src/chown.c

   1 /* chown -- change user and group ownership of files
   2    Copyright (C) 1989-2022 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 <https://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 "die.h"
  27 #include "error.h"
  28 #include "fts_.h"
  29 #include "quote.h"
  30 #include "root-dev-ino.h"
  31 #include "userspec.h"
  32
  33 /* The official name of this program (e.g., no 'g' prefix).  */
  34 #define PROGRAM_NAME "chown"
  35
  36 #define AUTHORS \
  37   proper_name ("David MacKenzie"), \
  38   proper_name ("Jim Meyering")
  39
  40 /* The argument to the --reference option.  Use the owner and group IDs
  41    of this file.  This file must exist.  */
  42 static char *reference_file;
  43
  44 /* For long options that have no equivalent short option, use a
  45    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  46 enum
  47 {
  48   DEREFERENCE_OPTION = CHAR_MAX + 1,
  49   FROM_OPTION,
  50   NO_PRESERVE_ROOT,
  51   PRESERVE_ROOT,
  52   REFERENCE_FILE_OPTION
  53 };
  54
  55 static struct option const long_options[] =
  56 {
  57   {"recursive", no_argument, NULL, 'R'},
  58   {"changes", no_argument, NULL, 'c'},
  59   {"dereference", no_argument, NULL, DEREFERENCE_OPTION},
  60   {"from", required_argument, NULL, FROM_OPTION},
  61   {"no-dereference", no_argument, NULL, 'h'},
  62   {"no-preserve-root", no_argument, NULL, NO_PRESERVE_ROOT},
  63   {"preserve-root", no_argument, NULL, PRESERVE_ROOT},
  64   {"quiet", no_argument, NULL, 'f'},
  65   {"silent", no_argument, NULL, 'f'},
  66   {"reference", required_argument, NULL, REFERENCE_FILE_OPTION},
  67   {"verbose", no_argument, NULL, 'v'},
  68   {GETOPT_HELP_OPTION_DECL},
  69   {GETOPT_VERSION_OPTION_DECL},
  70   {NULL, 0, NULL, 0}
  71 };
  72
  73 void
  74 usage (int status)
  75 {
  76   if (status != EXIT_SUCCESS)
  77     emit_try_help ();
  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 "), stdout);
  90       fputs (_("\
  91   -c, --changes          like verbose but report only when a change is made\n\
  92   -f, --silent, --quiet  suppress most error messages\n\
  93   -v, --verbose          output a diagnostic for every file processed\n\
  94 "), stdout);
  95       fputs (_("\
  96       --dereference      affect the referent of each symbolic link (this is\n\
  97                          the default), rather than the symbolic link itself\n\
  98   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
  99 "), stdout);
 100       fputs (_("\
 101                          (useful only on systems that can change the\n\
 102                          ownership of a symlink)\n\
 103 "), stdout);
 104       fputs (_("\
 105       --from=CURRENT_OWNER:CURRENT_GROUP\n\
 106                          change the owner and/or group of each file only if\n\
 107                          its current owner and/or group match those specified\n\
 108                          here.  Either may be omitted, in which case a match\n\
 109                          is not required for the omitted attribute\n\
 110 "), stdout);
 111       fputs (_("\
 112       --no-preserve-root  do not treat '/' specially (the default)\n\
 113       --preserve-root    fail to operate recursively on '/'\n\
 114 "), stdout);
 115       fputs (_("\
 116       --reference=RFILE  use RFILE's owner and group rather than\n\
 117                          specifying OWNER:GROUP values\n\
 118 "), stdout);
 119       fputs (_("\
 120   -R, --recursive        operate on files and directories recursively\n\
 121 "), stdout);
 122       fputs (_("\
 123 \n\
 124 The following options modify how a hierarchy is traversed when the -R\n\
 125 option is also specified.  If more than one is specified, only the final\n\
 126 one takes effect.\n\
 127 \n\
 128   -H                     if a command line argument is a symbolic link\n\
 129                          to a directory, traverse it\n\
 130   -L                     traverse every symbolic link to a directory\n\
 131                          encountered\n\
 132   -P                     do not traverse any symbolic links (default)\n\
 133 \n\
 134 "), stdout);
 135       fputs (HELP_OPTION_DESCRIPTION, stdout);
 136       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 137       fputs (_("\
 138 \n\
 139 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 140 to login group if implied by a ':' following a symbolic OWNER.\n\
 141 OWNER and GROUP may be numeric as well as symbolic.\n\
 142 "), stdout);
 143       printf (_("\
 144 \n\
 145 Examples:\n\
 146   %s root /u        Change the owner of /u to \"root\".\n\
 147   %s root:staff /u  Likewise, but also change its group to \"staff\".\n\
 148   %s -hR root /u    Change the owner of /u and subfiles to \"root\".\n\
 149 "),
 150               program_name, program_name, program_name);
 151       emit_ancillary_info (PROGRAM_NAME);
 152     }
 153   exit (status);
 154 }
 155
 156 int
 157 main (int argc, char **argv)
 158 {
 159   bool preserve_root = false;
 160
 161   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 162   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 163
 164   /* Change the owner (group) of a file only if it has this uid (gid).
