dbf5a6da6
Ari Sundholm
2016-01-02
Subject
blkdiscard: new applet
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util-linux/blkdiscard.c+83 -0
| @@ -0,0 +1,83 @@ | |
| + | /* |
| + | * Mini blkdiscard implementation for busybox |
| + | * |
| + | * Copyright (C) 2015 by Ari Sundholm <[email protected]> and Tuxera Inc. |
| + | * |
| + | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| + | */ |
| + | |
| + | //config:config BLKDISCARD |
| + | //config: bool "blkdiscard" |
| + | //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> |
| + | |
| + | 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; |
| + | } |