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92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/*
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* Mini blkdiscard implementation for busybox
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*
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* Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> and Tuxera Inc.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config BLKDISCARD
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//config: bool "blkdiscard (4.6 kb)"
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//config: default y
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//config: help
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//config: blkdiscard discards sectors on a given device.
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//applet:IF_BLKDISCARD(APPLET_NOEXEC(blkdiscard, blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP, blkdiscard))
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//kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o
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//usage:#define blkdiscard_trivial_usage
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//usage: "[-o OFS] [-l LEN] [-s] DEVICE"
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//usage:#define blkdiscard_full_usage "\n\n"
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//usage: "Discard sectors on DEVICE\n"
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//usage: "\n -o OFS Byte offset into device"
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//usage: "\n -l LEN Number of bytes to discard"
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//usage: "\n -s Perform a secure discard"
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///////: "\n -f Disable check for mounted filesystem"
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//////////////// -f: accepted but is a nop (we do no check anyway)
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//usage:
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//usage:#define blkdiscard_example_usage
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//usage: "$ blkdiscard -o 0 -l 1G /dev/sdb"
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#include "libbb.h"
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#include <linux/fs.h>
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#ifndef BLKDISCARD
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#define BLKDISCARD 0x1277
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#endif
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#ifndef BLKSECDISCARD
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#define BLKSECDISCARD 0x127d
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#endif
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int blkdiscard_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int blkdiscard_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opts;
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const char *offset_str = "0";
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const char *length_str;
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uint64_t offset; /* Leaving these two variables out does not */
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uint64_t length; /* shrink code size and hampers readability. */
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uint64_t range[2];
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int fd;
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enum {
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OPT_OFFSET = (1 << 0),
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OPT_LENGTH = (1 << 1),
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OPT_SECURE = (1 << 2),
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OPT_FORCE = (1 << 3), //nop
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};
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opts = getopt32(argv, "^" "o:l:sf" "\0" "=1", &offset_str, &length_str);
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argv += optind;
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fd = xopen(argv[0], O_RDWR|O_EXCL);
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//Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway?
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// xfstat(fd, &st);
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// if (!S_ISBLK(st.st_mode))
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// bb_error_msg_and_die("%s: not a block device", argv[0]);
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offset = xatoull_sfx(offset_str, kMG_suffixes);
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if (opts & OPT_LENGTH)
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length = xatoull_sfx(length_str, kMG_suffixes);
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else {
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xioctl(fd, BLKGETSIZE64, &length);
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length -= offset;
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}
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range[0] = offset;
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range[1] = length;
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ioctl_or_perror_and_die(fd,
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(opts & OPT_SECURE) ? BLKSECDISCARD : BLKDISCARD,
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&range,
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"%s: %s failed",
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argv[0],
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(opts & OPT_SECURE) ? "BLKSECDISCARD" : "BLKDISCARD"
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);
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if (ENABLE_FEATURE_CLEAN_UP)
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close(fd);
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return EXIT_SUCCESS;
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}
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