src/chown.c

   1 /* chown, chgrp -- change user and group ownership of files
   2    Copyright (C) 1989-2024 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.h"
  26 #include "chown-core.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_mode == CHOWN_CHOWN ? "chown" : "chgrp")
  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, nullptr, 'R'},
  57   {"changes", no_argument, nullptr, 'c'},
  58   {"dereference", no_argument, nullptr, DEREFERENCE_OPTION},
  59   {"from", required_argument, nullptr, FROM_OPTION},
  60   {"no-dereference", no_argument, nullptr, 'h'},
  61   {"no-preserve-root", no_argument, nullptr, NO_PRESERVE_ROOT},
  62   {"preserve-root", no_argument, nullptr, PRESERVE_ROOT},
  63   {"quiet", no_argument, nullptr, 'f'},
  64   {"silent", no_argument, nullptr, 'f'},
  65   {"reference", required_argument, nullptr, REFERENCE_FILE_OPTION},
  66   {"verbose", no_argument, nullptr, 'v'},
  67   {GETOPT_HELP_OPTION_DECL},
  68   {GETOPT_VERSION_OPTION_DECL},
  69   {nullptr, 0, nullptr, 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]... %s FILE...\n\
  81   or:  %s [OPTION]... --reference=RFILE FILE...\n\
  82 "),
  83               program_name,
  84               chown_mode == CHOWN_CHOWN ? _("[OWNER][:[GROUP]]") : _("GROUP"),
  85               program_name);
  86       if (chown_mode == CHOWN_CHOWN)
  87         fputs (_("\
  88 Change the owner and/or group of each FILE to OWNER and/or GROUP.\n\
  89 With --reference, change the owner and group of each FILE to those of RFILE.\n\
  90 \n\
  91 "), stdout);
  92       else
  93         fputs (_("\
  94 Change the group of each FILE to GROUP.\n\
  95 With --reference, change the group of each FILE to that of RFILE.\n\
  96 \n\
  97 "), stdout);
  98       fputs (_("\
  99   -c, --changes          like verbose but report only when a change is made\n\
 100   -f, --silent, --quiet  suppress most error messages\n\
 101   -v, --verbose          output a diagnostic for every file processed\n\
 102 "), stdout);
 103       fputs (_("\
 104       --dereference      affect the referent of each symbolic link (this is\n\
 105                          the default), rather than the symbolic link itself\n\
 106   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
 107 "), stdout);
 108       fputs (_("\
 109                          (useful only on systems that can change the\n\
 110                          ownership of a symlink)\n\
 111 "), stdout);
 112       fputs (_("\
 113       --from=CURRENT_OWNER:CURRENT_GROUP\n\
 114                          change the ownership of each file only if\n\
 115                          its current owner and/or group match those specified\n\
 116                          here. Either may be omitted, in which case a match\n\
 117                          is not required for the omitted attribute\n\
 118 "), stdout);
 119       fputs (_("\
 120       --no-preserve-root  do not treat '/' specially (the default)\n\
 121       --preserve-root    fail to operate recursively on '/'\n\
 122 "), stdout);
 123       fputs (_("\
 124       --reference=RFILE  use RFILE's ownership rather than specifying values.\n\
 125                          RFILE is always dereferenced if a symbolic link.\n\
 126 "), stdout);
 127       fputs (_("\
 128   -R, --recursive        operate on files and directories recursively\n\
 129 "), stdout);
 130       emit_symlink_recurse_options ("-P");
 131       fputs (HELP_OPTION_DESCRIPTION, stdout);
 132       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 133       if (chown_mode == CHOWN_CHOWN)
 134         fputs (_("\
 135 \n\
 136 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 137 to login group if implied by a ':' following a symbolic OWNER.\n\
 138 OWNER and GROUP may be numeric as well as symbolic.\n\
 139 "), stdout);
 140
 141       if (chown_mode == CHOWN_CHOWN)
 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       else
 151         printf (_("\
 152 \n\
 153 Examples:\n\
 154   %s staff /u      Change the group of /u to \"staff\".\n\
 155   %s -hR staff /u  Change the group of /u and subfiles to \"staff\".\n\
 156 "),
 157               program_name, program_name);
 158       emit_ancillary_info (PROGRAM_NAME);
 159     }
 160   exit (status);
 161 }
 162
 163 int
 164 main (int argc, char **argv)
 165 {
 166   bool preserve_root = false;
 167
 168   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 169   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 170
 171   /* Change the owner (group) of a file only if it has this uid (gid).
