Merge pull request #1784 from wwbmmm/fix-dl-sym

Fix _dl_sym undefined reference
apache · Jun 9, 2022 · f831430 · f831430
2 parents 4b80e95 + ded02c1
commit f831430
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/src/bthread/mutex.cpp b/src/bthread/mutex.cpp
@@ -44,7 +44,7 @@
 #include "bthread/log.h"
 
 extern "C" {
-extern void* _dl_sym(void* handle, const char* symbol, void* caller);
+extern void* __attribute__((weak)) _dl_sym(void* handle, const char* symbol, void* caller);
 }
 
 namespace bthread {
@@ -408,8 +408,14 @@ static void init_sys_mutex_lock() {
 #if defined(OS_LINUX)
     // TODO: may need dlvsym when GLIBC has multiple versions of a same symbol.
     // http://blog.fesnel.com/blog/2009/08/25/preloading-with-multiple-symbol-versions
-    sys_pthread_mutex_lock = (MutexOp)_dl_sym(RTLD_NEXT, "pthread_mutex_lock", (void*)init_sys_mutex_lock);
-    sys_pthread_mutex_unlock = (MutexOp)_dl_sym(RTLD_NEXT, "pthread_mutex_unlock", (void*)init_sys_mutex_lock);
+    if (_dl_sym) {
+        sys_pthread_mutex_lock = (MutexOp)_dl_sym(RTLD_NEXT, "pthread_mutex_lock", (void*)init_sys_mutex_lock);
+        sys_pthread_mutex_unlock = (MutexOp)_dl_sym(RTLD_NEXT, "pthread_mutex_unlock", (void*)init_sys_mutex_lock);
+    } else {
+        // _dl_sym may be undefined reference in some system, fallback to dlsym
+        sys_pthread_mutex_lock = (MutexOp)dlsym(RTLD_NEXT, "pthread_mutex_lock");
+        sys_pthread_mutex_unlock = (MutexOp)dlsym(RTLD_NEXT, "pthread_mutex_unlock");
+    }
 #elif defined(OS_MACOSX)
     // TODO: look workaround for dlsym on mac
     sys_pthread_mutex_lock = (MutexOp)dlsym(RTLD_NEXT, "pthread_mutex_lock");