fix: fix memory leak of the using of dlerror (#328)

core/src/ten_utils/lib/sys/posix/darwin/pc/module.c

@@ -24,6 +24,11 @@ void *ten_module_load(const ten_string_t *name, int as_local) {
     const char *err_msg = dlerror();
     TEN_LOGE("Failed to dlopen %s: %s", ten_string_get_raw_str(name),
              err_msg ? err_msg : "Unknown error");
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
   }
 
   return handle;
@@ -40,6 +45,13 @@ int ten_module_close(void *handle) {
     const char *err_msg = dlerror();
     TEN_LOGE("Failed to dlclose handle: %s",
              err_msg ? err_msg : "Unknown error");
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
+
+    return -1;
   }
 
   return result;
@@ -57,6 +69,12 @@ void *ten_module_get_symbol(void *handle, const char *symbol_name) {
   }
 
   // Clear previous errors.
+  //
+  // Since `dlsym` returning `NULL` can be a normal occurrence (e.g., when the
+  // symbol is not defined), the return value of `dlsym` being `NULL` cannot be
+  // used to determine whether it is an error. Therefore, it is necessary to
+  // first call `dlerror` to clear any existing errors, then call `dlsym`, and
+  // finally call `dlerror` again to check if an error has occurred.
   dlerror();
 
   void *symbol = dlsym(handle, symbol_name);
@@ -67,6 +85,12 @@ void *ten_module_get_symbol(void *handle, const char *symbol_name) {
 #if 0
     TEN_LOGD("Failed to find symbol %s: %s", symbol_name, error);
 #endif
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
+
     return NULL;
   }
 

core/src/ten_utils/lib/sys/posix/linux/pc/module.c

@@ -6,12 +6,11 @@
 //
 #include "ten_utils/lib/module.h"
 
-#include "ten_utils/lib/string.h"
-
 #define _GNU_SOURCE
 #include <dlfcn.h>
 
 #include "include_internal/ten_utils/log/log.h"
+#include "ten_utils/lib/string.h"
 
 void *ten_module_load(const ten_string_t *name, int as_local) {
   if (!name || !ten_string_check_integrity(name)) {
@@ -26,6 +25,11 @@ void *ten_module_load(const ten_string_t *name, int as_local) {
     const char *err_msg = dlerror();
     TEN_LOGE("Failed to dlopen %s: %s", ten_string_get_raw_str(name),
              err_msg ? err_msg : "Unknown error");
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
   }
 
   return handle;
@@ -42,6 +46,13 @@ int ten_module_close(void *handle) {
     const char *err_msg = dlerror();
     TEN_LOGE("Failed to dlclose handle: %s",
              err_msg ? err_msg : "Unknown error");
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
+
+    return -1;
   }
 
   return result;
@@ -59,6 +70,12 @@ void *ten_module_get_symbol(void *handle, const char *symbol_name) {
   }
 
   // Clear previous errors.
+  //
+  // Since `dlsym` returning `NULL` can be a normal occurrence (e.g., when the
+  // symbol is not defined), the return value of `dlsym` being `NULL` cannot be
+  // used to determine whether it is an error. Therefore, it is necessary to
+  // first call `dlerror` to clear any existing errors, then call `dlsym`, and
+  // finally call `dlerror` again to check if an error has occurred.
   dlerror();
 
   void *symbol = dlsym(handle, symbol_name);
@@ -69,6 +86,12 @@ void *ten_module_get_symbol(void *handle, const char *symbol_name) {
 #if 0
     TEN_LOGD("Failed to find symbol %s: %s", symbol_name, error);
 #endif
+
+    // It is necessary to call `dlerror` again to clear the memory allocated for
+    // the previous error string by `dlerror`, to avoid the leak sanitizer
+    // reporting a memory leak for this error string.
+    dlerror();
+
     return NULL;
   }
 

tests/ten_runtime/integration/cpp/standalone_test_cpp/test_case.py

@@ -4,40 +4,10 @@
 
 import subprocess
 import os
-import pytest
 from sys import stdout
 from .common import build_config
 
 
-# TODO(Wei): Remove this after solving the dlsym memory leakages.
-@pytest.fixture(scope="function")
-def manage_env_var_for_memory_issue_detection():
-    original_ten_enable_memory_sanitizer = os.environ.get(
-        "TEN_ENABLE_MEMORY_TRACKING"
-    )
-    original_asan_options = os.environ.get("ASAN_OPTIONS")
-
-    # Set the environment variable before the test.
-    os.environ["TEN_ENABLE_MEMORY_TRACKING"] = "false"
-    os.environ["ASAN_OPTIONS"] = "detect_leaks=0"
-
-    yield
-
-    # Remove the environment variable after the test.
-    if original_ten_enable_memory_sanitizer is not None:
-        os.environ["TEN_ENABLE_MEMORY_TRACKING"] = (
-            original_ten_enable_memory_sanitizer
-        )
-    else:
-        del os.environ["TEN_ENABLE_MEMORY_TRACKING"]
-
-    if original_asan_options is not None:
-        os.environ["ASAN_OPTIONS"] = original_asan_options
-    else:
-        del os.environ["ASAN_OPTIONS"]
-
-
-@pytest.mark.usefixtures("manage_env_var_for_memory_issue_detection")
 def test_standalone_test_cpp():
     base_path = os.path.dirname(os.path.abspath(__file__))
     root_dir = os.path.join(base_path, "../../../../../")