src/mktemp.c

   1 /* Create a temporary file or directory, safely.
   2    Copyright (C) 2007-2016 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 "tempname.h"
  30
  31 /* The official name of this program (e.g., no 'g' prefix).  */
  32 #define PROGRAM_NAME "mktemp"
  33
  34 #define AUTHORS \
  35   proper_name ("Jim Meyering"), \
  36   proper_name ("Eric Blake")
  37
  38 static const char *default_template = "tmp.XXXXXXXXXX";
  39
  40 /* For long options that have no equivalent short option, use a
  41    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  42 enum
  43 {
  44   SUFFIX_OPTION = CHAR_MAX + 1,
  45 };
  46
  47 static struct option const longopts[] =
  48 {
  49   {"directory", no_argument, NULL, 'd'},
  50   {"quiet", no_argument, NULL, 'q'},
  51   {"dry-run", no_argument, NULL, 'u'},
  52   {"suffix", required_argument, NULL, SUFFIX_OPTION},
  53   {"tmpdir", optional_argument, NULL, 'p'},
  54   {GETOPT_HELP_OPTION_DECL},
  55   {GETOPT_VERSION_OPTION_DECL},
  56   {NULL, 0, NULL, 0}
  57 };
  58
  59 void
  60 usage (int status)
  61 {
  62   if (status != EXIT_SUCCESS)
  63     emit_try_help ();
  64   else
  65     {
  66       printf (_("Usage: %s [OPTION]... [TEMPLATE]\n"), program_name);
  67       fputs (_("\
  68 Create a temporary file or directory, safely, and print its name.\n\
  69 TEMPLATE must contain at least 3 consecutive 'X's in last component.\n\
  70 If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.\n\
  71 "), stdout);
  72       fputs (_("\
  73 Files are created u+rw, and directories u+rwx, minus umask restrictions.\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 a slash.\n\
  83                         This option is implied if TEMPLATE does not end in X\n\
  84 "), stdout);
  85       fputs (_("\
  86   -p DIR, --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 (_("\
  93   -t                  interpret TEMPLATE as a single file name component,\n\
  94                         relative to a directory: $TMPDIR, if set; else the\n\
  95                         directory specified via -p; else /tmp [deprecated]\n\
  96 "), stdout);
  97       fputs (HELP_OPTION_DESCRIPTION, stdout);
  98       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  99       emit_ancillary_info (PROGRAM_NAME);
 100     }
 101
 102   exit (status);
 103 }
 104
 105 static size_t
 106 count_consecutive_X_s (const char *s, size_t len)
 107 {
 108   size_t n = 0;
 109   for ( ; len && s[len-1] == 'X'; len--)
 110     ++n;
 111   return n;
 112 }
 113
 114 static int
 115 mkstemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 116 {
 117   return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_FILE,
 118                            x_len);
 119 }
 120
 121 static int
 122 mkdtemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 123 {
 124   return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_DIR,
 125                            x_len);
 126 }
 127
 128 /* True if we have already closed standard output.  */
 129 static bool stdout_closed;
 130
 131 /* Avoid closing stdout twice.  Since we conditionally call
 132    close_stream (stdout) in order to decide whether to clean up a
 133    temporary file, the exit hook needs to know whether to do all of
 134    close_stdout or just the stderr half.  */
 135 static void
 136 maybe_close_stdout (void)
 137 {
 138   if (!stdout_closed)
 139     close_stdout ();
 140   else if (close_stream (stderr) != 0)
 141     _exit (EXIT_FAILURE);
 142 }
 143
 144 int
 145 main (int argc, char **argv)
 146 {
 147   char const *dest_dir;
 148   char const *dest_dir_arg = NULL;
 149   bool suppress_file_err = false;
 150   int c;
 151   unsigned int n_args;
 152   char *template;
 153   char *suffix = NULL;
 154   bool use_dest_dir = false;
 155   bool deprecated_t_option = false;
 156   bool create_directory = false;
 157   bool dry_run = false;
 158   int status = EXIT_SUCCESS;
 159   size_t x_count;
 160   size_t suffix_len;
 161   char *dest_name;
 162
 163   initialize_main (&argc, &argv);
 164   set_program_name (argv[0]);
 165   setlocale (LC_ALL, "");
 166   bindtextdomain (PACKAGE, LOCALEDIR);
 167   textdomain (PACKAGE);
 168
 169   atexit (maybe_close_stdout);
 170
 171   while ((c = getopt_long (argc, argv, "dp:qtuV", longopts, NULL)) != -1)
 172     {
 173       switch (c)
 174         {
 175         case 'd':
 176           create_directory = true;
 177           break;
 178         case 'p':
 179           dest_dir_arg = optarg;
 180           use_dest_dir = true;
 181           break;
 182         case 'q':
 183           suppress_file_err = true;
 184           break;
 185         case 't':
 186           use_dest_dir = true;
 187           deprecated_t_option = true;
 188           break;
 189         case 'u':
 190           dry_run = true;
 191           break;
 192
 193         case SUFFIX_OPTION:
 194           suffix = optarg;
 195           break;
 196
 197         case_GETOPT_HELP_CHAR;
