| /* |
| * 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 (4.3 kb)" |
| //config: default y |
| //config: help |
| //config: blkdiscard discards sectors on a given device. |
| |
| //applet:IF_BLKDISCARD(APPLET_NOEXEC(blkdiscard, blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP, blkdiscard)) |
| |
| //kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o |
| |
| //usage:#define blkdiscard_trivial_usage |
| //usage: "[-o OFS] [-l LEN] [-s] DEVICE" |
| //usage:#define blkdiscard_full_usage "\n\n" |
| //usage: "Discard sectors on DEVICE\n" |
| //usage: "\n -o OFS Byte offset into device" |
| //usage: "\n -l LEN Number of bytes to discard" |
| //usage: "\n -s Perform a secure discard" |
| //usage: |
| //usage:#define blkdiscard_example_usage |
| //usage: "$ 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]; |
| int fd; |
| |
| enum { |
| OPT_OFFSET = (1 << 0), |
| OPT_LENGTH = (1 << 1), |
| OPT_SECURE = (1 << 2), |
| }; |
| |
| opts = getopt32(argv, "^" "o:l:s" "\0" "=1", &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; |
| } |