stdio/mktemp.c

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 #if 0
  36 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
  37 #endif
  38 static const char rcsid[] =
  39   "$FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.19.2.1 2001/01/20 09:35:24 kris Exp $";
  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 <stdlib.h>
  48 #include <string.h>
  49 #include <ctype.h>
  50 #include <unistd.h>
  51 #include <stdint.h>
  52
  53 char *_mktemp __P((char *));
  54
  55 static int _gettemp __P((char *, int *, int, int));
  56
  57 static const unsigned char padchar[] =
  58 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  59
  60 int
  61 mkstemps(path, slen)
  62         char *path;
  63         int slen;
  64 {
  65         int fd;
  66
  67         return (_gettemp(path, &fd, 0, slen) ? fd : -1);
  68 }
  69
  70 int
  71 mkstemp(path)
  72         char *path;
  73 {
  74         int fd;
  75
  76         return (_gettemp(path, &fd, 0, 0) ? fd : -1);
  77 }
  78
  79 char *
  80 mkdtemp(path)
  81         char *path;
  82 {
  83         return(_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
  84 }
  85
  86 char *
  87 _mktemp(path)
  88         char *path;
  89 {
  90         return(_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
  91 }
  92
  93 char *
  94 mktemp(path)
  95         char *path;
  96 {
  97         return(_mktemp(path));
  98 }
  99
 100 static int
 101 _gettemp(path, doopen, domkdir, slen)
 102         char *path;
 103         register int *doopen;
 104         int domkdir;
 105         int slen;
 106 {
 107         register char *start, *trv, *suffp;
 108         char *pad;
 109         struct stat sbuf;
 110         int rval;
 111         uint32_t rand;
 112
 113         if (doopen && domkdir) {
 114                 errno = EINVAL;
 115                 return(0);
 116         }
 117
 118         for (trv = path; *trv; ++trv)
 119                 ;
 120         trv -= slen;
 121         suffp = trv;
 122         --trv;
 123         if (trv < path) {
 124                 errno = EINVAL;
 125                 return (0);
 126         }
 127
 128         /* Fill space with random characters */
 129         while (trv >= path && *trv == 'X') {
 130                 rand = arc4random() % (sizeof(padchar) - 1);
 131                 *trv-- = padchar[rand];
 132         }
 133         start = trv + 1;
 134
 135         /*
 136          * check the target directory.
 137          */
 138         if (doopen || domkdir) {
 139                 for (;; --trv) {
 140                         if (trv <= path)
 141                                 break;
 142                         if (*trv == '/') {
 143                                 *trv = '\0';
 144                                 rval = stat(path, &sbuf);
 145                                 *trv = '/';
 146                                 if (rval != 0)
 147                                         return(0);
 148                                 if (!S_ISDIR(sbuf.st_mode)) {
 149                                         errno = ENOTDIR;
 150                                         return(0);
 151                                 }
 152                                 break;
 153                         }
 154                 }
 155         }
 156
 157         for (;;) {
 158                 if (doopen) {
 159                         if ((*doopen =
 160                             open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
 161                                 return(1);
 162                         if (errno != EEXIST)
 163                                 return(0);
 164                 } else if (domkdir) {
 165                         if (mkdir(path, 0700) == 0)
 166                                 return(1);
 167                         if (errno != EEXIST)
 168                                 return(0);
 169                 } else if (lstat(path, &sbuf))
 170                         return(errno == ENOENT ? 1 : 0);
 171
 172                 /* If we have a collision, cycle through the space of filenames */
 173                 for (trv = start;;) {
 174                         if (*trv == '\0' || trv == suffp)
 175                                 return(0);
 176                         pad = strchr(padchar, *trv);
 177                         if (pad == NULL || !*++pad)
 178                                 *trv++ = padchar[0];
 179                         else {
 180                                 *trv++ = *pad;
 181                                 break;
 182                         }
 183                 }
 184         }
 185         /*NOTREACHED*/
 186 }