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authorMichael Adam <obnox@samba.org>2007-07-17 12:49:22 +0000
committerGerald (Jerry) Carter <jerry@samba.org>2007-10-10 12:28:46 -0500
commit7291251efb6669c8895440e05edbb4967f0a4632 (patch)
treeda9e72428541274331bd13142f3a1ddcfbae14b9
parentd9c902cb5959ab40be0a7f5a4d10f7fe84e927a4 (diff)
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r23930: Introduce tdb_validate_and_backup:
This is a wrapper around tdb_validate, that does backup handling: * if the given tdb is valid, a backup is created (name.bak) * if the tdb is invalid, if a valid bakup is found (validated with the same validation function) under the name "name.bak" the orignal tdb is moved to name.corrupt and the backup is restored. For the backup handling, a variant of the backup_tdb function from lib/tdb/tools/tdbbackup.c is included in lib/util_tdb.c. The copy function for the traverse action eliminates the need to maintain a global success state by using a struct wrapping the target tdb and a success flag as the private data. Michael (This used to be commit ca63a99b6188c0976603dc2852e478cc7a6b2f8b)
-rw-r--r--source3/lib/util_tdb.c240
1 files changed, 239 insertions, 1 deletions
diff --git a/source3/lib/util_tdb.c b/source3/lib/util_tdb.c
index 22831d97ac..7bba22f4bc 100644
--- a/source3/lib/util_tdb.c
+++ b/source3/lib/util_tdb.c
@@ -1044,6 +1044,9 @@ out:
return ret;
}
+/*
+ * tdb validation function returns 0 if tdb is ok, != 0 if it isn't.
+ */
int tdb_validate(const char *tdb_path, tdb_validate_data_func validate_fn)
{
pid_t child_pid = -1;
@@ -1099,7 +1102,7 @@ int tdb_validate(const char *tdb_path, tdb_validate_data_func validate_fn)
ret = WEXITSTATUS(child_status);
}
if (WIFSIGNALED(child_status)) {
- DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
+ DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
WTERMSIG(child_status)));
#ifdef WCOREDUMP
if (WCOREDUMP(child_status)) {
@@ -1119,3 +1122,238 @@ int tdb_validate(const char *tdb_path, tdb_validate_data_func validate_fn)
return ret;
}
+
+/*
+ * tdb backup function and helpers for tdb_validate wrapper with backup
+ * handling.
+ */
+
+/* this structure eliminates the need for a global overall status for
+ * the traverse-copy */
+struct tdb_copy_data {
+ struct tdb_context *dst;
+ BOOL success;
+};
+
+static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
+ TDB_DATA dbuf, void *private_data)
+{
+ struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;
+
+ if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
+ DEBUG(4, ("Failed to insert into %s\n", tdb_name(data->dst)));
+ data->success = False;
+ return 1;
+ }
+ return 0;
+}
+
+static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
+{
+ struct tdb_copy_data data;
+ int count;
+
+ data.dst = dst;
+ data.success = True;
+
+ count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
+ if ((count < 0) || (data.success == False)) {
+ return -1;
+ }
+ return count;
+}
+
+static int tdb_verify_basic(struct tdb_context *tdb)
+{
+ return tdb_traverse(tdb, NULL, NULL);
+}
+
+/* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
+ */
+static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
+ const char *dst_path, int hash_size)
+{
+ struct tdb_context *src_tdb = NULL;
+ struct tdb_context *dst_tdb = NULL;
+ char *tmp_path = NULL;
+ struct stat st;
+ int count1, count2;
+ int ret = -1;
+
+ if (stat(src_path, &st) != 0) {
+ DEBUG(3, ("Could not stat '%s': %s\n", src_path,
+ strerror(errno)));
+ goto done;
+ }
+
+ /* open old tdb RDWR - so we can lock it */
+ src_tdb = tdb_open(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
+ if (src_tdb == NULL) {
+ DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
+ goto done;
+ }
+
+ if (tdb_lockall(src_tdb) != 0) {
+ DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
+ goto done;
+ }
+
+ tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
+ unlink(tmp_path);
+ dst_tdb = tdb_open(tmp_path,
+ hash_size ? hash_size : tdb_hash_size(src_tdb),
+ TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
+ st.st_mode & 0777);
+ if (dst_tdb == NULL) {
+ DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
+ strerror(errno)));
+ unlink(tmp_path);
+ goto done;
+ }
+
+ count1 = tdb_copy(src_tdb, dst_tdb);
+ if (count1 < 0) {
+ DEBUG(3, ("Failed to copy tdb '%s'\n", src_path));
+ tdb_close(dst_tdb);
+ goto done;
+ }
+
+ /* reopen ro and do basic verification */
+ tdb_close(dst_tdb);
+ dst_tdb = tdb_open(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
+ if (!dst_tdb) {
+ DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
+ strerror(errno)));
+ goto done;
+ }
+ count2 = tdb_verify_basic(dst_tdb);
+ if (count2 != count1) {
+ DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
+ src_path));
+ tdb_close(dst_tdb);
+ goto done;
+ }
+
+ /* make sure the new tdb has reached stable storage
+ * then rename it to its destination */
+ fsync(tdb_fd(dst_tdb));
+ tdb_close(dst_tdb);
+ unlink(dst_path);
+ if (rename(tmp_path, dst_path) != 0) {
+ DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
+ tmp_path, dst_path, strerror(errno)));
+ goto done;
+ }
+
+ /* success */
+ ret = 0;
+
+done:
+ if (src_tdb != NULL) {
+ tdb_close(src_tdb);
+ }
+ if (tmp_path != NULL) {
+ unlink(tmp_path);
+ TALLOC_FREE(tmp_path);
+ }
+ return ret;
+}
+
+/*
+ * do a backup of a tdb, moving the destination out of the way first
+ */
+static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
+ const char *dst_path, int hash_size,
+ const char *rotate_suffix)
+{
+ char *rotate_path;
+ int ret = -1;
+
+ rotate_path = talloc_asprintf(ctx, "%s%s", dst_path, rotate_suffix);
+ if ((rename(dst_path, rotate_path) != 0) && (errno != ENOENT)) {
+ DEBUG(0, ("tdb_backup_with_rotate: error renaming "
+ "%s to %s: %s\n", dst_path, rotate_path,
+ strerror(errno)));
+ goto done;
+ }
+ ret = tdb_backup(ctx, src_path, dst_path, hash_size);
+
+done:
+ TALLOC_FREE(rotate_path);
+ return ret;
+}
+
+/*
+ * validation function with backup handling:
+ *
+ * - calls tdb_validate
+ * - if the tdb is ok, create a backup "name.bak", possibly moving
+ * existing backup to name.bak.old
+ * - if the tdb is corrupt, check if there is a valid backup.
+ * if so, move corrupt tdb to "name.corrupt",
+ * and restore the backup
+ * (give up if there is no backup or if it is invalid)
+ */
+int tdb_validate_and_backup(const char *tdb_path,
+ tdb_validate_data_func validate_fn)
+{
+ int ret = -1;
+ const char *backup_suffix = ".bak";
+ const char *corrupt_suffix = ".corrupt";
+ const char *rotate_suffix = ".old";
+ char *tdb_path_backup;
+ struct stat st;
+ TALLOC_CTX *ctx = NULL;
+
+ ctx = talloc_new(NULL);
+ if (ctx == NULL) {
+ DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
+ goto done;
+ }
+
+ tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);
+
+ ret = tdb_validate(tdb_path, validate_fn);
+
+ if (ret == 0) {
+ DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
+ ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
+ rotate_suffix);
+ if (ret != 0) {
+ DEBUG(1, ("Error creating backup of tdb '%s'\n",
+ tdb_path));
+ goto done;
+ }
+ DEBUG(1, ("Created backup '%s' of tdb '%s'\n", tdb_path_backup,
+ tdb_path));
+ } else {
+ DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));
+ if (stat(tdb_path_backup, &st) != 0) {
+ DEBUG(3, ("Could not stat '%s': %s\n", tdb_path_backup,
+ strerror(errno)));
+ DEBUG(1, ("No backup found. Giving up.\n"));
+ goto done;
+ }
+ ret = tdb_validate(tdb_path_backup, validate_fn);
+ if (ret != 0) {
+ DEBUG(1, ("Backup '%s' found but it is invalid.\n",
+ tdb_path_backup));
+ goto done;
+ }
+ DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
+ ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
+ corrupt_suffix);
+ if (ret != 0) {
+ DEBUG(1, ("Error restoring backup from '%s'\n",
+ tdb_path_backup));
+ goto done;
+ }
+ DEBUG(1, ("Restored tdb backup from '%s'\n", tdb_path_backup));
+ DEBUGADD(1, ("Corrupt tdb stored as '%s%s'\n", tdb_path,
+ corrupt_suffix));
+ }
+
+done:
+ TALLOC_FREE(ctx);
+ return ret;
+}