winsup/cygwin/mktemp.cc

   1 /* mktemp.cc: mktemp functions
   2
   3 This file is adapted for Cygwin from FreeBSD and newlib.
   4
   5 See the copyright at the bottom of this file. */
   6
   7 #include "winsup.h"
   8 #include "cygerrno.h"
   9 #include <fcntl.h>
  10 #include <sys/stat.h>
  11 #include <unistd.h>
  12
  13 static int _gettemp(char *, int *, int, size_t, int);
  14
  15 static const char padchar[] =
  16 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  17
  18 extern "C" int
  19 mkstemp(char *path)
  20 {
  21   int fd;
  22   return _gettemp(path, &fd, 0, 0, O_BINARY) ? fd : -1;
  23 }
  24
  25 extern "C" char *
  26 mkdtemp(char *path)
  27 {
  28   return _gettemp(path, NULL, 1, 0, 0) ? path : NULL;
  29 }
  30
  31 extern "C" int
  32 mkstemps(char *path, int len)
  33 {
  34   int fd;
  35   return _gettemp(path, &fd, 0, len, O_BINARY) ? fd : -1;
  36 }
  37
  38 extern "C" int
  39 mkostemp(char *path, int flags)
  40 {
  41   int fd;
  42   return _gettemp(path, &fd, 0, 0, flags & ~O_ACCMODE) ? fd : -1;
  43 }
  44
  45 extern "C" int
  46 mkostemps(char *path, int len, int flags)
  47 {
  48   int fd;
  49   return _gettemp(path, &fd, 0, len, flags & ~O_ACCMODE) ? fd : -1;
  50 }
  51
  52 extern "C" char *
  53 mktemp(char *path)
  54 {
  55   return _gettemp(path, NULL, 0, 0, 0) ? path : (char *) NULL;
  56 }
  57
  58 static int
  59 _gettemp(char *path, int *doopen, int domkdir, size_t suffixlen, int flags)
  60 {
  61   char *start, *trv, *suffp;
  62   char *pad;
  63
  64   if (doopen && domkdir)
  65     {
  66       set_errno (EINVAL);
  67       return 0;
  68     }
  69
  70   trv = strchr (path, '\0');
  71   if ((size_t) (trv - path) < suffixlen)
  72     {
  73       set_errno (EINVAL);
  74       return 0;
  75     }
  76   trv -= suffixlen;
  77   suffp = trv--;
  78
  79   /* Fill space with random characters */
  80   while (trv >= path && *trv == 'X')
  81     {
  82       uint32_t rand = arc4random () % (sizeof (padchar) - 1);
  83       *trv-- = padchar[rand];
  84     }
  85   if (suffp - trv < 6)
  86     {
  87       set_errno (EINVAL);
  88       return 0;
  89     }
  90   start = trv + 1;
  91
  92   /*
  93    * check the target directory.
  94    */
  95   struct stat sbuf;
  96   if (doopen != NULL || domkdir)
  97     {
  98       for (; trv > path; trv--)
  99         {
 100           if (*trv == '/')
 101             {
 102               *trv = '\0';
 103               int rval = stat (path, &sbuf);
 104               *trv = '/';
 105               if (rval != 0)
 106                 return 0;
 107               if (!S_ISDIR (sbuf.st_mode))
 108                 {
 109                   set_errno (ENOTDIR);
 110                   return 0;
 111                 }
 112               break;
 113             }
 114         }
 115     }
 116
 117   for (;;)
 118     {
 119       if (doopen)
 120         {
 121           if ((*doopen = open (path, O_CREAT | O_EXCL | O_RDWR | flags,
 122                                S_IRUSR | S_IWUSR)) >= 0)
 123             return 1;
 124           if (errno != EEXIST)
 125             return 0;
 126         }
 127       else if (domkdir)
 128         {
 129           if (mkdir (path, 0700) == 0)
 130             return 1;
 131           if (errno != EEXIST)
 132             return 0;
 133           }
 134       else if (lstat (path, &sbuf))
 135         return errno == ENOENT;
 136
 137       /* If we have a collision, cycle through the space of filenames */
 138       for (trv = start;;)
 139         {
 140           if (*trv == '\0' || trv == suffp)
 141             return 0;
 142           pad = strchr (padchar, *trv);
 143           if (pad == NULL || *++pad == '\0')
 144             *trv++ = padchar[0];
 145           else
 146             {
 147               *trv++ = *pad;
 148               break;
 149             }
 150         }
 151     }
 152   /*NOTREACHED*/
 153 }
 154
 155 /*
 156 * Copyright (c) 1987, 1993
 157 *       The Regents of the University of California.  All rights reserved.
 158 *
 159 * Redistribution and use in source and binary forms, with or without
 160 * modification, are permitted provided that the following conditions
 161 * are met:
 162 * 1. Redistributions of source code must retain the above copyright
 163 *    notice, this list of conditions and the following disclaimer.
 164 * 2. Redistributions in binary form must reproduce the above copyright
 165 *    notice, this list of conditions and the following disclaimer in the
 166 *    documentation and/or other materials provided with the distribution.
 167 * 4. Neither the name of the University nor the names of its contributors
 168 *    may be used to endorse or promote products derived from this software
 169 *    without specific prior written permission.
 170 *
 171 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 172 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 173 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 174 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 175 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 176 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 177 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 178 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 179 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 180 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 181 * SUCH DAMAGE.
 182 */