tdb2: tools/tdb2backup

Minor changes from tdb/tools/tdbbackup.c.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 370 insertions, 0 deletions

diff --git a/lib/tdb2/tools/tdb2backup.c b/lib/tdb2/tools/tdb2backup.c
new file mode 100644
index 0000000000..531bf29acc
--- /dev/null
+++ b/lib/tdb2/tools/tdb2backup.c
@@ -0,0 +1,370 @@
+/*
+   Unix SMB/CIFS implementation.
+   low level tdb backup and restore utility
+   Copyright (C) Andrew Tridgell              2002
+
+   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; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+
+  This program is meant for backup/restore of tdb databases. Typical usage would be:
+     tdbbackup *.tdb
+  when Samba shuts down cleanly, which will make a backup of all the local databases
+  to *.bak files. Then on Samba startup you would use:
+     tdbbackup -v *.tdb
+  and this will check the databases for corruption and if corruption is detected then
+  the backup will be restored.
+
+  You may also like to do a backup on a regular basis while Samba is
+  running, perhaps using cron.
+
+  The reason this program is needed is to cope with power failures
+  while Samba is running. A power failure could lead to database
+  corruption and Samba will then not start correctly.
+
+  Note that many of the databases in Samba are transient and thus
+  don't need to be backed up, so you can optimise the above a little
+  by only running the backup on the critical databases.
+
+ */
+
+#include "tdb2.h"
+#include "system/filesys.h"
+
+/* Currently we default to creating a tdb1.  This will change! */
+#define TDB2_IS_DEFAULT false
+
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#endif
+
+static int failed;
+
+static void tdb_log(struct tdb_context *tdb,
+		    enum tdb_log_level level,
+		    enum TDB_ERROR ecode,
+		    const char *message,
+		    void *data)
+{
+	fprintf(stderr, "%s:%s\n", tdb_errorstr(ecode), message);
+}
+
+static char *add_suffix(const char *name, const char *suffix)
+{
+	char *ret;
+	int len = strlen(name) + strlen(suffix) + 1;
+	ret = (char *)malloc(len);
+	if (!ret) {
+		fprintf(stderr,"Out of memory!\n");
+		exit(1);
+	}
+	snprintf(ret, len, "%s%s", name, suffix);
+	return ret;
+}
+
+static int copy_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
+{
+	struct tdb_context *tdb_new = (struct tdb_context *)state;
+	enum TDB_ERROR err;
+
+	err = tdb_store(tdb_new, key, dbuf, TDB_INSERT);
+	if (err) {
+		fprintf(stderr,"Failed to insert into %s: %s\n",
+			tdb_name(tdb_new), tdb_errorstr(err));
+		failed = 1;
+		return 1;
+	}
+	return 0;
+}
+
+
+static int test_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
+{
+	return 0;
+}
+
+/*
+  carefully backup a tdb, validating the contents and
+  only doing the backup if its OK
+  this function is also used for restore
+*/
+static int backup_tdb(const char *old_name, const char *new_name,
+		      bool tdb2, int hash_size)
+{
+	struct tdb_context *tdb;
+	struct tdb_context *tdb_new;
+	char *tmp_name;
+	struct stat st;
+	int count1, count2;
+	enum TDB_ERROR err;
+	union tdb_attribute log_attr, hsize_attr;
+	int tdb_flags = TDB_DEFAULT;
+
+	if (!tdb2) {
+		tdb_flags |= TDB_VERSION1;
+	}
+
+	tmp_name = add_suffix(new_name, ".tmp");
+
+	/* stat the old tdb to find its permissions */
+	if (stat(old_name, &st) != 0) {
+		perror(old_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	log_attr.base.attr = TDB_ATTRIBUTE_LOG;
+	log_attr.base.next = NULL;
+	log_attr.log.fn = tdb_log;
+
+	/* open the old tdb */
+	tdb = tdb_open(old_name, TDB_DEFAULT, O_RDWR, 0, &log_attr);
+	if (!tdb) {
+		printf("Failed to open %s\n", old_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	/* create the new tdb */
+	if (!tdb2 && hash_size) {
+		hsize_attr.base.attr = TDB_ATTRIBUTE_TDB1_HASHSIZE;
+		hsize_attr.base.next = NULL;
+		hsize_attr.tdb1_hashsize.hsize = hash_size;
+		log_attr.base.next = &hsize_attr;
+	}
+
+	unlink(tmp_name);
+	tdb_new = tdb_open(tmp_name, tdb_flags,
+			   O_RDWR|O_CREAT|O_EXCL, st.st_mode & 0777,
+			   &log_attr);
+	if (!tdb_new) {
+		perror(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	err = tdb_transaction_start(tdb);
+	if (err) {
+		fprintf(stderr, "Failed to start transaction on old tdb: %s\n",
