src/mknod.c

   1 /* mknod -- make special files
   2    Copyright (C) 1990-2013 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 <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by David MacKenzie <djm@ai.mit.edu>  */
  18
  19 #include <config.h>
  20 #include <stdio.h>
  21 #include <getopt.h>
  22 #include <sys/types.h>
  23 #include <selinux/selinux.h>
  24
  25 #include "system.h"
  26 #include "error.h"
  27 #include "modechange.h"
  28 #include "quote.h"
  29 #include "smack.h"
  30 #include "xstrtol.h"
  31
  32 /* The official name of this program (e.g., no 'g' prefix).  */
  33 #define PROGRAM_NAME "mknod"
  34
  35 #define AUTHORS proper_name ("David MacKenzie")
  36
  37 static struct option const longopts[] =
  38 {
  39   {GETOPT_SELINUX_CONTEXT_OPTION_DECL},
  40   {"mode", required_argument, NULL, 'm'},
  41   {GETOPT_HELP_OPTION_DECL},
  42   {GETOPT_VERSION_OPTION_DECL},
  43   {NULL, 0, NULL, 0}
  44 };
  45
  46 void
  47 usage (int status)
  48 {
  49   if (status != EXIT_SUCCESS)
  50     emit_try_help ();
  51   else
  52     {
  53       printf (_("Usage: %s [OPTION]... NAME TYPE [MAJOR MINOR]\n"),
  54               program_name);
  55       fputs (_("\
  56 Create the special file NAME of the given TYPE.\n\
  57 "), stdout);
  58
  59       emit_mandatory_arg_note ();
  60
  61       fputs (_("\
  62   -m, --mode=MODE    set file permission bits to MODE, not a=rw - umask\n\
  63 "), stdout);
  64       fputs (_("\
  65   -Z, --context=CTX  set the SELinux security context of NAME to CTX\n\
  66 "), stdout);
  67       fputs (HELP_OPTION_DESCRIPTION, stdout);
  68       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  69       fputs (_("\
  70 \n\
  71 Both MAJOR and MINOR must be specified when TYPE is b, c, or u, and they\n\
  72 must be omitted when TYPE is p.  If MAJOR or MINOR begins with 0x or 0X,\n\
  73 it is interpreted as hexadecimal; otherwise, if it begins with 0, as octal;\n\
  74 otherwise, as decimal.  TYPE may be:\n\
  75 "), stdout);
  76       fputs (_("\
  77 \n\
  78   b      create a block (buffered) special file\n\
  79   c, u   create a character (unbuffered) special file\n\
  80   p      create a FIFO\n\
  81 "), stdout);
  82       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
  83       emit_ancillary_info ();
  84     }
  85   exit (status);
  86 }
  87
  88 int
  89 main (int argc, char **argv)
  90 {
  91   mode_t newmode;
  92   char const *specified_mode = NULL;
  93   int optc;
  94   int expected_operands;
  95   mode_t node_type;
  96   security_context_t scontext = NULL;
  97
  98   initialize_main (&argc, &argv);
  99   set_program_name (argv[0]);
 100   setlocale (LC_ALL, "");
 101   bindtextdomain (PACKAGE, LOCALEDIR);
 102   textdomain (PACKAGE);
 103
 104   atexit (close_stdout);
 105
 106   while ((optc = getopt_long (argc, argv, "m:Z:", longopts, NULL)) != -1)
 107     {
 108       switch (optc)
 109         {
 110         case 'm':
 111           specified_mode = optarg;
 112           break;
 113         case 'Z':
 114           scontext = optarg;
 115           break;
 116         case_GETOPT_HELP_CHAR;
 117         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 118         default:
 119           usage (EXIT_FAILURE);
 120         }
 121     }
 122
 123   newmode = MODE_RW_UGO;
 124   if (specified_mode)
 125     {
 126       mode_t umask_value;
 127       struct mode_change *change = mode_compile (specified_mode);
 128       if (!change)
 129         error (EXIT_FAILURE, 0, _("invalid mode"));
 130       umask_value = umask (0);
 131       umask (umask_value);
 132       newmode = mode_adjust (newmode, false, umask_value, change, NULL);
 133       free (change);
 134       if (newmode & ~S_IRWXUGO)
 135         error (EXIT_FAILURE, 0,
 136                _("mode must specify only file permission bits"));
 137     }
 138
 139   /* If the number of arguments is 0 or 1,
