Move the android library loader from content to base

content/common/android/linker/linker_jni.cc

Index: content/common/android/linker/linker_jni.cc
diff --git a/content/common/android/linker/linker_jni.cc b/content/common/android/linker/linker_jni.cc
deleted file mode 100644
index 7db9fea48e2cc05baf353c4b6e623f8beb093003..0000000000000000000000000000000000000000
--- a/content/common/android/linker/linker_jni.cc
+++ /dev/null
@@ -1,457 +0,0 @@
-// Copyright 2013 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 content linker, a tiny shared library
-// implementing a custom dynamic linker that can be used to load the
-// real content-based libraries (e.g. libcontentshell.so).
-
-// 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.
-
-#include <android/log.h>
-#include <crazy_linker.h>
-#include <jni.h>
-#include <stdlib.h>
-#include <unistd.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 "content_android_linker"
-
-#if DEBUG
-#define LOG_INFO(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
-#define LOG_ERROR(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)
-#else
-#define LOG_INFO(...) ((void)0)
-#define LOG_ERROR(...) ((void)0)
-#endif
-
-#define UNUSED __attribute__((unused))
-
-namespace {
-
-// A simply 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);
-
-  ~String() {
-    if (ptr_)
-      ::free(ptr_);
-  }
-
-  const char* c_str() const { return ptr_ ? ptr_ : ""; }
-  size_t size() const { return size_; }
-
- private:
-  char* ptr_;
-  size_t size_;
-};
-
-String::String(JNIEnv* env, jstring str) {
-  size_ = env->GetStringUTFLength(str);
-  ptr_ = static_cast<char*>(::malloc(size_ + 1));
-
-  // Note: the result contains Java "modified UTF-8" bytes.
-  // Good enough for the linker though.
-  const char* bytes = env->GetStringUTFChars(str, NULL);
-  ::memcpy(ptr_, bytes, size_);
-  ptr_[size_] = '\0';
-
-  env->ReleaseStringUTFChars(str, bytes);
-}
-
-// A scoped crazy_library_t that automatically closes the handle
-// on scope exit, unless Release() has been called.
-class ScopedLibrary {
- public:
-  ScopedLibrary() : lib_(NULL) {}
-
-  ~ScopedLibrary() {
-    if (lib_)
-      crazy_library_close(lib_);
-  }
-
-  crazy_library_t* Get() { return lib_; }
-
-  crazy_library_t** GetPtr() { return &lib_; }
-
-  crazy_library_t* Release() {
-    crazy_library_t* ret = lib_;
-    lib_ = NULL;
-    return ret;
-  }
-
- private:
-  crazy_library_t* lib_;
-};
-
-// Return a pointer to the base name from an input |path| string.
-const char* GetBaseNamePtr(const char* path) {
-  const char* p = strrchr(path, '/');
-  if (p)
-    return p + 1;
-  return path;
-}
-
-// Return true iff |address| is a valid address for the target CPU.
-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|.
-bool InitClassReference(JNIEnv* env, const char* class_name, jclass* clazz) {
-  *clazz = env->FindClass(class_name);
-  if (!*clazz) {
-    LOG_ERROR("Could not find class for %s", class_name);
-    return false;
-  }
-  return true;
-}
-
-// 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|.
-bool InitFieldId(JNIEnv* env,
-                 jclass clazz,
-                 const char* field_name,
-                 const char* field_sig,
-                 jfieldID* field_id) {
-  *field_id = env->GetFieldID(clazz, field_name, field_sig);
-  if (!*field_id) {
-    LOG_ERROR("Could not find ID for field '%s'", field_name);
-    return false;
-  }
-  LOG_INFO(
-      "%s: Found ID %p for field '%s'", __FUNCTION__, *field_id, field_name);
-  return true;
-}
-
-// 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/content/app/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);
-  }
-
-  // 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) {
-    *relro_start = static_cast<size_t>(
-        env->GetLongField(library_info_obj, relro_start_id));
-
-    *relro_size =
-        static_cast<size_t>(env->GetLongField(library_info_obj, relro_size_id));
-
-    *relro_fd = env->GetIntField(library_info_obj, relro_fd_id);
-  }
-
-  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);
-  }
-};
-
-static LibInfo_class s_lib_info_fields;
-
-// The linker uses a single crazy_context_t object created on demand.
-// There is no need to protect this against concurrent access, locking
-// is already handled on the Java side.
-static crazy_context_t* s_crazy_context;
-
-crazy_context_t* GetCrazyContext() {
-  if (!s_crazy_context) {
-    // Create new context.
