coreutils/mknod.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * mknod implementation for busybox
   4  *
   5  * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config MKNOD
  10 //config:       bool "mknod (4.6 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       mknod is used to create FIFOs or block/character special
  14 //config:       files with the specified names.
  15
  16 //applet:IF_MKNOD(APPLET_NOEXEC(mknod, mknod, BB_DIR_BIN, BB_SUID_DROP, mknod))
  17
  18 //kbuild:lib-$(CONFIG_MKNOD) += mknod.o
  19
  20 /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
  21
  22 //usage:#define mknod_trivial_usage
  23 //usage:       "[-m MODE] " IF_SELINUX("[-Z] ") "NAME TYPE [MAJOR MINOR]"
  24 //usage:#define mknod_full_usage "\n\n"
  25 //usage:       "Create a special file (block, character, or pipe)\n"
  26 //usage:     "\n        -m MODE Creation mode (default a=rw)"
  27 //usage:        IF_SELINUX(
  28 //usage:     "\n        -Z      Set security context"
  29 //usage:        )
  30 //usage:     "\nTYPE:"
  31 //usage:     "\n        b       Block device"
  32 //usage:     "\n        c or u  Character device"
  33 //usage:     "\n        p       Named pipe (MAJOR MINOR must be omitted)"
  34 //usage:
  35 //usage:#define mknod_example_usage
  36 //usage:       "$ mknod /dev/fd0 b 2 0\n"
  37 //usage:       "$ mknod -m 644 /tmp/pipe p\n"
  38
  39 #ifdef __linux__
  40 # include <sys/sysmacros.h>  // For makedev
  41 #endif
  42
  43 #include "libbb.h"
  44 #include "libcoreutils/coreutils.h"
  45
  46 /* This is a NOEXEC applet. Be very careful! */
  47
  48 static const char modes_chars[] ALIGN1 = { 'p', 'c', 'u', 'b', 0, 1, 1, 2 };
  49 static const mode_t modes_cubp[] = { S_IFIFO, S_IFCHR, S_IFBLK };
  50
  51 int mknod_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  52 int mknod_main(int argc UNUSED_PARAM, char **argv)
  53 {
  54         mode_t mode;
  55         dev_t dev;
  56         const char *type, *arg;
  57
  58         mode = getopt_mk_fifo_nod(argv);
  59         argv += optind;
  60         //argc -= optind;
  61
  62         if (!argv[0] || !argv[1])
  63                 bb_show_usage();
  64         type = strchr(modes_chars, argv[1][0]);
  65         if (!type)
  66                 bb_show_usage();
  67
  68         mode |= modes_cubp[(int)(type[4])];
  69
  70         dev = 0;
  71         arg = argv[2];
  72         if (*type != 'p') {
  73                 if (!argv[2] || !argv[3])
  74                         bb_show_usage();
  75                 /* Autodetect what the system supports; these macros should
  76                  * optimize out to two constants. */
  77                 dev = makedev(xatoul_range(argv[2], 0, major(UINT_MAX)),
  78                                 xatoul_range(argv[3], 0, minor(UINT_MAX)));
  79                 arg = argv[4];
  80         }
  81         if (arg)
  82                 bb_show_usage();
  83
  84         if (mknod(argv[0], mode, dev) != 0) {
  85                 bb_simple_perror_msg_and_die(argv[0]);
  86         }
  87         return EXIT_SUCCESS;
  88 }