 198
 199         case 'V': /* Undocumented alias, for compatibility with the original
 200                      mktemp program.  */
 201         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 202         default:
 203           usage (EXIT_FAILURE);
 204         }
 205     }
 206
 207   n_args = argc - optind;
 208   if (2 <= n_args)
 209     {
 210       error (0, 0, _("too many templates"));
 211       usage (EXIT_FAILURE);
 212     }
 213
 214   if (n_args == 0)
 215     {
 216       use_dest_dir = true;
 217       template = (char *) default_template;
 218     }
 219   else
 220     {
 221       template = argv[optind];
 222     }
 223
 224   if (suffix)
 225     {
 226       size_t len = strlen (template);
 227       if (!len || template[len - 1] != 'X')
 228         {
 229           error (EXIT_FAILURE, 0,
 230                  _("with --suffix, template %s must end in X"),
 231                  quote (template));
 232         }
 233       suffix_len = strlen (suffix);
 234       dest_name = xcharalloc (len + suffix_len + 1);
 235       memcpy (dest_name, template, len);
 236       memcpy (dest_name + len, suffix, suffix_len + 1);
 237       template = dest_name;
 238       suffix = dest_name + len;
 239     }
 240   else
 241     {
 242       template = xstrdup (template);
 243       suffix = strrchr (template, 'X');
 244       if (!suffix)
 245         suffix = strchr (template, '\0');
 246       else
 247         suffix++;
 248       suffix_len = strlen (suffix);
 249     }
 250
 251   /* At this point, template is malloc'd, and suffix points into template.  */
 252   if (suffix_len && last_component (suffix) != suffix)
 253     {
 254       error (EXIT_FAILURE, 0,
 255              _("invalid suffix %s, contains directory separator"),
 256              quote (suffix));
 257     }
 258   x_count = count_consecutive_X_s (template, suffix - template);
 259   if (x_count < 3)
 260     error (EXIT_FAILURE, 0, _("too few X's in template %s"), quote (template));
 261
 262   if (use_dest_dir)
 263     {
 264       if (deprecated_t_option)
 265         {
 266           char *env = getenv ("TMPDIR");
 267           if (env && *env)
 268             dest_dir = env;
 269           else if (dest_dir_arg && *dest_dir_arg)
 270             dest_dir = dest_dir_arg;
 271           else
 272             dest_dir = "/tmp";
 273
 274           if (last_component (template) != template)
 275             error (EXIT_FAILURE, 0,
 276                    _("invalid template, %s, contains directory separator"),
 277                    quote (template));
 278         }
 279       else
 280         {
 281           if (dest_dir_arg && *dest_dir_arg)
 282             dest_dir = dest_dir_arg;
 283           else
 284             {
 285               char *env = getenv ("TMPDIR");
 286               dest_dir = (env && *env ? env : "/tmp");
 287             }
 288           if (IS_ABSOLUTE_FILE_NAME (template))
 289             error (EXIT_FAILURE, 0,
 290                    _("invalid template, %s; with --tmpdir,"
 291                      " it may not be absolute"),
 292                    quote (template));
 293         }
 294
 295       dest_name = file_name_concat (dest_dir, template, NULL);
 296       free (template);
 297       template = dest_name;
 298       /* Note that suffix is now invalid.  */
 299     }
 300
 301   /* Make a copy to be used in case of diagnostic, since failing
 302      mkstemp may leave the buffer in an undefined state.  */
 303   dest_name = xstrdup (template);
 304
 305   if (create_directory)
 306     {
 307       int err = mkdtemp_len (dest_name, suffix_len, x_count, dry_run);
 308       if (err != 0)
 309         {
 310           if (!suppress_file_err)
 311             error (0, errno, _("failed to create directory via template %s"),
 312                    quote (template));
 313           status = EXIT_FAILURE;
 314         }
 315     }
 316   else
 317     {
 318       int fd = mkstemp_len (dest_name, suffix_len, x_count, dry_run);
 319       if (fd < 0 || (!dry_run && close (fd) != 0))
 320         {
 321           if (!suppress_file_err)
 322             error (0, errno, _("failed to create file via template %s"),
 323                    quote (template));
 324           status = EXIT_FAILURE;
 325         }
 326     }
 327
 328   if (status == EXIT_SUCCESS)
 329     {
 330       puts (dest_name);
 331       /* If we created a file, but then failed to output the file
 332          name, we should clean up the mess before failing.  */
 333       if (!dry_run && ((stdout_closed = true), close_stream (stdout) != 0))
 334         {
 335           int saved_errno = errno;
 336           remove (dest_name);
 337           if (!suppress_file_err)
 338             error (0, saved_errno, _("write error"));
 339           status = EXIT_FAILURE;
 340         }
 341     }
 342
 343 #ifdef lint
 344   free (dest_name);
 345   free (template);
 346 #endif
 347
 348   return status;
 349 }