lib/libc/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  * @(#)mktemp.c 8.1 (Berkeley) 6/4/93
  34  * $FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.19.2.3 2002/06/18 09:53:07 robert Exp $
  35  * $DragonFly: src/lib/libc/stdio/mktemp.c,v 1.7 2005/11/20 11:07:30 swildner Exp $
  36  */
  37
  38 /* #include "namespace.h" */
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <fcntl.h>
  42 #include <errno.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <ctype.h>
  47 #include <unistd.h>
  48 /* #include "un-namespace.h" */
  49
  50 char *_mktemp (char *);
  51
  52 static int _gettemp (char *, int *, int, int);
  53
  54 static const unsigned char padchar[] =
  55 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  56
  57 int
  58 mkstemps(char *path, int slen)
  59 {
  60         int fd;
  61
  62         return (_gettemp(path, &fd, 0, slen) ? fd : -1);
  63 }
  64
  65 int
  66 mkstemp(char *path)
  67 {
  68         int fd;
  69
  70         return (_gettemp(path, &fd, 0, 0) ? fd : -1);
  71 }
  72
  73 char *
  74 mkdtemp(char *path)
  75 {
  76         return (_gettemp(path, NULL, 1, 0) ? path : NULL);
  77 }
  78
  79 char *
  80 _mktemp(char *path)
  81 {
  82         return (_gettemp(path, NULL, 0, 0) ? path : NULL);
  83 }
  84
  85 __warn_references(mktemp,
  86     "warning: mktemp() possibly used unsafely; consider using mkstemp()");
  87
  88 char *
  89 mktemp(char *path)
  90 {
  91         return (_mktemp(path));
  92 }
  93
  94 static int
  95 _gettemp(char *path, int *doopen, int domkdir, int slen)
  96 {
  97         char *start, *trv, *suffp;
  98         char *pad;
  99         struct stat sbuf;
 100         int rval;
 101         uint32_t psrand;
 102
 103         if (doopen != NULL && domkdir) {
 104                 errno = EINVAL;
 105                 return (0);
 106         }
 107
 108         for (trv = path; *trv != '\0'; ++trv)
 109                 ;
 110         trv -= slen;
 111         suffp = trv;
 112         --trv;
 113         if (trv < path) {
 114                 errno = EINVAL;
 115                 return (0);
 116         }
 117
 118         /* Fill space with random characters */
 119         while (trv >= path && *trv == 'X') {
 120                 psrand = arc4random() % (sizeof(padchar) - 1);
 121                 *trv-- = padchar[psrand];
 122         }
 123         start = trv + 1;
 124
 125         /*
 126          * check the target directory.
 127          */
 128         if (doopen != NULL || domkdir) {
 129                 for (; trv > path; --trv) {
 130                         if (*trv == '/') {
 131                                 *trv = '\0';
 132                                 rval = stat(path, &sbuf);
 133                                 *trv = '/';
 134                                 if (rval != 0)
 135                                         return (0);
 136                                 if (!S_ISDIR(sbuf.st_mode)) {
 137                                         errno = ENOTDIR;
 138                                         return (0);
 139                                 }
 140                                 break;
 141                         }
 142                 }
 143         }
 144
 145         for (;;) {
 146                 if (doopen) {
 147                         if ((*doopen =
 148                             _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
 149                                 return (1);
 150                         if (errno != EEXIST)
 151                                 return (0);
 152                 } else if (domkdir) {
 153                         if (mkdir(path, 0700) == 0)
 154                                 return (1);
 155                         if (errno != EEXIST)
 156                                 return (0);
 157                 } else if (lstat(path, &sbuf))
 158                         return (errno == ENOENT);
 159
 160                 /* If we have a collision, cycle through the space of filenames */
 161                 for (trv = start;;) {
 162                         if (*trv == '\0' || trv == suffp)
 163                                 return (0);
 164                         pad = strchr(padchar, *trv);
 165                         if (pad == NULL || *++pad == '\0')
 166                                 *trv++ = padchar[0];
 167                         else {
 168                                 *trv++ = *pad;
 169                                 break;
 170                         }
 171                 }
 172         }
 173         /*NOTREACHED*/
 174 }