Add API to allow apps to attach extra information to tombstones.
Test: atest debuggerd_test
Bug: 155462331
Bug: 309446525
Change-Id: Idc8387307738957dbba3daaae59f605566329f0f
diff --git a/libc/bionic/android_set_abort_message.cpp b/libc/bionic/android_set_abort_message.cpp
index d5f8cb9..53d7576 100644
--- a/libc/bionic/android_set_abort_message.cpp
+++ b/libc/bionic/android_set_abort_message.cpp
@@ -28,9 +28,13 @@
#include <android/set_abort_message.h>
+#include <async_safe/log.h>
+#include <bionic/set_abort_message_internal.h>
+
+#include <bits/stdatomic.h>
#include <pthread.h>
-#include <stdint.h>
#include <stddef.h>
+#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/prctl.h>
@@ -56,6 +60,8 @@
"The in-memory layout of magic_abort_msg_t is not consistent with what automated "
"tools expect.");
+static _Atomic(crash_detail_t*) free_head = nullptr;
+
[[clang::optnone]]
static void fill_abort_message_magic(magic_abort_msg_t* new_magic_abort_message) {
// 128-bit magic for the abort message. Chosen by fair dice roll.
@@ -97,3 +103,65 @@
strcpy(new_magic_abort_message->msg.msg, msg);
__libc_shared_globals()->abort_msg = &new_magic_abort_message->msg;
}
+
+__BIONIC_WEAK_FOR_NATIVE_BRIDGE
+crash_detail_t* android_register_crash_detail(const void* name, size_t name_size, const void* data,
+ size_t data_size) {
+ auto populate_crash_detail = [&](crash_detail_t* result) {
+ result->name = reinterpret_cast<const char*>(name);
+ result->name_size = name_size;
+ result->data = reinterpret_cast<const char*>(data);
+ result->data_size = data_size;
+ };
+ // This is a atomic fast-path for RAII use-cases where the app keeps creating and deleting
+ // crash details for short periods of time to capture detailed scopes.
+ if (crash_detail_t* head = atomic_load(&free_head)) {
+ while (head != nullptr && !atomic_compare_exchange_strong(&free_head, &head, head->prev_free)) {
+ // intentionally left blank.
+ }
+ if (head) {
+ head->prev_free = nullptr;
+ populate_crash_detail(head);
+ return head;
+ }
+ }
+ ScopedPthreadMutexLocker locker(&__libc_shared_globals()->crash_detail_page_lock);
+ struct crash_detail_page_t* prev = nullptr;
+ struct crash_detail_page_t* page = __libc_shared_globals()->crash_detail_page;
+ if (page != nullptr && page->used == kNumCrashDetails) {
+ prev = page;
+ page = nullptr;
+ }
+ if (page == nullptr) {
+ size_t size = sizeof(crash_detail_page_t);
+ void* map = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
+ if (map == MAP_FAILED) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc", "failed to allocate crash_detail_page: %m");
+ return nullptr;
+ }
+ prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, map, size, "crash details");
+ page = reinterpret_cast<struct crash_detail_page_t*>(map);
+ page->prev = prev;
+ __libc_shared_globals()->crash_detail_page = page;
+ }
+ crash_detail_t* result = &page->crash_details[page->used];
+ populate_crash_detail(result);
+ page->used++;
+ return result;
+}
+
+__BIONIC_WEAK_FOR_NATIVE_BRIDGE
+void android_unregister_crash_detail(crash_detail_t* crash_detail) {
+ if (crash_detail) {
+ if (crash_detail->prev_free) {
+ // removing already removed would mess up the free-list by creating a circle.
+ return;
+ }
+ crash_detail->data = nullptr;
+ crash_detail->name = nullptr;
+ crash_detail_t* prev = atomic_load(&free_head);
+ do {
+ crash_detail->prev_free = prev;
+ } while (!atomic_compare_exchange_strong(&free_head, &prev, crash_detail));
+ }
+}