-    s_crazy_context = crazy_context_create();
-
-    // Ensure libraries located in the same directory as the linker
-    // can be loaded before system ones.
-    crazy_context_add_search_path_for_address(
-        s_crazy_context, reinterpret_cast<void*>(&s_crazy_context));
-  }
-
-  return s_crazy_context;
-}
-
-// Load a library with the content linker. This will also call its
-// JNI_OnLoad() method, which shall register its methods. Note that
-// lazy native method resolution will _not_ work after this, because
-// Dalvik uses the system's dlsym() which won't see the new library,
-// so explicit registration is mandatory.
-// |env| is the current JNI environment handle.
-// |clazz| is the static class handle for org.chromium.base.Linker,
-// and is ignored here.
-// |library_name| is the library name (e.g. libfoo.so).
-// |load_address| is an explicit load address.
-// |library_info| is a LibInfo handle used to communicate information
-// with the Java side.
-// Return true on success.
-jboolean LoadLibrary(JNIEnv* env,
-                     jclass clazz,
-                     jstring library_name,
-                     jlong load_address,
-                     jobject lib_info_obj) {
-  String lib_name(env, library_name);
-  const char* UNUSED lib_basename = GetBaseNamePtr(lib_name.c_str());
-
-  crazy_context_t* context = GetCrazyContext();
-
-  if (!IsValidAddress(load_address)) {
-    LOG_ERROR("%s: Invalid address 0x%llx", __FUNCTION__, load_address);
-    return false;
-  }
-
-  // Set the desired load address (0 means randomize it).
-  crazy_context_set_load_address(context, static_cast<size_t>(load_address));
-
-  // Open the library now.
-  LOG_INFO("%s: Opening shared library: %s", __FUNCTION__, lib_name.c_str());
-
-  ScopedLibrary library;
-  if (!crazy_library_open(library.GetPtr(), lib_name.c_str(), context)) {
-    LOG_ERROR("%s: Could not open %s: %s",
-              __FUNCTION__,
-              lib_basename,
-              crazy_context_get_error(context));
-    return false;
-  }
-
-  crazy_library_info_t info;
-  if (!crazy_library_get_info(library.Get(), context, &info)) {
-    LOG_ERROR("%s: Could not get library information for %s: %s",
-              __FUNCTION__,
-              lib_basename,
-              crazy_context_get_error(context));
-    return false;
-  }
-
-  // Release library object to keep it alive after the function returns.
-  library.Release();
-
-  s_lib_info_fields.SetLoadInfo(
-      env, lib_info_obj, info.load_address, info.load_size);
-  LOG_INFO("%s: Success loading library %s", __FUNCTION__, lib_basename);
-  return true;
-}
-
-jboolean CreateSharedRelro(JNIEnv* env,
-                           jclass clazz,
-                           jstring library_name,
-                           jlong load_address,
-                           jobject lib_info_obj) {
-  String lib_name(env, library_name);
-
-  LOG_INFO("%s: Called for %s", __FUNCTION__, lib_name.c_str());
-
-  if (!IsValidAddress(load_address)) {
-    LOG_ERROR("%s: Invalid address 0x%llx", __FUNCTION__, load_address);
-    return false;
-  }
-
-  ScopedLibrary library;
-  if (!crazy_library_find_by_name(lib_name.c_str(), library.GetPtr())) {
-    LOG_ERROR("%s: Could not find %s", __FUNCTION__, lib_name.c_str());
-    return false;
-  }
-
-  crazy_context_t* context = GetCrazyContext();
-  size_t relro_start = 0;
-  size_t relro_size = 0;
-  int relro_fd = -1;
-
-  if (!crazy_library_create_shared_relro(library.Get(),
-                                         context,
-                                         static_cast<size_t>(load_address),
-                                         &relro_start,
-                                         &relro_size,
-                                         &relro_fd)) {
-    LOG_ERROR("%s: Could not create shared RELRO sharing for %s: %s\n",
-              __FUNCTION__,
-              lib_name.c_str(),
-              crazy_context_get_error(context));
