Refactor malloc debug.

Changes
- Refactor the code so that only guards require creating a special header
  for every pointer allocated.
- Store only a single copy of every backtrace. This saves memory so that
  turning on the backtrace option doesn't result in 10X memory usage.
- Added new option track_allocs that only verifies pointers are valid for
  free/malloc_usable_size/realloc.
- Remove suffix from test names.
- Add the TRACK_ALLOCS options to all guard options.
- Add new option verify_pointers that is a lightweight way to verify
  pointers that are passed to allocation routines.
- Do auto-formatting of the code.
- Updated documentation for all of these changes.

Bug: 74361929

Test: Ran unit tests.
Test: Ran libmemunreachable unit tests.
Test: Ran an app with backtrace enabled.

Change-Id: I3246c48ae4f9811f64622d90d0a9b4d9d818702c

1 files changed, 37 insertions, 15 deletions

diff --git a/libc/malloc_debug/tests/malloc_debug_config_tests.cpp b/libc/malloc_debug/tests/malloc_debug_config_tests.cpp
index ee8fe0691..460353583 100644
--- a/libc/malloc_debug/tests/malloc_debug_config_tests.cpp
+++ b/libc/malloc_debug/tests/malloc_debug_config_tests.cpp
@@ -135,6 +135,10 @@ std::string usage_string(
   "6 malloc_debug     This option only has meaning if the record_allocs options has been specified.\n"
   "6 malloc_debug     This is the name of the file to which recording information will be dumped.\n"
   "6 malloc_debug     The default is /data/local/tmp/record_allocs.txt.\n"
+  "6 malloc_debug \n"
+  "6 malloc_debug   verify_pointers\n"
+  "6 malloc_debug     A lightweight way to verify that free/malloc_usable_size/realloc\n"
+  "6 malloc_debug     are passed valid pointers.\n"
 );
 
 TEST_F(MallocDebugConfigTest, unknown_option) {
@@ -250,15 +254,15 @@ TEST_F(MallocDebugConfigTest, multiple_options) {
 
 TEST_F(MallocDebugConfigTest, front_guard) {
   ASSERT_TRUE(InitConfig("front_guard=48")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(48U, config->front_guard_bytes());
 
   ASSERT_TRUE(InitConfig("front_guard")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(32U, config->front_guard_bytes());
 
   ASSERT_TRUE(InitConfig("front_guard=39")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | TRACK_ALLOCS, config->options());
 #if defined(__LP64__)
   ASSERT_EQ(48U, config->front_guard_bytes());
 #else
@@ -266,7 +270,7 @@ TEST_F(MallocDebugConfigTest, front_guard) {
 #endif
 
   ASSERT_TRUE(InitConfig("front_guard=41")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(48U, config->front_guard_bytes());
 
   ASSERT_STREQ("", getFakeLogBuf().c_str());
@@ -275,11 +279,11 @@ TEST_F(MallocDebugConfigTest, front_guard) {
 
 TEST_F(MallocDebugConfigTest, rear_guard) {
   ASSERT_TRUE(InitConfig("rear_guard=50")) << getFakeLogPrint();
-  ASSERT_EQ(REAR_GUARD, config->options());
+  ASSERT_EQ(REAR_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(50U, config->rear_guard_bytes());
 
   ASSERT_TRUE(InitConfig("rear_guard")) << getFakeLogPrint();
-  ASSERT_EQ(REAR_GUARD, config->options());
+  ASSERT_EQ(REAR_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(32U, config->rear_guard_bytes());
 
   ASSERT_STREQ("", getFakeLogBuf().c_str());
@@ -288,12 +292,12 @@ TEST_F(MallocDebugConfigTest, rear_guard) {
 
 TEST_F(MallocDebugConfigTest, guard) {
   ASSERT_TRUE(InitConfig("guard=32")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD | REAR_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | REAR_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(32U, config->front_guard_bytes());
   ASSERT_EQ(32U, config->rear_guard_bytes());
 
