libdebuggerd: extract and print the fdsan table.
This commit only prints the raw value of the owner tag, pretty-printing
will come in a follow-up commit.
Test: debuggerd `pidof adbd`
Test: static_crasher fdsan_file + manual inspection of tombstone
Change-Id: Idb7375a12e410d5b51e6fcb6885d4beb20bccd0e
diff --git a/debuggerd/Android.bp b/debuggerd/Android.bp
index 385f385..03b3287 100644
--- a/debuggerd/Android.bp
+++ b/debuggerd/Android.bp
@@ -166,6 +166,9 @@
local_include_dirs: ["libdebuggerd/include"],
export_include_dirs: ["libdebuggerd/include"],
+ // Needed for private/bionic_fdsan.h
+ include_dirs: ["bionic/libc"],
+
static_libs: [
"libbacktrace",
"libunwindstack",
diff --git a/debuggerd/crash_dump.cpp b/debuggerd/crash_dump.cpp
index 43b7e05..93f7572 100644
--- a/debuggerd/crash_dump.cpp
+++ b/debuggerd/crash_dump.cpp
@@ -412,7 +412,7 @@
OpenFilesList open_files;
{
ATRACE_NAME("open files");
- populate_open_files_list(g_target_thread, &open_files);
+ populate_open_files_list(&open_files, g_target_thread);
}
// In order to reduce the duration that we pause the process for, we ptrace
@@ -567,9 +567,16 @@
ATRACE_NAME("dump_backtrace");
dump_backtrace(std::move(g_output_fd), map.get(), thread_info, g_target_thread);
} else {
- ATRACE_NAME("engrave_tombstone");
- engrave_tombstone(std::move(g_output_fd), map.get(), process_memory.get(), thread_info,
- g_target_thread, abort_msg_address, &open_files, &amfd_data);
+ {
+ ATRACE_NAME("fdsan table dump");
+ populate_fdsan_table(&open_files, process_memory, fdsan_table_address);
+ }
+
+ {
+ ATRACE_NAME("engrave_tombstone");
+ engrave_tombstone(std::move(g_output_fd), map.get(), process_memory.get(), thread_info,
+ g_target_thread, abort_msg_address, &open_files, &amfd_data);
+ }
}
if (fatal_signal) {
diff --git a/debuggerd/libdebuggerd/include/libdebuggerd/open_files_list.h b/debuggerd/libdebuggerd/include/libdebuggerd/open_files_list.h
index 4727ca4..d47f2dd 100644
--- a/debuggerd/libdebuggerd/include/libdebuggerd/open_files_list.h
+++ b/debuggerd/libdebuggerd/include/libdebuggerd/open_files_list.h
@@ -14,23 +14,31 @@
* limitations under the License.
*/
-#ifndef _DEBUGGERD_OPEN_FILES_LIST_H
-#define _DEBUGGERD_OPEN_FILES_LIST_H
+#pragma once
+#include <stdint.h>
#include <sys/types.h>
+#include <map>
+#include <optional>
#include <string>
#include <utility>
-#include <vector>
#include "utility.h"
-typedef std::vector<std::pair<int, std::string>> OpenFilesList;
+struct FDInfo {
+ std::optional<std::string> path;
+ std::optional<uint64_t> fdsan_owner;
+};
-/* Populates the given list with open files for the given process. */
-void populate_open_files_list(pid_t pid, OpenFilesList* list);
+using OpenFilesList = std::map<int, FDInfo>;
-/* Dumps the open files list to the log. */
+// Populates the given list with open files for the given process.
+void populate_open_files_list(OpenFilesList* list, pid_t pid);
+
+// Populates the given list with the target process's fdsan table.
+void populate_fdsan_table(OpenFilesList* list, std::shared_ptr<unwindstack::Memory> memory,
+ uint64_t fdsan_table_address);
+
+// Dumps the open files list to the log.
