base/android/linker/linker_jni.h - bauxite - Git at Google

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // This is the Android-specific Chromium linker, a tiny shared library
 // implementing a custom dynamic linker that can be used to load the
 // real Chromium libraries.

 // The main point of this linker is to be able to share the RELRO
 // section of libcontentshell.so (or equivalent) between the browser and
 // renderer process.

 // This source code *cannot* depend on anything from base/ or the C++
 // STL, to keep the final library small, and avoid ugly dependency issues.

 #ifndef BASE_ANDROID_LINKER_LINKER_JNI_H_
 #define BASE_ANDROID_LINKER_LINKER_JNI_H_

 #include <android/log.h>
 #include <jni.h>
 #include <stdlib.h>

 // Set this to 1 to enable debug traces to the Android log.
 // Note that LOG() from "base/logging.h" cannot be used, since it is
 // in base/ which hasn't been loaded yet.
 #define DEBUG 0

 #define TAG "cr_ChromiumAndroidLinker"

 #if DEBUG
 #define LOG_INFO(FORMAT, ...) \
     __android_log_print(ANDROID_LOG_INFO, TAG, \
                         "%s: " FORMAT, __FUNCTION__, ##__VA_ARGS__)
 #else
 #define LOG_INFO(FORMAT, ...) ((void)0)
 #endif
 #define LOG_ERROR(FORMAT, ...) \
     __android_log_print(ANDROID_LOG_ERROR, TAG, \
                         "%s: " FORMAT, __FUNCTION__, ##__VA_ARGS__)

 #define UNUSED __attribute__((unused))

 // See commentary in crazy_linker_elf_loader.cpp for the effect of setting
 // this. If changing there, change here also.
 //
 // For more, see:
 //   https://crbug.com/504410
 #define RESERVE_BREAKPAD_GUARD_REGION 1

 namespace chromium_android_linker {

 // Larger than the largest library we might attempt to load.
 static const size_t kAddressSpaceReservationSize = 192 * 1024 * 1024;

 // Size of any Breakpad guard region. 16MB is comfortably larger than the
 // ~6MB relocation packing of the current 64-bit libchrome.so, the largest we
 // expect to encounter.
 #if RESERVE_BREAKPAD_GUARD_REGION
 static const size_t kBreakpadGuardRegionBytes = 16 * 1024 * 1024;
 #endif

 // A simple scoped UTF String class that can be initialized from
 // a Java jstring handle. Modeled like std::string, which cannot
 // be used here.
 class String {
  public:
   String(JNIEnv* env, jstring str);

   inline ~String() { ::free(ptr_); }

   inline const char* c_str() const { return ptr_ ? ptr_ : ""; }
   inline size_t size() const { return size_; }

  private:
   char* ptr_;
   size_t size_;
 };

 // Return true iff |address| is a valid address for the target CPU.
 inline bool IsValidAddress(jlong address) {
   return static_cast<jlong>(static_cast<size_t>(address)) == address;
 }

 // Find the jclass JNI reference corresponding to a given |class_name|.
 // |env| is the current JNI environment handle.
 // On success, return true and set |*clazz|.
 extern bool InitClassReference(JNIEnv* env,
                                const char* class_name,
                                jclass* clazz);

 // Initialize a jfieldID corresponding to the field of a given |clazz|,
 // with name |field_name| and signature |field_sig|.
 // |env| is the current JNI environment handle.
 // On success, return true and set |*field_id|.
 extern bool InitFieldId(JNIEnv* env,
                         jclass clazz,
                         const char* field_name,
                         const char* field_sig,
                         jfieldID* field_id);

 // Initialize a jmethodID corresponding to the static method of a given
 // |clazz|, with name |method_name| and signature |method_sig|.
 // |env| is the current JNI environment handle.
 // On success, return true and set |*method_id|.
 extern bool InitStaticMethodId(JNIEnv* env,
                                jclass clazz,
                                const char* method_name,
                                const char* method_sig,
                                jmethodID* method_id);

 // Initialize a jfieldID corresponding to the static field of a given |clazz|,
 // with name |field_name| and signature |field_sig|.
 // |env| is the current JNI environment handle.
 // On success, return true and set |*field_id|.
 extern bool InitStaticFieldId(JNIEnv* env,
                               jclass clazz,
                               const char* field_name,
                               const char* field_sig,
                               jfieldID* field_id);

 // Initialize a jint corresponding to the static integer field of a class
 // with class name |class_name| and field name |field_name|.
 // |env| is the current JNI environment handle.
 // On success, return true and set |*value|.
 extern bool InitStaticInt(JNIEnv* env,
                           const char* class_name,
                           const char* field_name,
                           jint* value);

 // Use Android ASLR to create a random library load address.
 // |env| is the current JNI environment handle, and |clazz| a class.
 // Returns the address selected by ASLR.
 extern jlong GetRandomBaseLoadAddress(JNIEnv* env, jclass clazz);

