src/chown.c

   1 /* chown -- change user and group ownership of files
   2    Copyright (C) 1989-2015 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 David MacKenzie <djm@gnu.ai.mit.edu>. */
  18
  19 #include <config.h>
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include <getopt.h>
  23
  24 #include "system.h"
  25 #include "chown-core.h"
  26 #include "error.h"
  27 #include "fts_.h"
  28 #include "quote.h"
  29 #include "root-dev-ino.h"
  30 #include "userspec.h"
  31
  32 /* The official name of this program (e.g., no 'g' prefix).  */
  33 #define PROGRAM_NAME "chown"
  34
  35 #define AUTHORS \
  36   proper_name ("David MacKenzie"), \
  37   proper_name ("Jim Meyering")
  38
  39 /* The argument to the --reference option.  Use the owner and group IDs
  40    of this file.  This file must exist.  */
  41 static char *reference_file;
  42
  43 /* For long options that have no equivalent short option, use a
  44    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  45 enum
  46 {
  47   DEREFERENCE_OPTION = CHAR_MAX + 1,
  48   FROM_OPTION,
  49   NO_PRESERVE_ROOT,
  50   PRESERVE_ROOT,
  51   REFERENCE_FILE_OPTION
  52 };
  53
  54 static struct option const long_options[] =
  55 {
  56   {"recursive", no_argument, NULL, 'R'},
  57   {"changes", no_argument, NULL, 'c'},
  58   {"dereference", no_argument, NULL, DEREFERENCE_OPTION},
  59   {"from", required_argument, NULL, FROM_OPTION},
  60   {"no-dereference", no_argument, NULL, 'h'},
  61   {"no-preserve-root", no_argument, NULL, NO_PRESERVE_ROOT},
  62   {"preserve-root", no_argument, NULL, PRESERVE_ROOT},
  63   {"quiet", no_argument, NULL, 'f'},
  64   {"silent", no_argument, NULL, 'f'},
  65   {"reference", required_argument, NULL, REFERENCE_FILE_OPTION},
  66   {"verbose", no_argument, NULL, 'v'},
  67   {GETOPT_HELP_OPTION_DECL},
  68   {GETOPT_VERSION_OPTION_DECL},
  69   {NULL, 0, NULL, 0}
  70 };
  71
  72 void
  73 usage (int status)
  74 {
  75   if (status != EXIT_SUCCESS)
  76     emit_try_help ();
  77   else
  78     {
  79       printf (_("\
  80 Usage: %s [OPTION]... [OWNER][:[GROUP]] FILE...\n\
  81   or:  %s [OPTION]... --reference=RFILE FILE...\n\
  82 "),
  83               program_name, program_name);
  84       fputs (_("\
  85 Change the owner and/or group of each FILE to OWNER and/or GROUP.\n\
  86 With --reference, change the owner and group of each FILE to those of RFILE.\n\
  87 \n\
  88 "), stdout);
  89       fputs (_("\
  90   -c, --changes          like verbose but report only when a change is made\n\
  91   -f, --silent, --quiet  suppress most error messages\n\
  92   -v, --verbose          output a diagnostic for every file processed\n\
  93 "), stdout);
  94       fputs (_("\
  95       --dereference      affect the referent of each symbolic link (this is\n\
  96                          the default), rather than the symbolic link itself\n\
  97   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
  98 "), stdout);
  99       fputs (_("\
 100                          (useful only on systems that can change the\n\
 101                          ownership of a symlink)\n\
 102 "), stdout);
 103       fputs (_("\
 104       --from=CURRENT_OWNER:CURRENT_GROUP\n\
 105                          change the owner and/or group of each file only if\n\
 106                          its current owner and/or group match those specified\n\
 107                          here.  Either may be omitted, in which case a match\n\
 108                          is not required for the omitted attribute\n\
 109 "), stdout);
 110       fputs (_("\
 111       --no-preserve-root  do not treat '/' specially (the default)\n\
 112       --preserve-root    fail to operate recursively on '/'\n\
 113 "), stdout);
 114       fputs (_("\
 115       --reference=RFILE  use RFILE's owner and group rather than\n\
 116                          specifying OWNER:GROUP values\n\
 117 "), stdout);
 118       fputs (_("\
 119   -R, --recursive        operate on files and directories recursively\n\
 120 "), stdout);
 121       fputs (_("\
 122 \n\
 123 The following options modify how a hierarchy is traversed when the -R\n\
 124 option is also specified.  If more than one is specified, only the final\n\
 125 one takes effect.\n\
 126 \n\
 127   -H                     if a command line argument is a symbolic link\n\
 128                          to a directory, traverse it\n\
 129   -L                     traverse every symbolic link to a directory\n\
 130                          encountered\n\
 131   -P                     do not traverse any symbolic links (default)\n\
 132 \n\
 133 "), stdout);
 134       fputs (HELP_OPTION_DESCRIPTION, stdout);
 135       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 136       fputs (_("\
 137 \n\
 138 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 139 to login group if implied by a ':' following a symbolic OWNER.\n\
 140 OWNER and GROUP may be numeric as well as symbolic.\n\
 141 "), stdout);
 142       printf (_("\
 143 \n\
 144 Examples:\n\
 145   %s root /u        Change the owner of /u to \"root\".\n\
 146   %s root:staff /u  Likewise, but also change its group to \"staff\".\n\
 147   %s -hR root /u    Change the owner of /u and subfiles to \"root\".\n\
 148 "),
 149               program_name, program_name, program_name);
 150       emit_ancillary_info (PROGRAM_NAME);
 151     }
 152   exit (status);
 153 }
 154
 155 int
 156 main (int argc, char **argv)
 157 {
 158   bool preserve_root = false;
 159
 160   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 161   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 162
 163   /* Change the owner (group) of a file only if it has this uid (gid).
