Added missing error checking in the C API.

pthread_mutex_init(3) may fail for several reasons, and failing to
check will cause Undefined Behavior when those errors happen.  Add
missing checks, and correctly deinitialize previously created
stuff before exiting from the API.

Signed-off-by: Alejandro Colomar <alx@nginx.com>
Reviewed-by: Andrew Clayton <a.clayton@nginx.com>
Reviewed-by: Zhidao HONG <z.hong@f5.com>

2 files changed, 29 insertions, 11 deletions

diff --git a/docs/changes.xml b/docs/changes.xml
index 91cf8fe3..5da00d88 100644
--- a/docs/changes.xml
+++ b/docs/changes.xml
@@ -177,7 +177,7 @@ the Ruby application process could crash on SIGINT.
 
 <change type="bugfix">
 <para>
-mutex leak in the C API.
+mutex leaks in the C API.
 </para>
 </change>
 
diff --git a/src/nxt_unit.c b/src/nxt_unit.c
index e5cb0b58..3932b2ab 100644
--- a/src/nxt_unit.c
+++ b/src/nxt_unit.c
@@ -116,7 +116,7 @@ static int nxt_unit_incoming_mmap(nxt_unit_ctx_t *ctx, pid_t pid, int fd);
 
 static void nxt_unit_awake_ctx(nxt_unit_ctx_t *ctx,
     nxt_unit_ctx_impl_t *ctx_impl);
-static void nxt_unit_mmaps_init(nxt_unit_mmaps_t *mmaps);
+static int nxt_unit_mmaps_init(nxt_unit_mmaps_t *mmaps);
 nxt_inline void nxt_unit_process_use(nxt_unit_process_t *process);
 nxt_inline void nxt_unit_process_release(nxt_unit_process_t *process);
 static void nxt_unit_mmaps_destroy(nxt_unit_mmaps_t *mmaps);
@@ -606,7 +606,7 @@ nxt_unit_create(nxt_unit_init_t *init)
     if (nxt_slow_path(rc != 0)) {
         nxt_unit_alert(NULL, "failed to initialize mutex (%d)", rc);
 
-        goto fail;
+        goto out_unit_free;
     }
 
     lib->unit.data = init->data;
@@ -631,17 +631,35 @@ nxt_unit_create(nxt_unit_init_t *init)
 
     rc = nxt_unit_ctx_init(lib, &lib->main_ctx, init->ctx_data);
     if (nxt_slow_path(rc != NXT_UNIT_OK)) {
-        pthread_mutex_destroy(&lib->mutex);
-        goto fail;
+        goto out_mutex_destroy;
+    }
+
+    rc = nxt_unit_mmaps_init(&lib->incoming);
+    if (nxt_slow_path(rc != 0)) {
+        nxt_unit_alert(NULL, "failed to initialize mutex (%d)", rc);
+
+        goto out_ctx_free;
     }
 
-    nxt_unit_mmaps_init(&lib->incoming);
-    nxt_unit_mmaps_init(&lib->outgoing);
+    rc = nxt_unit_mmaps_init(&lib->outgoing);
+    if (nxt_slow_path(rc != 0)) {
+        nxt_unit_alert(NULL, "failed to initialize mutex (%d)", rc);
+
+        goto out_mmaps_destroy;
+    }
 
     return lib;
 
-fail:
+out_mmaps_destroy:
+    nxt_unit_mmaps_destroy(&lib->incoming);
+
+out_ctx_free:
+    nxt_unit_ctx_free(&lib->main_ctx);
+
+out_mutex_destroy:
+    pthread_mutex_destroy(&lib->mutex);
 
+out_unit_free:
     nxt_unit_free(NULL, lib);
 
     return NULL;
@@ -4093,15 +4111,15 @@ nxt_unit_awake_ctx(nxt_unit_ctx_t *ctx, nxt_unit_ctx_impl_t *ctx_impl)
 }
 
 
-static void
+static int
 nxt_unit_mmaps_init(nxt_unit_mmaps_t *mmaps)
 {
-    pthread_mutex_init(&mmaps->mutex, NULL);
-
     mmaps->size = 0;
     mmaps->cap = 0;
     mmaps->elts = NULL;
     mmaps->allocated_chunks = 0;
+
+    return pthread_mutex_init(&mmaps->mutex, NULL);
 }