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 LONG_OPTS
  11//config:       help
  12//config:       Halt new accesses and flush writes on a mounted filesystem.
  13
  14//applet:IF_FSFREEZE(APPLET_NOEXEC(fsfreeze, fsfreeze, BB_DIR_USR_SBIN, BB_SUID_DROP, fsfreeze))
  15
  16//kbuild:lib-$(CONFIG_FSFREEZE) += fsfreeze.o
  17
  18//usage:#define fsfreeze_trivial_usage
  19//usage:       "--[un]freeze MOUNTPOINT"
  20//usage:#define fsfreeze_full_usage "\n\n"
  21//usage:        "Flush and halt writes to MOUNTPOINT"
  22
  23#include "libbb.h"
  24#include <linux/fs.h>
  25
  26#ifndef FIFREEZE
  27# define FIFREEZE _IOWR('X', 119, int)
  28# define FITHAW   _IOWR('X', 120, int)
  29#endif
  30
  31int fsfreeze_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  32int fsfreeze_main(int argc UNUSED_PARAM, char **argv)
  33{
  34        unsigned opts;
  35        int fd;
  36
  37        /* exactly one non-option arg: the mountpoint */
  38        /* one of opts is required */
  39        /* opts are mutually exclusive */
  40        opts = getopt32long(argv, "^"
  41                "" /* no opts */
  42                "\0" "=1:""\xff:\xfe:""\xff--\xfe:\xfe--\xff",
  43                "freeze\0"   No_argument "\xff"
  44                "unfreeze\0" No_argument "\xfe"
  45        );
  46
  47        fd = xopen(argv[optind], O_RDONLY);
  48        /* Works with NULL arg on linux-4.8.0 */
  49        xioctl(fd, (opts & 1) ? FIFREEZE : FITHAW, NULL);
  50
  51        return EXIT_SUCCESS;
  52}
  53