src/mktemp.c

   1 /* Create a temporary file or directory, safely.
   2    Copyright (C) 2007-2012 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Jim Meyering and Eric Blake.  */
  18
  19 #include <config.h>
  20 #include <sys/types.h>
  21 #include <getopt.h>
  22
  23 #include "system.h"
  24
  25 #include "close-stream.h"
  26 #include "error.h"
  27 #include "filenamecat.h"
  28 #include "quote.h"
  29 #include "stdio--.h"
  30 #include "tempname.h"
  31
  32 /* The official name of this program (e.g., no 'g' prefix).  */
  33 #define PROGRAM_NAME "mktemp"
  34
  35 #define AUTHORS \
  36   proper_name ("Jim Meyering"), \
  37   proper_name ("Eric Blake")
  38
  39 static const char *default_template = "tmp.XXXXXXXXXX";
  40
  41 /* For long options that have no equivalent short option, use a
  42    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  43 enum
  44 {
  45   SUFFIX_OPTION = CHAR_MAX + 1,
  46   TMPDIR_OPTION
  47 };
  48
  49 static struct option const longopts[] =
  50 {
  51   {"directory", no_argument, NULL, 'd'},
  52   {"quiet", no_argument, NULL, 'q'},
  53   {"dry-run", no_argument, NULL, 'u'},
  54   {"suffix", required_argument, NULL, SUFFIX_OPTION},
  55   {"tmpdir", optional_argument, NULL, TMPDIR_OPTION},
  56   {GETOPT_HELP_OPTION_DECL},
  57   {GETOPT_VERSION_OPTION_DECL},
  58   {NULL, 0, NULL, 0}
  59 };
  60
  61 void
  62 usage (int status)
  63 {
  64   if (status != EXIT_SUCCESS)
  65     emit_try_help ();
  66   else
  67     {
  68       printf (_("Usage: %s [OPTION]... [TEMPLATE]\n"), program_name);
  69       fputs (_("\
  70 Create a temporary file or directory, safely, and print its name.\n\
  71 TEMPLATE must contain at least 3 consecutive 'X's in last component.\n\
  72 If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.\n\
  73 "), stdout);
  74       fputs (_("\
  75 Files are created u+rw, and directories u+rwx, minus umask restrictions.\n\
  76 "), stdout);
  77       fputs ("\n", stdout);
  78       fputs (_("\
  79   -d, --directory     create a directory, not a file\n\
  80   -u, --dry-run       do not create anything; merely print a name (unsafe)\n\
  81   -q, --quiet         suppress diagnostics about file/dir-creation failure\n\
  82 "), stdout);
  83       fputs (_("\
  84       --suffix=SUFF   append SUFF to TEMPLATE.  SUFF must not contain slash.\n\
  85                         This option is implied if TEMPLATE does not end in X.\n\
  86 "), stdout);
  87       fputs (_("\
  88       --tmpdir[=DIR]  interpret TEMPLATE relative to DIR.  If DIR is not\n\
  89                         specified, use $TMPDIR if set, else /tmp.  With\n\
  90                         this option, TEMPLATE must not be an absolute name.\n\
  91                         Unlike with -t, TEMPLATE may contain slashes, but\n\
  92                         mktemp creates only the final component\n\
  93 "), stdout);
  94       fputs ("\n", stdout);
  95       fputs (_("\
  96   -p DIR              use DIR as a prefix; implies -t [deprecated]\n\
  97   -t                  interpret TEMPLATE as a single file name component,\n\
  98                         relative to a directory: $TMPDIR, if set; else the\n\
  99                         directory specified via -p; else /tmp [deprecated]\n\
 100 "), stdout);