 // A class used to model the field IDs of the org.chromium.base.Linker
 // LibInfo inner class, used to communicate data with the Java side
 // of the linker.
 struct LibInfo_class {
   jfieldID load_address_id;
   jfieldID load_size_id;
   jfieldID relro_start_id;
   jfieldID relro_size_id;
   jfieldID relro_fd_id;

   // Initialize an instance.
   bool Init(JNIEnv* env) {
     jclass clazz;
     if (!InitClassReference(
              env, "org/chromium/base/library_loader/Linker$LibInfo", &clazz)) {
       return false;
     }

     return InitFieldId(env, clazz, "mLoadAddress", "J", &load_address_id) &&
            InitFieldId(env, clazz, "mLoadSize", "J", &load_size_id) &&
            InitFieldId(env, clazz, "mRelroStart", "J", &relro_start_id) &&
            InitFieldId(env, clazz, "mRelroSize", "J", &relro_size_id) &&
            InitFieldId(env, clazz, "mRelroFd", "I", &relro_fd_id);
   }

   void SetLoadInfo(JNIEnv* env,
                    jobject library_info_obj,
                    size_t load_address,
                    size_t load_size) {
     env->SetLongField(library_info_obj, load_address_id, load_address);
     env->SetLongField(library_info_obj, load_size_id, load_size);
   }

   void SetRelroInfo(JNIEnv* env,
                     jobject library_info_obj,
                     size_t relro_start,
                     size_t relro_size,
                     int relro_fd) {
     env->SetLongField(library_info_obj, relro_start_id, relro_start);
     env->SetLongField(library_info_obj, relro_size_id, relro_size);
     env->SetIntField(library_info_obj, relro_fd_id, relro_fd);
   }

   // Use this instance to convert a RelroInfo reference into
   // a crazy_library_info_t.
   void GetRelroInfo(JNIEnv* env,
                     jobject library_info_obj,
                     size_t* relro_start,
                     size_t* relro_size,
                     int* relro_fd) {
     if (relro_start) {
       *relro_start = static_cast<size_t>(
           env->GetLongField(library_info_obj, relro_start_id));
     }

     if (relro_size) {
       *relro_size = static_cast<size_t>(
           env->GetLongField(library_info_obj, relro_size_id));
     }

     if (relro_fd) {
       *relro_fd = env->GetIntField(library_info_obj, relro_fd_id);
     }
   }
 };

 // Variable containing LibInfo for the loaded library.
 extern LibInfo_class s_lib_info_fields;

 }  // namespace chromium_android_linker

 #endif  // BASE_ANDROID_LINKER_LINKER_JNI_H_
	// Copyright 2015 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// This is the Android-specific Chromium linker, a tiny shared library
	// implementing a custom dynamic linker that can be used to load the
	// real Chromium libraries.

	// The main point of this linker is to be able to share the RELRO
	// section of libcontentshell.so (or equivalent) between the browser and
	// renderer process.

	// This source code cannot depend on anything from base/ or the C++
	// STL, to keep the final library small, and avoid ugly dependency issues.

	#ifndef BASE_ANDROID_LINKER_LINKER_JNI_H_
	#define BASE_ANDROID_LINKER_LINKER_JNI_H_

	#include <android/log.h>
	#include <jni.h>
	#include <stdlib.h>

	// Set this to 1 to enable debug traces to the Android log.
	// Note that LOG() from "base/logging.h" cannot be used, since it is
	// in base/ which hasn't been loaded yet.
	#define DEBUG 0

	#define TAG "cr_ChromiumAndroidLinker"

	#if DEBUG
	#define LOG_INFO(FORMAT, ...) \
	__android_log_print(ANDROID_LOG_INFO, TAG, \
	"%s: " FORMAT, __FUNCTION__, ##__VA_ARGS__)
	#else
	#define LOG_INFO(FORMAT, ...) ((void)0)
	#endif
	#define LOG_ERROR(FORMAT, ...) \
	__android_log_print(ANDROID_LOG_ERROR, TAG, \
	"%s: " FORMAT, __FUNCTION__, ##__VA_ARGS__)

	#define UNUSED __attribute__((unused))

	// See commentary in crazy_linker_elf_loader.cpp for the effect of setting
	// this. If changing there, change here also.
	//
	// For more, see:
	// https://crbug.com/504410
	#define RESERVE_BREAKPAD_GUARD_REGION 1

	namespace chromium_android_linker {

	// Larger than the largest library we might attempt to load.
	static const size_t kAddressSpaceReservationSize = 192 * 1024 * 1024;

	// Size of any Breakpad guard region. 16MB is comfortably larger than the
	// ~6MB relocation packing of the current 64-bit libchrome.so, the largest we
	// expect to encounter.
	#if RESERVE_BREAKPAD_GUARD_REGION
	static const size_t kBreakpadGuardRegionBytes = 16 * 1024 * 1024;
	#endif

	// A simple scoped UTF String class that can be initialized from
	// a Java jstring handle. Modeled like std::string, which cannot
	// be used here.
	class String {
	public:
	String(JNIEnv* env, jstring str);

	inline ~String() { ::free(ptr_); }

	inline const char* c_str() const { return ptr_ ? ptr_ : ""; }
	inline size_t size() const { return size_; }

	private:
	char* ptr_;
	size_t size_;
	};