 165      -1 means there's no restriction.  */
 166   uid_t required_uid = -1;
 167   gid_t required_gid = -1;
 168
 169   /* Bit flags that control how fts works.  */
 170   int bit_flags = FTS_PHYSICAL;
 171
 172   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 173      specified.  */
 174   int dereference = -1;
 175
 176   struct Chown_option chopt;
 177   bool ok;
 178   int optc;
 179
 180   initialize_main (&argc, &argv);
 181   set_program_name (argv[0]);
 182   setlocale (LC_ALL, "");
 183   bindtextdomain (PACKAGE, LOCALEDIR);
 184   textdomain (PACKAGE);
 185
 186   atexit (close_stdout);
 187
 188   chopt_init (&chopt);
 189
 190   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, NULL))
 191          != -1)
 192     {
 193       switch (optc)
 194         {
 195         case 'H': /* Traverse command-line symlinks-to-directories.  */
 196           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 197           break;
 198
 199         case 'L': /* Traverse all symlinks-to-directories.  */
 200           bit_flags = FTS_LOGICAL;
 201           break;
 202
 203         case 'P': /* Traverse no symlinks-to-directories.  */
 204           bit_flags = FTS_PHYSICAL;
 205           break;
 206
 207         case 'h': /* --no-dereference: affect symlinks */
 208           dereference = 0;
 209           break;
 210
 211         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 212                                     of each symlink */
 213           dereference = 1;
 214           break;
 215
 216         case NO_PRESERVE_ROOT:
 217           preserve_root = false;
 218           break;
 219
 220         case PRESERVE_ROOT:
 221           preserve_root = true;
 222           break;
 223
 224         case REFERENCE_FILE_OPTION:
 225           reference_file = optarg;
 226           break;
 227
 228         case FROM_OPTION:
 229           {
 230             char const *e = parse_user_spec (optarg,
 231                                              &required_uid, &required_gid,
 232                                              NULL, NULL);
 233             if (e)
 234               die (EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
 235             break;
 236           }
 237
 238         case 'R':
 239           chopt.recurse = true;
 240           break;
 241
 242         case 'c':
 243           chopt.verbosity = V_changes_only;
 244           break;
 245
 246         case 'f':
 247           chopt.force_silent = true;
 248           break;
 249
 250         case 'v':
 251           chopt.verbosity = V_high;
 252           break;
 253
 254         case_GETOPT_HELP_CHAR;
 255         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 256         default:
 257           usage (EXIT_FAILURE);
 258         }
 259     }
 260
 261   if (chopt.recurse)
 262     {
 263       if (bit_flags == FTS_PHYSICAL)
 264         {
 265           if (dereference == 1)
 266             die (EXIT_FAILURE, 0,
 267                  _("-R --dereference requires either -H or -L"));
 268           dereference = 0;
 269         }
 270     }
 271   else
 272     {
 273       bit_flags = FTS_PHYSICAL;
 274     }
 275   chopt.affect_symlink_referent = (dereference != 0);
 276
 277   if (argc - optind < (reference_file ? 1 : 2))
 278     {
 279       if (argc <= optind)
 280         error (0, 0, _("missing operand"));
 281       else
 282         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 283       usage (EXIT_FAILURE);
 284     }
 285
 286   if (reference_file)
 287     {
 288       struct stat ref_stats;
 289       if (stat (reference_file, &ref_stats))
 290         die (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 291              quoteaf (reference_file));
 292
 293       uid = ref_stats.st_uid;
 294       gid = ref_stats.st_gid;
 295       chopt.user_name = uid_to_name (ref_stats.st_uid);
 296       chopt.group_name = gid_to_name (ref_stats.st_gid);
 297     }
 298   else
 299     {
 300       char const *e = parse_user_spec (argv[optind], &uid, &gid,
 301                                        &chopt.user_name, &chopt.group_name);
 302       if (e)
 303         die (EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 304
 305       /* If a group is specified but no user, set the user name to the
 306          empty string so that diagnostics say "ownership :GROUP"
 307          rather than "group GROUP".  */
 308       if (!chopt.user_name && chopt.group_name)
 309         chopt.user_name = xstrdup ("");
 310
 311       optind++;
 312     }
 313
 314   if (chopt.recurse && preserve_root)
 315     {
 316       static struct dev_ino dev_ino_buf;
 317       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 318       if (chopt.root_dev_ino == NULL)
 319         die (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 320              quoteaf ("/"));
 321     }
 322
 323   bit_flags |= FTS_DEFER_STAT;
 324   ok = chown_files (argv + optind, bit_flags,
 325                     uid, gid,
 326                     required_uid, required_gid, &chopt);
 327
 328   IF_LINT (chopt_free (&chopt));
 329
 330   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 331 }