src/chgrp.c

   1 /* chgrp -- change 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 <grp.h>
  23 #include <getopt.h>
  24
  25 #include "system.h"
  26 #include "chown-core.h"
  27 #include "fts_.h"
  28 #include "quote.h"
  29 #include "root-dev-ino.h"
  30 #include "xstrtol.h"
  31
  32 /* The official name of this program (e.g., no 'g' prefix).  */
  33 #define PROGRAM_NAME "chgrp"
  34
  35 #define AUTHORS \
  36   proper_name ("David MacKenzie"), \
  37   proper_name ("Jim Meyering")
  38
  39 #if ! HAVE_ENDGRENT
  40 # define endgrent() ((void) 0)
  41 #endif
  42
  43 /* The argument to the --reference option.  Use the group ID of this file.
  44    This file must exist.  */
  45 static char *reference_file;
  46
  47 /* For long options that have no equivalent short option, use a
  48    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  49 enum
  50 {
  51   DEREFERENCE_OPTION = CHAR_MAX + 1,
  52   NO_PRESERVE_ROOT,
  53   PRESERVE_ROOT,
  54   REFERENCE_FILE_OPTION
  55 };
  56
  57 static struct option const long_options[] =
  58 {
  59   {"recursive", no_argument, nullptr, 'R'},
  60   {"changes", no_argument, nullptr, 'c'},
  61   {"dereference", no_argument, nullptr, DEREFERENCE_OPTION},
  62   {"no-dereference", no_argument, nullptr, 'h'},
  63   {"no-preserve-root", no_argument, nullptr, NO_PRESERVE_ROOT},
  64   {"preserve-root", no_argument, nullptr, PRESERVE_ROOT},
  65   {"quiet", no_argument, nullptr, 'f'},
  66   {"silent", no_argument, nullptr, 'f'},
  67   {"reference", required_argument, nullptr, REFERENCE_FILE_OPTION},
  68   {"verbose", no_argument, nullptr, 'v'},
  69   {GETOPT_HELP_OPTION_DECL},
  70   {GETOPT_VERSION_OPTION_DECL},
  71   {nullptr, 0, nullptr, 0}
  72 };
  73
  74 /* Return the group ID of NAME, or -1 if no name was specified.  */
  75
  76 static gid_t
  77 parse_group (char const *name)
  78 {
  79   gid_t gid = -1;
  80
  81   if (*name)
  82     {
  83       struct group *grp = getgrnam (name);
  84       if (grp)
  85         gid = grp->gr_gid;
  86       else
  87         {
  88           uintmax_t tmp;
  89           if (! (xstrtoumax (name, nullptr, 10, &tmp, "") == LONGINT_OK
  90                  && tmp <= GID_T_MAX))
  91             error (EXIT_FAILURE, 0, _("invalid group: %s"),
  92                    quote (name));
  93           gid = tmp;
  94         }
  95       endgrent ();              /* Save a file descriptor. */
  96     }
  97
  98   return gid;
  99 }
 100
 101 void
 102 usage (int status)
 103 {
 104   if (status != EXIT_SUCCESS)
 105     emit_try_help ();
 106   else
 107     {
 108       printf (_("\
 109 Usage: %s [OPTION]... GROUP FILE...\n\
 110   or:  %s [OPTION]... --reference=RFILE FILE...\n\
 111 "),
 112               program_name, program_name);
 113       fputs (_("\
 114 Change the group of each FILE to GROUP.\n\
 115 With --reference, change the group of each FILE to that of RFILE.\n\
 116 \n\
 117 "), stdout);
 118       fputs (_("\
 119   -c, --changes          like verbose but report only when a change is made\n\
 120   -f, --silent, --quiet  suppress most error messages\n\
 121   -v, --verbose          output a diagnostic for every file processed\n\
 122 "), stdout);
 123       fputs (_("\
 124       --dereference      affect the referent of each symbolic link (this is\n\
 125                          the default), rather than the symbolic link itself\n\
 126   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
 127 "), stdout);
 128       fputs (_("\
 129                          (useful only on systems that can change the\n\
 130                          ownership of a symlink)\n\
 131 "), stdout);
 132       fputs (_("\
 133       --no-preserve-root  do not treat '/' specially (the default)\n\
 134       --preserve-root    fail to operate recursively on '/'\n\
 135 "), stdout);
 136       fputs (_("\
