Merge "Add test of undefined return address."

libunwindstack/Android.bp

@@ -211,6 +211,7 @@ cc_test {
         "tests/UnwindOfflineTest.cpp",
         "tests/UnwindTest.cpp",
         "tests/UnwinderTest.cpp",
+        "tests/VerifyBionicTerminationTest.cpp",
     ],
 
     cflags: [

libunwindstack/Unwinder.cpp

@@ -309,7 +309,7 @@ void Unwinder::Unwind(const std::vector<std::string>* initial_map_names_to_skip,
   }
 }
 
-std::string Unwinder::FormatFrame(const FrameData& frame) {
+std::string Unwinder::FormatFrame(const FrameData& frame) const {
   std::string data;
   if (regs_->Is32Bit()) {
     data += android::base::StringPrintf("  #%02zu pc %08" PRIx64, frame.num, frame.rel_pc);
@@ -355,7 +355,7 @@ std::string Unwinder::FormatFrame(const FrameData& frame) {
   return data;
 }
 
-std::string Unwinder::FormatFrame(size_t frame_num) {
+std::string Unwinder::FormatFrame(size_t frame_num) const {
   if (frame_num >= frames_.size()) {
     return "";
   }

libunwindstack/include/unwindstack/Unwinder.h

@@ -77,7 +77,7 @@ class Unwinder {
   void Unwind(const std::vector<std::string>* initial_map_names_to_skip = nullptr,
               const std::vector<std::string>* map_suffixes_to_ignore = nullptr);
 
-  size_t NumFrames() { return frames_.size(); }
+  size_t NumFrames() const { return frames_.size(); }
 
   const std::vector<FrameData>& frames() { return frames_; }
 
@@ -87,8 +87,8 @@ class Unwinder {
     return frames;
   }
 
-  std::string FormatFrame(size_t frame_num);
-  std::string FormatFrame(const FrameData& frame);
+  std::string FormatFrame(size_t frame_num) const;
+  std::string FormatFrame(const FrameData& frame) const;
 
   void SetJitDebug(JitDebug* jit_debug, ArchEnum arch);
 

libunwindstack/tests/VerifyBionicTerminationTest.cpp

@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE 1
+#include <stdint.h>
+#include <string.h>
+
+#include <string>
+
+#if defined(__BIONIC__)
+
+#include <gtest/gtest.h>
+
+#include <unwindstack/DwarfSection.h>
+#include <unwindstack/Elf.h>
+#include <unwindstack/ElfInterface.h>
+#include <unwindstack/Regs.h>
+#include <unwindstack/RegsGetLocal.h>
+#include <unwindstack/Unwinder.h>
+
+// This test is specific to bionic to verify that __libc_init is
+// properly setting the return address to undefined so that the
+// unwind properly terminates.
+
+namespace unwindstack {
+
+static std::string DumpFrames(const UnwinderFromPid& unwinder) {
+  std::string unwind;
+  for (size_t i = 0; i < unwinder.NumFrames(); i++) {
+    unwind += unwinder.FormatFrame(i) + '\n';
+  }
+  return unwind;
+}
+
+static DwarfLocationEnum GetReturnAddressLocation(uint64_t rel_pc, DwarfSection* section) {
+  if (section == nullptr) {
+    return DWARF_LOCATION_INVALID;
+  }
+
+  const DwarfFde* fde = section->GetFdeFromPc(rel_pc);
+  if (fde == nullptr || fde->cie == nullptr) {
+    return DWARF_LOCATION_INVALID;
+  }
+  dwarf_loc_regs_t regs;
+  if (!section->GetCfaLocationInfo(rel_pc, fde, &regs)) {
+    return DWARF_LOCATION_INVALID;
+  }
+
+  auto reg_entry = regs.find(fde->cie->return_address_register);
+  if (reg_entry == regs.end()) {
+    return DWARF_LOCATION_INVALID;
+  }
+  return reg_entry->second.type;
+}
+
+static void VerifyReturnAddress(const FrameData& frame) {
+  // Now go and find information about the register data and verify that the relative pc results in
+  // an undefined register.
+  Elf elf(Memory::CreateFileMemory(frame.map_name, 0).release());
+  ASSERT_TRUE(elf.Init()) << "Failed to init elf object from " << frame.map_name;
+  ASSERT_TRUE(elf.valid()) << "Elf " << frame.map_name << " is not valid.";
+  ElfInterface* interface = elf.interface();
+
+  // Only check the eh_frame and the debug_frame since the undefined register
+  // is set using a cfi directive.
+  // Check debug_frame first, then eh_frame since debug_frame always
+  // contains the most specific data.
+  DwarfLocationEnum location = GetReturnAddressLocation(frame.rel_pc, interface->debug_frame());
+  if (location == DWARF_LOCATION_UNDEFINED) {
+    return;
+  }
+
+  location = GetReturnAddressLocation(frame.rel_pc, interface->eh_frame());
+  ASSERT_EQ(DWARF_LOCATION_UNDEFINED, location);
+}
+
+// This test assumes that it starts from the main thread, and that the
+// libc.so on device will include symbols so that function names can
+// be resolved.
+TEST(VerifyBionicTermination, local_terminate) {
+  std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
+
+  UnwinderFromPid unwinder(512, getpid());
+  ASSERT_TRUE(unwinder.Init(regs->Arch()));
+  unwinder.SetRegs(regs.get());
+
+  RegsGetLocal(regs.get());
+  unwinder.Unwind();
+  ASSERT_LT(0U, unwinder.NumFrames());
+
+  SCOPED_TRACE(DumpFrames(unwinder));
+
+  // Look for the frame that includes __libc_init, there should only
+  // be one and it should be the last.
+  bool found = false;
+  const std::vector<FrameData>& frames = unwinder.frames();
+  for (size_t i = 0; i < unwinder.NumFrames(); i++) {
+    const FrameData& frame = frames[i];
+    if (frame.function_name == "__libc_init" && !frame.map_name.empty() &&
+        std::string("libc.so") == basename(frame.map_name.c_str())) {
+      ASSERT_EQ(unwinder.NumFrames(), i + 1) << "__libc_init is not last frame.";
+      ASSERT_NO_FATAL_FAILURE(VerifyReturnAddress(frame));
+      found = true;
+    }
+  }
+  ASSERT_TRUE(found) << "Unable to find libc.so:__libc_init frame\n";
+}
+
+}  // namespace unwindstack
+
+#endif