LXR busybox/util-linux/fsfreeze.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
   4 *
   5 * Licensed under GPLv2, see file LICENSE in this source tree.
   6 */
   7//config:config FSFREEZE
   8//config:       bool "fsfreeze (3.5 kb)"
   9//config:       default y
  10//config:       select PLATFORM_LINUX
  11//config:       select LONG_OPTS
  12//config:       help
  13//config:       Halt new accesses and flush writes on a mounted filesystem.
  14
  15//applet:IF_FSFREEZE(APPLET_NOEXEC(fsfreeze, fsfreeze, BB_DIR_USR_SBIN, BB_SUID_DROP, fsfreeze))
  16
  17//kbuild:lib-$(CONFIG_FSFREEZE) += fsfreeze.o
  18
  19//usage:#define fsfreeze_trivial_usage
  20//usage:       "--[un]freeze MOUNTPOINT"
  21//usage:#define fsfreeze_full_usage "\n\n"
  22//usage:        "Flush and halt writes to MOUNTPOINT"
  23
  24#include "libbb.h"
  25#include <linux/fs.h>
  26
  27#ifndef FIFREEZE
  28# define FIFREEZE _IOWR('X', 119, int)
  29# define FITHAW   _IOWR('X', 120, int)
  30#endif
  31
  32int fsfreeze_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  33int fsfreeze_main(int argc UNUSED_PARAM, char **argv)
  34{
  35        unsigned opts;
  36        int fd;
  37
  38        /* exactly one non-option arg: the mountpoint */
  39        /* one of opts is required */
  40        /* opts are mutually exclusive */
  41        opts = getopt32long(argv, "^"
  42                "" /* no opts */
  43                "\0" "=1:""\xff:\xfe:""\xff--\xfe:\xfe--\xff",
  44                "freeze\0"   No_argument "\xff"
  45                "unfreeze\0" No_argument "\xfe"
  46        );
  47
  48        fd = xopen(argv[optind], O_RDONLY);
  49        /* Works with NULL arg on linux-4.8.0 */
  50        xioctl(fd, (opts & 1) ? FIFREEZE : FITHAW, NULL);
  51
  52        return EXIT_SUCCESS;
  53}
  54