL &&
  		    ctx->options[option->index] != NULL)
  			if (option->setter(ctx,
  			    ctx->options[option->index]) == FALSE) {
  				mg_fini(ctx);
  				return (NULL);
  			}
  
  	/* Initial document root is set to current working directory */
  	if (ctx->options[OPT_ROOT] == NULL) {
  		if (mg_getcwd(web_root, sizeof(web_root)) == NULL) {
  			cry(fc(ctx), "%s: getcwd: %s",
  			    __func__, strerror(errno));
  			mg_strlcpy(web_root, ".", sizeof(web_root));
  		}
  		ctx->options[OPT_ROOT] = mg_strdup(web_root);
  	}
  
  	DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: root [%s]",
  	    __func__, ctx->options[OPT_ROOT]));
  
  #if !defined(_WIN32)
  	/*
  	 * Ignore SIGPIPE signal, so if browser cancels the request, it
  	 * won't kill the whole process.
  	 */
  	(void) signal(SIGPIPE, SIG_IGN);
  #endif /* _WIN32 */
  
  	/* Initialize options mutexes */
  	for (i = 0; i < NUM_OPTIONS; i++)
  		(void) pthread_mutex_init(&ctx->opt_mutex[i], NULL);
  
  	(void) pthread_mutex_init(&ctx->thr_mutex, NULL);
  	(void) pthread_mutex_init(&ctx->bind_mutex, NULL);
  	(void) pthread_cond_init(&ctx->thr_cond, NULL);
  	(void) pthread_cond_init(&ctx->empty_cond, NULL);
  	(void) pthread_cond_init(&ctx->full_cond, NULL);
  
  	/* Start master (listening) thread */
  	start_thread(ctx, (mg_thread_func_t) master_thread, ctx);
  
  	return (ctx);
  }
  