diff options
| -rw-r--r-- | coreutils/cksum.c | 4 | ||||
| -rw-r--r-- | coreutils/shred.c | 104 |
2 files changed, 106 insertions, 2 deletions
diff --git a/coreutils/cksum.c b/coreutils/cksum.c index aeec0188d..9034fc19a 100644 --- a/coreutils/cksum.c +++ b/coreutils/cksum.c @@ -17,9 +17,9 @@ //kbuild:lib-$(CONFIG_CKSUM) += cksum.o //usage:#define cksum_trivial_usage -//usage: "FILES..." +//usage: "FILE..." //usage:#define cksum_full_usage "\n\n" -//usage: "Calculate the CRC32 checksums of FILES" +//usage: "Calculate the CRC32 checksums of FILEs" #include "libbb.h" #include "common_bufsiz.h" diff --git a/coreutils/shred.c b/coreutils/shred.c new file mode 100644 index 000000000..9cd39b79c --- /dev/null +++ b/coreutils/shred.c @@ -0,0 +1,104 @@ +/* vi: set sw=4 ts=4: */ +/* + * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com> + * + * Licensed under GPLv2, see file LICENSE in this source tree. + */ +//config:config SHRED +//config: bool "shred" +//config: default y +//config: help +//config: Overwrite a file to hide its contents, and optionally delete it + +//applet:IF_SHRED(APPLET(shred, BB_DIR_USR_BIN, BB_SUID_DROP)) + +//kbuild:lib-$(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; +} |