X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Fcheck.c;h=53fb286613a3e829e8f2aa159109124c3e182503;hp=dca8d1d98e003e91466957150c8e4aa681450886;hb=a1ace0cd114e0c588d6ce1b9e7386af11716e0bd;hpb=f7b3eb1ecf6935dbf2b6c283e848ebfbaaeca47c

diff --git a/ccan/tdb/check.c b/ccan/tdb/check.c
index dca8d1d9..53fb2866 100644
--- a/ccan/tdb/check.c
+++ b/ccan/tdb/check.c
@@ -1,14 +1,14 @@
- /* 
+ /*
    Unix SMB/CIFS implementation.
 
    trivial database library
 
    Copyright (C) Rusty Russell		   2009
-   
+
      ** NOTE! The following LGPL license applies to the tdb
      ** library. This does NOT imply that all of Samba is released
      ** under the LGPL
-   
+
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
@@ -30,7 +30,7 @@ static bool tdb_check_header(struct tdb_context *tdb, tdb_off_t *recovery)
 {
 	struct tdb_header hdr;
 
-	if (tdb->methods->tdb_read(tdb, 0, &hdr, sizeof(hdr), DOCONV()) == -1)
+	if (tdb->methods->tdb_read(tdb, 0, &hdr, sizeof(hdr), 0) == -1)
 		return false;
 	if (strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0)
 		goto corrupt;
@@ -39,7 +39,7 @@ static bool tdb_check_header(struct tdb_context *tdb, tdb_off_t *recovery)
 	if (hdr.version != TDB_VERSION)
 		goto corrupt;
 
-	if (hdr.rwlocks != 0)
+	if (hdr.hashcheck != hashcheck(tdb))
 		goto corrupt;
 
 	if (hdr.hash_size == 0)
@@ -232,7 +232,7 @@ static bool tdb_check_used_record(struct tdb_context *tdb,
 				  const struct tdb_record *rec,
 				  unsigned char **hashes,
 				  int (*check)(TDB_DATA, TDB_DATA, void *),
-				  void *private)
+				  void *private_data)
 {
 	TDB_DATA key, data;
 
@@ -270,7 +270,7 @@ static bool tdb_check_used_record(struct tdb_context *tdb,
 		if (!data.dptr)
 			goto fail_put_key;
 
-		if (check(key, data, private) == -1)
+		if (check(key, data, private_data) == -1)
 			goto fail_put_data;
 		put_bytes(tdb, data);
 	}
@@ -302,18 +302,42 @@ static bool tdb_check_free_record(struct tdb_context *tdb,
 	return true;
 }
 
+/* Slow, but should be very rare. */
+static size_t dead_space(struct tdb_context *tdb, tdb_off_t off)
+{
+	size_t len;
+
+	for (len = 0; off + len < tdb->map_size; len++) {
+		char c;
+		if (tdb->methods->tdb_read(tdb, off, &c, 1, 0))
+			return 0;
+		if (c != 0 && c != 0x42)
+			break;
+	}
+	return len;
+}
+
 int tdb_check(struct tdb_context *tdb,
-	      int (*check)(TDB_DATA key, TDB_DATA data, void *private),
-	      void *private)
+	      int (*check)(TDB_DATA key, TDB_DATA data, void *private_data),
+	      void *private_data)
 {
 	unsigned int h;
 	unsigned char **hashes;
 	tdb_off_t off, recovery_start;
 	struct tdb_record rec;
 	bool found_recovery = false;
-
-	if (tdb_lockall(tdb) == -1)
-		return -1;
+	tdb_len_t dead;
+	bool locked;
+
+	/* Read-only databases use no locking at all: it's best-effort.
+	 * We may have a write lock already, so skip that case too. */
+	if (tdb->read_only || tdb->allrecord_lock.count != 0) {
+		locked = false;
+	} else {
+		if (tdb_lockall_read(tdb) == -1)
+			return -1;
+		locked = true;
+	}
 
 	/* Make sure we know true size of the underlying file. */
 	tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
@@ -330,7 +354,8 @@ int tdb_check(struct tdb_context *tdb,
 	}
 
 	/* One big malloc: pointers then bit arrays. */
-	hashes = calloc(1, sizeof(hashes[0]) * (1+tdb->header.hash_size)
+	hashes = (unsigned char **)calloc(
+			1, sizeof(hashes[0]) * (1+tdb->header.hash_size)
 			+ BITMAP_BITS / CHAR_BIT * (1+tdb->header.hash_size));
 	if (!hashes) {
 		tdb->ecode = TDB_ERR_OOM;
@@ -362,15 +387,30 @@ int tdb_check(struct tdb_context *tdb,
 		case TDB_MAGIC:
 		case TDB_DEAD_MAGIC:
 			if (!tdb_check_used_record(tdb, off, &rec, hashes,
-						   check, private))
+						   check, private_data))
 				goto free;
 			break;
 		case TDB_FREE_MAGIC:
 			if (!tdb_check_free_record(tdb, off, &rec, hashes))
 				goto free;
 			break;
-		case TDB_RECOVERY_MAGIC:
+		/* If we crash after ftruncate, we can get zeroes or fill. */
 		case TDB_RECOVERY_INVALID_MAGIC:
+		case 0x42424242:
+			if (recovery_start == off) {
+				found_recovery = true;
+				break;
+			}
+			dead = dead_space(tdb, off);
+			if (dead < sizeof(rec))
+				goto corrupt;
+
+			TDB_LOG((tdb, TDB_DEBUG_ERROR,
+				 "Dead space at %d-%d (of %u)\n",
+				 off, off + dead, tdb->map_size));
+			rec.rec_len = dead - sizeof(rec);
+			break;
+		case TDB_RECOVERY_MAGIC:
 			if (recovery_start != off) {
 				TDB_LOG((tdb, TDB_DEBUG_ERROR,
 					 "Unexpected recovery record at offset %d\n",
@@ -379,7 +419,8 @@ int tdb_check(struct tdb_context *tdb,
 			}
 			found_recovery = true;
 			break;
-		default:
+		default: ;
+		corrupt:
 			tdb->ecode = TDB_ERR_CORRUPT;
 			TDB_LOG((tdb, TDB_DEBUG_ERROR,
 				 "Bad magic 0x%x at offset %d\n",
@@ -405,19 +446,22 @@ int tdb_check(struct tdb_context *tdb,
 	/* We must have found recovery area if there was one. */
 	if (recovery_start != 0 && !found_recovery) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR,
-			 "Expected %s recovery area, got %s\n",
-			 recovery_start ? "a" : "no",
-			 found_recovery ? "one" : "none"));
+			 "Expected a recovery area at %u\n",
+			 recovery_start));
 		goto free;
 	}
 
 	free(hashes);
-	tdb_unlockall(tdb);
+	if (locked) {
+		tdb_unlockall_read(tdb);
+	}
 	return 0;
 
 free:
 	free(hashes);
 unlock:
-	tdb_unlockall(tdb);
+	if (locked) {
+		tdb_unlockall_read(tdb);
+	}
 	return -1;
 }