Merge "Small behavioral changes to the unwinder."

libunwindstack/Android.bp

@@ -170,6 +170,8 @@ cc_test {
     data: [
         "tests/files/elf32.xz",
         "tests/files/elf64.xz",
+        "tests/files/offline/bad_eh_frame_hdr_arm64/*",
+        "tests/files/offline/debug_frame_first_x86/*",
         "tests/files/offline/jit_debug_arm32/*",
         "tests/files/offline/jit_debug_x86_32/*",
         "tests/files/offline/gnu_debugdata_arm32/*",

libunwindstack/DwarfEhFrameWithHdr.cpp

@@ -64,6 +64,11 @@ bool DwarfEhFrameWithHdr<AddressType>::Init(uint64_t offset, uint64_t size) {
     return false;
   }
 
+  if (fde_count_ == 0) {
+    last_error_ = DWARF_ERROR_NO_FDES;
+    return false;
+  }
+
   entries_offset_ = memory_.cur_offset();
   entries_end_ = offset + size;
   entries_data_offset_ = offset;

libunwindstack/DwarfError.h

@@ -31,6 +31,7 @@ enum DwarfError : uint8_t {
   DWARF_ERROR_TOO_MANY_ITERATIONS,
   DWARF_ERROR_CFA_NOT_DEFINED,
   DWARF_ERROR_UNSUPPORTED_VERSION,
+  DWARF_ERROR_NO_FDES,
 };
 
 }  // namespace unwindstack

libunwindstack/DwarfSection.cpp

@@ -835,9 +835,8 @@ bool DwarfSectionImpl<AddressType>::CreateSortedFdeList() {
     }
 
     if (next_entry_offset < memory_.cur_offset()) {
-      // This indicates some kind of corruption, or malformed section data.
-      last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
-      return false;
+      // Simply consider the processing done in this case.
+      break;
     }
     memory_.set_cur_offset(next_entry_offset);
   }

libunwindstack/ElfInterface.cpp

@@ -126,22 +126,26 @@ void ElfInterface::InitHeadersWithTemplate() {
   if (eh_frame_hdr_offset_ != 0) {
     eh_frame_.reset(new DwarfEhFrameWithHdr<AddressType>(memory_));
     if (!eh_frame_->Init(eh_frame_hdr_offset_, eh_frame_hdr_size_)) {
-      // Even if the eh_frame_offset_ is non-zero, do not bother
-      // trying to read that since something has gone wrong.
       eh_frame_.reset(nullptr);
-      eh_frame_hdr_offset_ = 0;
-      eh_frame_hdr_size_ = static_cast<uint64_t>(-1);
     }
-  } else if (eh_frame_offset_ != 0) {
-    // If there is a eh_frame section without a eh_frame_hdr section.
+  }
+
+  if (eh_frame_.get() == nullptr && eh_frame_offset_ != 0) {
+    // If there is an eh_frame section without an eh_frame_hdr section,
+    // or using the frame hdr object failed to init.
     eh_frame_.reset(new DwarfEhFrame<AddressType>(memory_));
     if (!eh_frame_->Init(eh_frame_offset_, eh_frame_size_)) {
       eh_frame_.reset(nullptr);
-      eh_frame_offset_ = 0;
-      eh_frame_size_ = static_cast<uint64_t>(-1);
     }
   }
 
+  if (eh_frame_.get() == nullptr) {
+    eh_frame_hdr_offset_ = 0;
+    eh_frame_hdr_size_ = static_cast<uint64_t>(-1);
+    eh_frame_offset_ = 0;
+    eh_frame_size_ = static_cast<uint64_t>(-1);
+  }
+
   if (debug_frame_offset_ != 0) {
     debug_frame_.reset(new DwarfDebugFrame<AddressType>(memory_));
     if (!debug_frame_->Init(debug_frame_offset_, debug_frame_size_)) {
@@ -436,15 +440,16 @@ bool ElfInterface::Step(uint64_t pc, uint64_t load_bias, Regs* regs, Memory* pro
   }
   uint64_t adjusted_pc = pc - load_bias;
 
-  // Try the eh_frame first.
-  DwarfSection* eh_frame = eh_frame_.get();
-  if (eh_frame != nullptr && eh_frame->Step(adjusted_pc, regs, process_memory, finished)) {
+  // Try the debug_frame first since it contains the most specific unwind
+  // information.
+  DwarfSection* debug_frame = debug_frame_.get();
+  if (debug_frame != nullptr && debug_frame->Step(adjusted_pc, regs, process_memory, finished)) {
     return true;
   }
 
