text: /*-
   * Copyright (c) 1990, 1993, 1994
   *	The Regents of the University of California.  All rights reserved.
   *
   * %sccs.include.redist.c%
   */
  
  #ifndef lint
  static char copyright[] =
  "@(#) Copyright (c) 1990, 1993, 1994\n\
  	The Regents of the University of California.  All rights reserved.\n";
  #endif /* not lint */
  
  #ifndef lint
  static char sccsid[] = "@(#)mail.local.c	8.22 (Berkeley) 06/21/95";
  #endif /* not lint */
  
  /*
   * This is not intended to compile on System V derived systems
   * such as Solaris or HP-UX, since they use a totally different
   * approach to mailboxes (essentially, they have a setgid program
   * rather than setuid, and they rely on the ability to "give away"
   * files to do their work).  IT IS NOT A BUG that this doesn't
   * compile on such architectures.
   */
  
  #include <sys/param.h>
  #include <sys/stat.h>
  #include <sys/socket.h>
  
  #include <netinet/in.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <netdb.h>
  #include <pwd.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sysexits.h>
  #include <syslog.h>
  #include <time.h>
  #include <unistd.h>
  #include <ctype.h>
  
  #if __STDC__
  #include <stdarg.h>
  #else
  #include <varargs.h>
  #endif
  
  #ifndef LOCK_EX
  # include <sys/file.h>
  #endif
  
  #ifdef BSD4_4
  # include "pathnames.h"
  #endif
  
  #ifndef __P
  # ifdef __STDC__
  #  define __P(protos)	protos
  # else
  #  define __P(protos)	()
  #  define const
  # endif
  #endif
  #ifndef __dead
  # if defined(__GNUC__) && (__GNUC__ < 2 || __GNUC_MINOR__ < 5) && !defined(__STRICT_ANSI__)
  #  define __dead	__volatile
  # else
  #  define __dead
  # endif
  #endif
  
  #ifndef BSD4_4
  # define _BSD_VA_LIST_	va_list
  extern char	*strerror __P((int));
  extern int	snprintf __P((char *, int, const char *, ...));
  #endif
  
  /*
   * If you don't have setreuid, and you have saved uids, and you have
   * a seteuid() call that doesn't try to emulate using setuid(), then
   * you can try defining USE_SETEUID.
   */
  #ifdef USE_SETEUID
  # define setreuid(r, e)		seteuid(e)
  #endif
  
  #ifndef _PATH_LOCTMP
  # define _PATH_LOCTMP	"/tmp/local.XXXXXX"
  #endif
  #ifndef _PATH_MAILDIR
  # define _PATH_MAILDIR	"/var/spool/mail"
  #endif
  
  #ifndef S_ISREG
  # define S_ISREG(mode)	(((mode) & _S_IFMT) == S_IFREG)
  #endif
  
  int eval = EX_OK;			/* sysexits.h error value. */
  
  void		deliver __P((int, char *));
  void		e_to_sys __P((int));
  __dead void	err __P((const char *, ...));
  void		notifybiff __P((char *));
  int		store __P((char *));
  void		usage __P((void));
  void		vwarn __P((const char *, _BSD_VA_LIST_));
  void		warn __P((const char *, ...));
  
  int
  main(argc, argv)
  	int argc;
  	char *argv[];
  {
  	struct passwd *pw;
  	int ch, fd;
  	uid_t uid;
  	char *from;
  	extern char *optarg;
  	extern int optind;
  
  	/* make sure we have some open file descriptors */
  	for (fd = 10; fd < 30; fd++)
  		(void) close(fd);
  
  	/* use a reasonable umask */
  	(void) umask(0077);
  
