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Commit 22035ccb authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Display offset in backtraces if necessary. 

When moving to a proto tombstone, backtraces no longer contain
an offset when a frame is in a shared library from an apk.
Add the offset display again if needed, and add a test to
verify this behavior.

Bug: 267341682

Test: All unit tests pass.
Test: Dumped a process running through an apk to verify the offset
Test: is present.
Change-Id: Ib720ccb5bfcc8531d1e407f3d01817e8a0b9128c
parent d34157e2

debuggerd/debuggerd_test.cpp

+58 −2
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <string>

#include <thread>



#include <android/dlext.h>

#include <android/fdsan.h>

#include <android/set_abort_message.h>

#include <bionic/malloc.h>
@@ -1909,7 +1910,7 @@ TEST_F(CrasherTest, stack_overflow) { 
  ASSERT_MATCH(result, R"(Cause: stack pointer[^\n]*stack overflow.\n)");

}



static bool CopySharedLibrary(const char* tmp_dir, std::string* tmp_so_name) {

static std::string GetTestLibraryPath() {

  std::string test_lib(testing::internal::GetArgvs()[0]);

  auto const value = test_lib.find_last_of('/');

  if (value == std::string::npos) {
@@ -1917,7 +1918,62 @@ static bool CopySharedLibrary(const char* tmp_dir, std::string* tmp_so_name) { 
  } else {

    test_lib = test_lib.substr(0, value + 1) + "./";

  }

  test_lib += "libcrash_test.so";

  return test_lib + "libcrash_test.so";

}



static void CreateEmbeddedLibrary(int out_fd) {

  std::string test_lib(GetTestLibraryPath());

  android::base::unique_fd fd(open(test_lib.c_str(), O_RDONLY | O_CLOEXEC));

  ASSERT_NE(fd.get(), -1);

  off_t file_size = lseek(fd, 0, SEEK_END);

  ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);

  std::vector<uint8_t> contents(file_size);

  ASSERT_TRUE(android::base::ReadFully(fd, contents.data(), contents.size()));



  // Put the shared library data at a pagesize() offset.

  ASSERT_EQ(lseek(out_fd, 4 * getpagesize(), SEEK_CUR), 4 * getpagesize());

  ASSERT_EQ(static_cast<size_t>(write(out_fd, contents.data(), contents.size())), contents.size());

}



TEST_F(CrasherTest, non_zero_offset_in_library) {

  int intercept_result;

  unique_fd output_fd;

  TemporaryFile tf;

  CreateEmbeddedLibrary(tf.fd);

  StartProcess([&tf]() {

    android_dlextinfo extinfo{};

    extinfo.flags = ANDROID_DLEXT_USE_LIBRARY_FD | ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET;

    extinfo.library_fd = tf.fd;

    extinfo.library_fd_offset = 4 * getpagesize();

    void* handle = android_dlopen_ext(tf.path, RTLD_NOW, &extinfo);

    if (handle == nullptr) {

      _exit(1);

    }

    void (*crash_func)() = reinterpret_cast<void (*)()>(dlsym(handle, "crash"));

    if (crash_func == nullptr) {

      _exit(1);

    }

    crash_func();

  });



  StartIntercept(&output_fd);

  FinishCrasher();

  AssertDeath(SIGSEGV);

  FinishIntercept(&intercept_result);



  ASSERT_EQ(1, intercept_result) << "tombstoned reported failure";



  std::string result;

  ConsumeFd(std::move(output_fd), &result);



  // Verify the crash includes an offset value in the backtrace.

  std::string match_str = android::base::StringPrintf("%s\\!libcrash_test.so \\(offset 0x%x\\)",

                                                      tf.path, 4 * getpagesize());

  ASSERT_MATCH(result, match_str);

}



static bool CopySharedLibrary(const char* tmp_dir, std::string* tmp_so_name) {

  std::string test_lib(GetTestLibraryPath());



  *tmp_so_name = std::string(tmp_dir) + "/libcrash_test.so";

  std::string cp_cmd = android::base::StringPrintf("cp %s %s", test_lib.c_str(), tmp_dir);

debuggerd/libdebuggerd/tombstone_proto_to_text.cpp

+8 −2
Original line number Diff line number Diff line
@@ -176,8 +176,14 @@ static void print_backtrace(CallbackType callback, const Tombstone& tombstone, 
      build_id = StringPrintf(" (BuildId: %s)", frame.build_id().c_str());

    }



    CB(should_log, "      #%02d pc %0*" PRIx64 "  %s%s%s", index++, pointer_width(tombstone) * 2,

       frame.rel_pc(), frame.file_name().c_str(), function.c_str(), build_id.c_str());

    std::string line =

        StringPrintf("      #%02d pc %0*" PRIx64 "  %s", index++, pointer_width(tombstone) * 2,

                     frame.rel_pc(), frame.file_name().c_str());

    if (frame.file_map_offset() != 0) {

      line += StringPrintf(" (offset 0x%" PRIx64 ")", frame.file_map_offset());

    }

    line += function + build_id;

    CB(should_log, "%s", line.c_str());

  }

}