src/chown.c

   1 /* chown -- change user and group ownership of files
   2    Copyright (C) 1989-2023 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 "fts_.h"
  27 #include "quote.h"
  28 #include "root-dev-ino.h"
  29 #include "userspec.h"
  30
  31 /* The official name of this program (e.g., no 'g' prefix).  */
  32 #define PROGRAM_NAME "chown"
  33
  34 #define AUTHORS \
  35   proper_name ("David MacKenzie"), \
  36   proper_name ("Jim Meyering")
  37
  38 /* The argument to the --reference option.  Use the owner and group IDs
  39    of this file.  This file must exist.  */
  40 static char *reference_file;
  41
  42 /* For long options that have no equivalent short option, use a
  43    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  44 enum
  45 {
  46   DEREFERENCE_OPTION = CHAR_MAX + 1,
  47   FROM_OPTION,
  48   NO_PRESERVE_ROOT,
  49   PRESERVE_ROOT,
  50   REFERENCE_FILE_OPTION
  51 };
  52
  53 static struct option const long_options[] =
  54 {
  55   {"recursive", no_argument, nullptr, 'R'},
  56   {"changes", no_argument, nullptr, 'c'},
  57   {"dereference", no_argument, nullptr, DEREFERENCE_OPTION},
  58   {"from", required_argument, nullptr, FROM_OPTION},
  59   {"no-dereference", no_argument, nullptr, 'h'},
  60   {"no-preserve-root", no_argument, nullptr, NO_PRESERVE_ROOT},
  61   {"preserve-root", no_argument, nullptr, PRESERVE_ROOT},
  62   {"quiet", no_argument, nullptr, 'f'},
  63   {"silent", no_argument, nullptr, 'f'},
  64   {"reference", required_argument, nullptr, REFERENCE_FILE_OPTION},
  65   {"verbose", no_argument, nullptr, 'v'},
  66   {GETOPT_HELP_OPTION_DECL},
  67   {GETOPT_VERSION_OPTION_DECL},
  68   {nullptr, 0, nullptr, 0}
  69 };
  70
  71 void
  72 usage (int status)
  73 {
  74   if (status != EXIT_SUCCESS)
  75     emit_try_help ();
  76   else
  77     {
  78       printf (_("\
  79 Usage: %s [OPTION]... [OWNER][:[GROUP]] FILE...\n\
  80   or:  %s [OPTION]... --reference=RFILE FILE...\n\
  81 "),
  82               program_name, program_name);
  83       fputs (_("\
  84 Change the owner and/or group of each FILE to OWNER and/or GROUP.\n\
  85 With --reference, change the owner and group of each FILE to those of RFILE.\n\
  86 \n\
  87 "), stdout);
  88       fputs (_("\
  89   -c, --changes          like verbose but report only when a change is made\n\
  90   -f, --silent, --quiet  suppress most error messages\n\
  91   -v, --verbose          output a diagnostic for every file processed\n\
  92 "), stdout);
  93       fputs (_("\
  94       --dereference      affect the referent of each symbolic link (this is\n\
  95                          the default), rather than the symbolic link itself\n\
  96   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
  97 "), stdout);
  98       fputs (_("\
  99                          (useful only on systems that can change the\n\
 100                          ownership of a symlink)\n\
 101 "), stdout);
 102       fputs (_("\
 103       --from=CURRENT_OWNER:CURRENT_GROUP\n\
 104                          change the owner and/or group of each file only if\n\
 105                          its current owner and/or group match those specified\n\
 106                          here.  Either may be omitted, in which case a match\n\
 107                          is not required for the omitted attribute\n\
 108 "), stdout);
 109       fputs (_("\
 110       --no-preserve-root  do not treat '/' specially (the default)\n\
 111       --preserve-root    fail to operate recursively on '/'\n\
 112 "), stdout);
 113       fputs (_("\
 114       --reference=RFILE  use RFILE's owner and group rather than specifying\n\
 115                          OWNER:GROUP values.  RFILE is always dereferenced.\n\
 116 "), stdout);
 117       fputs (_("\
 118   -R, --recursive        operate on files and directories recursively\n\
 119 "), stdout);
 120       fputs (_("\
 121 \n\
 122 The following options modify how a hierarchy is traversed when the -R\n\
 123 option is also specified.  If more than one is specified, only the final\n\
 124 one takes effect.\n\
 125 \n\
 126   -H                     if a command line argument is a symbolic link\n\
 127                          to a directory, traverse it\n\
 128   -L                     traverse every symbolic link to a directory\n\
 129                          encountered\n\
 130   -P                     do not traverse any symbolic links (default)\n\
 131 \n\
 132 "), stdout);
 133       fputs (HELP_OPTION_DESCRIPTION, stdout);
 134       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 135       fputs (_("\
 136 \n\
 137 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 138 to login group if implied by a ':' following a symbolic OWNER.\n\
 139 OWNER and GROUP may be numeric as well as symbolic.\n\
 140 "), stdout);
 141       printf (_("\
 142 \n\
 143 Examples:\n\
 144   %s root /u        Change the owner of /u to \"root\".\n\
 145   %s root:staff /u  Likewise, but also change its group to \"staff\".\n\
 146   %s -hR root /u    Change the owner of /u and subfiles to \"root\".\n\
 147 "),
 148               program_name, program_name, program_name);
 149       emit_ancillary_info (PROGRAM_NAME);
 150     }
 151   exit (status);
 152 }
 153
 154 int
 155 main (int argc, char **argv)
 156 {
 157   bool preserve_root = false;
 158
 159   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 160   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 161
 162   /* Change the owner (group) of a file only if it has this uid (gid).
