Add .gnu_debugdata support.

Update the unwind_info tool to dump all of the sections.

Bug: 23762183

Test: Passes new unit tests.
Change-Id: I8b223bc208a1a2ef06ed333e6d96943c8f273681
diff --git a/libunwindstack/tests/ElfTest.cpp b/libunwindstack/tests/ElfTest.cpp
index 25fec8e..22cade2 100644
--- a/libunwindstack/tests/ElfTest.cpp
+++ b/libunwindstack/tests/ElfTest.cpp
@@ -15,6 +15,10 @@
  */
 
 #include <elf.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
 
 #include <gtest/gtest.h>
 
@@ -26,10 +30,6 @@
 #define PT_ARM_EXIDX 0x70000001
 #endif
 
-#if !defined(EM_AARCH64)
-#define EM_AARCH64 183
-#endif
-
 class ElfTest : public ::testing::Test {
  protected:
   void SetUp() override {
@@ -43,17 +43,18 @@
     ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
     ehdr->e_ident[EI_VERSION] = EV_CURRENT;
     ehdr->e_ident[EI_OSABI] = ELFOSABI_SYSV;
+
+    ehdr->e_type = ET_DYN;
+    ehdr->e_version = EV_CURRENT;
   }
 
-  void InitElf32(uint32_t type) {
+  void InitElf32(uint32_t machine) {
     Elf32_Ehdr ehdr;
 
     InitEhdr<Elf32_Ehdr>(&ehdr);
     ehdr.e_ident[EI_CLASS] = ELFCLASS32;
 
-    ehdr.e_type = ET_DYN;
-    ehdr.e_machine = type;
-    ehdr.e_version = EV_CURRENT;
+    ehdr.e_machine = machine;
     ehdr.e_entry = 0;
     ehdr.e_phoff = 0x100;
     ehdr.e_shoff = 0;
@@ -64,7 +65,7 @@
     ehdr.e_shentsize = sizeof(Elf32_Shdr);
     ehdr.e_shnum = 0;
     ehdr.e_shstrndx = 0;
-    if (type == EM_ARM) {
+    if (machine == EM_ARM) {
       ehdr.e_flags = 0x5000200;
       ehdr.e_phnum = 2;
     }
@@ -82,7 +83,7 @@
     phdr.p_align = 0x1000;
     memory_->SetMemory(0x100, &phdr, sizeof(phdr));
 
-    if (type == EM_ARM) {
+    if (machine == EM_ARM) {
       memset(&phdr, 0, sizeof(phdr));
       phdr.p_type = PT_ARM_EXIDX;
       phdr.p_offset = 0x30000;
@@ -96,15 +97,13 @@
     }
   }
 
-  void InitElf64(uint32_t type) {
+  void InitElf64(uint32_t machine) {
     Elf64_Ehdr ehdr;
 
     InitEhdr<Elf64_Ehdr>(&ehdr);
     ehdr.e_ident[EI_CLASS] = ELFCLASS64;
 
-    ehdr.e_type = ET_DYN;
-    ehdr.e_machine = type;
-    ehdr.e_version = EV_CURRENT;
+    ehdr.e_machine = machine;
     ehdr.e_entry = 0;
     ehdr.e_phoff = 0x100;
     ehdr.e_shoff = 0;
@@ -130,6 +129,12 @@
     memory_->SetMemory(0x100, &phdr, sizeof(phdr));
   }
 
+  template <typename Ehdr, typename Shdr>
+  void GnuDebugdataInitFail(Ehdr* ehdr);
+
+  template <typename Ehdr, typename Shdr>
+  void GnuDebugdataInit(Ehdr* ehdr);
+
   MemoryFake* memory_;
 };
 