	// Return true iff \|address\| is a valid address for the target CPU.
	inline bool IsValidAddress(jlong address) {
	return static_cast<jlong>(static_cast<size_t>(address)) == address;
	}

	// Find the jclass JNI reference corresponding to a given \|class_name\|.
	// \|env\| is the current JNI environment handle.
	// On success, return true and set \|*clazz\|.
	extern bool InitClassReference(JNIEnv* env,
	const char* class_name,
	jclass* clazz);

	// Initialize a jfieldID corresponding to the field of a given \|clazz\|,
	// with name \|field_name\| and signature \|field_sig\|.
	// \|env\| is the current JNI environment handle.
	// On success, return true and set \|*field_id\|.
	extern bool InitFieldId(JNIEnv* env,
	jclass clazz,
	const char* field_name,
	const char* field_sig,
	jfieldID* field_id);

	// Initialize a jmethodID corresponding to the static method of a given
	// \|clazz\|, with name \|method_name\| and signature \|method_sig\|.
	// \|env\| is the current JNI environment handle.
	// On success, return true and set \|*method_id\|.
	extern bool InitStaticMethodId(JNIEnv* env,
	jclass clazz,
	const char* method_name,
	const char* method_sig,
	jmethodID* method_id);

	// Initialize a jfieldID corresponding to the static field of a given \|clazz\|,
	// with name \|field_name\| and signature \|field_sig\|.
	// \|env\| is the current JNI environment handle.
	// On success, return true and set \|*field_id\|.
	extern bool InitStaticFieldId(JNIEnv* env,
	jclass clazz,
	const char* field_name,
	const char* field_sig,
	jfieldID* field_id);

	// Initialize a jint corresponding to the static integer field of a class
	// with class name \|class_name\| and field name \|field_name\|.
	// \|env\| is the current JNI environment handle.
	// On success, return true and set \|*value\|.
	extern bool InitStaticInt(JNIEnv* env,
	const char* class_name,
	const char* field_name,
	jint* value);

	// Use Android ASLR to create a random library load address.
	// \|env\| is the current JNI environment handle, and \|clazz\| a class.
	// Returns the address selected by ASLR.
	extern jlong GetRandomBaseLoadAddress(JNIEnv* env, jclass clazz);

	// A class used to model the field IDs of the org.chromium.base.Linker
	// LibInfo inner class, used to communicate data with the Java side
	// of the linker.
	struct LibInfo_class {
	jfieldID load_address_id;
	jfieldID load_size_id;
	jfieldID relro_start_id;
	jfieldID relro_size_id;
	jfieldID relro_fd_id;

	// Initialize an instance.
	bool Init(JNIEnv* env) {
	jclass clazz;
	if (!InitClassReference(
	env, "org/chromium/base/library_loader/Linker$LibInfo", &clazz)) {
	return false;
	}

	return InitFieldId(env, clazz, "mLoadAddress", "J", &load_address_id) &&
	InitFieldId(env, clazz, "mLoadSize", "J", &load_size_id) &&
	InitFieldId(env, clazz, "mRelroStart", "J", &relro_start_id) &&
	InitFieldId(env, clazz, "mRelroSize", "J", &relro_size_id) &&
	InitFieldId(env, clazz, "mRelroFd", "I", &relro_fd_id);
	}

	void SetLoadInfo(JNIEnv* env,
	jobject library_info_obj,
	size_t load_address,
	size_t load_size) {
	env->SetLongField(library_info_obj, load_address_id, load_address);
	env->SetLongField(library_info_obj, load_size_id, load_size);
	}

	void SetRelroInfo(JNIEnv* env,
	jobject library_info_obj,
	size_t relro_start,
	size_t relro_size,
	int relro_fd) {
	env->SetLongField(library_info_obj, relro_start_id, relro_start);
	env->SetLongField(library_info_obj, relro_size_id, relro_size);
	env->SetIntField(library_info_obj, relro_fd_id, relro_fd);
	}

	// Use this instance to convert a RelroInfo reference into
	// a crazy_library_info_t.
	void GetRelroInfo(JNIEnv* env,
	jobject library_info_obj,
	size_t* relro_start,
	size_t* relro_size,
	int* relro_fd) {
	if (relro_start) {
	*relro_start = static_cast<size_t>(
	env->GetLongField(library_info_obj, relro_start_id));
	}

	if (relro_size) {
	*relro_size = static_cast<size_t>(
	env->GetLongField(library_info_obj, relro_size_id));
	}

	if (relro_fd) {
	*relro_fd = env->GetIntField(library_info_obj, relro_fd_id);
	}
	}
	};

	// Variable containing LibInfo for the loaded library.
	extern LibInfo_class s_lib_info_fields;

	} // namespace chromium_android_linker

	#endif // BASE_ANDROID_LINKER_LINKER_JNI_H_