blob: ace88a1f0a36ab1006a3e07fc9c4506ae17e71e3 [file] [log] [blame]
Ari Sundholmdbf5a6d2016-01-02 01:18:32 +01001/*
2 * Mini blkdiscard implementation for busybox
3 *
4 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> and Tuxera Inc.
5 *
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
7 */
8
9//config:config BLKDISCARD
10//config: bool "blkdiscard"
11//config: default y
12//config: help
13//config: blkdiscard discards sectors on a given device.
14
15//kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o
16//applet:IF_BLKDISCARD(APPLET(blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP))
17
18//usage:#define blkdiscard_trivial_usage
19//usage: "[-o OFS] [-l LEN] [-s] DEVICE"
20//usage:#define blkdiscard_full_usage "\n\n"
21//usage: "Discard sectors on DEVICE\n"
22//usage: "\n -o OFS Byte offset into device"
23//usage: "\n -l LEN Number of bytes to discard"
24//usage: "\n -s Perform a secure discard"
25//usage:
26//usage:#define blkdiscard_example_usage
27//usage: "$ blkdiscard -o 0 -l 1G /dev/sdb"
28
29#include "libbb.h"
30#include <linux/fs.h>
31
32int blkdiscard_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
33int blkdiscard_main(int argc UNUSED_PARAM, char **argv)
34{
35 unsigned opts;
36 const char *offset_str = "0";
37 const char *length_str;
38 uint64_t offset; /* Leaving these two variables out does not */
39 uint64_t length; /* shrink code size and hampers readability. */
40 uint64_t range[2];
41// struct stat st;
42 int fd;
43
44 enum {
45 OPT_OFFSET = (1 << 0),
46 OPT_LENGTH = (1 << 1),
47 OPT_SECURE = (1 << 2),
48 };
49
50 opt_complementary = "=1";
51 opts = getopt32(argv, "o:l:s", &offset_str, &length_str);
52 argv += optind;
53
54 fd = xopen(argv[0], O_RDWR|O_EXCL);
55//Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway?
56// xfstat(fd, &st);
57// if (!S_ISBLK(st.st_mode))
58// bb_error_msg_and_die("%s: not a block device", argv[0]);
59
60 offset = xatoull_sfx(offset_str, kMG_suffixes);
61
62 if (opts & OPT_LENGTH)
63 length = xatoull_sfx(length_str, kMG_suffixes);
64 else {
65 xioctl(fd, BLKGETSIZE64, &length);
66 length -= offset;
67 }
68
69 range[0] = offset;
70 range[1] = length;
71 ioctl_or_perror_and_die(fd,
72 (opts & OPT_SECURE) ? BLKSECDISCARD : BLKDISCARD,
73 &range,
74 "%s: %s failed",
75 argv[0],
76 (opts & OPT_SECURE) ? "BLKSECDISCARD" : "BLKDISCARD"
77 );
78
79 if (ENABLE_FEATURE_CLEAN_UP)
80 close(fd);
81
82 return EXIT_SUCCESS;
83}