 140      or (if it's 2 or more and the second one starts with 'p'), then there
 141      must be exactly two operands.  Otherwise, there must be four.  */
 142   expected_operands = (argc <= optind
 143                        || (optind + 1 < argc && argv[optind + 1][0] == 'p')
 144                        ? 2 : 4);
 145
 146   if (argc - optind < expected_operands)
 147     {
 148       if (argc <= optind)
 149         error (0, 0, _("missing operand"));
 150       else
 151         error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
 152       if (expected_operands == 4 && argc - optind == 2)
 153         fprintf (stderr, "%s\n",
 154                  _("Special files require major and minor device numbers."));
 155       usage (EXIT_FAILURE);
 156     }
 157
 158   if (expected_operands < argc - optind)
 159     {
 160       error (0, 0, _("extra operand %s"),
 161              quote (argv[optind + expected_operands]));
 162       if (expected_operands == 2 && argc - optind == 4)
 163         fprintf (stderr, "%s\n",
 164                  _("Fifos do not have major and minor device numbers."));
 165       usage (EXIT_FAILURE);
 166     }
 167
 168   if (scontext)
 169     {
 170       int ret = 0;
 171       if (is_smack_enabled ())
 172         ret = smack_set_label_for_self (scontext);
 173       else
 174         ret = setfscreatecon (scontext);
 175
 176       if (ret < 0)
 177         error (EXIT_FAILURE, errno,
 178                _("failed to set default file creation context to %s"),
 179                quote (scontext));
 180     }
 181
 182   /* Only check the first character, to allow mnemonic usage like
 183      'mknod /dev/rst0 character 18 0'. */
 184
 185   switch (argv[optind + 1][0])
 186     {
 187     case 'b':                   /* 'block' or 'buffered' */
 188 #ifndef S_IFBLK
 189       error (EXIT_FAILURE, 0, _("block special files not supported"));
 190 #else
 191       node_type = S_IFBLK;
 192 #endif
 193       goto block_or_character;
 194
 195     case 'c':                   /* 'character' */
 196     case 'u':                   /* 'unbuffered' */
 197 #ifndef S_IFCHR
 198       error (EXIT_FAILURE, 0, _("character special files not supported"));
 199 #else
 200       node_type = S_IFCHR;
 201 #endif
 202       goto block_or_character;
 203
 204     block_or_character:
 205       {
 206         char const *s_major = argv[optind + 2];
 207         char const *s_minor = argv[optind + 3];
 208         uintmax_t i_major, i_minor;
 209         dev_t device;
 210
 211         if (xstrtoumax (s_major, NULL, 0, &i_major, NULL) != LONGINT_OK
 212             || i_major != (major_t) i_major)
 213           error (EXIT_FAILURE, 0,
 214                  _("invalid major device number %s"), quote (s_major));
 215
 216         if (xstrtoumax (s_minor, NULL, 0, &i_minor, NULL) != LONGINT_OK
 217             || i_minor != (minor_t) i_minor)
 218           error (EXIT_FAILURE, 0,
 219                  _("invalid minor device number %s"), quote (s_minor));
 220
 221         device = makedev (i_major, i_minor);
 222 #ifdef NODEV
 223         if (device == NODEV)
 224           error (EXIT_FAILURE, 0, _("invalid device %s %s"), s_major, s_minor);
 225 #endif
 226
 227         if (mknod (argv[optind], newmode | node_type, device) != 0)
 228           error (EXIT_FAILURE, errno, "%s", quote (argv[optind]));
 229       }
 230       break;
 231
 232     case 'p':                   /* 'pipe' */
 233       if (mkfifo (argv[optind], newmode) != 0)
 234         error (EXIT_FAILURE, errno, "%s", quote (argv[optind]));
 235       break;
 236
 237     default:
 238       error (0, 0, _("invalid device type %s"), quote (argv[optind + 1]));
 239       usage (EXIT_FAILURE);
 240     }
 241
 242   if (specified_mode && lchmod (argv[optind], newmode) != 0)
 243     error (EXIT_FAILURE, errno, _("cannot set permissions of `%s'"),
 244            quote (argv[optind]));
 245
 246   exit (EXIT_SUCCESS);
 247 }