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  * 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 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.28 2003/02/16 17:29:10 nectar Exp $");
  39
  40 #include "namespace.h"
  41 #include <sys/types.h>
  42 #include <sys/stat.h>
  43 #include <sys/syslimits.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 "un-namespace.h"
  52
  53 char *_mktemp(char *);
  54
  55 static int _gettemp(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 __warn_references(mktemp,
  94     "warning: mktemp() possibly used unsafely; consider using mkstemp()");
  95
  96 char *
  97 mktemp(path)
  98         char *path;
  99 {
 100         return (_mktemp(path));
 101 }
 102
 103 static int
 104 _gettemp(path, doopen, domkdir, slen)
 105         char *path;
 106         int *doopen;
 107         int domkdir;
 108         int slen;
 109 {
 110         char *start, *trv, *suffp, *carryp;
 111         char *pad;
 112         struct stat sbuf;
 113         int rval;
 114         uint32_t rand;
 115         char carrybuf[NAME_MAX];
 116
 117         if ((doopen != NULL && domkdir) || slen < 0) {
 118                 errno = EINVAL;
 119                 return (0);
 120         }
 121
 122         for (trv = path; *trv != '\0'; ++trv)
 123                 ;
 124         trv -= slen;
 125         suffp = trv;
 126         --trv;
 127         if (trv < path || NULL != strchr(suffp, '/')) {
 128                 errno = EINVAL;
 129                 return (0);
 130         }
 131
 132         /* Fill space with random characters */
 133         while (trv >= path && *trv == 'X') {
 134                 rand = arc4random() % (sizeof(padchar) - 1);
 135                 *trv-- = padchar[rand];
 136         }
 137         start = trv + 1;
 138
 139         /* save first combination of random characters */
 140         memcpy(carrybuf, start, suffp - start);
 141
 142         /*
 143          * check the target directory.
 144          */
 145         if (doopen != NULL || domkdir) {
 146                 for (; trv > path; --trv) {
 147                         if (*trv == '/') {
 148                                 *trv = '\0';
 149                                 rval = stat(path, &sbuf);
 150                                 *trv = '/';
 151                                 if (rval != 0)
 152                                         return (0);
 153                                 if (!S_ISDIR(sbuf.st_mode)) {
 154                                         errno = ENOTDIR;
 155                                         return (0);
 156                                 }
 157                                 break;
 158                         }
 159                 }
 160         }
 161
 162         for (;;) {
 163                 if (doopen) {
 164                         if ((*doopen =
 165                             _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
 166                                 return (1);
 167                         if (errno != EEXIST)
 168                                 return (0);
 169                 } else if (domkdir) {
 170                         if (mkdir(path, 0700) == 0)
 171                                 return (1);
 172                         if (errno != EEXIST)
 173                                 return (0);
 174                 } else if (lstat(path, &sbuf))
 175                         return (errno == ENOENT);
 176
 177                 /* If we have a collision, cycle through the space of filenames */
 178                 for (trv = start, carryp = carrybuf;;) {
 179                         /* have we tried all possible permutations? */
 180                         if (trv == suffp)
 181                                 return (0); /* yes - exit with EEXIST */
 182                         pad = strchr(padchar, *trv);
 183                         if (pad == NULL) {
 184                                 /* this should never happen */
 185                                 errno = EIO;
 186                                 return (0);
 187                         }
 188                         /* increment character */
 189                         *trv = (*++pad == '\0') ? padchar[0] : *pad;
 190                         /* carry to next position? */
 191                         if (*trv == *carryp) {
 192                                 /* increment position and loop */
 193                                 ++trv;
 194                                 ++carryp;
 195                         } else {
 196                                 /* try with new name */
 197                                 break;
 198                         }
 199                 }
 200         }
 201         /*NOTREACHED*/
 202 }