src/chown.c

   1 /* chown -- change user and group ownership of files
   2    Copyright (C) 1989-1991, 1995-2010 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     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  77              program_name);
  78   else
  79     {
  80       printf (_("\
  81 Usage: %s [OPTION]... [OWNER][:[GROUP]] FILE...\n\
  82   or:  %s [OPTION]... --reference=RFILE FILE...\n\
  83 "),
  84               program_name, program_name);
  85       fputs (_("\
  86 Change the owner and/or group of each FILE to OWNER and/or GROUP.\n\
  87 With --reference, change the owner and group of each FILE to those of RFILE.\n\
  88 \n\
  89   -c, --changes          like verbose but report only when a change is made\n\
  90       --dereference      affect the referent of each symbolic link (this is\n\
  91                          the default), rather than the symbolic link itself\n\
  92 "), stdout);
  93       fputs (_("\
  94   -h, --no-dereference   affect each symbolic link instead of any referenced\n\
  95                          file (useful only on systems that can change the\n\
  96                          ownership of a symlink)\n\
  97 "), stdout);
  98       fputs (_("\
  99       --from=CURRENT_OWNER:CURRENT_GROUP\n\
 100                          change the owner and/or group of each file only if\n\
 101                          its current owner and/or group match those specified\n\
 102                          here.  Either may be omitted, in which case a match\n\
 103                          is not required for the omitted attribute.\n\
 104 "), stdout);
 105       fputs (_("\
 106       --no-preserve-root  do not treat `/' specially (the default)\n\
 107       --preserve-root    fail to operate recursively on `/'\n\
 108 "), stdout);
 109       fputs (_("\
 110   -f, --silent, --quiet  suppress most error messages\n\
 111       --reference=RFILE  use RFILE's owner and group rather than\n\
 112                          specifying OWNER:GROUP values\n\
 113   -R, --recursive        operate on files and directories recursively\n\
 114   -v, --verbose          output a diagnostic for every file processed\n\
 115 \n\
 116 "), stdout);
 117       fputs (_("\
 118 The following options modify how a hierarchy is traversed when the -R\n\
 119 option is also specified.  If more than one is specified, only the final\n\
 120 one takes effect.\n\
 121 \n\
 122   -H                     if a command line argument is a symbolic link\n\
 123                          to a directory, traverse it\n\
 124   -L                     traverse every symbolic link to a directory\n\
 125                          encountered\n\
 126   -P                     do not traverse any symbolic links (default)\n\
 127 \n\
 128 "), stdout);
 129       fputs (HELP_OPTION_DESCRIPTION, stdout);
 130       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 131       fputs (_("\
 132 \n\
 133 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 134 to login group if implied by a `:' following a symbolic OWNER.\n\
 135 OWNER and GROUP may be numeric as well as symbolic.\n\
 136 "), stdout);
 137       printf (_("\
 138 \n\
 139 Examples:\n\
 140   %s root /u        Change the owner of /u to \"root\".\n\
 141   %s root:staff /u  Likewise, but also change its group to \"staff\".\n\
 142   %s -hR root /u    Change the owner of /u and subfiles to \"root\".\n\
 143 "),
 144               program_name, program_name, program_name);
 145       emit_ancillary_info ();
 146     }
 147   exit (status);
 148 }
 149
 150 int
 151 main (int argc, char **argv)
 152 {
 153   bool preserve_root = false;
 154
 155   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 156   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 157
 158   /* Change the owner (group) of a file only if it has this uid (gid).
