stdio/mktemp-fbsd.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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.32 2010/02/28 13:31:29 jh Exp $");
  35
  36 #include "namespace.h"
  37 #include <sys/param.h>
  38 #include <sys/stat.h>
  39 #include <fcntl.h>
  40 #include <errno.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <ctype.h>
  45 #include <unistd.h>
  46 #include "un-namespace.h"
  47
  48 char *_mktemp(char *);
  49
  50 static int _gettemp(char *, int *, int, int);
  51
  52 static const unsigned char padchar[] =
  53 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  54
  55 int
  56 mkstemps(path, slen)
  57         char *path;
  58         int slen;
  59 {
  60         int fd;
  61
  62         return (_gettemp(path, &fd, 0, slen) ? fd : -1);
  63 }
  64
  65 int
  66 mkstemp(path)
  67         char *path;
  68 {
  69         int fd;
  70
  71         return (_gettemp(path, &fd, 0, 0) ? fd : -1);
  72 }
  73
  74 char *
  75 mkdtemp(path)
  76         char *path;
  77 {
  78         return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
  79 }
  80
  81 char *
  82 _mktemp(path)
  83         char *path;
  84 {
  85         return (_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
  86 }
  87
  88 __warn_references(mktemp,
  89     "warning: mktemp() possibly used unsafely; consider using mkstemp()");
  90
  91 char *
  92 mktemp(path)
  93         char *path;
  94 {
  95         return (_mktemp(path));
  96 }
  97
  98 static int
  99 _gettemp(path, doopen, domkdir, slen)
 100         char *path;
 101         int *doopen;
 102         int domkdir;
 103         int slen;
 104 {
 105         char *start, *trv, *suffp, *carryp;
 106         char *pad;
 107         struct stat sbuf;
 108         int rval;
 109         uint32_t rand;
 110         char carrybuf[MAXPATHLEN];
 111
 112         if ((doopen != NULL && domkdir) || slen < 0) {
 113                 errno = EINVAL;
 114                 return (0);
 115         }
 116
 117         for (trv = path; *trv != '\0'; ++trv)
 118                 ;
 119         if (trv - path >= MAXPATHLEN) {
 120                 errno = ENAMETOOLONG;
 121                 return (0);
 122         }
 123         trv -= slen;
 124         suffp = trv;
 125         --trv;
 126         if (trv < path || NULL != strchr(suffp, '/')) {
 127                 errno = EINVAL;
 128                 return (0);
 129         }
 130
 131         /* Fill space with random characters */
 132         while (trv >= path && *trv == 'X') {
 133                 rand = arc4random() % (sizeof(padchar) - 1);
 134                 *trv-- = padchar[rand];
 135         }
 136         start = trv + 1;
 137
 138         /* save first combination of random characters */
 139         memcpy(carrybuf, start, suffp - start);
 140
 141         /*
 142          * check the target directory.
 143          */
 144         if (doopen != NULL || domkdir) {
 145                 for (; trv > path; --trv) {
 146                         if (*trv == '/') {
 147                                 *trv = '\0';
 148                                 rval = stat(path, &sbuf);
 149                                 *trv = '/';
 150                                 if (rval != 0)
 151                                         return (0);
 152                                 if (!S_ISDIR(sbuf.st_mode)) {
 153                                         errno = ENOTDIR;
 154                                         return (0);
 155                                 }
 156                                 break;
 157                         }
 158                 }
 159         }
 160
 161         for (;;) {
 162                 if (doopen) {
 163                         if ((*doopen =
 164                             _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
 165                                 return (1);
 166                         if (errno != EEXIST)
 167                                 return (0);
 168                 } else if (domkdir) {
 169                         if (mkdir(path, 0700) == 0)
 170                                 return (1);
 171                         if (errno != EEXIST)
 172                                 return (0);
 173                 } else if (lstat(path, &sbuf))
 174                         return (errno == ENOENT);
 175
 176                 /* If we have a collision, cycle through the space of filenames */
 177                 for (trv = start, carryp = carrybuf;;) {
 178                         /* have we tried all possible permutations? */
 179                         if (trv == suffp)
 180                                 return (0); /* yes - exit with EEXIST */
 181                         pad = strchr(padchar, *trv);
 182                         if (pad == NULL) {
 183                                 /* this should never happen */
 184                                 errno = EIO;
 185                                 return (0);
 186                         }
 187                         /* increment character */
 188                         *trv = (*++pad == '\0') ? padchar[0] : *pad;
 189                         /* carry to next position? */
 190                         if (*trv == *carryp) {
 191                                 /* increment position and loop */
 192                                 ++trv;
 193                                 ++carryp;
 194                         } else {
 195                                 /* try with new name */
 196                                 break;
 197                         }
 198                 }
 199         }
 200         /*NOTREACHED*/
 201 }