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/*
* Mini blkdiscard implementation for busybox
*
* Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> and Tuxera Inc.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config BLKDISCARD
//config: bool "blkdiscard (5.3 kb)"
//config: default y
//config: help
//config: blkdiscard discards sectors on a given device.
//kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o
//applet:IF_BLKDISCARD(APPLET(blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP))
//usage:#define blkdiscard_trivial_usage
//usage: "[-o OFS] [-l LEN] [-s] DEVICE"
//usage:#define blkdiscard_full_usage "\n\n"
//usage: "Discard sectors on DEVICE\n"
//usage: "\n -o OFS Byte offset into device"
//usage: "\n -l LEN Number of bytes to discard"
//usage: "\n -s Perform a secure discard"
//usage:
//usage:#define blkdiscard_example_usage
//usage: "$ blkdiscard -o 0 -l 1G /dev/sdb"
#include "libbb.h"
#include <linux/fs.h>
#ifndef BLKDISCARD
#define BLKDISCARD 0x1277
#endif
#ifndef BLKSECDISCARD
#define BLKSECDISCARD 0x127d
#endif
int blkdiscard_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int blkdiscard_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
const char *offset_str = "0";
const char *length_str;
uint64_t offset; /* Leaving these two variables out does not */
uint64_t length; /* shrink code size and hampers readability. */
uint64_t range[2];
// struct stat st;
int fd;
enum {
OPT_OFFSET = (1 << 0),
OPT_LENGTH = (1 << 1),
OPT_SECURE = (1 << 2),
};
opt_complementary = "=1";
opts = getopt32(argv, "o:l:s", &offset_str, &length_str);
argv += optind;
fd = xopen(argv[0], O_RDWR|O_EXCL);
//Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway?
// xfstat(fd, &st);
// if (!S_ISBLK(st.st_mode))
// bb_error_msg_and_die("%s: not a block device", argv[0]);
offset = xatoull_sfx(offset_str, kMG_suffixes);
if (opts & OPT_LENGTH)
length = xatoull_sfx(length_str, kMG_suffixes);
else {
xioctl(fd, BLKGETSIZE64, &length);
length -= offset;
}
range[0] = offset;
range[1] = length;
ioctl_or_perror_and_die(fd,
(opts & OPT_SECURE) ? BLKSECDISCARD : BLKDISCARD,
&range,
"%s: %s failed",
argv[0],
(opts & OPT_SECURE) ? "BLKSECDISCARD" : "BLKDISCARD"
);
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return EXIT_SUCCESS;
}
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