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-rw-r--r--coreutils/truncate.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/coreutils/truncate.c b/coreutils/truncate.c
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+++ b/coreutils/truncate.c
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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_RDWR;
+ 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 = xopen(*argv, flags);
+ if (ftruncate(fd, size) == -1) {
+ bb_perror_msg("%s: ftruncate", *argv);
+ ret = EXIT_FAILURE;
+ }
+ xclose(fd);
+ ++argv;
+ }
+
+ return ret;
+}