2 * Mini truncate implementation for busybox
4 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 //config:config TRUNCATE
9 //config: bool "truncate"
12 //config: truncate truncates files to a given size. If a file does
13 //config: not exist, it is created unless told otherwise.
15 //applet:IF_TRUNCATE(APPLET_NOFORK(truncate, truncate, BB_DIR_USR_BIN, BB_SUID_DROP, truncate))
17 //kbuild:lib-$(CONFIG_TRUNCATE) += truncate.o
19 //usage:#define truncate_trivial_usage
20 //usage: "[-c] -s SIZE FILE..."
21 //usage:#define truncate_full_usage "\n\n"
22 //usage: "Truncate FILEs to the given size\n"
23 //usage: "\n -c Do not create files"
24 //usage: "\n -s SIZE Truncate to SIZE"
26 //usage:#define truncate_example_usage
27 //usage: "$ truncate -s 1G foo"
32 # define XATOU_SFX xatoull_sfx
34 # define XATOU_SFX xatoul_sfx
37 /* This is a NOFORK applet. Be very careful! */
39 int truncate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
40 int truncate_main(int argc UNUSED_PARAM, char **argv)
43 int flags = O_WRONLY | O_NONBLOCK;
44 int ret = EXIT_SUCCESS;
49 OPT_NOCREATE = (1 << 0),
53 opt_complementary = "s:-1";
54 opts = getopt32(argv, "cs:", &size_str);
56 if (!(opts & OPT_NOCREATE))
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);
67 int fd = open(*argv, flags, 0666);
69 if (errno != ENOENT || !(opts & OPT_NOCREATE)) {
70 bb_perror_msg("%s: open", *argv);
73 /* else: ENOENT && OPT_NOCREATE:
74 * do not report error, exitcode is also 0.
77 if (ftruncate(fd, size) == -1) {
78 bb_perror_msg("%s: truncate", *argv);