]> err.no Git - util-linux/commitdiff
wipefs: new command
authorKarel Zak <kzak@redhat.com>
Mon, 5 Oct 2009 11:14:07 +0000 (13:14 +0200)
committerKarel Zak <kzak@redhat.com>
Tue, 6 Oct 2009 21:56:23 +0000 (23:56 +0200)
 # ./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@redhat.com>
misc-utils/.gitignore
misc-utils/Makefile.am
misc-utils/blkid.8
misc-utils/wipefs.8 [new file with mode: 0644]
misc-utils/wipefs.c [new file with mode: 0644]

index 2242b9201f3a7e06ee54e4115d950d61346c4aac..5d34a50dbc811f972809895d01387ebf9a387f7e 100644 (file)
@@ -16,3 +16,4 @@ uuidgen
 uuidd
 findfs
 blkid
+wipefs
index a4f2f44ea834fd9cfa107fa8bb1749edd7603aa1..6cd9cf7bb838733ac4e6b38ed79b892970bd96e9 100644 (file)
@@ -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)
index 801fbdd3bc3abc611b052c7c39708e6a0b69811d..9fc83937ab2170965c47bd1b733e95383e5efec6 100644 (file)
@@ -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 (file)
index 0000000..3217c10
--- /dev/null
@@ -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 [ \-ahnp ]
+.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\-h, \-\-help\fP"
+Print help and exit.
+.IP "\fB\-n, \-\-no\-act\fP"
+Causes everything to be done except for the write() call.
+.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@redhat.com>.
+.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 (file)
index 0000000..b34ecfa
--- /dev/null
@@ -0,0 +1,386 @@
+/*
+ * wipefs - utility to wipe filesystems of partition tables from device
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
+ * Written by Karel Zak <kzak@redhat.com>
+ *
+ * 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 <limits.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) {
+               printf("offset               type\n");
+               printf("----------------------------------------------------------------\n");
+       }
+
+       printf("0x%-17jx  %s   [%s]", wp->offset, wp->type, wp->usage);
+
+       if (wp->label && *wp->label)
+               printf("\n%27s %s", "LABEL:", wp->label);
+       if (wp->uuid)
+               printf("\n%27s %s", "UUID: ", wp->uuid);
+       puts("\n");
+}
+
+static void
+print_parsable(struct wipe_desc *wp, int line)
+{
+       char enc[256];
+
+       if (!line)
+               printf("# offset,uuid,label,type\n");
+
+       printf("0x%jx,", wp->offset);
+
+       if (wp->uuid) {
+               blkid_encode_string(wp->uuid, enc, sizeof(enc));
+               printf("%s,", enc);
+       } else
+               fputc(',', stdout);
+
+       if (wp->label) {
+               blkid_encode_string(wp->label, enc, sizeof(enc));
+               printf("%s,", enc);
+       } else
+               fputc(',', stdout);
+
+       blkid_encode_string(wp->type, enc, sizeof(enc));
+       printf("%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, _("calloc failed"));
+
+       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, _("malloc failed"));
+       return x;
+}
+
+static inline char *xstrdup(const char *s)
+{
+       char *x = strdup(s);
+       if (!x)
+               err(EXIT_FAILURE, _("strdup failed"));
+       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 noact)
+{
+       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 (noact == 0 && write_all(fd, buf, len))
+               err(EXIT_FAILURE, _("%s: write failed"), fname);
+
+       printf(_("%zd bytes ["), wp->len);
+
+       for (i = 0; i < len; i++) {
+               printf("%02x", wp->magic[i]);
+               if (i + 1 < len)
+                       fputc(' ', stdout);
+       }
+
+       printf(_("] 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 noact)
+{
+       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, noact);
+               wp = wp->next;
+       }
+
+       close(fd);
+       return 0;
+}
+
+static loff_t
+strtoll_offset(const char *str)
+{
+       char *end = NULL;
+       loff_t off;
+
+       errno = 0;
+       off = strtoll(str, &end, 0);
+
+       if ((errno == ERANGE && (off == LLONG_MAX || off == LONG_MIN)) ||
+           (errno != 0 && off == 0))
+               err(EXIT_FAILURE, _("invalid offset '%s' value specified"), str);
+
+       if (*end != '\0')
+               errx(EXIT_FAILURE, _("invalid offset '%s' value specified"), str);
+
+       return off;
+}
+
+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"
+       " -h, --help          this help\n"
+       " -n, --no-act        everything to be done except for the write() call\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, noact = 0, mode = 0;
+       const char *fname;
+
+       struct option longopts[] = {
+           { "all",       0, 0, 'a' },
+           { "help",      0, 0, 'h' },
+           { "no-act",    0, 0, 'n' },
+           { "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, "ahno:p", longopts, NULL)) != -1) {
+               switch(c) {
+               case 'a':
+                       all++;
+                       break;
+               case 'h':
+                       usage(stdout);
+                       break;
+               case 'n':
+                       noact++;
+                       break;
+               case 'o':
+                       wp = add_offset(wp, strtoll_offset(optarg), 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, noact);
+               else
+                       print_all(wp, mode);
+       }
+       return EXIT_SUCCESS;
+}