Merge "Elf interface for new unwinder."

1 files changed, 113 insertions, 0 deletions

diff --git a/libunwindstack/Elf.cpp b/libunwindstack/Elf.cpp
new file mode 100644
index 000000000..272b5f029
--- /dev/null
+++ b/libunwindstack/Elf.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include <elf.h>
+#include <string.h>
+
+#include <memory>
+#include <string>
+
+#define LOG_TAG "unwind"
+#include <log/log.h>
+
+#include "Elf.h"
+#include "ElfInterface.h"
+#include "ElfInterfaceArm.h"
+#include "Machine.h"
+#include "Memory.h"
+#include "Regs.h"
+
+bool Elf::Init() {
+  if (!memory_) {
+    return false;
+  }
+
+  interface_.reset(CreateInterfaceFromMemory(memory_.get()));
+  if (!interface_) {
+    return false;
+  }
+
+  valid_ = interface_->Init();
+  if (valid_) {
+    interface_->InitHeaders();
+  } else {
+    interface_.reset(nullptr);
+  }
+  return valid_;
+}
+
+bool Elf::IsValidElf(Memory* memory) {
+  if (memory == nullptr) {
+    return false;
+  }
+
+  // Verify that this is a valid elf file.
+  uint8_t e_ident[SELFMAG + 1];
+  if (!memory->Read(0, e_ident, SELFMAG)) {
+    return false;
+  }
+
+  if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
+    return false;
+  }
+  return true;
+}
+
+ElfInterface* Elf::CreateInterfaceFromMemory(Memory* memory) {
+  if (!IsValidElf(memory)) {
+    return nullptr;
+  }
+
+  std::unique_ptr<ElfInterface> interface;
+  if (!memory->Read(EI_CLASS, &class_type_, 1)) {
+    return nullptr;
+  }
+  if (class_type_ == ELFCLASS32) {
+    Elf32_Half e_machine;
+    if (!memory->Read(EI_NIDENT + sizeof(Elf32_Half), &e_machine, sizeof(e_machine))) {
+      return nullptr;
+    }
+
+    if (e_machine != EM_ARM && e_machine != EM_386) {
+      // Unsupported.
+      ALOGI("32 bit elf that is neither arm nor x86: e_machine = %d\n", e_machine);
+      return nullptr;
+    }
+
+    machine_type_ = e_machine;
+    if (e_machine == EM_ARM) {
+      interface.reset(new ElfInterfaceArm(memory));
+    } else {
+      interface.reset(new ElfInterface32(memory));
+    }
+  } else if (class_type_ == ELFCLASS64) {
+    Elf64_Half e_machine;
+    if (!memory->Read(EI_NIDENT + sizeof(Elf64_Half), &e_machine, sizeof(e_machine))) {
+      return nullptr;
+    }
+
+    if (e_machine != EM_AARCH64 && e_machine != EM_X86_64) {
+      // Unsupported.
+      ALOGI("64 bit elf that is neither aarch64 nor x86_64: e_machine = %d\n", e_machine);
+      return nullptr;
+    }
+
+    machine_type_ = e_machine;
+    interface.reset(new ElfInterface64(memory));
+  }
+
+  return interface.release();
+}