   ASSERT_TRUE(InitConfig("guard")) << getFakeLogPrint();
-  ASSERT_EQ(FRONT_GUARD | REAR_GUARD, config->options());
+  ASSERT_EQ(FRONT_GUARD | REAR_GUARD | TRACK_ALLOCS, config->options());
   ASSERT_EQ(32U, config->front_guard_bytes());
   ASSERT_EQ(32U, config->rear_guard_bytes());
 
@@ -465,13 +469,13 @@ TEST_F(MallocDebugConfigTest, expand_alloc) {
 
 TEST_F(MallocDebugConfigTest, free_track) {
   ASSERT_TRUE(InitConfig("free_track=1234")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(1234U, config->free_track_allocations());
   ASSERT_EQ(SIZE_MAX, config->fill_on_free_bytes());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
 
   ASSERT_TRUE(InitConfig("free_track")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(100U, config->free_track_allocations());
   ASSERT_EQ(SIZE_MAX, config->fill_on_free_bytes());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
@@ -482,20 +486,20 @@ TEST_F(MallocDebugConfigTest, free_track) {
 
 TEST_F(MallocDebugConfigTest, free_track_and_fill_on_free) {
   ASSERT_TRUE(InitConfig("free_track=1234 fill_on_free=32")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(1234U, config->free_track_allocations());
   ASSERT_EQ(32U, config->fill_on_free_bytes());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
 
   ASSERT_TRUE(InitConfig("free_track fill_on_free=60")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(100U, config->free_track_allocations());
   ASSERT_EQ(60U, config->fill_on_free_bytes());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
 
   // Now reverse the arguments.
   ASSERT_TRUE(InitConfig("fill_on_free=32 free_track=1234")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(1234U, config->free_track_allocations());
   ASSERT_EQ(32U, config->fill_on_free_bytes());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
@@ -530,11 +534,11 @@ TEST_F(MallocDebugConfigTest, free_track_backtrace_num_frames_zero) {
 
 TEST_F(MallocDebugConfigTest, free_track_backtrace_num_frames_and_free_track) {
   ASSERT_TRUE(InitConfig("free_track free_track_backtrace_num_frames=123")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(123U, config->free_track_backtrace_num_frames());
 
   ASSERT_TRUE(InitConfig("free_track free_track_backtrace_num_frames")) << getFakeLogPrint();
-  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE, config->options());
+  ASSERT_EQ(FREE_TRACK | FILL_ON_FREE | TRACK_ALLOCS, config->options());
   ASSERT_EQ(16U, config->free_track_backtrace_num_frames());
 
   ASSERT_STREQ("", getFakeLogBuf().c_str());
@@ -559,6 +563,24 @@ TEST_F(MallocDebugConfigTest, leak_track_fail) {
   ASSERT_STREQ((log_msg + usage_string).c_str(), getFakeLogPrint().c_str());
 }
 
+TEST_F(MallocDebugConfigTest, verify_pointers) {
+  ASSERT_TRUE(InitConfig("verify_pointers")) << getFakeLogPrint();
+  ASSERT_EQ(TRACK_ALLOCS, config->options());
+
+  ASSERT_STREQ("", getFakeLogBuf().c_str());
+  ASSERT_STREQ("", getFakeLogPrint().c_str());
+}
+
+TEST_F(MallocDebugConfigTest, verify_pointers_fail) {
+  ASSERT_FALSE(InitConfig("verify_pointers=200")) << getFakeLogPrint();
+
+  ASSERT_STREQ("", getFakeLogBuf().c_str());
+  std::string log_msg(
+      "6 malloc_debug malloc_testing: value set for option 'verify_pointers' "
+      "which does not take a value\n");
+  ASSERT_STREQ((log_msg + usage_string).c_str(), getFakeLogPrint().c_str());
+}
+
 TEST_F(MallocDebugConfigTest, record_allocs) {
   ASSERT_TRUE(InitConfig("record_allocs=1234")) << getFakeLogPrint();
   ASSERT_EQ(RECORD_ALLOCS, config->options());