src/chgrp.c

   1 /* chgrp -- change group ownership of files
   2    Copyright (C) 1989-2017 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 "die.h"
  28 #include "error.h"
  29 #include "fts_.h"
  30 #include "quote.h"
  31 #include "root-dev-ino.h"
  32 #include "xstrtol.h"
  33
  34 /* The official name of this program (e.g., no 'g' prefix).  */
  35 #define PROGRAM_NAME "chgrp"
  36
  37 #define AUTHORS \
  38   proper_name ("David MacKenzie"), \
  39   proper_name ("Jim Meyering")
  40
  41 #if ! HAVE_ENDGRENT
  42 # define endgrent() ((void) 0)
  43 #endif
  44
  45 /* The argument to the --reference option.  Use the group ID of this file.
  46    This file must exist.  */
  47 static char *reference_file;
  48
  49 /* For long options that have no equivalent short option, use a
  50    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  51 enum
  52 {
  53   DEREFERENCE_OPTION = CHAR_MAX + 1,
  54   NO_PRESERVE_ROOT,
  55   PRESERVE_ROOT,
  56   REFERENCE_FILE_OPTION
  57 };
  58
  59 static struct option const long_options[] =
  60 {
  61   {"recursive", no_argument, NULL, 'R'},
  62   {"changes", no_argument, NULL, 'c'},
  63   {"dereference", no_argument, NULL, DEREFERENCE_OPTION},
  64   {"no-dereference", no_argument, NULL, 'h'},
  65   {"no-preserve-root", no_argument, NULL, NO_PRESERVE_ROOT},
  66   {"preserve-root", no_argument, NULL, PRESERVE_ROOT},
  67   {"quiet", no_argument, NULL, 'f'},
  68   {"silent", no_argument, NULL, 'f'},
  69   {"reference", required_argument, NULL, REFERENCE_FILE_OPTION},
  70   {"verbose", no_argument, NULL, 'v'},
  71   {GETOPT_HELP_OPTION_DECL},
  72   {GETOPT_VERSION_OPTION_DECL},
  73   {NULL, 0, NULL, 0}
  74 };
  75
  76 /* Return the group ID of NAME, or -1 if no name was specified.  */
  77
  78 static gid_t
  79 parse_group (const char *name)
  80 {
  81   gid_t gid = -1;
  82
  83   if (*name)
  84     {
  85       struct group *grp = getgrnam (name);
  86       if (grp)
  87         gid = grp->gr_gid;
  88       else
  89         {
  90           unsigned long int tmp;
  91           if (! (xstrtoul (name, NULL, 10, &tmp, "") == LONGINT_OK
  92                  && tmp <= GID_T_MAX))
  93             die (EXIT_FAILURE, 0, _("invalid group: %s"),
  94                  quote (name));
  95           gid = tmp;
  96         }
  97       endgrent ();              /* Save a file descriptor. */
  98     }
  99
 100   return gid;
 101 }
 102
 103 void
 104 usage (int status)
 105 {
 106   if (status != EXIT_SUCCESS)
 107     emit_try_help ();
 108   else
 109     {
 110       printf (_("\
 111 Usage: %s [OPTION]... GROUP FILE...\n\
 112   or:  %s [OPTION]... --reference=RFILE FILE...\n\
 113 "),
 114               program_name, program_name);
 115       fputs (_("\
 116 Change the group of each FILE to GROUP.\n\
 117 With --reference, change the group of each FILE to that of RFILE.\n\
 118 \n\
 119 "), stdout);
 120       fputs (_("\
 121   -c, --changes          like verbose but report only when a change is made\n\
 122   -f, --silent, --quiet  suppress most error messages\n\
 123   -v, --verbose          output a diagnostic for every file processed\n\
 124 "), stdout);
 125       fputs (_("\
 126       --dereference      affect the referent of each symbolic link (this is\n\
 127                          the default), rather than the symbolic link itself\n\
 128   -h, --no-dereference   affect symbolic links instead of any referenced file\n\
 129 "), stdout);
 130       fputs (_("\
 131                          (useful only on systems that can change the\n\
 132                          ownership of a symlink)\n\
 133 "), stdout);
 134       fputs (_("\
 135       --no-preserve-root  do not treat '/' specially (the default)\n\
 136       --preserve-root    fail to operate recursively on '/'\n\
 137 "), stdout);
 138       fputs (_("\
 139       --reference=RFILE  use RFILE's group rather than specifying a\n\
 140                          GROUP value\n\
 141 "), stdout);
 142       fputs (_("\
 143   -R, --recursive        operate on files and directories recursively\n\
