text: /* vi: set sw=4 ts=4: */
  /*
   * helper routines
   *
   * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   *
   * Licensed under GPLv2, see file LICENSE in this source tree.
   */
  #include "libbb.h"
  #include "mail.h"
  
  static void kill_helper(void)
  {
  	if (G.helper_pid > 0) {
  		kill(G.helper_pid, SIGTERM);
  		G.helper_pid = 0;
  	}
  }
  
  // generic signal handler
  static void signal_handler(int signo)
  {
  #define err signo
  	if (SIGALRM == signo) {
  		kill_helper();
  		bb_error_msg_and_die("timed out");
  	}
  
  	// SIGCHLD. reap zombies
  	if (safe_waitpid(G.helper_pid, &err, WNOHANG) > 0) {
  		if (WIFSIGNALED(err))
  			bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(err));
  		if (WIFEXITED(err)) {
  			G.helper_pid = 0;
  			if (WEXITSTATUS(err))
  				bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(err));
  		}
  	}
  #undef err
  }
  
  void FAST_FUNC launch_helper(const char **argv)
  {
  	// setup vanilla unidirectional pipes interchange
  	int i;
  	int pipes[4];
  
  	xpipe(pipes);
  	xpipe(pipes + 2);
  
  	// NB: handler must be installed before vfork
  	bb_signals(0
  		+ (1 << SIGCHLD)
  		+ (1 << SIGALRM)
  		, signal_handler);
  
  	G.helper_pid = xvfork();
  
  	i = (!G.helper_pid) * 2; // for parent:0, for child:2
  	close(pipes[i + 1]); // 1 or 3 - closing one write end
  	close(pipes[2 - i]); // 2 or 0 - closing one read end
  	xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end
  	xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - other write end
  
  	if (!G.helper_pid) {
  		// child: try to execute connection helper
  		// NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
  		BB_EXECVP_or_die((char**)argv);
  	}
  
  	// parent
  	// check whether child is alive
  	//redundant:signal_handler(SIGCHLD);
  	// child seems OK -> parent goes on
  	atexit(kill_helper);
  }
  
  char* FAST_FUNC send_mail_command(const char *fmt, const char *param)
  {
  	char *msg;
  	if (timeout)
  		alarm(timeout);
  	msg = (char*)fmt;
  	if (fmt) {
  		msg = xasprintf(fmt, param);
  		if (verbose)
  			bb_error_msg("send:'%s'", msg);
  		printf("%s\r\n", msg);
  	}
  	fflush_all();
  	return msg;
  }
  
  // NB: parse_url can modify url[] (despite const), but only if '@' is there
  /*
  static char* FAST_FUNC parse_url(char *url, char **user, char **pass)
  {
  	// parse [user[:pass]@]host
  	// return host
  	char *s = strchr(url, '@');
  	*user = *pass = NULL;
  	if (s) {
  		*s++ = '\0';
  		*user = url;
  		url = s;
  		s = strchr(*user, ':');
  		if (s) {
  			*s++ = '\0';
  			*pass = s;
  		}
  	}
  	return url;
  }
  */
  
  void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
  {
  	enum {
  		SRC_BUF_SIZE = 45,  /* This *MUST* be a multiple of 3 */
  		DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
  	};
  #define src_buf text
  	char src[SRC_BUF_SIZE];
  	FILE *fp = fp;
  	ssize_t len = len;
  	char dst_buf[DST_BUF_SIZE + 1];
  
  	if (fname) {
  		fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
  		src_buf = src;
  	} else if (text) {
  		// though we do not call uuencode(NULL, NULL) explicitly
  		// still we do not want to break things suddenly
  		len = strlen(text);
  	} else
  		return;
  
  	while (1) {
  		size_t size;
  		if (fname) {
  			size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
  			if ((ssize_t)size < 0)
  				bb_perror_msg_and_die(bb_msg_read_error);
  		} else {
  			size = len;
  			if (len > SRC_BUF_SIZE)
  				size = SRC_BUF_SIZE;
  		}
  		if (!size)
  			break;
  		// encode the buffer we just read in
  		bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
  		if (fname) {
  			printf("%s\n", eol);
  		} else {
  			src_buf += size;
  			len -= size;
  		}
  		fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
  	}
  	if (fname && NOT_LONE_DASH(fname))
  		fclose(fp);
  #undef src_buf
  }
  
  /*
   * get username and password from a file descriptor
   */
  void FAST_FUNC get_cred_or_die(int fd)
  {
  	if (isatty(fd)) {
  		G.user = xstrdup(bb_ask(fd, /* timeout: */ 0, "User: "));
  		G.pass = xstrdup(bb_ask(fd, /* timeout: */ 0, "Password: "));
  	} else {
  		G.user = xmalloc_reads(fd, /* maxsize: */ NULL);
  		G.pass = xmalloc_reads(fd, /* maxsize: */ NULL);
  	}
  	if (!G.user || !*G.user || !G.pass)
  		bb_error_msg_and_die("no username or password");
  }
  