 159      -1 means there's no restriction.  */
 160   uid_t required_uid = -1;
 161   gid_t required_gid = -1;
 162
 163   /* Bit flags that control how fts works.  */
 164   int bit_flags = FTS_PHYSICAL;
 165
 166   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 167      specified.  */
 168   int dereference = -1;
 169
 170   struct Chown_option chopt;
 171   bool ok;
 172   int optc;
 173
 174   initialize_main (&argc, &argv);
 175   set_program_name (argv[0]);
 176   setlocale (LC_ALL, "");
 177   bindtextdomain (PACKAGE, LOCALEDIR);
 178   textdomain (PACKAGE);
 179
 180   atexit (close_stdout);
 181
 182   chopt_init (&chopt);
 183
 184   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, NULL))
 185          != -1)
 186     {
 187       switch (optc)
 188         {
 189         case 'H': /* Traverse command-line symlinks-to-directories.  */
 190           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 191           break;
 192
 193         case 'L': /* Traverse all symlinks-to-directories.  */
 194           bit_flags = FTS_LOGICAL;
 195           break;
 196
 197         case 'P': /* Traverse no symlinks-to-directories.  */
 198           bit_flags = FTS_PHYSICAL;
 199           break;
 200
 201         case 'h': /* --no-dereference: affect symlinks */
 202           dereference = 0;
 203           break;
 204
 205         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 206                                     of each symlink */
 207           dereference = 1;
 208           break;
 209
 210         case NO_PRESERVE_ROOT:
 211           preserve_root = false;
 212           break;
 213
 214         case PRESERVE_ROOT:
 215           preserve_root = true;
 216           break;
 217
 218         case REFERENCE_FILE_OPTION:
 219           reference_file = optarg;
 220           break;
 221
 222         case FROM_OPTION:
 223           {
 224             char *u_dummy, *g_dummy;
 225             const char *e = parse_user_spec (optarg,
 226                                              &required_uid, &required_gid,
 227                                              &u_dummy, &g_dummy);
 228             if (e)
 229               error (EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
 230             break;
 231           }
 232
 233         case 'R':
 234           chopt.recurse = true;
 235           break;
 236
 237         case 'c':
 238           chopt.verbosity = V_changes_only;
 239           break;
 240
 241         case 'f':
 242           chopt.force_silent = true;
 243           break;
 244
 245         case 'v':
 246           chopt.verbosity = V_high;
 247           break;
 248
 249         case_GETOPT_HELP_CHAR;
 250         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 251         default:
 252           usage (EXIT_FAILURE);
 253         }
 254     }
 255
 256   if (chopt.recurse)
 257     {
 258       if (bit_flags == FTS_PHYSICAL)
 259         {
 260           if (dereference == 1)
 261             error (EXIT_FAILURE, 0,
 262                    _("-R --dereference requires either -H or -L"));
 263           dereference = 0;
 264         }
 265     }
 266   else
 267     {
 268       bit_flags = FTS_PHYSICAL;
 269     }
 270   chopt.affect_symlink_referent = (dereference != 0);
 271
 272   if (argc - optind < (reference_file ? 1 : 2))
 273     {
 274       if (argc <= optind)
 275         error (0, 0, _("missing operand"));
 276       else
 277         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 278       usage (EXIT_FAILURE);
 279     }
 280
 281   if (reference_file)
 282     {
 283       struct stat ref_stats;
 284       if (stat (reference_file, &ref_stats))
 285         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 286                quote (reference_file));
 287
 288       uid = ref_stats.st_uid;
 289       gid = ref_stats.st_gid;
 290       chopt.user_name = uid_to_name (ref_stats.st_uid);
 291       chopt.group_name = gid_to_name (ref_stats.st_gid);
 292     }
 293   else
 294     {
 295       const char *e = parse_user_spec (argv[optind], &uid, &gid,
 296                                        &chopt.user_name, &chopt.group_name);
 297       if (e)
 298         error (EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 299
 300       /* If a group is specified but no user, set the user name to the
 301          empty string so that diagnostics say "ownership :GROUP"
 302          rather than "group GROUP".  */
 303       if (!chopt.user_name && chopt.group_name)
 304         chopt.user_name = bad_cast ("");
 305
 306       optind++;
 307     }
 308
 309   if (chopt.recurse && preserve_root)
 310     {
 311       static struct dev_ino dev_ino_buf;
 312       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 313       if (chopt.root_dev_ino == NULL)
 314         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 315                quote ("/"));
 316     }
 317
 318   bit_flags |= FTS_DEFER_STAT;
 319   ok = chown_files (argv + optind, bit_flags,
 320                     uid, gid,
 321                     required_uid, required_gid, &chopt);
 322
 323   chopt_free (&chopt);
 324
 325   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 326 }