uwrap: Make initialization check faster.

diff --git a/src/uid_wrapper.c b/src/uid_wrapper.c
index 9a170b06071eef8cd0e83b5257d314864f6771d7..8c91d8b07a5f7ab07a8a4311baac3de1fab9a098 100644 (file)
--- a/src/uid_wrapper.c
+++ b/src/uid_wrapper.c
@@ -248,14 +248,16 @@ static struct uwrap_thread *find_uwrap_id(pthread_t tid)
        return NULL;
 }
 
-static int uwrap_new_id(pthread_t tid)
+static int uwrap_new_id(pthread_t tid, bool do_alloc)
 {
-       struct uwrap_thread *id;
+       struct uwrap_thread *id = uwrap_tls_id;
 
-       id = malloc(sizeof(struct uwrap_thread));
-       if (id == NULL) {
-               errno = ENOMEM;
-               return -1;
+       if (do_alloc) {
+               id = malloc(sizeof(struct uwrap_thread));
+               if (id == NULL) {
+                       errno = ENOMEM;
+                       return -1;
+               }
        }
 
        id->tid = tid;
@@ -268,8 +270,10 @@ static int uwrap_new_id(pthread_t tid)
        id->groups = malloc(sizeof(gid_t) * id->ngroups);
        id->groups[0] = uwrap.mygid;
 
-       UWRAP_DLIST_ADD(uwrap.ids, id);
-       uwrap_tls_id = id;
+       if (do_alloc) {
+               UWRAP_DLIST_ADD(uwrap.ids, id);
+               uwrap_tls_id = id;
+       }
 
        return 0;
 }
@@ -280,25 +284,35 @@ static void uwrap_init(void)
        pthread_t tid = pthread_self();
 
 
-       pthread_mutex_lock(&uwrap_id_mutex);
 
        if (uwrap.initialised) {
-               struct uwrap_thread *id;
+               struct uwrap_thread *id = uwrap_tls_id;
+               int rc;
 
+               if (id != NULL) {
+                       return;
+               }
+
+               pthread_mutex_lock(&uwrap_id_mutex);
                id = find_uwrap_id(tid);
                if (id == NULL) {
-                       int rc;
-
-                       rc = uwrap_new_id(tid);
+                       rc = uwrap_new_id(tid, 1);
                        if (rc < 0) {
                                exit(-1);
                        }
-               }
+               } else {
+                       /* We reuse an old thread id */
+                       uwrap_tls_id = id;
 
+                       uwrap_new_id(tid, 0);
+               }
                pthread_mutex_unlock(&uwrap_id_mutex);
+
                return;
        }
 
+       pthread_mutex_lock(&uwrap_id_mutex);
+
        uwrap_libc_init(&uwrap);
 
        uwrap.initialised = true;
@@ -317,7 +331,7 @@ static void uwrap_init(void)
                        uwrap.mygid = uwrap.libc.fns._libc_getegid();
                }
 
-               rc = uwrap_new_id(tid);
+               rc = uwrap_new_id(tid, 1);
                if (rc < 0) {
                        exit(-1);
                }