  #ifdef LOG_MAIL
  	openlog("mail.local", 0, LOG_MAIL);
  #else
  	openlog("mail.local", 0);
  #endif
  
  	from = NULL;
  	while ((ch = getopt(argc, argv, "df:r:")) != EOF)
  		switch(ch) {
  		case 'd':		/* Backward compatible. */
  			break;
  		case 'f':
  		case 'r':		/* Backward compatible. */
  			if (from != NULL) {
  				warn("multiple -f options");
  				usage();
  			}
  			from = optarg;
  			break;
  		case '?':
  		default:
  			usage();
  		}
  	argc -= optind;
  	argv += optind;
  
  	if (!*argv)
  		usage();
  
  	/*
  	 * If from not specified, use the name from getlogin() if the
  	 * uid matches, otherwise, use the name from the password file
  	 * corresponding to the uid.
  	 */
  	uid = getuid();
  	if (!from && (!(from = getlogin()) ||
  	    !(pw = getpwnam(from)) || pw->pw_uid != uid))
  		from = (pw = getpwuid(uid)) ? pw->pw_name : "???";
  
  	/*
  	 * There is no way to distinguish the error status of one delivery
  	 * from the rest of the deliveries.  So, if we failed hard on one
  	 * or more deliveries, but had no failures on any of the others, we
  	 * return a hard failure.  If we failed temporarily on one or more
  	 * deliveries, we return a temporary failure regardless of the other
  	 * failures.  This results in the delivery being reattempted later
  	 * at the expense of repeated failures and multiple deliveries.
  	 */
  	for (fd = store(from); *argv; ++argv)
  		deliver(fd, *argv);
  	exit(eval);
  }
  
  int
  store(from)
  	char *from;
  {
  	FILE *fp;
  	time_t tval;
  	int fd, eline;
  	char line[2048];
  	char tmpbuf[sizeof _PATH_LOCTMP + 1];
  
  	strcpy(tmpbuf, _PATH_LOCTMP);
  	if ((fd = mkstemp(tmpbuf)) == -1 || (fp = fdopen(fd, "w+")) == NULL) {
  		e_to_sys(errno);
  		err("unable to open temporary file");
  	}
  	(void)unlink(tmpbuf);
  
  	(void)time(&tval);
  	(void)fprintf(fp, "From %s %s", from, ctime(&tval));
  
  	line[0] = '\0';
  	for (eline = 1; fgets(line, sizeof(line), stdin);) {
  		if (line[0] == '\n')
  			eline = 1;
  		else {
  			if (eline && line[0] == 'F' &&
  			    !memcmp(line, "From ", 5))
  				(void)putc('>', fp);
  			eline = 0;
  		}
  		(void)fprintf(fp, "%s", line);
  		if (ferror(fp)) {
  			e_to_sys(errno);
  			err("temporary file write error");
  		}
  	}
  
  	/* If message not newline terminated, need an extra. */
  	if (!strchr(line, '\n'))
  		(void)putc('\n', fp);
  	/* Output a newline; note, empty messages are allowed. */
  	(void)putc('\n', fp);
  
  	if (fflush(fp) == EOF || ferror(fp)) {
  		e_to_sys(errno);
  		err("temporary file write error");
  	}
  	return (fd);
  }
  
  void
  deliver(fd, name)
  	int fd;
  	char *name;
  {
  	struct stat fsb, sb;
  	struct passwd *pw;
  	int mbfd, nr, nw, off;
  	char *p;
  	char biffmsg[100], buf[8*1024], path[MAXPATHLEN];
  	off_t curoff;
  
  	/*
  	 * Disallow delivery to unknown names -- special mailboxes can be
  	 * handled in the sendmail aliases file.
  	 */
  	if (!(pw = getpwnam(name))) {
  		if (eval != EX_TEMPFAIL)
  			eval = EX_UNAVAILABLE;
  		warn("unknown name: %s", name);
  		return;
  	}
  	endpwent();
  
