busybox/coreutils/mknod.c
Denys Vlasenko 2f55404bbc mknod: better --help, much clearer code
function                                             old     new   delta
packed_usage                                       32066   32091     +25
mknod_main                                           173     174      +1

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2018-01-08 11:22:37 +01:00

87 lines
2.3 KiB
C

/* vi: set sw=4 ts=4: */
/*
* mknod implementation for busybox
*
* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config MKNOD
//config: bool "mknod (4 kb)"
//config: default y
//config: help
//config: mknod is used to create FIFOs or block/character special
//config: files with the specified names.
//applet:IF_MKNOD(APPLET_NOEXEC(mknod, mknod, BB_DIR_BIN, BB_SUID_DROP, mknod))
//kbuild:lib-$(CONFIG_MKNOD) += mknod.o
/* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
//usage:#define mknod_trivial_usage
//usage: "[-m MODE] " IF_SELINUX("[-Z] ") "NAME TYPE [MAJOR MINOR]"
//usage:#define mknod_full_usage "\n\n"
//usage: "Create a special file (block, character, or pipe)\n"
//usage: "\n -m MODE Creation mode (default a=rw)"
//usage: IF_SELINUX(
//usage: "\n -Z Set security context"
//usage: )
//usage: "\nTYPE:"
//usage: "\n b Block device"
//usage: "\n c or u Character device"
//usage: "\n p Named pipe (MAJOR MINOR must be omitted)"
//usage:
//usage:#define mknod_example_usage
//usage: "$ mknod /dev/fd0 b 2 0\n"
//usage: "$ mknod -m 644 /tmp/pipe p\n"
#include <sys/sysmacros.h> // For makedev
#include "libbb.h"
#include "libcoreutils/coreutils.h"
/* This is a NOEXEC applet. Be very careful! */
static const char modes_chars[] ALIGN1 = { 'p', 'c', 'u', 'b', 0, 1, 1, 2 };
static const mode_t modes_cubp[] = { S_IFIFO, S_IFCHR, S_IFBLK };
int mknod_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mknod_main(int argc UNUSED_PARAM, char **argv)
{
mode_t mode;
dev_t dev;
const char *type, *arg;
mode = getopt_mk_fifo_nod(argv);
argv += optind;
//argc -= optind;
if (!argv[0] || !argv[1])
bb_show_usage();
type = strchr(modes_chars, argv[1][0]);
if (!type)
bb_show_usage();
mode |= modes_cubp[(int)(type[4])];
dev = 0;
arg = argv[2];
if (*type != 'p') {
if (!argv[2] || !argv[3])
bb_show_usage();
/* Autodetect what the system supports; these macros should
* optimize out to two constants. */
dev = makedev(xatoul_range(argv[2], 0, major(UINT_MAX)),
xatoul_range(argv[3], 0, minor(UINT_MAX)));
arg = argv[4];
}
if (arg)
bb_show_usage();
if (mknod(argv[0], mode, dev) != 0) {
bb_simple_perror_msg_and_die(argv[0]);
}
return EXIT_SUCCESS;
}