 101       fputs ("\n", stdout);
 102       fputs (HELP_OPTION_DESCRIPTION, stdout);
 103       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 104       emit_ancillary_info ();
 105     }
 106
 107   exit (status);
 108 }
 109
 110 static size_t
 111 count_consecutive_X_s (const char *s, size_t len)
 112 {
 113   size_t n = 0;
 114   for ( ; len && s[len-1] == 'X'; len--)
 115     ++n;
 116   return n;
 117 }
 118
 119 static int
 120 mkstemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 121 {
 122   return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_FILE,
 123                            x_len);
 124 }
 125
 126 static int
 127 mkdtemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 128 {
 129   return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_DIR,
 130                            x_len);
 131 }
 132
 133 /* True if we have already closed standard output.  */
 134 static bool stdout_closed;
 135
 136 /* Avoid closing stdout twice.  Since we conditionally call
 137    close_stream (stdout) in order to decide whether to clean up a
 138    temporary file, the exit hook needs to know whether to do all of
 139    close_stdout or just the stderr half.  */
 140 static void
 141 maybe_close_stdout (void)
 142 {
 143   if (!stdout_closed)
 144     close_stdout ();
 145   else if (close_stream (stderr) != 0)
 146     _exit (EXIT_FAILURE);
 147 }
 148
 149 int
 150 main (int argc, char **argv)
 151 {
 152   char const *dest_dir;
 153   char const *dest_dir_arg = NULL;
 154   bool suppress_stderr = false;
 155   int c;
 156   unsigned int n_args;
 157   char *template;
 158   char *suffix = NULL;
 159   bool use_dest_dir = false;
 160   bool deprecated_t_option = false;
 161   bool create_directory = false;
 162   bool dry_run = false;
 163   int status = EXIT_SUCCESS;
 164   size_t x_count;
 165   size_t suffix_len;
 166   char *dest_name;
 167
 168   initialize_main (&argc, &argv);
 169   set_program_name (argv[0]);
 170   setlocale (LC_ALL, "");
 171   bindtextdomain (PACKAGE, LOCALEDIR);
 172   textdomain (PACKAGE);
 173
 174   atexit (maybe_close_stdout);
 175
 176   while ((c = getopt_long (argc, argv, "dp:qtuV", longopts, NULL)) != -1)
 177     {
 178       switch (c)
 179         {
 180         case 'd':
 181           create_directory = true;
 182           break;
 183         case 'p':
 184           dest_dir_arg = optarg;
 185           use_dest_dir = true;
 186           break;
 187         case 'q':
 188           suppress_stderr = true;
 189           break;
 190         case 't':
 191           use_dest_dir = true;
 192           deprecated_t_option = true;
 193           break;
 194         case 'u':
 195           dry_run = true;
 196           break;
 197
 198         case TMPDIR_OPTION:
 199           use_dest_dir = true;
 200           dest_dir_arg = optarg;
 201           break;
 202
 203         case SUFFIX_OPTION:
 204           suffix = optarg;
 205           break;
 206
 207         case_GETOPT_HELP_CHAR;
 208
 209         case 'V': /* Undocumented alias.  FIXME: remove in 2011.  */
 210         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 211         default:
 212           usage (EXIT_FAILURE);
 213         }
 214     }
 215
 216   if (suppress_stderr)
 217     {
 218       /* From here on, redirect stderr to /dev/null.
