2 * Mini blkdiscard implementation for busybox
4 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> and Tuxera Inc.
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 //config:config BLKDISCARD
9 //config: bool "blkdiscard (5.3 kb)"
12 //config: blkdiscard discards sectors on a given device.
14 //applet:IF_BLKDISCARD(APPLET_NOEXEC(blkdiscard, blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP, blkdiscard))
16 //kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o
18 //usage:#define blkdiscard_trivial_usage
19 //usage: "[-o OFS] [-l LEN] [-s] DEVICE"
20 //usage:#define blkdiscard_full_usage "\n\n"
21 //usage: "Discard sectors on DEVICE\n"
22 //usage: "\n -o OFS Byte offset into device"
23 //usage: "\n -l LEN Number of bytes to discard"
24 //usage: "\n -s Perform a secure discard"
26 //usage:#define blkdiscard_example_usage
27 //usage: "$ blkdiscard -o 0 -l 1G /dev/sdb"
33 #define BLKDISCARD 0x1277
36 #define BLKSECDISCARD 0x127d
39 int blkdiscard_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
40 int blkdiscard_main(int argc UNUSED_PARAM, char **argv)
43 const char *offset_str = "0";
44 const char *length_str;
45 uint64_t offset; /* Leaving these two variables out does not */
46 uint64_t length; /* shrink code size and hampers readability. */
51 OPT_OFFSET = (1 << 0),
52 OPT_LENGTH = (1 << 1),
53 OPT_SECURE = (1 << 2),
56 opts = getopt32(argv, "^" "o:l:s" "\0" "=1", &offset_str, &length_str);
59 fd = xopen(argv[0], O_RDWR|O_EXCL);
60 //Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway?
62 // if (!S_ISBLK(st.st_mode))
63 // bb_error_msg_and_die("%s: not a block device", argv[0]);
65 offset = xatoull_sfx(offset_str, kMG_suffixes);
67 if (opts & OPT_LENGTH)
68 length = xatoull_sfx(length_str, kMG_suffixes);
70 xioctl(fd, BLKGETSIZE64, &length);
76 ioctl_or_perror_and_die(fd,
77 (opts & OPT_SECURE) ? BLKSECDISCARD : BLKDISCARD,
81 (opts & OPT_SECURE) ? "BLKSECDISCARD" : "BLKDISCARD"
84 if (ENABLE_FEATURE_CLEAN_UP)