  	/*
  	 * Keep name reasonably short to avoid buffer overruns.
  	 *	This isn't necessary on BSD because of the proper
  	 *	definition of snprintf(), but it can cause problems
  	 *	on other systems.
  	 * Also, clear out any bogus characters.
  	 */
  
  	if (strlen(name) > 40)
  		name[40] = '\0';
  	for (p = name; *p != '\0'; p++)
  	{
  		if (!isascii(*p))
  			*p &= 0x7f;
  		else if (!isprint(*p))
  			*p = '.';
  	}
  
  	(void)snprintf(path, sizeof(path), "%s/%s", _PATH_MAILDIR, name);
  
  	/*
  	 * If the mailbox is linked or a symlink, fail.  There's an obvious
  	 * race here, that the file was replaced with a symbolic link after
  	 * the lstat returned, but before the open.  We attempt to detect
  	 * this by comparing the original stat information and information
  	 * returned by an fstat of the file descriptor returned by the open.
  	 *
  	 * NB: this is a symptom of a larger problem, that the mail spooling
  	 * directory is writeable by the wrong users.  If that directory is
  	 * writeable, system security is compromised for other reasons, and
  	 * it cannot be fixed here.
  	 *
  	 * If we created the mailbox, set the owner/group.  If that fails,
  	 * just return.  Another process may have already opened it, so we
  	 * can't unlink it.  Historically, binmail set the owner/group at
  	 * each mail delivery.  We no longer do this, assuming that if the
  	 * ownership or permissions were changed there was a reason.
  	 *
  	 * XXX
  	 * open(2) should support flock'ing the file.
  	 */
  tryagain:
  	lockmbox(path);
  	if (lstat(path, &sb)) {
  		mbfd = open(path,
  		    O_APPEND|O_CREAT|O_EXCL|O_WRONLY, S_IRUSR|S_IWUSR);
  		if (mbfd == -1) {
  			if (errno == EEXIST)
  				goto tryagain;
  		} else if (fchown(mbfd, pw->pw_uid, pw->pw_gid)) {
  			e_to_sys(errno);
  			warn("chown %u.%u: %s", pw->pw_uid, pw->pw_gid, name);
  			goto err1;
  		}
  	} else if (sb.st_nlink != 1 || !S_ISREG(sb.st_mode)) {
  		e_to_sys(errno);
  		warn("%s: irregular file", path);
  		goto err0;
  	} else if (sb.st_uid != pw->pw_uid) {
  		warn("%s: wrong ownership (%d)", path, sb.st_uid);
  		unlockmbox();
  		return;
  	} else {
  		mbfd = open(path, O_APPEND|O_WRONLY, 0);
  		if (mbfd != -1 &&
  		    (fstat(mbfd, &fsb) || fsb.st_nlink != 1 ||
  		    !S_ISREG(fsb.st_mode) || sb.st_dev != fsb.st_dev ||
  		    sb.st_ino != fsb.st_ino || sb.st_uid != fsb.st_uid)) {
  			warn("%s: file changed after open", path);
  			goto err1;
  		}
  	}
  
  	if (mbfd == -1) {
  		e_to_sys(errno);
  		warn("%s: %s", path, strerror(errno));
  		goto err0;
  	}
  
  	/* Wait until we can get a lock on the file. */
  	if (flock(mbfd, LOCK_EX)) {
  		e_to_sys(errno);
  		warn("%s: %s", path, strerror(errno));
  		goto err1;
  	}
  
  	/* Get the starting offset of the new message for biff. */
  	curoff = lseek(mbfd, (off_t)0, SEEK_END);
  	(void)snprintf(biffmsg, sizeof(biffmsg),
  		sizeof curoff > sizeof(long) ? "%s@%qd\n" : "%s@%ld\n", 
  		name, curoff);
  
