!1027 Fix weak symbol dlclose

Merge pull request !1027 from guzhihao4/fix_weak_dlclose

libc-test/src/functional/BUILD.gn

@@ -39,6 +39,11 @@ test_sharedlib("tls_align_dso") {
 }
 test_sharedlib("atexit_dlclose_dso") {
 }
+test_sharedlib("dlopen_weak_deps") {
+}
+test_sharedlib("dlopen_weak") {
+  deps = [ ":dlopen_weak_deps" ]
+}
 
 group("dso_shared") {
   testonly = true
@@ -51,6 +56,8 @@ group("dso_shared") {
     ":dlopen_for_load_by_local_dso",
     ":dlopen_ns_dso",
     ":dlopen_so_dep_dlopen_ns_dso",
+    ":dlopen_weak",
+    ":dlopen_weak_deps",
     ":tls_align_dso",
     ":tls_init_dso",
   ]

libc-test/src/functional/dlopen.c

@@ -121,6 +121,23 @@ void dlopen_dlclose()
 	}
 }
 
+#define DLOPEN_WEAK "libdlopen_weak.so"
+typedef int (*FuncPtr_TestNumber)(int input);
+
+void dlopen_dlclose_weak()
+{
+	void* handle = dlopen(DLOPEN_WEAK, RTLD_LAZY | RTLD_GLOBAL);
+	if (!handle)
+		t_error("dlopen(name=%s, mode=%d) failed: %s\n", DLOPEN_WEAK, RTLD_LAZY | RTLD_GLOBAL, dlerror());
+	FuncPtr_TestNumber fn = (FuncPtr_TestNumber)dlsym(handle, "TestNumber");
+	if (fn) {
+		int ret = fn(12);
+		if (ret != 0)
+			t_error("weak symbol relocation error: so_name: %s, symbol: TestNumber\n", DLOPEN_WEAK);
+	}
+	dlclose(handle);
+}
+
 int main(int argc, char *argv[])
 {
 	void *h, *g;
@@ -179,6 +196,7 @@ int main(int argc, char *argv[])
 	dlopen_so_used_by_dlsym();
 	dlopen_nodelete_and_noload();
 	dlopen_dlclose();
+	dlopen_dlclose_weak();
 
 	return t_status;
 }

libc-test/src/functional/dlopen_weak.c

+#include "dlopen_weak_deps.h"
+
+__attribute__((weak)) int TestFunction(int input)
+{
+	return input % 2;
+}
+
+int TestNumber(int input)
+{
+	return TestNumber2(input);
+}

libc-test/src/functional/dlopen_weak_deps.c

+__attribute__((weak)) int TestFunction(int input)
+{
+	return input % 5;
+}
+
+int TestNumber2(int input)
+{
+	return TestFunction(input) == 2;
+}

libc-test/src/functional/dlopen_weak_deps.h

+int TestNumber2(int input);
+__attribute__((weak)) int TestFunction(int input);

porting/linux/user/ldso/dynlink.c

@@ -3754,7 +3754,7 @@ static void *do_dlsym(struct dso *p, const char *s, const char *v, void *ra)
 
 extern int invalidate_exit_funcs(struct dso *p);
 
-static int dlclose_impl(struct dso *p)
+static int dlclose_impl(struct dso *p, struct dso **dso_close_list, int *dso_close_list_size)
 {
 	size_t n;
 	struct dso *d;
@@ -3864,7 +3864,9 @@ static int dlclose_impl(struct dso *p)
 	if (p->deps != no_deps)
 		free(p->deps);
 	LD_LOGD("dlclose unloading %{public}s @%{public}p", p->name, p);
-	unmap_library(p);
+
+	dso_close_list[*dso_close_list_size] = p;
+	*dso_close_list_size += 1;
 
 	if (p->parents) {
 		free(p->parents);
@@ -3906,16 +3908,25 @@ static int do_dlclose(struct dso *p)
 		memcpy(deps_bak, p->deps, deps_num*sizeof(struct dso*));
 	}
 
+	struct dso **dso_close_list = malloc((deps_num + 1) * sizeof(struct dso*));
+	memset(dso_close_list, 0, deps_num + 1);
+	int dso_close_list_size = 0;
+
 	LD_LOGI("do_dlclose name=%{public}s count=%{public}d by_dlopen=%{public}d", p->name, p->nr_dlopen, p->by_dlopen);
-	dlclose_impl(p);
+	dlclose_impl(p, dso_close_list, &dso_close_list_size);
 
 	if (ldclose_deps) {
 		for (size_t i = 0; i < deps_num; i++) {
 			LD_LOGI("do_dlclose name=%{public}s count=%{public}d by_dlopen=%{public}d", deps_bak[i]->name, deps_bak[i]->nr_dlopen, deps_bak[i]->by_dlopen);
-			dlclose_impl(deps_bak[i]);
+			dlclose_impl(deps_bak[i], dso_close_list, &dso_close_list_size);
 		}
 	}
 
+	for (size_t i = 0; i < dso_close_list_size; i++) {
+		unmap_library(dso_close_list[i]);
+	}
+
+	free(dso_close_list);
 	free(deps_bak);
 
 	return 0;