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       emit_from_option_description (chown_mode == CHOWN_CHOWN);
 113       fputs (_("\
 114       --no-preserve-root  do not treat '/' specially (the default)\n\
 115       --preserve-root    fail to operate recursively on '/'\n\
 116 "), stdout);
 117       fputs (_("\
 118       --reference=RFILE  use RFILE's ownership rather than specifying values\n\
 119                          RFILE is always dereferenced if a symbolic link.\n\
 120 "), stdout);
 121       fputs (_("\
 122   -R, --recursive        operate on files and directories recursively\n\
 123 "), stdout);
 124       emit_symlink_recurse_options ("-P");
 125       fputs (HELP_OPTION_DESCRIPTION, stdout);
 126       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 127       if (chown_mode == CHOWN_CHOWN)
 128         fputs (_("\
 129 \n\
 130 Owner is unchanged if missing.  Group is unchanged if missing, but changed\n\
 131 to login group if implied by a ':' following a symbolic OWNER.\n\
 132 OWNER and GROUP may be numeric as well as symbolic.\n\
 133 "), stdout);
 134
 135       if (chown_mode == CHOWN_CHOWN)
 136         printf (_("\
 137 \n\
 138 Examples:\n\
 139   %s root /u        Change the owner of /u to \"root\".\n\
 140   %s root:staff /u  Likewise, but also change its group to \"staff\".\n\
 141   %s -hR root /u    Change the owner of /u and subfiles to \"root\".\n\
 142 "),
 143               program_name, program_name, program_name);
 144       else
 145         printf (_("\
 146 \n\
 147 Examples:\n\
 148   %s staff /u      Change the group of /u to \"staff\".\n\
 149   %s -hR staff /u  Change the group of /u and subfiles to \"staff\".\n\
 150 "),
 151               program_name, program_name);
 152       emit_ancillary_info (PROGRAM_NAME);
 153     }
 154   exit (status);
 155 }
 156
 157 int
 158 main (int argc, char **argv)
 159 {
 160   bool preserve_root = false;
 161
 162   uid_t uid = -1;       /* Specified uid; -1 if not to be changed. */
 163   gid_t gid = -1;       /* Specified gid; -1 if not to be changed. */
 164
 165   /* Change the owner (group) of a file only if it has this uid (gid).
 166      -1 means there's no restriction.  */
 167   uid_t required_uid = -1;
 168   gid_t required_gid = -1;
 169
 170   /* Bit flags that control how fts works.  */
 171   int bit_flags = FTS_PHYSICAL;
 172
 173   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 174      specified.  */
 175   int dereference = -1;
 176
 177   struct Chown_option chopt;
 178   bool ok;
 179   int optc;
 180
 181   initialize_main (&argc, &argv);
 182   set_program_name (argv[0]);
 183   setlocale (LC_ALL, "");
 184   bindtextdomain (PACKAGE, LOCALEDIR);
 185   textdomain (PACKAGE);
 186
 187   atexit (close_stdout);
 188
 189   chopt_init (&chopt);
 190
 191   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, nullptr))
 192          != -1)
 193     {
 194       switch (optc)
 195         {
 196         case 'H': /* Traverse command-line symlinks-to-directories.  */
 197           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 198           break;
 199
 200         case 'L': /* Traverse all symlinks-to-directories.  */
 201           bit_flags = FTS_LOGICAL;
 202           break;
 203
 204         case 'P': /* Traverse no symlinks-to-directories.  */
 205           bit_flags = FTS_PHYSICAL;
 206           break;
 207
 208         case 'h': /* --no-dereference: affect symlinks */
 209           dereference = 0;
 210           break;
 211
 212         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 213                                     of each symlink */
 214           dereference = 1;
 215           break;
 216
 217         case NO_PRESERVE_ROOT:
 218           preserve_root = false;
 219           break;
 220
 221         case PRESERVE_ROOT:
 222           preserve_root = true;
 223           break;
 224
 225         case REFERENCE_FILE_OPTION:
