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