-  // Try the debug_frame next.
-  DwarfSection* debug_frame = debug_frame_.get();
-  if (debug_frame != nullptr && debug_frame->Step(adjusted_pc, regs, process_memory, finished)) {
+  // Try the eh_frame next.
+  DwarfSection* eh_frame = eh_frame_.get();
+  if (eh_frame != nullptr && eh_frame->Step(adjusted_pc, regs, process_memory, finished)) {
     return true;
   }
 

libunwindstack/tests/DwarfDebugFrameTest.cpp

@@ -145,6 +145,45 @@ TYPED_TEST_P(DwarfDebugFrameTest, Init32_fde_not_following_cie) {
   ASSERT_EQ(DWARF_ERROR_ILLEGAL_VALUE, this->debug_frame_->last_error());
 }
 
+TYPED_TEST_P(DwarfDebugFrameTest, Init32_do_not_fail_on_bad_next_entry) {
+  // CIE 32 information.
+  this->memory_.SetData32(0x5000, 0xfc);
+  this->memory_.SetData32(0x5004, 0xffffffff);
+  this->memory_.SetData8(0x5008, 1);
+  this->memory_.SetData8(0x5009, '\0');
+
+  // FDE 32 information.
+  this->memory_.SetData32(0x5100, 0xfc);
+  this->memory_.SetData32(0x5104, 0);
+  this->memory_.SetData32(0x5108, 0x1500);
+  this->memory_.SetData32(0x510c, 0x200);
+
+  this->memory_.SetData32(0x5200, 0xfc);
+  this->memory_.SetData32(0x5204, 0);
+  this->memory_.SetData32(0x5208, 0x2500);
+  this->memory_.SetData32(0x520c, 0x300);
+
+  // CIE 32 information.
+  this->memory_.SetData32(0x5300, 0);
+  this->memory_.SetData32(0x5304, 0xffffffff);
+  this->memory_.SetData8(0x5308, 1);
+  this->memory_.SetData8(0x5309, '\0');
+
+  // FDE 32 information.
+  this->memory_.SetData32(0x5400, 0xfc);
+  this->memory_.SetData32(0x5404, 0x300);
+  this->memory_.SetData32(0x5408, 0x3500);
+  this->memory_.SetData32(0x540c, 0x400);
+
+  this->memory_.SetData32(0x5500, 0xfc);
+  this->memory_.SetData32(0x5504, 0x300);
+  this->memory_.SetData32(0x5508, 0x4500);
+  this->memory_.SetData32(0x550c, 0x500);
+
+  ASSERT_TRUE(this->debug_frame_->Init(0x5000, 0x600));
+  ASSERT_EQ(2U, this->debug_frame_->TestGetFdeCount());
+}
+
 TYPED_TEST_P(DwarfDebugFrameTest, Init64) {
   // CIE 64 information.
   this->memory_.SetData32(0x5000, 0xffffffff);
@@ -231,6 +270,51 @@ TYPED_TEST_P(DwarfDebugFrameTest, Init64_fde_not_following_cie) {
   ASSERT_EQ(DWARF_ERROR_ILLEGAL_VALUE, this->debug_frame_->last_error());
 }
 
+TYPED_TEST_P(DwarfDebugFrameTest, Init64_do_not_fail_on_bad_next_entry) {
+  // CIE 64 information.
+  this->memory_.SetData32(0x5000, 0xffffffff);
+  this->memory_.SetData64(0x5004, 0xf4);
+  this->memory_.SetData64(0x500c, 0xffffffffffffffffULL);
+  this->memory_.SetData8(0x5014, 1);
+  this->memory_.SetData8(0x5015, '\0');
+
+  // FDE 64 information.
+  this->memory_.SetData32(0x5100, 0xffffffff);
+  this->memory_.SetData64(0x5104, 0xf4);
+  this->memory_.SetData64(0x510c, 0);
+  this->memory_.SetData64(0x5114, 0x1500);
+  this->memory_.SetData64(0x511c, 0x200);
+
+  this->memory_.SetData32(0x5200, 0xffffffff);
+  this->memory_.SetData64(0x5204, 0xf4);
+  this->memory_.SetData64(0x520c, 0);
+  this->memory_.SetData64(0x5214, 0x2500);
+  this->memory_.SetData64(0x521c, 0x300);
+
+  // CIE 64 information.
+  this->memory_.SetData32(0x5300, 0xffffffff);
+  this->memory_.SetData64(0x5304, 0);
+  this->memory_.SetData64(0x530c, 0xffffffffffffffffULL);
+  this->memory_.SetData8(0x5314, 1);
+  this->memory_.SetData8(0x5315, '\0');
+
+  // FDE 64 information.
+  this->memory_.SetData32(0x5400, 0xffffffff);
+  this->memory_.SetData64(0x5404, 0xf4);
+  this->memory_.SetData64(0x540c, 0x300);
+  this->memory_.SetData64(0x5414, 0x3500);
+  this->memory_.SetData64(0x541c, 0x400);
+
+  this->memory_.SetData32(0x5500, 0xffffffff);
+  this->memory_.SetData64(0x5504, 0xf4);
+  this->memory_.SetData64(0x550c, 0x300);
+  this->memory_.SetData64(0x5514, 0x4500);
+  this->memory_.SetData64(0x551c, 0x500);
+
+  ASSERT_TRUE(this->debug_frame_->Init(0x5000, 0x600));
+  ASSERT_EQ(2U, this->debug_frame_->TestGetFdeCount());
+}
+
 TYPED_TEST_P(DwarfDebugFrameTest, Init_version1) {
   // CIE 32 information.
   this->memory_.SetData32(0x5000, 0xfc);
@@ -450,9 +534,11 @@ TYPED_TEST_P(DwarfDebugFrameTest, GetCieFde64) {
   EXPECT_EQ(0x20U, fde->cie->return_address_register);
 }
 
