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authorDenys Vlasenko2017-04-07 20:45:08 +0200
committerDenys Vlasenko2017-04-07 20:45:08 +0200
commit2f59bf39e2ea6fb4c3ed3e74ea113a521e1a3558 (patch)
treeb42d8b7bfe0684a40ef669e09aa2a0cdfba8684f /coreutils/shred.c
parent42776708f21b8f7293627f88d8d5d3df00d8be1c (diff)
downloadbusybox-2f59bf39e2ea6fb4c3ed3e74ea113a521e1a3558.zip
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shred: new applet
function old new delta shred_main - 361 +361 packed_usage 31427 31467 +40 applet_names 2578 2584 +6 applet_main 1492 1496 +4 run_applet_and_exit 679 682 +3 ------------------------------------------------------------------------------ (add/remove: 2/0 grow/shrink: 4/0 up/down: 414/0) Total: 414 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'coreutils/shred.c')
-rw-r--r--coreutils/shred.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/coreutils/shred.c b/coreutils/shred.c
new file mode 100644
index 0000000..9cd39b7
--- /dev/null
+++ b/coreutils/shred.c
@@ -0,0 +1,104 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+//config:config SHRED
+//config: bool "shred"
+//config: default y
+//config: help
+//config: Overwrite a file to hide its contents, and optionally delete it
+
+//applet:IF_SHRED(APPLET(shred, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_SHRED) += shred.o
+
+//usage:#define shred_trivial_usage
+//usage: "FILE..."
+//usage:#define shred_full_usage "\n\n"
+//usage: "Overwrite/delete FILEs\n"
+//usage: "\n -f Chmod to ensure writability"
+//usage: "\n -n N Overwrite N times (default 3)"
+//usage: "\n -z Final overwrite with zeros"
+//usage: "\n -u Remove file"
+//-x and -v are accepted but have no effect
+
+/* shred (GNU coreutils) 8.25:
+-f, --force change permissions to allow writing if necessary
+-u truncate and remove file after overwriting
+-z, --zero add a final overwrite with zeros to hide shredding
+-n, --iterations=N overwrite N times instead of the default (3)
+-v, --verbose show progress
+-x, --exact do not round file sizes up to the next full block; this is the default for non-regular files
+--random-source=FILE get random bytes from FILE
+-s, --size=N shred this many bytes (suffixes like K, M, G accepted)
+--remove[=HOW] like -u but give control on HOW to delete; See below
+*/
+
+#include "libbb.h"
+
+int shred_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int shred_main(int argc UNUSED_PARAM, char **argv)
+{
+ int rand_fd = rand_fd; /* for compiler */
+ int zero_fd;
+ unsigned num_iter = 3;
+ unsigned opt;
+ enum {
+ OPT_f = (1 << 0),
+ OPT_u = (1 << 1),
+ OPT_z = (1 << 2),
+ OPT_n = (1 << 3),
+ OPT_v = (1 << 4),
+ OPT_x = (1 << 5),
+ };
+
+ opt = getopt32(argv, "fuzn:+vx", &num_iter);
+ argv += optind;
+
+ zero_fd = xopen("/dev/zero", O_RDONLY);
+ if (num_iter != 0)
+ rand_fd = xopen("/dev/urandom", O_RDONLY);
+
+ if (!*argv)
+ bb_show_usage();
+
+ for (;;) {
+ struct stat sb;
+ unsigned i;
+ int fd = -1;
+
+ if (opt & OPT_f) {
+ fd = open(*argv, O_WRONLY);
+ if (fd < 0)
+ chmod(*argv, 0666);
+ }
+ if (fd < 0)
+ fd = xopen(*argv, O_WRONLY);
+
+ if (fstat(fd, &sb) == 0 && sb.st_size > 0) {
+ off_t size = sb.st_size;
+
+ for (i = 0; i < num_iter; i++) {
+ bb_copyfd_size(rand_fd, fd, size);
+ fdatasync(fd);
+ xlseek(fd, 0, SEEK_SET);
+ }
+ if (opt & OPT_z) {
+ bb_copyfd_size(zero_fd, fd, size);
+ fdatasync(fd);
+ }
+ if (opt & OPT_u) {
+ ftruncate(fd, 0);
+ xunlink(*argv);
+ }
+ xclose(fd);
+ }
+ argv++;
+ if (!*argv)
+ break;
+ }
+
+ return EXIT_SUCCESS;
+}