  	/* Copy the message into the file. */
  	if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
  		e_to_sys(errno);
  		warn("temporary file: %s", strerror(errno));
  		goto err1;
  	}
  	if (setreuid(0, pw->pw_uid) < 0) {
  		e_to_sys(errno);
  		warn("setreuid(0, %d): %s (r=%d, e=%d)",
  		     pw->pw_uid, strerror(errno), getuid(), geteuid());
  		goto err1;
  	}
  #ifdef DEBUG
  	printf("new euid = %d\n", geteuid());
  #endif
  	while ((nr = read(fd, buf, sizeof(buf))) > 0)
  		for (off = 0; off < nr; off += nw)
  			if ((nw = write(mbfd, buf + off, nr - off)) < 0) {
  				e_to_sys(errno);
  				warn("%s: %s", path, strerror(errno));
  				goto err3;
  			}
  	if (nr < 0) {
  		e_to_sys(errno);
  		warn("temporary file: %s", strerror(errno));
  		goto err3;
  	}
  
  	/* Flush to disk, don't wait for update. */
  	if (fsync(mbfd)) {
  		e_to_sys(errno);
  		warn("%s: %s", path, strerror(errno));
  err3:
  		if (setreuid(0, 0) < 0) {
  			e_to_sys(errno);
  			warn("setreuid(0, 0): %s", strerror(errno));
  		}
  #ifdef DEBUG
  		printf("reset euid = %d\n", geteuid());
  #endif
  err2:		(void)ftruncate(mbfd, curoff);
  err1:		(void)close(mbfd);
  err0:		unlockmbox();
  		return;
  	}
  		
  	/* Close and check -- NFS doesn't write until the close. */
  	if (close(mbfd)) {
  		e_to_sys(errno);
  		warn("%s: %s", path, strerror(errno));
  		unlockmbox();
  		return;
  	}
  
  	if (setreuid(0, 0) < 0) {
  		e_to_sys(errno);
  		warn("setreuid(0, 0): %s", strerror(errno));
  	}
  #ifdef DEBUG
  	printf("reset euid = %d\n", geteuid());
  #endif
  	unlockmbox();
  	notifybiff(biffmsg);
  }
  
  /*
   * user.lock files are necessary for compatibility with other
   * systems, e.g., when the mail spool file is NFS exported.
   * Alas, mailbox locking is more than just a local matter.
   * EPA 11/94.
   */
  
  char	lockname[MAXPATHLEN];
  int	locked = 0;
  
  lockmbox(path)
  	char *path;
  {
  	int statfailed = 0;
  
  	if (locked)
  		return;
  	sprintf(lockname, "%s.lock", path);
  	for (;; sleep(5)) {
  		int fd;
  		struct stat st;
  		time_t now;
  
  		fd = open(lockname, O_WRONLY|O_EXCL|O_CREAT, 0);
  		if (fd >= 0) {
  			locked = 1;
  			close(fd);
  			return;
  		}
  		if (stat(lockname, &st) < 0) {
  			if (statfailed++ > 5)
  				return;
  			continue;
  		}
  		statfailed = 0;
  		time(&now);
  		if (now < st.st_ctime + 300)
  			continue;
  		unlink(lockname);
  	}
  }
  
  unlockmbox()
  {
  	if (!locked)
  		return;
  	unlink(lockname);
  	locked = 0;
  }
  
  void
  notifybiff(msg)
  	char *msg;
  {
  	static struct sockaddr_in addr;
  	static int f = -1;
  	struct hostent *hp;
  	struct servent *sp;
  	int len;
  
  	if (!addr.sin_family) {
  		/* Be silent if biff service not available. */
  		if (!(sp = getservbyname("biff", "udp")))
  			return;
  		if (!(hp = gethostbyname("localhost"))) {
  			warn("localhost: %s", strerror(errno));
  			return;
  		}
  		addr.sin_family = hp->h_addrtype;
  		memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
  		addr.sin_port = sp->s_port;
  	}
  	if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
  		warn("socket: %s", strerror(errno));
  		return;
  	}
  	len = strlen(msg) + 1;
  	if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr))
  	    != len)
  		warn("sendto biff: %s", strerror(errno));
  }
  
  void
  usage()
  {
  	eval = EX_USAGE;
  	err("usage: mail.local [-f from] user ...");
  }
  
