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/*
* Mini truncate implementation for busybox
*
* Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config TRUNCATE
//config: bool "truncate"
//config: default y
//config: help
//config: truncate truncates files to a given size. If a file does
//config: not exist, it is created unless told otherwise.
//kbuild:lib-$(CONFIG_TRUNCATE) += truncate.o
//applet:IF_TRUNCATE(APPLET_NOFORK(truncate, truncate, BB_DIR_USR_BIN, BB_SUID_DROP, truncate))
//usage:#define truncate_trivial_usage
//usage: "[-c] -s SIZE FILE..."
//usage:#define truncate_full_usage "\n\n"
//usage: "Truncate FILEs to the given size\n"
//usage: "\n -c Do not create files"
//usage: "\n -s SIZE Truncate to SIZE"
//usage:
//usage:#define truncate_example_usage
//usage: "$ truncate -s 1G foo"
#include "libbb.h"
#if ENABLE_LFS
# define XATOU_SFX xatoull_sfx
#else
# define XATOU_SFX xatoul_sfx
#endif
/* This is a NOFORK applet. Be very careful! */
int truncate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int truncate_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
int flags = O_WRONLY | O_NONBLOCK;
int ret = EXIT_SUCCESS;
char *size_str;
off_t size;
enum {
OPT_NOCREATE = (1 << 0),
OPT_SIZE = (1 << 1),
};
opt_complementary = "s:-1";
opts = getopt32(argv, "cs:", &size_str);
if (!(opts & OPT_NOCREATE))
flags |= O_CREAT;
// TODO: coreutils 8.17 also support "m" (lowercase) suffix
// with truncate, but not with dd!
// We share kMG_suffixes[], so we can't make both tools
// compatible at once...
size = XATOU_SFX(size_str, kMG_suffixes);
argv += optind;
while (*argv) {
int fd = open(*argv, flags, 0666);
if (fd < 0) {
if (errno != ENOENT || !(opts & OPT_NOCREATE)) {
bb_perror_msg("%s: open", *argv);
ret = EXIT_FAILURE;
}
/* else: ENOENT && OPT_NOCREATE:
* do not report error, exitcode is also 0.
*/
} else {
if (ftruncate(fd, size) == -1) {
bb_perror_msg("%s: truncate", *argv);
ret = EXIT_FAILURE;
}
xclose(fd);
}
++argv;
}
return ret;
}
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