tdb2: fix O_RDONLY opens.

We tried to get a F_WRLCK on the open lock; we shouldn't do that for a
read-only tdb.  (TDB1 gets away with it because a read-only open skips
all locking).

We also avoid leaking the fd in two tdb_open() failure paths revealed
by this extra testing.

ccan/tdb2/lock.c

@@ -328,13 +328,13 @@ enum TDB_ERROR tdb_lock_and_recover(struct tdb_context *tdb)
 		return ecode;
 	}
 
-	ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
+	ecode = tdb_lock_open(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
 	if (ecode != TDB_SUCCESS) {
 		tdb_allrecord_unlock(tdb, F_WRLCK);
 		return ecode;
 	}
 	ecode = tdb_transaction_recover(tdb);
-	tdb_unlock_open(tdb);
+	tdb_unlock_open(tdb, F_WRLCK);
 	tdb_allrecord_unlock(tdb, F_WRLCK);
 
 	return ecode;
@@ -615,14 +615,15 @@ again:
 	goto again;
 }
 
-enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb, enum tdb_lock_flags flags)
+enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb,
+			     int ltype, enum tdb_lock_flags flags)
 {
-	return tdb_nest_lock(tdb, TDB_OPEN_LOCK, F_WRLCK, flags);
+	return tdb_nest_lock(tdb, TDB_OPEN_LOCK, ltype, flags);
 }
 
-void tdb_unlock_open(struct tdb_context *tdb)
+void tdb_unlock_open(struct tdb_context *tdb, int ltype)
 {
-	tdb_nest_unlock(tdb, TDB_OPEN_LOCK, F_WRLCK);
+	tdb_nest_unlock(tdb, TDB_OPEN_LOCK, ltype);
 }
 
 bool tdb_has_open_lock(struct tdb_context *tdb)

ccan/tdb2/open.c

@@ -333,6 +333,7 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 	struct tdb_attribute_openhook *openhook = NULL;
 	tdb_bool_err berr;
 	enum TDB_ERROR ecode;
+	int openlock;
 
 	tdb = malloc(sizeof(*tdb) + (name ? strlen(name) + 1 : 0));
 	if (!tdb) {
@@ -399,9 +400,11 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 	if ((open_flags & O_ACCMODE) == O_RDONLY) {
 		tdb->read_only = true;
 		tdb->mmap_flags = PROT_READ;
+		openlock = F_RDLCK;
 	} else {
 		tdb->read_only = false;
 		tdb->mmap_flags = PROT_READ | PROT_WRITE;
+		openlock = F_WRLCK;
 	}
 
 	/* internal databases don't need any of the rest. */
@@ -446,12 +449,15 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 			tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 				   "tdb_open: could not stat open %s: %s",
 				   name, strerror(errno));
+			close(fd);
 			goto fail_errno;
 		}
 
 		ecode = tdb_new_file(tdb);
-		if (ecode != TDB_SUCCESS)
+		if (ecode != TDB_SUCCESS) {
+			close(fd);
 			goto fail;
+		}
 
 		tdb->file->next = files;
 		tdb->file->fd = fd;
@@ -462,7 +468,7 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
  	}
 
 	/* ensure there is only one process initialising at once */
-	ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
+	ecode = tdb_lock_open(tdb, openlock, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
 	if (ecode != TDB_SUCCESS) {
 		saved_errno = errno;
 		goto fail_errno;
@@ -534,7 +540,7 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 			goto fail;
 	}
 
-	tdb_unlock_open(tdb);
+	tdb_unlock_open(tdb, openlock);
 
 	/* This make sure we have current map_size and mmap. */
 	tdb->methods->oob(tdb, tdb->file->map_size + 1, true);

ccan/tdb2/private.h

@@ -570,8 +570,8 @@ enum TDB_ERROR tdb_allrecord_upgrade(struct tdb_context *tdb);
 
 /* Serialize db open. */
 enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb,
-			     enum tdb_lock_flags flags);
-void tdb_unlock_open(struct tdb_context *tdb);
+			     int ltype, enum tdb_lock_flags flags);
+void tdb_unlock_open(struct tdb_context *tdb, int ltype);
 bool tdb_has_open_lock(struct tdb_context *tdb);
 