  #if __STDC__
  void
  err(const char *fmt, ...)
  #else
  void
  err(fmt, va_alist)
  	const char *fmt;
  	va_dcl
  #endif
  {
  	va_list ap;
  
  #if __STDC__
  	va_start(ap, fmt);
  #else
  	va_start(ap);
  #endif
  	vwarn(fmt, ap);
  	va_end(ap);
  
  	exit(eval);
  }
  
  void
  #if __STDC__
  warn(const char *fmt, ...)
  #else
  warn(fmt, va_alist)
  	const char *fmt;
  	va_dcl
  #endif
  {
  	va_list ap;
  
  #if __STDC__
  	va_start(ap, fmt);
  #else
  	va_start(ap);
  #endif
  	vwarn(fmt, ap);
  	va_end(ap);
  }
  
  void
  vwarn(fmt, ap)
  	const char *fmt;
  	_BSD_VA_LIST_ ap;
  {
  	/*
  	 * Log the message to stderr.
  	 *
  	 * Don't use LOG_PERROR as an openlog() flag to do this,
  	 * it's not portable enough.
  	 */
  	if (eval != EX_USAGE)
  		(void)fprintf(stderr, "mail.local: ");
  	(void)vfprintf(stderr, fmt, ap);
  	(void)fprintf(stderr, "\n");
  
  #if !defined(ultrix) && !defined(__osf__)
  	/* Log the message to syslog. */
  	vsyslog(LOG_ERR, fmt, ap);
  #else
  	{
  		char fmtbuf[10240];
  
  		(void) sprintf(fmtbuf, fmt, ap);
  		syslog(LOG_ERR, "%s", fmtbuf);
  	}
  #endif
  }
  
  /*
   * e_to_sys --
   *	Guess which errno's are temporary.  Gag me.
   */
  void
  e_to_sys(num)
  	int num;
  {
  	/* Temporary failures override hard errors. */
  	if (eval == EX_TEMPFAIL)
  		return;
  
  	switch(num) {		/* Hopefully temporary errors. */
  #ifdef EAGAIN
  	case EAGAIN:		/* Resource temporarily unavailable */
  #endif
  #ifdef EDQUOT
  	case EDQUOT:		/* Disc quota exceeded */
  #endif
  #ifdef EBUSY
  	case EBUSY:		/* Device busy */
  #endif
  #ifdef EPROCLIM
  	case EPROCLIM:		/* Too many processes */
  #endif
  #ifdef EUSERS
  	case EUSERS:		/* Too many users */
  #endif
  #ifdef ECONNABORTED
  	case ECONNABORTED:	/* Software caused connection abort */
  #endif
  #ifdef ECONNREFUSED
  	case ECONNREFUSED:	/* Connection refused */
  #endif
  #ifdef ECONNRESET
  	case ECONNRESET:	/* Connection reset by peer */
  #endif
  #ifdef EDEADLK
  	case EDEADLK:		/* Resource deadlock avoided */
  #endif
  #ifdef EFBIG
  	case EFBIG:		/* File too large */
  #endif
  #ifdef EHOSTDOWN
  	case EHOSTDOWN:		/* Host is down */
  #endif
  #ifdef EHOSTUNREACH
  	case EHOSTUNREACH:	/* No route to host */
  #endif
  #ifdef EMFILE
  	case EMFILE:		/* Too many open files */
  #endif
  #ifdef ENETDOWN
  	case ENETDOWN:		/* Network is down */
  #endif
  #ifdef ENETRESET
  	case ENETRESET:		/* Network dropped connection on reset */
  #endif
  #ifdef ENETUNREACH
  	case ENETUNREACH:	/* Network is unreachable */
  #endif
  #ifdef ENFILE
  	case ENFILE:		/* Too many open files in system */
  #endif
  #ifdef ENOBUFS
  	case ENOBUFS:		/* No buffer space available */
  #endif
  #ifdef ENOMEM
  	case ENOMEM:		/* Cannot allocate memory */
  #endif
  #ifdef ENOSPC
  	case ENOSPC:		/* No space left on device */
  #endif
  #ifdef EROFS
  	case EROFS:		/* Read-only file system */
  #endif
  #ifdef ESTALE
  	case ESTALE:		/* Stale NFS file handle */
  #endif
  #ifdef ETIMEDOUT
  	case ETIMEDOUT:		/* Connection timed out */
  #endif
  #if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN && EWOULDBLOCK != EDEADLK
  	case EWOULDBLOCK:	/* Operation would block. */
  #endif
  		eval = EX_TEMPFAIL;
  		break;
  	default:
  		eval = EX_UNAVAILABLE;
  		break;
  	}
  }
  
