wipefs: new command

 # ./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>

1 files changed, 386 insertions, 0 deletions

diff --git a/misc-utils/wipefs.c b/misc-utils/wipefs.c
new file mode 100644
index 000000000..b34ecfaef
--- /dev/null
+++ b/misc-utils/wipefs.c
@@ -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;
+}