 219          A diagnostic from getopt_long, above, would still go to stderr.  */
 220       if (!freopen ("/dev/null", "wb", stderr))
 221         error (EXIT_FAILURE, errno,
 222                _("failed to redirect stderr to /dev/null"));
 223     }
 224
 225   n_args = argc - optind;
 226   if (2 <= n_args)
 227     {
 228       error (0, 0, _("too many templates"));
 229       usage (EXIT_FAILURE);
 230     }
 231
 232   if (n_args == 0)
 233     {
 234       use_dest_dir = true;
 235       template = (char *) default_template;
 236     }
 237   else
 238     {
 239       template = argv[optind];
 240     }
 241
 242   if (suffix)
 243     {
 244       size_t len = strlen (template);
 245       if (!len || template[len - 1] != 'X')
 246         {
 247           error (EXIT_FAILURE, 0,
 248                  _("with --suffix, template %s must end in X"),
 249                  quote (template));
 250         }
 251       suffix_len = strlen (suffix);
 252       dest_name = xcharalloc (len + suffix_len + 1);
 253       memcpy (dest_name, template, len);
 254       memcpy (dest_name + len, suffix, suffix_len + 1);
 255       template = dest_name;
 256       suffix = dest_name + len;
 257     }
 258   else
 259     {
 260       template = xstrdup (template);
 261       suffix = strrchr (template, 'X');
 262       if (!suffix)
 263         suffix = strchr (template, '\0');
 264       else
 265         suffix++;
 266       suffix_len = strlen (suffix);
 267     }
 268
 269   /* At this point, template is malloc'd, and suffix points into template.  */
 270   if (suffix_len && last_component (suffix) != suffix)
 271     {
 272       error (EXIT_FAILURE, 0,
 273              _("invalid suffix %s, contains directory separator"),
 274              quote (suffix));
 275     }
 276   x_count = count_consecutive_X_s (template, suffix - template);
 277   if (x_count < 3)
 278     error (EXIT_FAILURE, 0, _("too few X's in template %s"), quote (template));
 279
 280   if (use_dest_dir)
 281     {
 282       if (deprecated_t_option)
 283         {
 284           char *env = getenv ("TMPDIR");
 285           dest_dir = (env && *env
 286                       ? env
 287                       : (dest_dir_arg ? dest_dir_arg : "/tmp"));
 288
 289           if (last_component (template) != template)
 290             error (EXIT_FAILURE, 0,
 291                    _("invalid template, %s, contains directory separator"),
 292                    quote (template));
 293         }
 294       else
 295         {
 296           if (dest_dir_arg && *dest_dir_arg)
 297             dest_dir = dest_dir_arg;
 298           else
 299             {
 300               char *env = getenv ("TMPDIR");
 301               dest_dir = (env && *env ? env : "/tmp");
 302             }
 303           if (IS_ABSOLUTE_FILE_NAME (template))
 304             error (EXIT_FAILURE, 0,
 305                    _("invalid template, %s; with --tmpdir,"
 306                      " it may not be absolute"),
 307                    quote (template));
 308         }
 309
 310       dest_name = file_name_concat (dest_dir, template, NULL);
 311       free (template);
 312       template = dest_name;
 313       /* Note that suffix is now invalid.  */
 314     }
 315
 316   /* Make a copy to be used in case of diagnostic, since failing
 317      mkstemp may leave the buffer in an undefined state.  */
 318   dest_name = xstrdup (template);
 319
 320   if (create_directory)
 321     {
 322       int err = mkdtemp_len (dest_name, suffix_len, x_count, dry_run);
 323       if (err != 0)
 324         {
 325           error (0, errno, _("failed to create directory via template %s"),
 326                  quote (template));
 327           status = EXIT_FAILURE;
 328         }
 329     }
 330   else
 331     {
 332       int fd = mkstemp_len (dest_name, suffix_len, x_count, dry_run);
 333       if (fd < 0 || (!dry_run && close (fd) != 0))
 334         {
 335           error (0, errno, _("failed to create file via template %s"),
 336                  quote (template));
 337           status = EXIT_FAILURE;
 338         }
 339     }
 340
 341   if (status == EXIT_SUCCESS)
 342     {
 343       puts (dest_name);
 344       /* If we created a file, but then failed to output the file
 345          name, we should clean up the mess before failing.  */
 346       if (!dry_run && ((stdout_closed = true), close_stream (stdout) != 0))
 347         {
 348           int saved_errno = errno;
 349           remove (dest_name);
 350           error (EXIT_FAILURE, saved_errno, _("write error"));
 351         }
 352     }
 353
 354 #ifdef lint
 355   free (dest_name);
 356   free (template);
 357 #endif
 358
 359   exit (status);
 360 }