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/* vi: set sw=4 ts=4: */
/*
* Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config FSFREEZE
//config: bool "fsfreeze"
//config: default y
//config: select PLATFORM_LINUX
//config: select LONG_OPTS
//config: help
//config: Halt new accesses and flush writes on a mounted filesystem.
//applet:IF_FSFREEZE(APPLET(fsfreeze, BB_DIR_USR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_FSFREEZE) += fsfreeze.o
//usage:#define fsfreeze_trivial_usage
//usage: "--[un]freeze MOUNTPOINT"
//usage:#define fsfreeze_full_usage "\n\n"
//usage: "Flush and halt writes to MOUNTPOINT"
#include "libbb.h"
#include <linux/fs.h>
#ifndef FIFREEZE
# define FIFREEZE _IOWR('X', 119, int)
# define FITHAW _IOWR('X', 120, int)
#endif
int fsfreeze_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fsfreeze_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
int fd;
applet_long_options =
"freeze\0" No_argument "\xff"
"unfreeze\0" No_argument "\xfe"
;
/* exactly one non-option arg: the mountpoint */
/* one of opts is required */
/* opts are mutually exclusive */
opt_complementary = "=1:""\xff:\xfe:""\xff--\xfe:\xfe--\xff";
opts = getopt32(argv, "");
fd = xopen(argv[optind], O_RDONLY);
/* Works with NULL arg on linux-4.8.0 */
xioctl(fd, (opts & 1) ? FIFREEZE : FITHAW, NULL);
return EXIT_SUCCESS;
}
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