# ./wipefs /dev/sda4
offset type
----------------------------------------------------------------
0xff6 swap [other]
UUID: da6c54ea-77d9-470a-82f1-e793fd5d9131
0x36 vfat [filesystem]
UUID: 497F-3013
# ./wipefs --offset 0x36 /dev/sda4
8 bytes [46 41 54 31 32 20 20 20] erased at offset 0x36 (vfat)
Signed-off-by: Karel Zak <kzak@xxxxxxxxxx>
---
misc-utils/.gitignore | 1 +
misc-utils/Makefile.am | 6 +-
misc-utils/blkid.8 | 1 +
misc-utils/wipefs.8 | 45 ++++++
misc-utils/wipefs.c | 373 ++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 424 insertions(+), 2 deletions(-)
create mode 100644 misc-utils/wipefs.8
create mode 100644 misc-utils/wipefs.c
diff --git a/misc-utils/.gitignore b/misc-utils/.gitignore
index 2242b92..5d34a50 100644
--- a/misc-utils/.gitignore
+++ b/misc-utils/.gitignore
@@ -16,3 +16,4 @@ uuidgen
uuidd
findfs
blkid
+wipefs
diff --git a/misc-utils/Makefile.am b/misc-utils/Makefile.am
index a4f2f44..6cd9cf7 100644
--- a/misc-utils/Makefile.am
+++ b/misc-utils/Makefile.am
@@ -33,12 +33,14 @@ endif
endif
if BUILD_LIBBLKID
-sbin_PROGRAMS += blkid findfs
-dist_man_MANS += blkid.8 findfs.8
+sbin_PROGRAMS += blkid findfs wipefs
+dist_man_MANS += blkid.8 findfs.8 wipefs.8
blkid_LDADD = $(ul_libblkid_la)
blkid_CFLAGS = -I$(ul_libblkid_srcdir)
findfs_LDADD = $(ul_libblkid_la)
findfs_CFLAGS = -I$(ul_libblkid_srcdir)
+wipefs_LDADD = $(ul_libblkid_la)
+wipefs_CFLAGS = -I$(ul_libblkid_srcdir)
if HAVE_STATIC_BLKID
sbin_PROGRAMS += blkid.static
blkid_static_SOURCES = $(blkid_SOURCES)
diff --git a/misc-utils/blkid.8 b/misc-utils/blkid.8
index 801fbdd..9fc8393 100644
--- a/misc-utils/blkid.8
+++ b/misc-utils/blkid.8
@@ -212,3 +212,4 @@ ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
.SH "SEE ALSO"
.BR libblkid (3)
.BR findfs (8)
+.BR wipefs (8)
diff --git a/misc-utils/wipefs.8 b/misc-utils/wipefs.8
new file mode 100644
index 0000000..150863a
--- /dev/null
+++ b/misc-utils/wipefs.8
@@ -0,0 +1,45 @@
+.\" -*- nroff -*-
+.\" Copyright 2009 by Karel Zak. All Rights Reserved.
+.\" This file may be copied under the terms of the GNU Public License.
+.\"
+.TH WIPEFS 8 "October 2009" "Linux" "MAINTENANCE COMMANDS"
+.SH NAME
+wipefs \- wipe a filesystem signature from a device
+.SH SYNOPSIS
+.B wipefs
+.RB [ \-afhp ]
+.RB [ \-o
+.IR offset ]
+.I device
+.SH DESCRIPTION
+.B wipefs
+allows to erase filesystem or raid signatures (magic strings) from the
+.I device
+to make the device invisible for libblkid.
+.B wipefs
+does not erase the whole filesystem or any other data from the device.
+When used without options -a or -o, it lists all visible filesystems and offsets
+of their signatures.
+.SH OPTIONS
+.IP "\fB\-a, \-\-all\fP"
+Erase all available signatures.
+.IP "\fB\-f, \-\-fake\fP"
+Causes everything to be done except for the write() call.
+.IP "\fB\-h, \-\-help\fP"
+Print help and exit.
+.IP "\fB\-o, \-\-offset\fP \fIoffset\fP
+Specifies location (in bytes) of the signature which should be erased from the
+device. The offset number may include a "0x" prefix, and then the number will be
+read as a hex value. It is possible to specify multiple -o options.
+.IP "\fB\-p, \-\-parsable\fP"
+Print out in parsable instead of printable format. Encode all potentially unsafe
+characters of a string to the corresponding hex value prefixed by '\\x'.
+.SH AUTHOR
+Karel Zak <kzak@xxxxxxxxxx>.