-REGISTER_TYPED_TEST_CASE_P(DwarfDebugFrameTest, Init32, Init32_fde_not_following_cie, Init64,
-                           Init64_fde_not_following_cie, Init_version1, Init_version4,
-                           GetFdeOffsetFromPc, GetCieFde32, GetCieFde64);
+REGISTER_TYPED_TEST_CASE_P(DwarfDebugFrameTest, Init32, Init32_fde_not_following_cie,
+                           Init32_do_not_fail_on_bad_next_entry, Init64,
+                           Init64_do_not_fail_on_bad_next_entry, Init64_fde_not_following_cie,
+                           Init_version1, Init_version4, GetFdeOffsetFromPc, GetCieFde32,
+                           GetCieFde64);
 
 typedef ::testing::Types<uint32_t, uint64_t> DwarfDebugFrameTestTypes;
 INSTANTIATE_TYPED_TEST_CASE_P(, DwarfDebugFrameTest, DwarfDebugFrameTestTypes);

libunwindstack/tests/DwarfEhFrameWithHdrTest.cpp

@@ -94,7 +94,13 @@ TYPED_TEST_P(DwarfEhFrameWithHdrTest, Init) {
   EXPECT_EQ(0x1000U, this->eh_frame_->TestGetEntriesDataOffset());
   EXPECT_EQ(0x100aU, this->eh_frame_->TestGetCurEntriesOffset());
 
+  // Verify a zero fde count fails to init.
+  this->memory_.SetData32(0x1006, 0);
+  ASSERT_FALSE(this->eh_frame_->Init(0x1000, 0x100));
+  ASSERT_EQ(DWARF_ERROR_NO_FDES, this->eh_frame_->last_error());
+
   // Verify an unexpected version will cause a fail.
+  this->memory_.SetData32(0x1006, 126);
   this->memory_.SetData8(0x1000, 0);
   ASSERT_FALSE(this->eh_frame_->Init(0x1000, 0x100));
   ASSERT_EQ(DWARF_ERROR_UNSUPPORTED_VERSION, this->eh_frame_->last_error());

libunwindstack/tests/UnwindOfflineTest.cpp

@@ -625,4 +625,127 @@ TEST(UnwindOfflineTest, jit_debug_arm32) {
       frame_info);
 }
 
