commit 20f2c1ebd5b5860e69772b228ccda756eafc1398
author Christopher Ferris <cferris@google.com> Fri Mar 11 12:27:02 2016 -0800
committer Christopher Ferris <cferris@google.com> Fri Mar 11 12:27:02 2016 -0800
tree ac20170eeb693619808794ca272eef3f2fc621f9
parent ffd19ee64d89d5a9ba3757e8ecb1017e0ec5f135

Init functions after debug malloc succeeds.

Do not initialize all of the global function pointers associated with
debug malloc until the initialization has completed correctly.

Bug: 27600760
Change-Id: I0621b54bc2d9fab63805d7992d384e550d6fed2a

libc/bionic/malloc_common.cpp

diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index 863b07c..e050619 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -334,8 +334,8 @@
   }
 
   // Initialize malloc debugging in the loaded module.
-  void* sym = dlsym(malloc_impl_handle, "debug_initialize");
-  auto init_func = reinterpret_cast<bool (*)(const MallocDispatch*, int*)>(sym);
+  auto init_func = reinterpret_cast<bool (*)(const MallocDispatch*, int*)>(
+      dlsym(malloc_impl_handle, "debug_initialize"));
   if (init_func == nullptr) {
     error_log("%s: debug_initialize routine not found in %s", getprogname(), DEBUG_SHARED_LIB);
     dlclose(malloc_impl_handle);
@@ -343,41 +343,36 @@
   }
 
   // Get the syms for the external functions.
-  sym = dlsym(malloc_impl_handle, "debug_finalize");
-  if (sym == nullptr) {
+  void* finalize_sym = dlsym(malloc_impl_handle, "debug_finalize");
+  if (finalize_sym == nullptr) {
     error_log("%s: debug_finalize routine not found in %s", getprogname(), DEBUG_SHARED_LIB);
     dlclose(malloc_impl_handle);
     return;
   }
-  g_debug_finalize_func = reinterpret_cast<void (*)()>(sym);
 
-  sym = dlsym(malloc_impl_handle, "debug_get_malloc_leak_info");
-  if (sym == nullptr) {
+  void* get_leak_info_sym = dlsym(malloc_impl_handle, "debug_get_malloc_leak_info");
+  if (get_leak_info_sym == nullptr) {
     error_log("%s: debug_get_malloc_leak_info routine not found in %s", getprogname(),
               DEBUG_SHARED_LIB);
     dlclose(malloc_impl_handle);
     return;
   }
-  g_debug_get_malloc_leak_info_func = reinterpret_cast<void (*)(uint8_t**, size_t*, size_t*,
-                                                                size_t*, size_t*)>(sym);
 
-  sym = dlsym(malloc_impl_handle, "debug_free_malloc_leak_info");
-  if (sym == nullptr) {
+  void* free_leak_info_sym = dlsym(malloc_impl_handle, "debug_free_malloc_leak_info");
+  if (free_leak_info_sym == nullptr) {
     error_log("%s: debug_free_malloc_leak_info routine not found in %s", getprogname(),
               DEBUG_SHARED_LIB);
     dlclose(malloc_impl_handle);
     return;
   }
-  g_debug_free_malloc_leak_info_func = reinterpret_cast<void (*)(uint8_t*)>(sym);
 
-  sym = dlsym(malloc_impl_handle, "debug_malloc_backtrace");
-  if (sym == nullptr) {
+  void* malloc_backtrace_sym = dlsym(malloc_impl_handle, "debug_malloc_backtrace");
+  if (malloc_backtrace_sym == nullptr) {
     error_log("%s: debug_malloc_backtrace routine not found in %s", getprogname(),
               DEBUG_SHARED_LIB);
     dlclose(malloc_impl_handle);
     return;
   }
-  g_debug_malloc_backtrace_func = reinterpret_cast<ssize_t (*)(void*, uintptr_t*, size_t)>(sym);
 
   if (!init_func(&__libc_malloc_default_dispatch, &gMallocLeakZygoteChild)) {
     dlclose(malloc_impl_handle);
@@ -386,11 +381,19 @@
 
   MallocDispatch malloc_dispatch_table;
   if (!InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "debug")) {
-    g_debug_finalize_func();
+    auto finalize_func = reinterpret_cast<void (*)()>(finalize_sym);
+    finalize_func();
     dlclose(malloc_impl_handle);
     return;
   }
 
+  g_debug_finalize_func = reinterpret_cast<void (*)()>(finalize_sym);
+  g_debug_get_malloc_leak_info_func = reinterpret_cast<void (*)(
+      uint8_t**, size_t*, size_t*, size_t*, size_t*)>(get_leak_info_sym);
+  g_debug_free_malloc_leak_info_func = reinterpret_cast<void (*)(uint8_t*)>(free_leak_info_sym);
+  g_debug_malloc_backtrace_func = reinterpret_cast<ssize_t (*)(
+      void*, uintptr_t*, size_t)>(malloc_backtrace_sym);
+
   globals->malloc_dispatch = malloc_dispatch_table;
   libc_malloc_impl_handle = malloc_impl_handle;