 226           reference_file = optarg;
 227           break;
 228
 229         case FROM_OPTION:
 230           {
 231             bool warn;
 232             char const *e = parse_user_spec_warn (optarg,
 233                                                   &required_uid, &required_gid,
 234                                                   nullptr, nullptr, &warn);
 235             if (e)
 236               error (warn ? 0 : EXIT_FAILURE, 0, "%s: %s", e, quote (optarg));
 237             break;
 238           }
 239
 240         case 'R':
 241           chopt.recurse = true;
 242           break;
 243
 244         case 'c':
 245           chopt.verbosity = V_changes_only;
 246           break;
 247
 248         case 'f':
 249           chopt.force_silent = true;
 250           break;
 251
 252         case 'v':
 253           chopt.verbosity = V_high;
 254           break;
 255
 256         case_GETOPT_HELP_CHAR;
 257         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 258         default:
 259           usage (EXIT_FAILURE);
 260         }
 261     }
 262
 263   if (chopt.recurse)
 264     {
 265       if (bit_flags == FTS_PHYSICAL)
 266         {
 267           if (dereference == 1)
 268             error (EXIT_FAILURE, 0,
 269                    _("-R --dereference requires either -H or -L"));
 270           dereference = 0;
 271         }
 272     }
 273   else
 274     {
 275       bit_flags = FTS_PHYSICAL;
 276     }
 277   chopt.affect_symlink_referent = (dereference != 0);
 278
 279   if (argc - optind < (reference_file ? 1 : 2))
 280     {
 281       if (argc <= optind)
 282         error (0, 0, _("missing operand"));
 283       else
 284         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 285       usage (EXIT_FAILURE);
 286     }
 287
 288   if (reference_file)
 289     {
 290       struct stat ref_stats;
 291       if (stat (reference_file, &ref_stats))
 292         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 293                quoteaf (reference_file));
 294
 295       if (chown_mode == CHOWN_CHOWN)
 296         {
 297           uid = ref_stats.st_uid;
 298           chopt.user_name = uid_to_name (ref_stats.st_uid);
 299         }
 300       gid = ref_stats.st_gid;
 301       chopt.group_name = gid_to_name (ref_stats.st_gid);
 302     }
 303   else
 304     {
 305       char *ug = argv[optind];
 306       if (chown_mode == CHOWN_CHGRP)
 307         {
 308           ug = xmalloc (1 + strlen (argv[optind]) + 1);
 309           stpcpy (stpcpy (ug, ":"), argv[optind]);
 310         }
 311
 312       bool warn;
 313       char const *e = parse_user_spec_warn (ug, &uid, &gid,
 314                                             &chopt.user_name,
 315                                             &chopt.group_name, &warn);
 316
 317       if (ug != argv[optind])
 318         free (ug);
 319
 320       if (e)
 321         error (warn ? 0 : EXIT_FAILURE, 0, "%s: %s", e, quote (argv[optind]));
 322
 323       /* If a group is specified but no user, set the user name to the
 324          empty string so that diagnostics say "ownership :GROUP"
 325          rather than "group GROUP".  */
 326       if (chown_mode == CHOWN_CHOWN && !chopt.user_name && chopt.group_name)
 327         chopt.user_name = xstrdup ("");
 328
 329       optind++;
 330     }
 331
 332   if (chopt.recurse && preserve_root)
 333     {
 334       static struct dev_ino dev_ino_buf;
 335       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 336       if (chopt.root_dev_ino == nullptr)
 337         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 338                quoteaf ("/"));
 339     }
 340
 341   bit_flags |= FTS_DEFER_STAT;
 342   ok = chown_files (argv + optind, bit_flags,
 343                     uid, gid,
 344                     required_uid, required_gid, &chopt);
 345
 346   main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 347 }