+.SH AVAILABILITY
+The wipefs command is part of the util-linux-ng package and is available from
+ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
+.SH SEE ALSO
+.BR blkid (8)
+.BR findfs (8)
+
diff --git a/misc-utils/wipefs.c b/misc-utils/wipefs.c
new file mode 100644
index 0000000..65ac049
--- /dev/null
+++ b/misc-utils/wipefs.c
@@ -0,0 +1,373 @@
+/*
+ * wipefs - utility to wipe filesystems of partition tables from device
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
+ * Written by Karel Zak <kzak@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <err.h>
+#include <string.h>
+
+#include <blkid.h>
+
+#include "nls.h"
+
+struct wipe_desc {
+ loff_t offset; /* magic string offset */
+ size_t len; /* length of magic string */
+ unsigned char *magic; /* magic string */
+
+ int zap; /* zap this offset? */
+ char *usage; /* raid, filesystem, ... */
+ char *type; /* FS type */
+ char *label; /* FS label */
+ char *uuid; /* FS uuid */
+
+ struct wipe_desc *next;
+};
+
+#define WP_MODE_PRETTY 0 /* default */
+#define WP_MODE_PARSABLE 1
+
+static void
+print_pretty(struct wipe_desc *wp, int line)
+{
+ if (!line) {
+ fprintf(stdout, "offset type\n");
+ fprintf(stdout, "----------------------------------------------------------------\n");
+ }
+
+ fprintf(stdout, "0x%-17jx %s [%s]", wp->offset, wp->type, wp->usage);
+
+ if (wp->label && *wp->label)
+ fprintf(stdout, "\n%27s %s", "LABEL:", wp->label);
+ if (wp->uuid)
+ fprintf(stdout, "\n%27s %s", "UUID: ", wp->uuid);
+ fputs("\n\n", stdout);
+}
+
+static void
+print_parsable(struct wipe_desc *wp, int line)
+{
+ char enc[256];
+
+ if (!line)
+ fprintf(stdout, "# offset,uuid,label,type\n");
+
+ fprintf(stdout, "0x%jx,", wp->offset);
+
+ if (wp->uuid) {
+ blkid_encode_string(wp->uuid, enc, sizeof(enc));
+ fprintf(stdout, "%s,", enc);
+ } else
+ fputc(',', stdout);
+
+ if (wp->label) {
+ blkid_encode_string(wp->label, enc, sizeof(enc));
+ fprintf(stdout, "%s,", enc);
+ } else
+ fputc(',', stdout);
+
+ blkid_encode_string(wp->type, enc, sizeof(enc));
+ fprintf(stdout, "%s\n", enc);
+}
+
+static void
+print_all(struct wipe_desc *wp, int mode)
+{
+ int n = 0;
+
+ while (wp) {
+ switch (mode) {
+ case WP_MODE_PRETTY:
+ print_pretty(wp, n++);
+ break;
+ case WP_MODE_PARSABLE:
+ print_parsable(wp, n++);
+ break;
+ }
+ wp = wp->next;
+ }
+}
+
+static struct wipe_desc *
+add_offset(struct wipe_desc *wp0, loff_t offset, int zap)
+{
+ struct wipe_desc *wp = wp0;
+
+ while (wp) {
+ if (wp->offset == offset)
+ return wp;
+ wp = wp->next;
+ }
+
+ wp = calloc(1, sizeof(struct wipe_desc));
+ if (!wp)
+ err(EXIT_FAILURE, _("out of memory"));
+
+ wp->offset = offset;
+ wp->next = wp0;
+ wp->zap = zap;
+ return wp;
+}
+
+static inline void *xmalloc(size_t sz)
+{
+ void *x = malloc(sz);
+ if (!x)
+ err(EXIT_FAILURE, _("out of memory"));
+ return x;
+}
+
+static inline char *xstrdup(const char *s)
+{
+ char *x = strdup(s);
+ if (!x)
+ err(EXIT_FAILURE, _("out of memory"));
+ return x;
+}
+
+static struct wipe_desc *
+get_offset_from_probe(struct wipe_desc *wp, blkid_probe pr, int zap)
+{
+ const char *off, *type, *usage, *mag;
+ size_t len;
+
+ if (blkid_probe_lookup_value(pr, "TYPE", &type, NULL) == 0 &&
+ blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &off, NULL) == 0 &&
+ blkid_probe_lookup_value(pr, "SBMAGIC", &mag, &len) == 0 &&
+ blkid_probe_lookup_value(pr, "USAGE", &usage, NULL) == 0) {
+
+ loff_t offset = strtoll(off, NULL, 10);
+ const char *p;
+
+ wp = add_offset(wp, offset, zap);
+ if (!wp)
+ return NULL;
+
+ wp->usage = xstrdup(usage);
+ wp->type = xstrdup(type);
+
+ wp->magic = xmalloc(wp->len);
+ memcpy(wp->magic, mag, len);
+ wp->len = len;
+
+ if (blkid_probe_lookup_value(pr, "LABEL", &p, NULL) == 0)
+ wp->label = xstrdup(p);
+
+ if (blkid_probe_lookup_value(pr, "UUID", &p, NULL) == 0)
+ wp->uuid = xstrdup(p);
+ }
+
+ return wp;
+}
+
+static struct wipe_desc *
