[3621] | 1 | /*
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| 2 | * Mini blkdiscard implementation for busybox
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| 3 | *
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| 4 | * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> and Tuxera Inc.
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| 5 | *
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| 6 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 7 | */
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| 8 |
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| 9 | //config:config BLKDISCARD
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| 10 | //config: bool "blkdiscard"
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| 11 | //config: default y
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| 12 | //config: help
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| 13 | //config: blkdiscard discards sectors on a given device.
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| 14 |
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| 15 | //kbuild:lib-$(CONFIG_BLKDISCARD) += blkdiscard.o
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| 16 | //applet:IF_BLKDISCARD(APPLET(blkdiscard, BB_DIR_USR_BIN, BB_SUID_DROP))
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| 17 |
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| 18 | //usage:#define blkdiscard_trivial_usage
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| 19 | //usage: "[-o OFS] [-l LEN] [-s] DEVICE"
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| 20 | //usage:#define blkdiscard_full_usage "\n\n"
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| 21 | //usage: "Discard sectors on DEVICE\n"
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| 22 | //usage: "\n -o OFS Byte offset into device"
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| 23 | //usage: "\n -l LEN Number of bytes to discard"
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| 24 | //usage: "\n -s Perform a secure discard"
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| 25 | //usage:
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| 26 | //usage:#define blkdiscard_example_usage
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| 27 | //usage: "$ blkdiscard -o 0 -l 1G /dev/sdb"
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| 28 |
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| 29 | #include "libbb.h"
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| 30 | #include <linux/fs.h>
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| 31 |
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| 32 | int blkdiscard_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 33 | int blkdiscard_main(int argc UNUSED_PARAM, char **argv)
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| 34 | {
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| 35 | unsigned opts;
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| 36 | const char *offset_str = "0";
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| 37 | const char *length_str;
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| 38 | uint64_t offset; /* Leaving these two variables out does not */
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| 39 | uint64_t length; /* shrink code size and hampers readability. */
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| 40 | uint64_t range[2];
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| 41 | // struct stat st;
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| 42 | int fd;
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| 43 |
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| 44 | enum {
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| 45 | OPT_OFFSET = (1 << 0),
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| 46 | OPT_LENGTH = (1 << 1),
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| 47 | OPT_SECURE = (1 << 2),
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| 48 | };
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| 49 |
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| 50 | opt_complementary = "=1";
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| 51 | opts = getopt32(argv, "o:l:s", &offset_str, &length_str);
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| 52 | argv += optind;
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| 53 |
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| 54 | fd = xopen(argv[0], O_RDWR|O_EXCL);
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| 55 | //Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway?
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| 56 | // xfstat(fd, &st);
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| 57 | // if (!S_ISBLK(st.st_mode))
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| 58 | // bb_error_msg_and_die("%s: not a block device", argv[0]);
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| 59 |
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| 60 | offset = xatoull_sfx(offset_str, kMG_suffixes);
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| 61 |
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| 62 | if (opts & OPT_LENGTH)
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| 63 | length = xatoull_sfx(length_str, kMG_suffixes);
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| 64 | else {
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| 65 | xioctl(fd, BLKGETSIZE64, &length);
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| 66 | length -= offset;
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| 67 | }
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| 68 |
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| 69 | range[0] = offset;
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| 70 | range[1] = length;
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| 71 | ioctl_or_perror_and_die(fd,
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| 72 | (opts & OPT_SECURE) ? BLKSECDISCARD : BLKDISCARD,
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| 73 | &range,
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| 74 | "%s: %s failed",
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| 75 | argv[0],
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| 76 | (opts & OPT_SECURE) ? "BLKSECDISCARD" : "BLKDISCARD"
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| 77 | );
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| 78 |
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| 79 | if (ENABLE_FEATURE_CLEAN_UP)
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| 80 | close(fd);
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| 81 |
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| 82 | return EXIT_SUCCESS;
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| 83 | }
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