blob: 253fe00150cf0f16dfa46958ed6dfbe0b1674016
1 | /* |
2 | * Mini truncate implementation for busybox |
3 | * |
4 | * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> |
5 | * |
6 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
7 | */ |
8 | //config:config TRUNCATE |
9 | //config: bool "truncate" |
10 | //config: default y |
11 | //config: help |
12 | //config: truncate truncates files to a given size. If a file does |
13 | //config: not exist, it is created unless told otherwise. |
14 | |
15 | //applet:IF_TRUNCATE(APPLET_NOFORK(truncate, truncate, BB_DIR_USR_BIN, BB_SUID_DROP, truncate)) |
16 | |
17 | //kbuild:lib-$(CONFIG_TRUNCATE) += truncate.o |
18 | |
19 | //usage:#define truncate_trivial_usage |
20 | //usage: "[-c] -s SIZE FILE..." |
21 | //usage:#define truncate_full_usage "\n\n" |
22 | //usage: "Truncate FILEs to the given size\n" |
23 | //usage: "\n -c Do not create files" |
24 | //usage: "\n -s SIZE Truncate to SIZE" |
25 | //usage: |
26 | //usage:#define truncate_example_usage |
27 | //usage: "$ truncate -s 1G foo" |
28 | |
29 | #include "libbb.h" |
30 | |
31 | #if ENABLE_LFS |
32 | # define XATOU_SFX xatoull_sfx |
33 | #else |
34 | # define XATOU_SFX xatoul_sfx |
35 | #endif |
36 | |
37 | /* This is a NOFORK applet. Be very careful! */ |
38 | |
39 | int truncate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
40 | int truncate_main(int argc UNUSED_PARAM, char **argv) |
41 | { |
42 | unsigned opts; |
43 | int flags = O_WRONLY | O_NONBLOCK; |
44 | int ret = EXIT_SUCCESS; |
45 | char *size_str; |
46 | off_t size; |
47 | |
48 | enum { |
49 | OPT_NOCREATE = (1 << 0), |
50 | OPT_SIZE = (1 << 1), |
51 | }; |
52 | |
53 | opt_complementary = "s:-1"; |
54 | opts = getopt32(argv, "cs:", &size_str); |
55 | |
56 | if (!(opts & OPT_NOCREATE)) |
57 | flags |= O_CREAT; |
58 | |
59 | // TODO: coreutils 8.17 also support "m" (lowercase) suffix |
60 | // with truncate, but not with dd! |
61 | // We share kMG_suffixes[], so we can't make both tools |
62 | // compatible at once... |
63 | size = XATOU_SFX(size_str, kMG_suffixes); |
64 | |
65 | argv += optind; |
66 | while (*argv) { |
67 | int fd = open(*argv, flags, 0666); |
68 | if (fd < 0) { |
69 | if (errno != ENOENT || !(opts & OPT_NOCREATE)) { |
70 | bb_perror_msg("%s: open", *argv); |
71 | ret = EXIT_FAILURE; |
72 | } |
73 | /* else: ENOENT && OPT_NOCREATE: |
74 | * do not report error, exitcode is also 0. |
75 | */ |
76 | } else { |
77 | if (ftruncate(fd, size) == -1) { |
78 | bb_perror_msg("%s: truncate", *argv); |
79 | ret = EXIT_FAILURE; |
80 | } |
81 | xclose(fd); |
82 | } |
83 | ++argv; |
84 | } |
85 | |
86 | return ret; |
87 | } |
88 |