 137       --reference=RFILE  use RFILE's group rather than specifying a GROUP.\n\
 138                          RFILE is always dereferenced if a symbolic link.\n\
 139 "), stdout);
 140       fputs (_("\
 141   -R, --recursive        operate on files and directories recursively\n\
 142 "), stdout);
 143       fputs (_("\
 144 \n\
 145 The following options modify how a hierarchy is traversed when the -R\n\
 146 option is also specified.  If more than one is specified, only the final\n\
 147 one takes effect.\n\
 148 \n\
 149   -H                     if a command line argument is a symbolic link\n\
 150                          to a directory, traverse it\n\
 151   -L                     traverse every symbolic link to a directory\n\
 152                          encountered\n\
 153   -P                     do not traverse any symbolic links (default)\n\
 154 \n\
 155 "), stdout);
 156       fputs (HELP_OPTION_DESCRIPTION, stdout);
 157       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 158       printf (_("\
 159 \n\
 160 Examples:\n\
 161   %s staff /u      Change the group of /u to \"staff\".\n\
 162   %s -hR staff /u  Change the group of /u and subfiles to \"staff\".\n\
 163 "),
 164               program_name, program_name);
 165       emit_ancillary_info (PROGRAM_NAME);
 166     }
 167   exit (status);
 168 }
 169
 170 int
 171 main (int argc, char **argv)
 172 {
 173   bool preserve_root = false;
 174   gid_t gid;
 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 'R':
 236           chopt.recurse = true;
 237           break;
 238
 239         case 'c':
 240           chopt.verbosity = V_changes_only;
 241           break;
 242
 243         case 'f':
 244           chopt.force_silent = true;
 245           break;
 246
 247         case 'v':
 248           chopt.verbosity = V_high;
 249           break;
 250
 251         case_GETOPT_HELP_CHAR;
 252         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 253         default:
 254           usage (EXIT_FAILURE);
 255         }
 256     }
 257
 258   if (chopt.recurse)
 259     {
 260       if (bit_flags == FTS_PHYSICAL)
 261         {
 262           if (dereference == 1)
 263             error (EXIT_FAILURE, 0,
 264                    _("-R --dereference requires either -H or -L"));
 265           dereference = 0;
 266         }
 267     }
 268   else
 269     {
 270       bit_flags = FTS_PHYSICAL;
 271     }
 272   chopt.affect_symlink_referent = (dereference != 0);
 273
 274   if (argc - optind < (reference_file ? 1 : 2))
 275     {
 276       if (argc <= optind)
 277         error (0, 0, _("missing operand"));
 278       else
 279         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 280       usage (EXIT_FAILURE);
 281     }
 282
 283   if (reference_file)
 284     {
 285       struct stat ref_stats;
 286       if (stat (reference_file, &ref_stats))
 287         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 288                quoteaf (reference_file));
 289
 290       gid = ref_stats.st_gid;
 291       chopt.group_name = gid_to_name (ref_stats.st_gid);
 292     }
 293   else
 294     {
 295       char *group_name = argv[optind++];
 296       chopt.group_name = (*group_name ? xstrdup (group_name) : nullptr);
 297       gid = parse_group (group_name);
 298     }
 299
 300   if (chopt.recurse && preserve_root)
 301     {
 302       static struct dev_ino dev_ino_buf;
 303       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 304       if (chopt.root_dev_ino == nullptr)
 305         error (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 306                quoteaf ("/"));
 307     }
 308
 309   bit_flags |= FTS_DEFER_STAT;
 310   ok = chown_files (argv + optind, bit_flags,
 311                     (uid_t) -1, gid,
 312                     (uid_t) -1, (gid_t) -1, &chopt);
 313
 314   main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 315 }