void dump_open_files_list(log_t* log, const OpenFilesList& files, const char* prefix);
-
-#endif // _DEBUGGERD_OPEN_FILES_LIST_H
diff --git a/debuggerd/libdebuggerd/open_files_list.cpp b/debuggerd/libdebuggerd/open_files_list.cpp
index b12703e..1fdf236 100644
--- a/debuggerd/libdebuggerd/open_files_list.cpp
+++ b/debuggerd/libdebuggerd/open_files_list.cpp
@@ -32,10 +32,12 @@
#include <android-base/file.h>
#include <log/log.h>
+#include <unwindstack/Memory.h>
#include "libdebuggerd/utility.h"
+#include "private/bionic_fdsan.h"
-void populate_open_files_list(pid_t pid, OpenFilesList* list) {
+void populate_open_files_list(OpenFilesList* list, pid_t pid) {
std::string fd_dir_name = "/proc/" + std::to_string(pid) + "/fd";
std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(fd_dir_name.c_str()), closedir);
if (dir == nullptr) {
@@ -53,17 +55,84 @@
std::string path = fd_dir_name + "/" + std::string(de->d_name);
std::string target;
if (android::base::Readlink(path, &target)) {
- list->emplace_back(fd, target);
+ (*list)[fd].path = target;
} else {
+ (*list)[fd].path = "???";
ALOGE("failed to readlink %s: %s", path.c_str(), strerror(errno));
- list->emplace_back(fd, "???");
}
}
}
+void populate_fdsan_table(OpenFilesList* list, std::shared_ptr<unwindstack::Memory> memory,
+ uint64_t fdsan_table_address) {
+ constexpr size_t inline_fds = sizeof(FdTable::entries) / sizeof(*FdTable::entries);
+ static_assert(inline_fds == 128);
+ size_t entry_offset = offsetof(FdTable, entries);
+ for (size_t i = 0; i < inline_fds; ++i) {
+ uint64_t address = fdsan_table_address + entry_offset + sizeof(FdEntry) * i;
+ FdEntry entry;
+ if (!memory->Read(address, &entry, sizeof(entry))) {
+ ALOGE("failed to read fdsan table entry %zu: %s", i, strerror(errno));
+ return;
+ }
+ ALOGE("fd %zu = %#" PRIx64, i, entry.close_tag.load());
+ if (entry.close_tag) {
+ (*list)[i].fdsan_owner = entry.close_tag.load();
+ }
+ }
+
+ size_t overflow_offset = offsetof(FdTable, overflow);
+ uintptr_t overflow = 0;
+ if (!memory->Read(fdsan_table_address + overflow_offset, &overflow, sizeof(overflow))) {
+ ALOGE("failed to read fdsan table overflow pointer: %s", strerror(errno));
+ return;
+ }
+
+ if (!overflow) {
+ return;
+ }
+
+ size_t overflow_length;
+ if (!memory->Read(overflow, &overflow_length, sizeof(overflow_length))) {
+ ALOGE("failed to read fdsan overflow table length: %s", strerror(errno));
+ return;
+ }
+
+ if (overflow_length > 131072) {
+ ALOGE("unreasonable large fdsan overflow table size %zu, bailing out", overflow_length);
+ return;
+ }
+
+ for (size_t i = 0; i < overflow_length; ++i) {
+ int fd = i + inline_fds;
+ uint64_t address = overflow + offsetof(FdTableOverflow, entries) + i * sizeof(FdEntry);
+ FdEntry entry;
+ if (!memory->Read(address, &entry, sizeof(entry))) {
+ ALOGE("failed to read fdsan overflow entry for fd %d: %s", fd, strerror(errno));
+ return;
+ }
+ if (entry.close_tag) {
+ (*list)[fd].fdsan_owner = entry.close_tag;
+ }
+ }
+ return;
+}
+
void dump_open_files_list(log_t* log, const OpenFilesList& files, const char* prefix) {
- for (auto& file : files) {
- _LOG(log, logtype::OPEN_FILES, "%sfd %i: %s\n", prefix, file.first, file.second.c_str());
+ for (auto& [fd, entry] : files) {
+ const std::optional<std::string>& path = entry.path;
+ const std::optional<uint64_t>& fdsan_owner = entry.fdsan_owner;
+ if (path && fdsan_owner) {
+ _LOG(log, logtype::OPEN_FILES, "%sfd %i: %s (owned by %#" PRIx64 ")\n", prefix, fd,
+ path->c_str(), *fdsan_owner);
+ } else if (path && !fdsan_owner) {
+ _LOG(log, logtype::OPEN_FILES, "%sfd %i: %s (unowned)\n", prefix, fd, path->c_str());
+ } else if (!path && fdsan_owner) {
+ _LOG(log, logtype::OPEN_FILES, "%sfd %i: <MISSING> (owned by %#" PRIx64 ")\n", prefix, fd,
+ *fdsan_owner);
+ } else {
+ ALOGE("OpenFilesList contains an entry (fd %d) with no path or owner", fd);
+ }
}
}
diff --git a/debuggerd/libdebuggerd/test/open_files_list_test.cpp b/debuggerd/libdebuggerd/test/open_files_list_test.cpp
index acac72c..d7036fd 100644
--- a/debuggerd/libdebuggerd/test/open_files_list_test.cpp
+++ b/debuggerd/libdebuggerd/test/open_files_list_test.cpp
@@ -34,13 +34,13 @@
// Get the list of open files for this process.
OpenFilesList list;
- populate_open_files_list(getpid(), &list);
+ populate_open_files_list(&list, getpid());
// Verify our open file is in the list.
bool found = false;
- for (auto& file : list) {
+ for (auto& file : list) {
if (file.first == tf.fd) {
- EXPECT_EQ(file.second, std::string(tf.path));
+ EXPECT_EQ(file.second.path.value_or(""), std::string(tf.path));
found = true;
break;
}