+			tdb_errorstr(err));
+		tdb_close(tdb);
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	/* lock the backup tdb so that nobody else can change it */
+	err = tdb_lockall(tdb_new);
+	if (err) {
+		fprintf(stderr, "Failed to lock backup tdb: %s\n",
+			tdb_errorstr(err));
+		tdb_close(tdb);
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	failed = 0;
+
+	/* traverse and copy */
+	count1 = tdb_traverse(tdb, copy_fn, (void *)tdb_new);
+	if (count1 < 0 || failed) {
+		fprintf(stderr,"failed to copy %s\n", old_name);
+		tdb_close(tdb);
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	/* close the old tdb */
+	tdb_close(tdb);
+
+	/* copy done, unlock the backup tdb */
+	tdb_unlockall(tdb_new);
+
+#ifdef HAVE_FDATASYNC
+	if (fdatasync(tdb_fd(tdb_new)) != 0) {
+#else
+	if (fsync(tdb_fd(tdb_new)) != 0) {
+#endif
+		/* not fatal */
+		fprintf(stderr, "failed to fsync backup file\n");
+	}
+
+	/* close the new tdb and re-open read-only */
+	tdb_close(tdb_new);
+
+	/* we don't need the hash attr any more */
+	log_attr.base.next = NULL;
+
+	tdb_new = tdb_open(tmp_name, TDB_DEFAULT, O_RDONLY, 0, &log_attr);
+	if (!tdb_new) {
+		fprintf(stderr,"failed to reopen %s\n", tmp_name);
+		unlink(tmp_name);
+		perror(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	/* traverse the new tdb to confirm */
+	count2 = tdb_traverse(tdb_new, test_fn, NULL);
+	if (count2 != count1) {
+		fprintf(stderr,"failed to copy %s\n", old_name);
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	/* close the new tdb and rename it to .bak */
+	tdb_close(tdb_new);
+	if (rename(tmp_name, new_name) != 0) {
+		perror(new_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	free(tmp_name);
+
+	return 0;
+}
+
+/*
+  verify a tdb and if it is corrupt then restore from *.bak
+*/
+static int verify_tdb(const char *fname, const char *bak_name)
+{
+	struct tdb_context *tdb;
+	int count = -1;
+	union tdb_attribute log_attr;
+
+	log_attr.base.attr = TDB_ATTRIBUTE_LOG;
+	log_attr.base.next = NULL;
+	log_attr.log.fn = tdb_log;
+
+	/* open the tdb */
+	tdb = tdb_open(fname, TDB_DEFAULT, O_RDONLY, 0, &log_attr);
+
+	/* traverse the tdb, then close it */
+	if (tdb) {
+		count = tdb_traverse(tdb, test_fn, NULL);
+		tdb_close(tdb);
+	}
+
+	/* count is < 0 means an error */
+	if (count < 0) {
+		printf("restoring %s\n", fname);
+		return backup_tdb(bak_name, fname, TDB2_IS_DEFAULT, 0);
+	}
+
+	printf("%s : %d records\n", fname, count);
+
+	return 0;
+}
+
+/*
+  see if one file is newer than another
+*/
+static int file_newer(const char *fname1, const char *fname2)
+{
+	struct stat st1, st2;
+	if (stat(fname1, &st1) != 0) {
+		return 0;
+	}
+	if (stat(fname2, &st2) != 0) {
+		return 1;
+	}
+	return (st1.st_mtime > st2.st_mtime);
+}
+
+static void usage(void)
+{
+	printf("Usage: tdbbackup [options] <fname...>\n\n");
+	printf("   -h            this help message\n");
+	printf("   -1            make the backup a TDB1 file\n");
+	printf("   -2            make the backup a TDB2 file\n");
+	printf("   -v            verify mode (restore if corrupt)\n");
+	printf("   -s suffix     set the backup suffix\n");
+	printf("   -v            verify mode (restore if corrupt)\n");
+	printf("   -n hashsize   set the new hash size for the backup\n");
+}
+
+
+ int main(int argc, char *argv[])
+{
+	int i;
+	int ret = 0;
+	int c;
+	int verify = 0;
+	int hashsize = 0;
+	bool tdb2 = TDB2_IS_DEFAULT;
+	const char *suffix = ".bak";
+
+	while ((c = getopt(argc, argv, "vhs:n:12")) != -1) {
+		switch (c) {
+		case 'h':
+			usage();
+			exit(0);
+		case 'v':
+			verify = 1;
+			break;
+		case '1':
+			tdb2 = false;
+			break;
+		case '2':
+			tdb2 = true;
+			break;
+		case 's':
+			suffix = optarg;
+			break;
+		case 'n':
+			hashsize = atoi(optarg);
+			break;
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (argc < 1) {
+		usage();
+		exit(1);
+	}
+
+	for (i=0; i<argc; i++) {
+		const char *fname = argv[i];
+		char *bak_name;
+
+		bak_name = add_suffix(fname, suffix);
+
+		if (verify) {
+			if (verify_tdb(fname, bak_name) != 0) {
+				ret = 1;
+			}
+		} else {
+			if (file_newer(fname, bak_name) &&
+			    backup_tdb(fname, bak_name, tdb2, hashsize) != 0) {
+				ret = 1;
+			}
+		}
+
+		free(bak_name);
+	}
+
+	return ret;
+}