 172      -1 means there's no restriction.  */
 173   uid_t required_uid = -1;
 174   gid_t required_gid = -1;
 175
 176   /* Bit flags that control how fts works.  */
 177   int bit_flags = FTS_PHYSICAL;
 178
 179   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 180      specified.  */
 181   int dereference = -1;
 182
 183   struct Chown_option chopt;
 184   bool ok;
 185   int optc;
 186
 187   initialize_main (&argc, &argv);
 188   set_program_name (argv[0]);
 189   setlocale (LC_ALL, "");
 190   bindtextdomain (PACKAGE, LOCALEDIR);
 191   textdomain (PACKAGE);
 192
 193   atexit (close_stdout);
 194
 195   chopt_init (&chopt);
 196
 197   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, nullptr))
 198          != -1)
 199     {
 200       switch (optc)
 201         {
 202         case 'H': /* Traverse command-line symlinks-to-directories.  */
 203           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 204           break;
 205
 206         case 'L': /* Traverse all symlinks-to-directories.  */
 207           bit_flags = FTS_LOGICAL;
 208           break;
 209
 210         case 'P': /* Traverse no symlinks-to-directories.  */
 211           bit_flags = FTS_PHYSICAL;
 212           break;
 213
 214         case 'h': /* --no-dereference: affect symlinks */
 215           dereference = 0;
 216           break;
 217
 218         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 219                                     of each symlink */
 220           dereference = 1;
 221           break;
 222
 223         case NO_PRESERVE_ROOT:
 224           preserve_root = false;
 225           break;
 226
 227         case PRESERVE_ROOT:
 228           preserve_root = true;
 229           break;
 230
 231         case REFERENCE_FILE_OPTION:
 232           reference_file = optarg;
 233           break;
 234
 235         case FROM_OPTION:
 236           {
 237             bool warn;
 238             char const *e = parse_user_spec_warn (optarg,
 239                                                   &required_uid, &required_gid,
 240                                                   nullptr, nullptr, &warn);
 241             if (e)
 242               error (warn ? 0 : EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
 243             break;
 244           }
 245
 246         case 'R':
 247           chopt.recurse = true;
 248           break;
 249
 250         case 'c':
 251           chopt.verbosity = V_changes_only;
 252           break;
 253
 254         case 'f':
 255           chopt.force_silent = true;
 256           break;
 257
 258         case 'v':
 259           chopt.verbosity = V_high;
 260           break;
 261
 262         case_GETOPT_HELP_CHAR;
 263         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 264         default:
 265           usage (EXIT_FAILURE);
 266         }
 267     }
 268
 269   if (chopt.recurse)
 270     {
 271       if (bit_flags == FTS_PHYSICAL)
 272         {
 273           if (dereference == 1)
 274             error (EXIT_FAILURE, 0,
 275                    _("-R --dereference requires either -H or -L"));
 276           dereference = 0;
 277         }
 278     }
 279   else
 280     {
 281       bit_flags = FTS_PHYSICAL;
 282     }
 283   chopt.affect_symlink_referent = (dereference != 0);
 284
 285   if (argc - optind < (reference_file ? 1 : 2))
 286     {
 287       if (argc <= optind)
 288         error (0, 0, _("missing operand"));
 289       else
 290         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 291       usage (EXIT_FAILURE);
 292     }
 293
 294   if (reference_file)
 295     {
 296       struct stat ref_stats;
 297       if (stat (reference_file, &ref_stats))
 298         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 299                quoteaf (reference_file));
 300
 301       if (chown_mode == CHOWN_CHOWN)
 302         {
 303           uid = ref_stats.st_uid;
 304           chopt.user_name = uid_to_name (ref_stats.st_uid);
 305         }
 306       gid = ref_stats.st_gid;
 307       chopt.group_name = gid_to_name (ref_stats.st_gid);
 308     }
 309   else
 310     {
 311       char *ug = argv[optind];
 312       if (chown_mode == CHOWN_CHGRP)
 313         {
 314           ug = xmalloc (1 + strlen (argv[optind]) + 1);
 315           stpcpy (stpcpy (ug, ":"), argv[optind]);
 316         }
 317
 318       bool warn;
 319       char const *e = parse_user_spec_warn (ug, &uid, &gid,
 320                                             &chopt.user_name,
 321                                             &chopt.group_name, &warn);
 322
 323       if (ug != argv[optind])
 324         free (ug);
 325
 326       if (e)
 327         error (warn ? 0 : EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 328
 329       /* If a group is specified but no user, set the user name to the
 330          empty string so that diagnostics say "ownership :GROUP"
 331          rather than "group GROUP".  */
 332       if (chown_mode == CHOWN_CHOWN && !chopt.user_name && chopt.group_name)
 333         chopt.user_name = xstrdup ("");
 334
 335       optind++;
 336     }
 337
 338   if (chopt.recurse && preserve_root)
 339     {
 340       static struct dev_ino dev_ino_buf;
 341       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 342       if (chopt.root_dev_ino == nullptr)
 343         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 344                quoteaf ("/"));
 345     }
 346
 347   bit_flags |= FTS_DEFER_STAT;
 348   ok = chown_files (argv + optind, bit_flags,
 349                     uid, gid,
 350                     required_uid, required_gid, &chopt);
 351
 352   main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 353 }