commit 9cf99cbad89c8495828788ce693a99ced434f66f
author Dimitry Ivanov <dimitry@google.com> Fri Dec 11 14:22:24 2015 -0800
committer Dimitry Ivanov <dimitry@google.com> Wed Dec 16 15:24:13 2015 -0800
tree fa089662db2475f6e4e1260f029fcab805eb0a96
parent d3e5301a75256171199b23f6ba2c6651d05ce5f1

linker: add dlvsym(3)

This changes implements dlvsym - dlsym for versioned symbols.

Bug: http://b/22865643
Change-Id: Ic90a60d512104261a1416c43f9100f0d88e3b46f

linker/dlfcn.cpp

diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 788a7a0..ba54d39 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -88,11 +88,10 @@
 
 extern android_namespace_t* g_anonymous_namespace;
 
-void* dlsym(void* handle, const char* symbol) {
-  void* caller_addr = __builtin_return_address(0);
+void* dlsym_impl(void* handle, const char* symbol, const char* version, void* caller_addr) {
   ScopedPthreadMutexLocker locker(&g_dl_mutex);
   void* result;
-  if (!do_dlsym(handle, symbol, nullptr, caller_addr, &result)) {
+  if (!do_dlsym(handle, symbol, version, caller_addr, &result)) {
     __bionic_format_dlerror(linker_get_error_buffer(), nullptr);
     return nullptr;
   }
@@ -100,6 +99,16 @@
   return result;
 }
 
+void* dlsym(void* handle, const char* symbol) {
+  void* caller_addr = __builtin_return_address(0);
+  return dlsym_impl(handle, symbol, nullptr, caller_addr);
+}
+
+void* dlvsym(void* handle, const char* symbol, const char* version) {
+  void* caller_addr = __builtin_return_address(0);
+  return dlsym_impl(handle, symbol, version, caller_addr);
+}
+
 int dladdr(const void* addr, Dl_info* info) {
   ScopedPthreadMutexLocker locker(&g_dl_mutex);
   return do_dladdr(addr, info);
@@ -179,11 +188,11 @@
   // 00000000001 1111111112222222222 3333333333444444444455555555556666666666777 777777788888888889999999999
   // 01234567890 1234567890123456789 0123456789012345678901234567890123456789012 345678901234567890123456789
     "erate_phdr\0android_dlopen_ext\0android_set_application_target_sdk_version\0android_get_application_tar"
-  // 0000000000111111 111122222222223333333333 4444444444555555555566666
-  // 0123456789012345 678901234567890123456789 0123456789012345678901234
-    "get_sdk_version\0android_init_namespaces\0android_create_namespace\0"
+  // 0000000000111111 111122222222223333333333 4444444444555555555566666 6666677
+  // 0123456789012345 678901234567890123456789 0123456789012345678901234 5678901
+    "get_sdk_version\0android_init_namespaces\0android_create_namespace\0dlvsym\0"
 #if defined(__arm__)
-  // 265
+  // 272
     "dl_unwind_find_exidx\0"
 #endif
     ;
@@ -207,8 +216,9 @@
   ELFW(SYM_INITIALIZER)(173, &android_get_application_target_sdk_version, 1),
   ELFW(SYM_INITIALIZER)(216, &android_init_namespaces, 1),
   ELFW(SYM_INITIALIZER)(240, &android_create_namespace, 1),
+  ELFW(SYM_INITIALIZER)(265, &dlvsym, 1),
 #if defined(__arm__)
-  ELFW(SYM_INITIALIZER)(265, &dl_unwind_find_exidx, 1),
+  ELFW(SYM_INITIALIZER)(272, &dl_unwind_find_exidx, 1),
 #endif
 };
 
@@ -225,9 +235,9 @@
 // Note that adding any new symbols here requires stubbing them out in libdl.
 static unsigned g_libdl_buckets[1] = { 1 };
 #if defined(__arm__)
-static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0 };
+static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0 };
 #else
-static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 0 };
+static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0 };
 #endif
 
 static uint8_t __libdl_info_buf[sizeof(soinfo)] __attribute__((aligned(8)));