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| -rw-r--r-- | util-linux/blkdiscard.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/util-linux/blkdiscard.c b/util-linux/blkdiscard.c new file mode 100644 index 0000000..ace88a1 --- /dev/null +++ b/util-linux/blkdiscard.c @@ -0,0 +1,83 @@ +/* + * 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" +//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; +} |