+read_offsets(struct wipe_desc *wp, const char *fname, int zap)
+{
+ blkid_probe pr;
+
+ if (!fname)
+ return NULL;
+
+ pr = blkid_new_probe_from_filename(fname);
+ if (!pr)
+ errx(EXIT_FAILURE, _("probing initialization failed"));
+
+ blkid_probe_enable_superblocks(pr, 1);
+ blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC |
+ BLKID_SUBLKS_TYPE | BLKID_SUBLKS_USAGE |
+ BLKID_SUBLKS_LABEL | BLKID_SUBLKS_UUID);
+
+ while (blkid_do_probe(pr) == 0) {
+ wp = get_offset_from_probe(wp, pr, zap);
+ if (!wp)
+ break;
+ }
+
+ blkid_free_probe(pr);
+ return wp;
+}
+
+static int
+write_all(int fd, const void *buf, size_t count)
+{
+ while(count) {
+ ssize_t tmp;
+
+ errno = 0;
+ tmp = write(fd, buf, count);
+ if (tmp > 0) {
+ count -= tmp;
+ if (count)
+ buf += tmp;
+ } else if (errno != EINTR && errno != EAGAIN)
+ return -1;
+ }
+ return 0;
+}
+
+static int
+do_wipe_offset(int fd, struct wipe_desc *wp, const char *fname, int fake)
+{
+ char buf[BUFSIZ];
+ int i;
+ off_t l;
+ size_t len;
+
+ if (!wp->type) {
+ warnx(_("can't found a magic string at offset "
+ "0x%jx - ignore."), wp->offset);
+ return 0;
+ }
+
+ l = lseek(fd, wp->offset, SEEK_SET);
+ if (l == (off_t) -1)
+ err(EXIT_FAILURE, _("%s: failed to seek to offset 0x%jx"),
+ fname, wp->offset);
+
+ len = wp->len > sizeof(buf) ? sizeof(buf) : wp->len;
+
+ memset(buf, 0, len);
+ if (fake == 0 && write_all(fd, buf, len))
+ err(EXIT_FAILURE, _("%s: write failed"), fname);
+
+ fprintf(stdout, _("%zd bytes ["), wp->len);
+
+ for (i = 0; i < len; i++) {
+ fprintf(stdout, "%02x", wp->magic[i]);
+ if (i + 1 < len)
+ fputc(' ', stdout);
+ }
+
+ fprintf(stdout, _("] erased at offset 0x%jx (%s)\n"),
+ wp->offset, wp->type);
+ return 0;
+}
+
+static int
+do_wipe(struct wipe_desc *wp, const char *fname, int fake)
+{
+ int fd;
+
+ fd = open(fname, O_WRONLY);
+ if (fd < 0)
+ err(EXIT_FAILURE, _("%s: open failed"), fname);
+
+ while (wp) {
+ if (wp->zap)
+ do_wipe_offset(fd, wp, fname, fake);
+ wp = wp->next;
+ }
+
+ close(fd);
+ return 0;
+}
+
+static void __attribute__((__noreturn__)) usage(FILE *out)
+{
+ fprintf(out, _("Usage: %s [options] <filename>\n\nOptions:\n"),
+ program_invocation_short_name);
+
+ fprintf(out, _(
+ " -a, --all wipe all magic strings (BE CAREFUL!)\n"
+ " -f, --fake everything to be done except for the write() call\n"
+ " -h, --help this help\n"
+ " -o, --offset <num> offset to erase, in bytes\n"
+ " -p, --parsable print out in parsable instead of printable format\n"));
+
+ fprintf(out, _("\nFor more information see wipefs(1).\n"));
+
+ exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int
+main(int argc, char **argv)
+{
+ struct wipe_desc *wp = NULL;
+ int c, all = 0, has_offset = 0, fake = 0, mode = 0;
+ char *fname;
+
+ struct option longopts[] = {
+ { "all", 0, 0, 'a' },
+ { "fake", 0, 0, 'f' },
+ { "help", 0, 0, 'h' },
+ { "offset", 1, 0, 'o' },
+ { "parsable", 0, 0, 'p' },
+ { NULL, 0, 0, 0 }
+ };
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+
+ while ((c = getopt_long(argc, argv, "afho:p", longopts, NULL)) != -1) {
+ switch(c) {
+ case 'a':
+ all++;
+ break;
+ case 'f':
+ fake++;
+ break;
+ case 'h':
+ usage(stdout);
+ break;
+ case 'o':
+ {
+ char *end = NULL;
+ loff_t off = strtoll(optarg, &end, 0);
+
+ if (*end != '\0')
+ errx(EXIT_FAILURE, _("invalid offset value "
+ "'%s' specified"), optarg);
+ wp = add_offset(wp, off, 1);
+ has_offset++;
+ break;
+ }
+ case 'p':
+ mode = WP_MODE_PARSABLE;
+ break;
+ default:
+ usage(stderr);
+ break;
+ }
+ }
+
+ if (wp && all)
+ errx(EXIT_FAILURE, _("--offset and --all are mutually exclusive"));
+ if (optind == argc)
+ usage(stderr);
+
+ fname = argv[optind++];
+
+ wp = read_offsets(wp, fname, all);
+
+ if (wp) {
+ if (has_offset || all)
+ do_wipe(wp, fname, fake);
+ else
+ print_all(wp, mode);
+ }
+ return EXIT_SUCCESS;
+}
--
1.6.2.5
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