dist/nvi/clib/mkstemp.c

   1 /*      $NetBSD$ */
   2
   3 /*
   4  * Copyright (c) 1987, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "config.h"
  37
  38 #if defined(LIBC_SCCS) && !defined(lint)
  39 static const char sccsid[] = "@(#)mktemp.c      8.1 (Berkeley) 6/4/93";
  40 #endif /* LIBC_SCCS and not lint */
  41
  42 #include <sys/types.h>
  43 #include <sys/stat.h>
  44 #include <fcntl.h>
  45 #include <errno.h>
  46 #include <stdio.h>
  47 #include <ctype.h>
  48
  49 static int _gettemp(char *path, register int *doopen);
  50
  51 /*
  52  * PUBLIC: #ifndef HAVE_MKSTEMP
  53  * PUBLIC: int mkstemp __P((char *));
  54  * PUBLIC: #endif
  55  */
  56 mkstemp(char *path)
  57 {
  58         int fd;
  59
  60         return (_gettemp(path, &fd) ? fd : -1);
  61 }
  62
  63 char *
  64 mktemp(char *path)
  65 {
  66         return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
  67 }
  68
  69 static
  70 _gettemp(char *path, register int *doopen)
  71 {
  72         extern int errno;
  73         register char *start, *trv;
  74         struct stat sbuf;
  75         u_int pid;
  76
  77         pid = getpid();
  78         for (trv = path; *trv; ++trv);          /* extra X's get set to 0's */
  79         while (*--trv == 'X') {
  80                 *trv = (pid % 10) + '0';
  81                 pid /= 10;
  82         }
  83
  84         /*
  85          * check the target directory; if you have six X's and it
  86          * doesn't exist this runs for a *very* long time.
  87          */
  88         for (start = trv + 1;; --trv) {
  89                 if (trv <= path)
  90                         break;
  91                 if (*trv == '/') {
  92                         *trv = '\0';
  93                         if (stat(path, &sbuf))
  94                                 return(0);
  95                         if (!S_ISDIR(sbuf.st_mode)) {
  96                                 errno = ENOTDIR;
  97                                 return(0);
  98                         }
  99                         *trv = '/';
 100                         break;
 101                 }
 102         }
 103
 104         for (;;) {
 105                 if (doopen) {
 106                         if ((*doopen =
 107                             open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
 108                                 return(1);
 109                         if (errno != EEXIST)
 110                                 return(0);
 111                 }
 112                 else if (stat(path, &sbuf))
 113                         return(errno == ENOENT ? 1 : 0);
 114
 115                 /* tricky little algorithm for backward compatibility */
 116                 for (trv = start;;) {
 117                         if (!*trv)
 118                                 return(0);
 119                         if (*trv == 'z')
 120                                 *trv++ = 'a';
 121                         else {
 122                                 if (isdigit(*trv))
 123                                         *trv = 'a';
 124                                 else
 125                                         ++*trv;
 126                                 break;
 127                         }
 128                 }
 129         }
 130         /*NOTREACHED*/
 131 }