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87 lines
2.0 KiB
C
87 lines
2.0 KiB
C
/*
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* Mini truncate implementation for busybox
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*
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* Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config TRUNCATE
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//config: bool "truncate (4.4 kb)"
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//config: default y
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//config: help
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//config: truncate truncates files to a given size. If a file does
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//config: not exist, it is created unless told otherwise.
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//applet:IF_TRUNCATE(APPLET_NOFORK(truncate, truncate, BB_DIR_USR_BIN, BB_SUID_DROP, truncate))
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//kbuild:lib-$(CONFIG_TRUNCATE) += truncate.o
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//usage:#define truncate_trivial_usage
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//usage: "[-c] -s SIZE FILE..."
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//usage:#define truncate_full_usage "\n\n"
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//usage: "Truncate FILEs to SIZE\n"
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//usage: "\n -c Do not create files"
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//usage: "\n -s SIZE"
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//usage:
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//usage:#define truncate_example_usage
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//usage: "$ truncate -s 1G foo"
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#include "libbb.h"
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#if ENABLE_LFS
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# define XATOU_SFX xatoull_sfx
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#else
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# define XATOU_SFX xatoul_sfx
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#endif
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/* This is a NOFORK applet. Be very careful! */
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int truncate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int truncate_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opts;
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int flags = O_WRONLY | O_NONBLOCK;
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int ret = EXIT_SUCCESS;
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char *size_str;
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off_t size;
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enum {
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OPT_NOCREATE = (1 << 0),
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OPT_SIZE = (1 << 1),
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};
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opts = getopt32(argv, "^" "cs:" "\0" "s:-1", &size_str);
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if (!(opts & OPT_NOCREATE))
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flags |= O_CREAT;
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// TODO: coreutils 8.17 also support "m" (lowercase) suffix
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// with truncate, but not with dd!
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// We share kMG_suffixes[], so we can't make both tools
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// compatible at once...
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size = XATOU_SFX(size_str, kMG_suffixes);
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argv += optind;
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while (*argv) {
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int fd = open(*argv, flags, 0666);
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if (fd < 0) {
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if (errno != ENOENT || !(opts & OPT_NOCREATE)) {
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bb_perror_msg("%s: open", *argv);
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ret = EXIT_FAILURE;
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}
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/* else: ENOENT && OPT_NOCREATE:
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* do not report error, exitcode is also 0.
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*/
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} else {
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if (ftruncate(fd, size) == -1) {
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bb_perror_msg("%s: truncate", *argv);
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ret = EXIT_FAILURE;
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}
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xclose(fd);
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}
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++argv;
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}
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return ret;
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}
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