gnu/dist/gettext/gettext-tools/lib/mkdtemp.c

   1 /* Copyright (C) 1999, 2001-2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /* Extracted from misc/mkdtemp.c and sysdeps/posix/tempname.c.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 /* Specification.  */
  26 #include "mkdtemp.h"
  27
  28 #include <errno.h>
  29 #ifndef __set_errno
  30 # define __set_errno(Val) errno = (Val)
  31 #endif
  32
  33 #include <stddef.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include <stdio.h>
  38 #ifndef TMP_MAX
  39 # define TMP_MAX 238328
  40 #endif
  41
  42 #if HAVE_STDINT_H || _LIBC
  43 # include <stdint.h>
  44 #endif
  45 #if HAVE_INTTYPES_H
  46 # include <inttypes.h>
  47 #endif
  48
  49 #if HAVE_UNISTD_H || _LIBC
  50 # include <unistd.h>
  51 #endif
  52
  53 #if HAVE_GETTIMEOFDAY || _LIBC
  54 # if HAVE_SYS_TIME_H || _LIBC
  55 #  include <sys/time.h>
  56 # endif
  57 #else
  58 # if HAVE_TIME_H || _LIBC
  59 #  include <time.h>
  60 # endif
  61 #endif
  62
  63 #include <sys/stat.h>
  64 #if STAT_MACROS_BROKEN
  65 # undef S_ISDIR
  66 #endif
  67 #if !defined S_ISDIR && defined S_IFDIR
  68 # define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
  69 #endif
  70 #if !S_IRUSR && S_IREAD
  71 # define S_IRUSR S_IREAD
  72 #endif
  73 #if !S_IRUSR
  74 # define S_IRUSR 00400
  75 #endif
  76 #if !S_IWUSR && S_IWRITE
  77 # define S_IWUSR S_IWRITE
  78 #endif
  79 #if !S_IWUSR
  80 # define S_IWUSR 00200
  81 #endif
  82 #if !S_IXUSR && S_IEXEC
  83 # define S_IXUSR S_IEXEC
  84 #endif
  85 #if !S_IXUSR
  86 # define S_IXUSR 00100
  87 #endif
  88
  89 #ifdef __MINGW32__
  90 /* mingw's mkdir() function has 1 argument, but we pass 2 arguments.
  91    Therefore we have to disable the argument count checking.  */
  92 # define mkdir ((int (*)()) mkdir)
  93 #endif
  94
  95 #if !_LIBC
  96 # define __getpid getpid
  97 # define __gettimeofday gettimeofday
  98 # define __mkdir mkdir
  99 #endif
 100
 101 /* Use the widest available unsigned type if uint64_t is not
 102    available.  The algorithm below extracts a number less than 62**6
 103    (approximately 2**35.725) from uint64_t, so ancient hosts where
 104    uintmax_t is only 32 bits lose about 3.725 bits of randomness,
 105    which is better than not having mkstemp at all.  */
 106 #if !defined UINT64_MAX && !defined uint64_t
 107 # define uint64_t uintmax_t
 108 #endif
 109
 110 /* These are the characters used in temporary filenames.  */
 111 static const char letters[] =
 112 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 113
 114 /* Generate a temporary file name based on TMPL.  TMPL must match the
 115    rules for mk[s]temp (i.e. end in "XXXXXX").  The name constructed
 116    does not exist at the time of the call to __gen_tempname.  TMPL is
 117    overwritten with the result.
 118
 119    KIND is:
 120    __GT_DIR:            create a directory, which will be mode 0700.
 121
 122    We use a clever algorithm to get hard-to-predict names. */
 123 static int
 124 gen_tempname (char *tmpl)
 125 {
 126   int len;
 127   char *XXXXXX;
 128   static uint64_t value;
 129   uint64_t random_time_bits;
 130   int count, fd = -1;
 131   int save_errno = errno;
 132
 133   len = strlen (tmpl);
 134   if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
 135     {
 136       __set_errno (EINVAL);
 137       return -1;
 138     }
 139
 140   /* This is where the Xs start.  */
 141   XXXXXX = &tmpl[len - 6];
 142
 143   /* Get some more or less random data.  */
 144 #ifdef RANDOM_BITS
 145   RANDOM_BITS (random_time_bits);
 146 #else
 147 # if HAVE_GETTIMEOFDAY || _LIBC
 148   {
 149     struct timeval tv;
 150     __gettimeofday (&tv, NULL);
 151     random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
 152   }
 153 # else
 154   random_time_bits = time (NULL);
 155 # endif
 156 #endif
 157   value += random_time_bits ^ __getpid ();
 158
 159   for (count = 0; count < TMP_MAX; value += 7777, ++count)
 160     {
 161       uint64_t v = value;
 162
 163       /* Fill in the random bits.  */
 164       XXXXXX[0] = letters[v % 62];
 165       v /= 62;
 166       XXXXXX[1] = letters[v % 62];
 167       v /= 62;
 168       XXXXXX[2] = letters[v % 62];
 169       v /= 62;
 170       XXXXXX[3] = letters[v % 62];
 171       v /= 62;
 172       XXXXXX[4] = letters[v % 62];
 173       v /= 62;
 174       XXXXXX[5] = letters[v % 62];
 175
 176       fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
 177
 178       if (fd >= 0)
 179         {
 180           __set_errno (save_errno);
 181           return fd;
 182         }
 183       else if (errno != EEXIST)
 184         return -1;
 185     }
 186
 187   /* We got out of the loop because we ran out of combinations to try.  */
 188   __set_errno (EEXIST);
 189   return -1;
 190 }
 191
 192 /* Generate a unique temporary directory from TEMPLATE.
 193    The last six characters of TEMPLATE must be "XXXXXX";
 194    they are replaced with a string that makes the filename unique.
 195    The directory is created, mode 700, and its name is returned.
 196    (This function comes from OpenBSD.) */
 197 char *
 198 mkdtemp (char *template)
 199 {
 200   if (gen_tempname (template))
 201     return NULL;
 202   else
 203     return template;
 204 }