  #ifndef BSD4_4
  
  # ifndef __osf__
  char *
  strerror(eno)
  	int eno;
  {
  	extern int sys_nerr;
  	extern char *sys_errlist[];
  	static char ebuf[60];
  
  	if (eno >= 0 && eno <= sys_nerr)
  		return sys_errlist[eno];
  	(void) sprintf(ebuf, "Error %d", eno);
  	return ebuf;
  }
  # endif
  
  # if __STDC__
  snprintf(char *buf, int bufsiz, const char *fmt, ...)
  # else
  snprintf(buf, bufsiz, fmt, va_alist)
  	char *buf;
  	int bufsiz;
  	const char *fmt;
  	va_dcl
  # endif
  {
  	va_list ap;
  
  # if __STDC__
  	va_start(ap, fmt);
  # else
  	va_start(ap);
  # endif
  	vsprintf(buf, fmt, ap);
  	va_end(ap);
  }
  
  #endif
  
  #ifdef ultrix
  
  /*
   * Copyright (c) 1987, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the University of
   *	California, Berkeley and its contributors.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #if defined(LIBC_SCCS) && !defined(lint)
  static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
  #endif /* LIBC_SCCS and not lint */
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <errno.h>
  #include <stdio.h>
  #include <ctype.h>
  
  static int _gettemp();
  
  mkstemp(path)
  	char *path;
  {
  	int fd;
  
  	return (_gettemp(path, &fd) ? fd : -1);
  }
  
  /*
  char *
  mktemp(path)
  	char *path;
  {
  	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
  }
  */
  
  static
  _gettemp(path, doopen)
  	char *path;
  	register int *doopen;
  {
  	extern int errno;
  	register char *start, *trv;
  	struct stat sbuf;
  	u_int pid;
  
  	pid = getpid();
  	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
  	while (*--trv == 'X') {
  		*trv = (pid % 10) + '0';
  		pid /= 10;
  	}
  
  	/*
  	 * check the target directory; if you have six X's and it
  	 * doesn't exist this runs for a *very* long time.
  	 */
  	for (start = trv + 1;; --trv) {
  		if (trv <= path)
  			break;
  		if (*trv == '/') {
  			*trv = '\0';
  			if (stat(path, &sbuf))
  				return(0);
  			if (!S_ISDIR(sbuf.st_mode)) {
  				errno = ENOTDIR;
  				return(0);
  			}
  			*trv = '/';
  			break;
  		}
  	}
  
  	for (;;) {
  		if (doopen) {
  			if ((*doopen =
  			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
  				return(1);
  			if (errno != EEXIST)
  				return(0);
  		}
  		else if (stat(path, &sbuf))
  			return(errno == ENOENT ? 1 : 0);
  
  		/* tricky little algorithm for backward compatibility */
  		for (trv = start;;) {
  			if (!*trv)
  				return(0);
  			if (*trv == 'z')
  				*trv++ = 'a';
  			else {
  				if (isdigit(*trv))
  					*trv = 'a';
  				else
  					++*trv;
  				break;
  			}
  		}
  	}
  	/*NOTREACHED*/
  }
  
  #endif
  