commit ac81fe8657119c265edcc2f05b3e5b7c5b17ae9f
author Tamas Berghammer <tberghammer@google.com> Fri Aug 26 15:54:59 2016 +0100
committer Christopher Ferris <cferris@google.com> Thu Nov 17 13:13:27 2016 -0800
tree 99a6e825926829bb7c8d955cbc96ae1777691ef9
parent 8945d5e43a25737f3f888a90742cc918b1124a05

Enable malloc debug using environment variables

Previously malloc debug can be enabled only using global settings
accessible to the root user only. This CL adds a new option to enable
it using environment variables making it possible to use it with pure
native (shell) applications on production builds (from shell user) and
prepares it for using it from logwrapper on production devices.

Remove the old environment variable and property since they are not
necessary.

Test: Enable malloc debug using environment variable and verify
Test: that it only affects the commands launched from the shell.
Test: Enable malloc debug using the property variable and verify
Test: that it affects all commands.
Test: Run all unit tests in 32 bit and 64 bit.
Change-Id: Iecb75a3471552f619f196ad550c5f41fcd9ce8e5

libc/bionic/malloc_common.cpp

diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index e050619..3fceb71 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -175,8 +175,7 @@
 static const char* DEBUG_SHARED_LIB = "libc_malloc_debug.so";
 static const char* DEBUG_MALLOC_PROPERTY_OPTIONS = "libc.debug.malloc.options";
 static const char* DEBUG_MALLOC_PROPERTY_PROGRAM = "libc.debug.malloc.program";
-static const char* DEBUG_MALLOC_PROPERTY_ENV_ENABLED = "libc.debug.malloc.env_enabled";
-static const char* DEBUG_MALLOC_ENV_ENABLE = "LIBC_DEBUG_MALLOC_ENABLE";
+static const char* DEBUG_MALLOC_ENV_OPTIONS = "LIBC_DEBUG_MALLOC_OPTIONS";
 
 static void* libc_malloc_impl_handle = nullptr;
 
@@ -309,20 +308,21 @@
 // Initializes memory allocation framework once per process.
 static void malloc_init_impl(libc_globals* globals) {
   char value[PROP_VALUE_MAX];
-  if (__system_property_get(DEBUG_MALLOC_PROPERTY_OPTIONS, value) == 0 || value[0] == '\0') {
-    return;
-  }
 
-  // Check to see if only a specific program should have debug malloc enabled.
-  if (__system_property_get(DEBUG_MALLOC_PROPERTY_PROGRAM, value) != 0 &&
-      strstr(getprogname(), value) == nullptr) {
-    return;
-  }
+  // If DEBUG_MALLOC_ENV_OPTIONS is set then it overrides the system properties.
+  const char* options = getenv(DEBUG_MALLOC_ENV_OPTIONS);
+  if (options == nullptr || options[0] == '\0') {
+    if (__system_property_get(DEBUG_MALLOC_PROPERTY_OPTIONS, value) == 0 || value[0] == '\0') {
+      return;
+    }
+    options = value;
 
-  // Check for the special environment variable instead.
-  if (__system_property_get(DEBUG_MALLOC_PROPERTY_ENV_ENABLED, value) != 0
-      && value[0] != '\0' && getenv(DEBUG_MALLOC_ENV_ENABLE) == nullptr) {
-    return;
+    // Check to see if only a specific program should have debug malloc enabled.
+    char program[PROP_VALUE_MAX];
+    if (__system_property_get(DEBUG_MALLOC_PROPERTY_PROGRAM, program) != 0 &&
+        strstr(getprogname(), program) == nullptr) {
+      return;
+    }
   }
 
   // Load the debug malloc shared library.
@@ -334,7 +334,7 @@
   }
 
   // Initialize malloc debugging in the loaded module.
-  auto init_func = reinterpret_cast<bool (*)(const MallocDispatch*, int*)>(
+  auto init_func = reinterpret_cast<bool (*)(const MallocDispatch*, int*, const char*)>(
       dlsym(malloc_impl_handle, "debug_initialize"));
   if (init_func == nullptr) {
     error_log("%s: debug_initialize routine not found in %s", getprogname(), DEBUG_SHARED_LIB);
@@ -374,7 +374,7 @@
     return;
   }
 
-  if (!init_func(&__libc_malloc_default_dispatch, &gMallocLeakZygoteChild)) {
+  if (!init_func(&__libc_malloc_default_dispatch, &gMallocLeakZygoteChild, options)) {
     dlclose(malloc_impl_handle);
     return;
   }