-    return false;
-  }
-
-  s_lib_info_fields.SetRelroInfo(
-      env, lib_info_obj, relro_start, relro_size, relro_fd);
-  return true;
-}
-
-jboolean UseSharedRelro(JNIEnv* env,
-                        jclass clazz,
-                        jstring library_name,
-                        jobject lib_info_obj) {
-  String lib_name(env, library_name);
-
-  LOG_INFO("%s: called for %s, lib_info_ref=%p",
-           __FUNCTION__,
-           lib_name.c_str(),
-           lib_info_obj);
-
-  ScopedLibrary library;
-  if (!crazy_library_find_by_name(lib_name.c_str(), library.GetPtr())) {
-    LOG_ERROR("%s: Could not find %s", __FUNCTION__, lib_name.c_str());
-    return false;
-  }
-
-  crazy_context_t* context = GetCrazyContext();
-  size_t relro_start = 0;
-  size_t relro_size = 0;
-  int relro_fd = -1;
-  s_lib_info_fields.GetRelroInfo(
-      env, lib_info_obj, &relro_start, &relro_size, &relro_fd);
-
-  LOG_INFO("%s: library=%s relro start=%p size=%p fd=%d",
-           __FUNCTION__,
-           lib_name.c_str(),
-           (void*)relro_start,
-           (void*)relro_size,
-           relro_fd);
-
-  if (!crazy_library_use_shared_relro(
-           library.Get(), context, relro_start, relro_size, relro_fd)) {
-    LOG_ERROR("%s: Could not use shared RELRO for %s: %s",
-              __FUNCTION__,
-              lib_name.c_str(),
-              crazy_context_get_error(context));
-    return false;
-  }
-
-  LOG_INFO("%s: Library %s using shared RELRO section!",
-           __FUNCTION__,
-           lib_name.c_str());
-
-  return true;
-}
-
-jboolean CanUseSharedRelro(JNIEnv* env, jclass clazz) {
-  return crazy_system_can_share_relro();
-}
-
-jlong GetPageSize(JNIEnv* env, jclass clazz) {
-  jlong result = static_cast<jlong>(sysconf(_SC_PAGESIZE));
-  LOG_INFO("%s: System page size is %lld bytes\n", __FUNCTION__, result);
-  return result;
-}
-
-const JNINativeMethod kNativeMethods[] = {
-    {"nativeLoadLibrary",
-     "("
-     "Ljava/lang/String;"
-     "J"
-     "Lorg/chromium/content/app/Linker$LibInfo;"
-     ")"
-     "Z",
-     reinterpret_cast<void*>(&LoadLibrary)},
-    {"nativeCreateSharedRelro",
-     "("
-     "Ljava/lang/String;"
-     "J"
-     "Lorg/chromium/content/app/Linker$LibInfo;"
-     ")"
-     "Z",
-     reinterpret_cast<void*>(&CreateSharedRelro)},
-    {"nativeUseSharedRelro",
-     "("
-     "Ljava/lang/String;"
-     "Lorg/chromium/content/app/Linker$LibInfo;"
-     ")"
-     "Z",
-     reinterpret_cast<void*>(&UseSharedRelro)},
-    {"nativeCanUseSharedRelro",
-     "("
-     ")"
-     "Z",
-     reinterpret_cast<void*>(&CanUseSharedRelro)},
-    {"nativeGetPageSize",
-     "("
-     ")"
-     "J",
-     reinterpret_cast<void*>(&GetPageSize)}, };
-
-}  // namespace
-
-// JNI_OnLoad() hook called when the linker library is loaded through
-// the regular System.LoadLibrary) API. This shall save the Java VM
-// handle and initialize LibInfo fields.
-jint JNI_OnLoad(JavaVM* vm, void* reserved) {
-  LOG_INFO("%s: Entering", __FUNCTION__);
-  // Get new JNIEnv
-  JNIEnv* env;
-  if (JNI_OK != vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_4)) {
-    LOG_ERROR("Could not create JNIEnv");
-    return -1;
-  }
-
-  // Register native methods.
-  jclass linker_class;
-  if (!InitClassReference(
-           env, "org/chromium/content/app/Linker", &linker_class))
-    return -1;
-
-  LOG_INFO("%s: Registering native methods", __FUNCTION__);
-  env->RegisterNatives(linker_class,
-                       kNativeMethods,
-                       sizeof(kNativeMethods) / sizeof(kNativeMethods[0]));
-
-  // Find LibInfo field ids.
-  LOG_INFO("%s: Caching field IDs", __FUNCTION__);
-  if (!s_lib_info_fields.Init(env)) {
-    return -1;
-  }
-
-  // Save JavaVM* handle into context.
-  crazy_context_t* context = GetCrazyContext();
-  crazy_context_set_java_vm(context, vm, JNI_VERSION_1_4);
-
-  LOG_INFO("%s: Done", __FUNCTION__);
-  return JNI_VERSION_1_4;
-}