2f59bf39e
Denys Vlasenko
2017-04-07
Subject
shred: new applet
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Commit Diff GitHub →
coreutils/cksum.c+2 -2
| @@ -17,9 +17,9 @@ | |
| //kbuild:lib-$(CONFIG_CKSUM) += cksum.o | |
| //usage:#define cksum_trivial_usage | |
| - | //usage: "FILES..." |
| + | //usage: "FILE..." |
| //usage:#define cksum_full_usage "\n\n" | |
| - | //usage: "Calculate the CRC32 checksums of FILES" |
| + | //usage: "Calculate the CRC32 checksums of FILEs" |
| #include "libbb.h" | |
| #include "common_bufsiz.h" | |
coreutils/shred.c+104 -0
| @@ -0,0 +1,104 @@ | |
| + | /* vi: set sw=4 ts=4: */ |
| + | /* |
| + | * Copyright (C) 2017 Denys Vlasenko <[email protected]> |
| + | * |
| + | * Licensed under GPLv2, see file LICENSE in this source tree. |
| + | */ |
| + | //config:config SHRED |
| + | //config: bool "shred" |
| + | //config: default y |
| + | //config: help |
| + | //config: Overwrite a file to hide its contents, and optionally delete it |
| + | |
| + | //applet:IF_SHRED(APPLET(shred, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| + | |
| + | //kbuild:lib-$(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; |
| + | } |