Fix traverse nesting unlock bug.

diff --git a/ccan/tdb/test/run-nested-traverse.c b/ccan/tdb/test/run-nested-traverse.c
new file mode 100644 (file)
index 0000000..f4a36b6
--- /dev/null
+++ b/ccan/tdb/test/run-nested-traverse.c
@@ -0,0 +1,71 @@
+#define _XOPEN_SOURCE 500
+#include "tdb/tdb.h"
+#include "tdb/io.c"
+#include "tdb/tdb.c"
+#include "tdb/lock.c"
+#include "tdb/freelist.c"
+#include "tdb/traverse.c"
+#include "tdb/transaction.c"
+#include "tdb/error.c"
+#include "tdb/open.c"
+#include "tap/tap.h"
+#include <stdlib.h>
+#include <stdbool.h>
+#include <err.h>
+
+static bool correct_key(TDB_DATA key)
+{
+       return key.dsize == strlen("hi")
+               && memcmp(key.dptr, "hi", key.dsize) == 0;
+}
+
+static bool correct_data(TDB_DATA data)
+{
+       return data.dsize == strlen("world")
+               && memcmp(data.dptr, "world", data.dsize) == 0;
+}
+
+static int traverse2(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data,
+                    void *p)
+{
+       ok1(correct_key(key));
+       ok1(correct_data(data));
+       return 0;
+}
+
+static int traverse1(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data,
+                    void *p)
+{
+       ok1(correct_key(key));
+       ok1(correct_data(data));
+       ok1(tdb->have_transaction_lock);
+       tdb_traverse(tdb, traverse2, NULL);
+
+       /* That should *not* release the transaction lock! */
+       ok1(tdb->have_transaction_lock);
+       return 0;
+}
+
+int main(int argc, char *argv[])
+{
+       struct tdb_context *tdb;
+       TDB_DATA key, data;
+
+       plan_tests(14);
+       tdb = tdb_open("/tmp/test.tdb", 1024, TDB_CLEAR_IF_FIRST,
+                      O_CREAT|O_TRUNC|O_RDWR, 0600);
+       ok1(tdb);
+
+       /* Tickle bug on appending zero length buffer to zero length buffer. */
+       key.dsize = strlen("hi");
+       key.dptr = (void *)"hi";
+       data.dptr = (void *)"world";
+       data.dsize = strlen("world");
+
+       ok1(tdb_store(tdb, key, data, TDB_INSERT) == 0);
+       tdb_traverse(tdb, traverse1, NULL);
+       tdb_traverse_read(tdb, traverse1, NULL);
+       tdb_close(tdb);
+
+       return exit_status();
+}

diff --git a/ccan/tdb/traverse.c b/ccan/tdb/traverse.c
index 6bbaac8d635b96dc351b52a386ab02ea3d8eb2e8..6397930b469da5385663cee6987b2568af5d0a03 100644 (file)
--- a/ccan/tdb/traverse.c
+++ b/ccan/tdb/traverse.c
@@ -182,6 +182,7 @@ static int tdb_traverse_internal(struct tdb_context *tdb,
                }
                if (fn && fn(tdb, key, dbuf, private_data)) {
                        /* They want us to terminate traversal */
+                       tdb_trace(tdb, "tdb_traverse_end = %i\n", count);
                        ret = count;
                        if (tdb_unlock_record(tdb, tl->off) != 0) {
                                TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: unlock_record failed!\n"));;
@@ -192,6 +193,7 @@ static int tdb_traverse_internal(struct tdb_context *tdb,
                }
                SAFE_FREE(key.dptr);
        }
+       tdb_trace(tdb, "tdb_traverse_end\n");
 out:
        tdb->travlocks.next = tl->next;
        if (ret < 0)
@@ -212,17 +214,18 @@ int tdb_traverse_read(struct tdb_context *tdb,
 
        /* we need to get a read lock on the transaction lock here to
           cope with the lock ordering semantics of solaris10 */
-       if (tdb_transaction_lock(tdb, F_RDLCK)) {
+       if (tdb->traverse_read == 0 && tdb_transaction_lock(tdb, F_RDLCK)) {
                return -1;
        }
 
        tdb->traverse_read++;
        tdb_trace(tdb, "tdb_traverse_read_start\n");
        ret = tdb_traverse_internal(tdb, fn, private_data, &tl);
-       tdb_trace(tdb, "tdb_traverse_end = %i\n", ret);
        tdb->traverse_read--;
 
-       tdb_transaction_unlock(tdb);
+       if (tdb->traverse_read == 0) {
+               tdb_transaction_unlock(tdb);
+       }
 
        return ret;
 }
@@ -243,18 +246,20 @@ int tdb_traverse(struct tdb_context *tdb,
        if (tdb->read_only || tdb->traverse_read) {
                return tdb_traverse_read(tdb, fn, private_data);
        }
-       
-       if (tdb_transaction_lock(tdb, F_WRLCK)) {
+
+       /* Nested traversals: transaction lock doesn't nest. */
+       if (tdb->traverse_write == 0 && tdb_transaction_lock(tdb, F_WRLCK)) {
                return -1;
        }
 
        tdb->traverse_write++;
        tdb_trace(tdb, "tdb_traverse_start\n");
        ret = tdb_traverse_internal(tdb, fn, private_data, &tl);
-       tdb_trace(tdb, "tdb_traverse_end = %i\n", ret);
        tdb->traverse_write--;
 
-       tdb_transaction_unlock(tdb);
+       if (tdb->traverse_write == 0) {
+               tdb_transaction_unlock(tdb);
+       }
 
        return ret;
 }