@@ -208,3 +213,154 @@
   ASSERT_EQ(ELFCLASS64, elf.class_type());
   ASSERT_TRUE(elf.interface() != nullptr);
 }
+
+template <typename Ehdr, typename Shdr>
+void ElfTest::GnuDebugdataInitFail(Ehdr* ehdr) {
+  Elf elf(memory_);
+
+  uint64_t offset = 0x2000;
+
+  ehdr->e_shoff = offset;
+  ehdr->e_shnum = 3;
+  ehdr->e_shentsize = sizeof(Shdr);
+  ehdr->e_shstrndx = 2;
+  memory_->SetMemory(0, ehdr, sizeof(*ehdr));
+
+  Shdr shdr;
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_NULL;
+  memory_->SetMemory(offset, &shdr, sizeof(shdr));
+  offset += ehdr->e_shentsize;
+
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_PROGBITS;
+  shdr.sh_name = 0x100;
+  shdr.sh_addr = 0x5000;
+  shdr.sh_offset = 0x5000;
+  shdr.sh_entsize = 0x100;
+  shdr.sh_size = 0x800;
+  memory_->SetMemory(offset, &shdr, sizeof(shdr));
+  offset += ehdr->e_shentsize;
+
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_STRTAB;
+  shdr.sh_name = 0x200000;
+  shdr.sh_offset = 0xf000;
+  shdr.sh_size = 0x1000;
+  memory_->SetMemory(offset, &shdr, sizeof(shdr));
+  offset += ehdr->e_shentsize;
+
+  memory_->SetMemory(0xf100, ".gnu_debugdata", sizeof(".gnu_debugdata"));
+
+  ASSERT_TRUE(elf.Init());
+  ASSERT_TRUE(elf.interface() != nullptr);
+  ASSERT_TRUE(elf.gnu_debugdata_interface() == nullptr);
+  EXPECT_EQ(0x5000U, elf.interface()->gnu_debugdata_offset());
+  EXPECT_EQ(0x800U, elf.interface()->gnu_debugdata_size());
+
+  elf.InitGnuDebugdata();
+}
+
+TEST_F(ElfTest, gnu_debugdata_init_fail32) {
+  Elf32_Ehdr ehdr;
+  InitEhdr<Elf32_Ehdr>(&ehdr);
+  ehdr.e_ident[EI_CLASS] = ELFCLASS32;
+  ehdr.e_machine = EM_ARM;
+
+  GnuDebugdataInitFail<Elf32_Ehdr, Elf32_Shdr>(&ehdr);
+}
+
+TEST_F(ElfTest, gnu_debugdata_init_fail64) {
+  Elf64_Ehdr ehdr;
+  InitEhdr<Elf64_Ehdr>(&ehdr);
+  ehdr.e_ident[EI_CLASS] = ELFCLASS64;
+  ehdr.e_machine = EM_AARCH64;
+
+  GnuDebugdataInitFail<Elf64_Ehdr, Elf64_Shdr>(&ehdr);
+}
+
+template <typename Ehdr, typename Shdr>
+void ElfTest::GnuDebugdataInit(Ehdr* ehdr) {
+  Elf elf(memory_);
+
+  uint64_t offset = 0x2000;
+
+  ehdr->e_shoff = offset;
+  ehdr->e_shnum = 3;
+  ehdr->e_shentsize = sizeof(Shdr);
+  ehdr->e_shstrndx = 2;
+  memory_->SetMemory(0, ehdr, sizeof(*ehdr));
+
+  Shdr shdr;
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_NULL;
+  memory_->SetMemory(offset, &shdr, sizeof(shdr));
+  offset += ehdr->e_shentsize;
+
+  uint64_t gnu_offset = offset;
+  offset += ehdr->e_shentsize;
+
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_STRTAB;
+  shdr.sh_name = 0x200000;
+  shdr.sh_offset = 0xf000;
+  shdr.sh_size = 0x1000;
+  memory_->SetMemory(offset, &shdr, sizeof(shdr));
+  offset += ehdr->e_shentsize;
+
+  memory_->SetMemory(0xf100, ".gnu_debugdata", sizeof(".gnu_debugdata"));
+
+  // Read in the compressed elf data and put it in our fake memory.
+  std::string name("tests/");
+  if (sizeof(Ehdr) == sizeof(Elf32_Ehdr)) {
+    name += "elf32.xz";
+  } else {
+    name += "elf64.xz";
+  }
+  int fd = TEMP_FAILURE_RETRY(open(name.c_str(), O_RDONLY));
+  ASSERT_NE(-1, fd) << "Cannot open " + name;
+  // Assumes the file is less than 1024 bytes.
+  std::vector<uint8_t> buf(1024);
+  ssize_t bytes = TEMP_FAILURE_RETRY(read(fd, buf.data(), buf.size()));
+  ASSERT_GT(bytes, 0);
+  // Make sure the file isn't too big.
+  ASSERT_NE(static_cast<size_t>(bytes), buf.size())
+      << "File " + name + " is too big, increase buffer size.";
+  close(fd);
+  buf.resize(bytes);
+  memory_->SetMemory(0x5000, buf);
+
+  memset(&shdr, 0, sizeof(shdr));
+  shdr.sh_type = SHT_PROGBITS;
+  shdr.sh_name = 0x100;
+  shdr.sh_addr = 0x5000;
+  shdr.sh_offset = 0x5000;
+  shdr.sh_size = bytes;
+  memory_->SetMemory(gnu_offset, &shdr, sizeof(shdr));
+
+  ASSERT_TRUE(elf.Init());
+  ASSERT_TRUE(elf.interface() != nullptr);
+  ASSERT_TRUE(elf.gnu_debugdata_interface() == nullptr);
+  EXPECT_EQ(0x5000U, elf.interface()->gnu_debugdata_offset());
+
+  elf.InitGnuDebugdata();
+  ASSERT_TRUE(elf.gnu_debugdata_interface() != nullptr);
+}
+
+TEST_F(ElfTest, gnu_debugdata_init32) {
+  Elf32_Ehdr ehdr;
+  InitEhdr<Elf32_Ehdr>(&ehdr);
+  ehdr.e_ident[EI_CLASS] = ELFCLASS32;
+  ehdr.e_machine = EM_ARM;
+
+  GnuDebugdataInit<Elf32_Ehdr, Elf32_Shdr>(&ehdr);
+}
+
+TEST_F(ElfTest, gnu_debugdata_init64) {
+  Elf64_Ehdr ehdr;
+  InitEhdr<Elf64_Ehdr>(&ehdr);
+  ehdr.e_ident[EI_CLASS] = ELFCLASS64;
+  ehdr.e_machine = EM_AARCH64;
+
+  GnuDebugdataInit<Elf64_Ehdr, Elf64_Shdr>(&ehdr);
+}