 /* Serialize db expand. */

ccan/tdb2/test/failtest_helper.h

@@ -4,7 +4,7 @@
 #include <stdbool.h>
 
 /* FIXME: Check these! */
-#define INITIAL_TDB_MALLOC	"open.c", 337, FAILTEST_MALLOC
+#define INITIAL_TDB_MALLOC	"open.c", 338, FAILTEST_MALLOC
 #define URANDOM_OPEN		"open.c", 45, FAILTEST_OPEN
 #define URANDOM_READ		"open.c", 25, FAILTEST_READ
 

ccan/tdb2/test/run-05-readonly-open.c

@@ -0,0 +1,88 @@
+#include <ccan/failtest/failtest_override.h>
+#include <ccan/tdb2/tdb.c>
+#include <ccan/tdb2/open.c>
+#include <ccan/tdb2/free.c>
+#include <ccan/tdb2/lock.c>
+#include <ccan/tdb2/io.c>
+#include <ccan/tdb2/hash.c>
+#include <ccan/tdb2/transaction.c>
+#include <ccan/tdb2/check.c>
+#include <ccan/tap/tap.h>
+#include <ccan/failtest/failtest.h>
+#include "logging.h"
+#include "failtest_helper.h"
+
+static bool failtest_suppress = false;
+
+/* Don't need to test everything here, just want expand testing. */
+static enum failtest_result
+suppress_failure(struct failtest_call *history, unsigned num)
+{
+	if (failtest_suppress)
+		return FAIL_DONT_FAIL;
+	return block_repeat_failures(history, num);
+}
+
+int main(int argc, char *argv[])
+{
+	unsigned int i;
+	struct tdb_context *tdb;
+	int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
+			TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT };
+	struct tdb_data key = tdb_mkdata("key", 3);
+	struct tdb_data data = tdb_mkdata("data", 4), d;
+	union tdb_attribute seed_attr;
+	unsigned int msgs = 0;
+
+	failtest_init(argc, argv);
+	failtest_hook = suppress_failure;
+	failtest_exit_check = exit_check_log;
+
+	seed_attr.base.attr = TDB_ATTRIBUTE_SEED;
+	seed_attr.base.next = &tap_log_attr;
+	seed_attr.seed.seed = 0;
+
+	failtest_suppress = true;
+	plan_tests(sizeof(flags) / sizeof(flags[0]) * 11);
+	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
+		tdb = tdb_open("run-05-readonly-open.tdb", flags[i],
+			       O_RDWR|O_CREAT|O_TRUNC, 0600, &seed_attr);
+		ok1(tdb_store(tdb, key, data, TDB_INSERT) == 0);
+		tdb_close(tdb);
+
+		failtest_suppress = false;
+		tdb = tdb_open("run-05-readonly-open.tdb", flags[i],
+			       O_RDONLY, 0600, &tap_log_attr);
+		if (!ok1(tdb))
+			break;
+		ok1(tap_log_messages == msgs);
+		/* Fetch should succeed, stores should fail. */
+		if (!ok1(tdb_fetch(tdb, key, &d) == 0))
+			goto fail;
+		ok1(tdb_deq(d, data));
+		free(d.dptr);
+		if (!ok1(tdb_store(tdb, key, data, TDB_MODIFY)
+			 == TDB_ERR_RDONLY))
+			goto fail;
+		ok1(tap_log_messages == ++msgs);
+		if (!ok1(tdb_store(tdb, key, data, TDB_INSERT)
+			 == TDB_ERR_RDONLY))
+			goto fail;
+		ok1(tap_log_messages == ++msgs);
+		failtest_suppress = true;
+		ok1(tdb_check(tdb, NULL, NULL) == 0);
+		tdb_close(tdb);
+		ok1(tap_log_messages == msgs);
+		/* SIGH: failtest bug, it doesn't save the tdb file because
+		 * we have it read-only.  If we go around again, it gets
+		 * changed underneath us and things get screwy. */
+		if (failtest_has_failed())
+			break;
+	}
+	failtest_exit(exit_status());
+
+fail:
+	failtest_suppress = true;
+	tdb_close(tdb);
+	failtest_exit(exit_status());
+}

ccan/tdb2/transaction.c

@@ -509,7 +509,7 @@ static void _tdb_transaction_cancel(struct tdb_context *tdb)
 	tdb_transaction_unlock(tdb, F_WRLCK);
 
 	if (tdb_has_open_lock(tdb))
-		tdb_unlock_open(tdb);
+		tdb_unlock_open(tdb, F_WRLCK);
 
 	SAFE_FREE(tdb->transaction);
 }
@@ -1005,7 +1005,7 @@ static enum TDB_ERROR _tdb_transaction_prepare_commit(struct tdb_context *tdb)
 
 	/* get the open lock - this prevents new users attaching to the database
 	   during the commit */
-	ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
+	ecode = tdb_lock_open(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
 	if (ecode != TDB_SUCCESS) {
 		return ecode;
 	}