 164      -1 means there's no restriction.  */
 165   uid_t required_uid = -1;
 166   gid_t required_gid = -1;
 167
 168   /* Bit flags that control how fts works.  */
 169   int bit_flags = FTS_PHYSICAL;
 170
 171   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 172      specified.  */
 173   int dereference = -1;
 174
 175   struct Chown_option chopt;
 176   bool ok;
 177   int optc;
 178
 179   initialize_main (&argc, &argv);
 180   set_program_name (argv[0]);
 181   setlocale (LC_ALL, "");
 182   bindtextdomain (PACKAGE, LOCALEDIR);
 183   textdomain (PACKAGE);
 184
 185   atexit (close_stdout);
 186
 187   chopt_init (&chopt);
 188
 189   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, NULL))
 190          != -1)
 191     {
 192       switch (optc)
 193         {
 194         case 'H': /* Traverse command-line symlinks-to-directories.  */
 195           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 196           break;
 197
 198         case 'L': /* Traverse all symlinks-to-directories.  */
 199           bit_flags = FTS_LOGICAL;
 200           break;
 201
 202         case 'P': /* Traverse no symlinks-to-directories.  */
 203           bit_flags = FTS_PHYSICAL;
 204           break;
 205
 206         case 'h': /* --no-dereference: affect symlinks */
 207           dereference = 0;
 208           break;
 209
 210         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 211                                     of each symlink */
 212           dereference = 1;
 213           break;
 214
 215         case NO_PRESERVE_ROOT:
 216           preserve_root = false;
 217           break;
 218
 219         case PRESERVE_ROOT:
 220           preserve_root = true;
 221           break;
 222
 223         case REFERENCE_FILE_OPTION:
 224           reference_file = optarg;
 225           break;
 226
 227         case FROM_OPTION:
 228           {
 229             const char *e = parse_user_spec (optarg,
 230                                              &required_uid, &required_gid,
 231                                              NULL, NULL);
 232             if (e)
 233               error (EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
 234             break;
 235           }
 236
 237         case 'R':
 238           chopt.recurse = true;
 239           break;
 240
 241         case 'c':
 242           chopt.verbosity = V_changes_only;
 243           break;
 244
 245         case 'f':
 246           chopt.force_silent = true;
 247           break;
 248
 249         case 'v':
 250           chopt.verbosity = V_high;
 251           break;
 252
 253         case_GETOPT_HELP_CHAR;
 254         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 255         default:
 256           usage (EXIT_FAILURE);
 257         }
 258     }
 259
 260   if (chopt.recurse)
 261     {
 262       if (bit_flags == FTS_PHYSICAL)
 263         {
 264           if (dereference == 1)
 265             error (EXIT_FAILURE, 0,
 266                    _("-R --dereference requires either -H or -L"));
 267           dereference = 0;
 268         }
 269     }
 270   else
 271     {
 272       bit_flags = FTS_PHYSICAL;
 273     }
 274   chopt.affect_symlink_referent = (dereference != 0);
 275
 276   if (argc - optind < (reference_file ? 1 : 2))
 277     {
 278       if (argc <= optind)
 279         error (0, 0, _("missing operand"));
 280       else
 281         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 282       usage (EXIT_FAILURE);
 283     }
 284
 285   if (reference_file)
 286     {
 287       struct stat ref_stats;
 288       if (stat (reference_file, &ref_stats))
 289         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 290                quote (reference_file));
 291
 292       uid = ref_stats.st_uid;
 293       gid = ref_stats.st_gid;
 294       chopt.user_name = uid_to_name (ref_stats.st_uid);
 295       chopt.group_name = gid_to_name (ref_stats.st_gid);
 296     }
 297   else
 298     {
 299       const char *e = parse_user_spec (argv[optind], &uid, &gid,
 300                                        &chopt.user_name, &chopt.group_name);
 301       if (e)
 302         error (EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 303
 304       /* If a group is specified but no user, set the user name to the
 305          empty string so that diagnostics say "ownership :GROUP"
 306          rather than "group GROUP".  */
 307       if (!chopt.user_name && chopt.group_name)
 308         chopt.user_name = bad_cast ("");
 309
 310       optind++;
 311     }
 312
 313   if (chopt.recurse && preserve_root)
 314     {
 315       static struct dev_ino dev_ino_buf;
 316       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 317       if (chopt.root_dev_ino == NULL)
 318         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 319                quote ("/"));
 320     }
 321
 322   bit_flags |= FTS_DEFER_STAT;
 323   ok = chown_files (argv + optind, bit_flags,
 324                     uid, gid,
 325                     required_uid, required_gid, &chopt);
 326
 327   chopt_free (&chopt);
 328
 329   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 330 }