+// The eh_frame_hdr data is present but set to zero fdes. This should
+// fallback to iterating over the cies/fdes and ignore the eh_frame_hdr.
+// No .gnu_debugdata section in the elf file, so no symbols.
+TEST(UnwindOfflineTest, bad_eh_frame_hdr_arm64) {
+  std::string dir(TestGetFileDirectory() + "offline/bad_eh_frame_hdr_arm64/");
+
+  MemoryOffline* memory = new MemoryOffline;
+  ASSERT_TRUE(memory->Init((dir + "stack.data").c_str(), 0));
+
+  FILE* fp = fopen((dir + "regs.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  RegsArm64 regs;
+  uint64_t reg_value;
+  ASSERT_EQ(1, fscanf(fp, "pc: %" SCNx64 "\n", &reg_value));
+  regs[ARM64_REG_PC] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "sp: %" SCNx64 "\n", &reg_value));
+  regs[ARM64_REG_SP] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "lr: %" SCNx64 "\n", &reg_value));
+  regs[ARM64_REG_LR] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "x29: %" SCNx64 "\n", &reg_value));
+  regs[ARM64_REG_R29] = reg_value;
+  regs.SetFromRaw();
+  fclose(fp);
+
+  fp = fopen((dir + "maps.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  // The file is guaranteed to be less than 4096 bytes.
+  std::vector<char> buffer(4096);
+  ASSERT_NE(0U, fread(buffer.data(), 1, buffer.size(), fp));
+  fclose(fp);
+
+  BufferMaps maps(buffer.data());
+  ASSERT_TRUE(maps.Parse());
+
+  ASSERT_EQ(ARCH_ARM64, regs.Arch());
+
+  std::shared_ptr<Memory> process_memory(memory);
+
+  char* cwd = getcwd(nullptr, 0);
+  ASSERT_EQ(0, chdir(dir.c_str()));
+  Unwinder unwinder(128, &maps, &regs, process_memory);
+  unwinder.Unwind();
+  ASSERT_EQ(0, chdir(cwd));
+  free(cwd);
+
+  std::string frame_info(DumpFrames(unwinder));
+  ASSERT_EQ(5U, unwinder.NumFrames()) << "Unwind:\n" << frame_info;
+  EXPECT_EQ(
+      "  #00 pc 0000000000000550  waiter64\n"
+      "  #01 pc 0000000000000568  waiter64\n"
+      "  #02 pc 000000000000057c  waiter64\n"
+      "  #03 pc 0000000000000590  waiter64\n"
+      "  #04 pc 00000000000a8e98  libc.so (__libc_init+88)\n",
+      frame_info);
+}
+
+// The elf has bad eh_frame unwind information for the pcs. If eh_frame
+// is used first, the unwind will not match the expected output.
+TEST(UnwindOfflineTest, debug_frame_first_x86) {
+  std::string dir(TestGetFileDirectory() + "offline/debug_frame_first_x86/");
+
+  MemoryOffline* memory = new MemoryOffline;
+  ASSERT_TRUE(memory->Init((dir + "stack.data").c_str(), 0));
+
+  FILE* fp = fopen((dir + "regs.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  RegsX86 regs;
+  uint64_t reg_value;
+  ASSERT_EQ(1, fscanf(fp, "eax: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EAX] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "ebx: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EBX] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "ecx: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_ECX] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "edx: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EDX] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "ebp: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EBP] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "edi: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EDI] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "esi: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_ESI] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "esp: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_ESP] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "eip: %" SCNx64 "\n", &reg_value));
+  regs[X86_REG_EIP] = reg_value;
+  regs.SetFromRaw();
+  fclose(fp);
+
+  fp = fopen((dir + "maps.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  // The file is guaranteed to be less than 4096 bytes.
+  std::vector<char> buffer(4096);
+  ASSERT_NE(0U, fread(buffer.data(), 1, buffer.size(), fp));
+  fclose(fp);
+
+  BufferMaps maps(buffer.data());
+  ASSERT_TRUE(maps.Parse());
+
+  ASSERT_EQ(ARCH_X86, regs.Arch());
+
+  std::shared_ptr<Memory> process_memory(memory);
+
+  char* cwd = getcwd(nullptr, 0);
+  ASSERT_EQ(0, chdir(dir.c_str()));
+  JitDebug jit_debug(process_memory);
+  Unwinder unwinder(128, &maps, &regs, process_memory);
+  unwinder.SetJitDebug(&jit_debug, regs.Arch());
+  unwinder.Unwind();
+  ASSERT_EQ(0, chdir(cwd));
+  free(cwd);
+
+  std::string frame_info(DumpFrames(unwinder));
+  ASSERT_EQ(5U, unwinder.NumFrames()) << "Unwind:\n" << frame_info;
+  EXPECT_EQ(
+      "  #00 pc 00000685  waiter (call_level3+53)\n"
+      "  #01 pc 000006b7  waiter (call_level2+23)\n"
+      "  #02 pc 000006d7  waiter (call_level1+23)\n"
+      "  #03 pc 000006f7  waiter (main+23)\n"
+      "  #04 pc 00018275  libc.so\n",
+      frame_info);
+}
+
 }  // namespace unwindstack

libunwindstack/tests/files/offline/bad_eh_frame_hdr_arm64/maps.txt

@@ -0,0 +1,2 @@
+60a9fdf000-60a9fe0000 r-xp 0 00:00 0   waiter64
+7542cc0000-7542d8e000 r-xp 0 00:00 0   libc.so

libunwindstack/tests/files/offline/bad_eh_frame_hdr_arm64/regs.txt

@@ -0,0 +1,4 @@
+pc: 60a9fdf550
+sp: 7fdd141990
+lr: 60a9fdf56c
+x29: 7fdd1419a0

libunwindstack/tests/files/offline/debug_frame_first_x86/maps.txt

@@ -0,0 +1,2 @@
+56598000-56599000 r-xp 0 00:00 0   waiter
+f7432000-f75e3000 r-xp 0 00:00 0   libc.so

libunwindstack/tests/files/offline/debug_frame_first_x86/regs.txt

@@ -0,0 +1,9 @@
+eax: 1d88ef8c
+ebx: 56599fe8
+ecx: 3
+edx: ffcf9ea4
+ebp: ffcf9e48
+edi: f75e5000
+esi: 1
+esp: ffcf9e38
+eip: 56598685