Fixed a mutex leak in the C API.

In nxt_unit_create() we could leak a mutex created in
nxt_unit_ctx_init().

This could happen if nxt_unit_ctx_init() succeeded but later on we
bailed out of nxt_unit_create(), we would destroy the mutex created in
nxt_unit_create() but not the one created in nxt_unit_ctx_init().

Reorder things so that we do the call to nxt_unit_create() after all the
other checks so if it fails we don't leak the mutex it created.

Co-developed-by: Andrew Clayton <a.clayton@f5.com>
Signed-off-by: Andrew Clayton <a.clayton@f5.com>
Signed-off-by: Alex Colomar <a.colomar@f5.com>

1 files changed, 8 insertions, 12 deletions

diff --git a/src/nxt_unit.c b/src/nxt_unit.c
index fd086b2c..e5cb0b58 100644
--- a/src/nxt_unit.c
+++ b/src/nxt_unit.c
@@ -585,9 +585,14 @@ fail:
 static nxt_unit_impl_t *
 nxt_unit_create(nxt_unit_init_t *init)
 {
-    int                   rc;
-    nxt_unit_impl_t       *lib;
-    nxt_unit_callbacks_t  *cb;
+    int              rc;
+    nxt_unit_impl_t  *lib;
+
+    if (nxt_slow_path(init->callbacks.request_handler == NULL)) {
+        nxt_unit_alert(NULL, "request_handler is NULL");
+
+        return NULL;
+    }
 
     lib = nxt_unit_malloc(NULL,
                           sizeof(nxt_unit_impl_t) + init->request_data_size);
@@ -630,15 +635,6 @@ nxt_unit_create(nxt_unit_init_t *init)
         goto fail;
     }
 
-    cb = &lib->callbacks;
-
-    if (cb->request_handler == NULL) {
-        nxt_unit_alert(NULL, "request_handler is NULL");
-
-        pthread_mutex_destroy(&lib->mutex);
-        goto fail;
-    }
-
     nxt_unit_mmaps_init(&lib->incoming);
     nxt_unit_mmaps_init(&lib->outgoing);