[3621] | 1 | /*
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| 2 | * Mini truncate implementation for busybox
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| 3 | *
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| 4 | * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
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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 TRUNCATE
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| 10 | //config: bool "truncate"
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| 11 | //config: default y
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| 12 | //config: help
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| 13 | //config: truncate truncates files to a given size. If a file does
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| 14 | //config: not exist, it is created unless told otherwise.
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| 15 |
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| 16 | //kbuild:lib-$(CONFIG_TRUNCATE) += truncate.o
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| 17 | //applet:IF_TRUNCATE(APPLET_NOFORK(truncate, truncate, BB_DIR_USR_BIN, BB_SUID_DROP, truncate))
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| 18 |
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| 19 | //usage:#define truncate_trivial_usage
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| 20 | //usage: "[-c] -s SIZE FILE..."
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| 21 | //usage:#define truncate_full_usage "\n\n"
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| 22 | //usage: "Truncate FILEs to the given size\n"
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| 23 | //usage: "\n -c Do not create files"
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| 24 | //usage: "\n -s SIZE Truncate to SIZE"
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| 25 | //usage:
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| 26 | //usage:#define truncate_example_usage
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| 27 | //usage: "$ truncate -s 1G foo"
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| 28 |
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| 29 | #include "libbb.h"
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| 30 |
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| 31 | #if ENABLE_LFS
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| 32 | # define XATOU_SFX xatoull_sfx
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| 33 | #else
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| 34 | # define XATOU_SFX xatoul_sfx
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| 35 | #endif
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| 36 |
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| 37 | /* This is a NOFORK applet. Be very careful! */
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| 38 |
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| 39 | int truncate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 40 | int truncate_main(int argc UNUSED_PARAM, char **argv)
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| 41 | {
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| 42 | unsigned opts;
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| 43 | int flags = O_WRONLY | O_NONBLOCK;
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| 44 | int ret = EXIT_SUCCESS;
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| 45 | char *size_str;
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| 46 | off_t size;
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| 47 |
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| 48 | enum {
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| 49 | OPT_NOCREATE = (1 << 0),
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| 50 | OPT_SIZE = (1 << 1),
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| 51 | };
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| 52 |
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| 53 | opt_complementary = "s:-1";
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| 54 | opts = getopt32(argv, "cs:", &size_str);
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| 55 |
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| 56 | if (!(opts & OPT_NOCREATE))
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| 57 | flags |= O_CREAT;
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| 58 |
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| 59 | // TODO: coreutils 8.17 also support "m" (lowercase) suffix
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| 60 | // with truncate, but not with dd!
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| 61 | // We share kMG_suffixes[], so we can't make both tools
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| 62 | // compatible at once...
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| 63 | size = XATOU_SFX(size_str, kMG_suffixes);
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| 64 |
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| 65 | argv += optind;
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| 66 | while (*argv) {
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| 67 | int fd = open(*argv, flags, 0666);
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| 68 | if (fd < 0) {
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| 69 | if (errno != ENOENT || !(opts & OPT_NOCREATE)) {
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| 70 | bb_perror_msg("%s: open", *argv);
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| 71 | ret = EXIT_FAILURE;
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| 72 | }
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| 73 | /* else: ENOENT && OPT_NOCREATE:
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| 74 | * do not report error, exitcode is also 0.
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| 75 | */
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| 76 | } else {
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| 77 | if (ftruncate(fd, size) == -1) {
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| 78 | bb_perror_msg("%s: truncate", *argv);
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| 79 | ret = EXIT_FAILURE;
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| 80 | }
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| 81 | xclose(fd);
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| 82 | }
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| 83 | ++argv;
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| 84 | }
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| 85 |
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| 86 | return ret;
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| 87 | }
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