 163      -1 means there's no restriction.  */
 164   uid_t required_uid = -1;
 165   gid_t required_gid = -1;
 166
 167   /* Bit flags that control how fts works.  */
 168   int bit_flags = FTS_PHYSICAL;
 169
 170   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 171      specified.  */
 172   int dereference = -1;
 173
 174   struct Chown_option chopt;
 175   bool ok;
 176   int optc;
 177
 178   initialize_main (&argc, &argv);
 179   set_program_name (argv[0]);
 180   setlocale (LC_ALL, "");
 181   bindtextdomain (PACKAGE, LOCALEDIR);
 182   textdomain (PACKAGE);
 183
 184   atexit (close_stdout);
 185
 186   chopt_init (&chopt);
 187
 188   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, nullptr))
 189          != -1)
 190     {
 191       switch (optc)
 192         {
 193         case 'H': /* Traverse command-line symlinks-to-directories.  */
 194           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 195           break;
 196
 197         case 'L': /* Traverse all symlinks-to-directories.  */
 198           bit_flags = FTS_LOGICAL;
 199           break;
 200
 201         case 'P': /* Traverse no symlinks-to-directories.  */
 202           bit_flags = FTS_PHYSICAL;
 203           break;
 204
 205         case 'h': /* --no-dereference: affect symlinks */
 206           dereference = 0;
 207           break;
 208
 209         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 210                                     of each symlink */
 211           dereference = 1;
 212           break;
 213
 214         case NO_PRESERVE_ROOT:
 215           preserve_root = false;
 216           break;
 217
 218         case PRESERVE_ROOT:
 219           preserve_root = true;
 220           break;
 221
 222         case REFERENCE_FILE_OPTION:
 223           reference_file = optarg;
 224           break;
 225
 226         case FROM_OPTION:
 227           {
 228             bool warn;
 229             char const *e = parse_user_spec_warn (optarg,
 230                                                   &required_uid, &required_gid,
 231                                                   nullptr, nullptr, &warn);
 232             if (e)
 233               error (warn ? 0 : 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                quoteaf (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       bool warn;
 300       char const *e = parse_user_spec_warn (argv[optind], &uid, &gid,
 301                                             &chopt.user_name,
 302                                             &chopt.group_name, &warn);
 303       if (e)
 304         error (warn ? 0 : EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 305
 306       /* If a group is specified but no user, set the user name to the
 307          empty string so that diagnostics say "ownership :GROUP"
 308          rather than "group GROUP".  */
 309       if (!chopt.user_name && chopt.group_name)
 310         chopt.user_name = xstrdup ("");
 311
 312       optind++;
 313     }
 314
 315   if (chopt.recurse && preserve_root)
 316     {
 317       static struct dev_ino dev_ino_buf;
 318       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 319       if (chopt.root_dev_ino == nullptr)
 320         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 321                quoteaf ("/"));
 322     }
 323
 324   bit_flags |= FTS_DEFER_STAT;
 325   ok = chown_files (argv + optind, bit_flags,
 326                     uid, gid,
 327                     required_uid, required_gid, &chopt);
 328
 329   main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 330 }