 144 "), stdout);
 145       fputs (_("\
 146 \n\
 147 The following options modify how a hierarchy is traversed when the -R\n\
 148 option is also specified.  If more than one is specified, only the final\n\
 149 one takes effect.\n\
 150 \n\
 151   -H                     if a command line argument is a symbolic link\n\
 152                          to a directory, traverse it\n\
 153   -L                     traverse every symbolic link to a directory\n\
 154                          encountered\n\
 155   -P                     do not traverse any symbolic links (default)\n\
 156 \n\
 157 "), stdout);
 158       fputs (HELP_OPTION_DESCRIPTION, stdout);
 159       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 160       printf (_("\
 161 \n\
 162 Examples:\n\
 163   %s staff /u      Change the group of /u to \"staff\".\n\
 164   %s -hR staff /u  Change the group of /u and subfiles to \"staff\".\n\
 165 "),
 166               program_name, program_name);
 167       emit_ancillary_info (PROGRAM_NAME);
 168     }
 169   exit (status);
 170 }
 171
 172 int
 173 main (int argc, char **argv)
 174 {
 175   bool preserve_root = false;
 176   gid_t gid;
 177
 178   /* Bit flags that control how fts works.  */
 179   int bit_flags = FTS_PHYSICAL;
 180
 181   /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been
 182      specified.  */
 183   int dereference = -1;
 184
 185   struct Chown_option chopt;
 186   bool ok;
 187   int optc;
 188
 189   initialize_main (&argc, &argv);
 190   set_program_name (argv[0]);
 191   setlocale (LC_ALL, "");
 192   bindtextdomain (PACKAGE, LOCALEDIR);
 193   textdomain (PACKAGE);
 194
 195   atexit (close_stdout);
 196
 197   chopt_init (&chopt);
 198
 199   while ((optc = getopt_long (argc, argv, "HLPRcfhv", long_options, NULL))
 200          != -1)
 201     {
 202       switch (optc)
 203         {
 204         case 'H': /* Traverse command-line symlinks-to-directories.  */
 205           bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL;
 206           break;
 207
 208         case 'L': /* Traverse all symlinks-to-directories.  */
 209           bit_flags = FTS_LOGICAL;
 210           break;
 211
 212         case 'P': /* Traverse no symlinks-to-directories.  */
 213           bit_flags = FTS_PHYSICAL;
 214           break;
 215
 216         case 'h': /* --no-dereference: affect symlinks */
 217           dereference = 0;
 218           break;
 219
 220         case DEREFERENCE_OPTION: /* --dereference: affect the referent
 221                                     of each symlink */
 222           dereference = 1;
 223           break;
 224
 225         case NO_PRESERVE_ROOT:
 226           preserve_root = false;
 227           break;
 228
 229         case PRESERVE_ROOT:
 230           preserve_root = true;
 231           break;
 232
 233         case REFERENCE_FILE_OPTION:
 234           reference_file = optarg;
 235           break;
 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             die (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         die (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 290              quoteaf (reference_file));
 291
 292       gid = ref_stats.st_gid;
 293       chopt.group_name = gid_to_name (ref_stats.st_gid);
 294     }
 295   else
 296     {
 297       char *group_name = argv[optind++];
 298       chopt.group_name = (*group_name ? group_name : NULL);
 299       gid = parse_group (group_name);
 300     }
 301
 302   if (chopt.recurse && preserve_root)
 303     {
 304       static struct dev_ino dev_ino_buf;
 305       chopt.root_dev_ino = get_root_dev_ino (&dev_ino_buf);
 306       if (chopt.root_dev_ino == NULL)
 307         die (EXIT_FAILURE, errno, _("failed to get attributes of %s"),
 308              quoteaf ("/"));
 309     }
 310
 311   bit_flags |= FTS_DEFER_STAT;
 312   ok = chown_files (argv + optind, bit_flags,
 313                     (uid_t) -1, gid,
 314                     (uid_t) -1, (gid_t) -1, &chopt);
 315
 316   chopt_free (&chopt);
 317
 318   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 319 }