src/mktemp.c

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