ravenwood/runtime-jni/ravenwood_runtime.cpp - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2024 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 <fcntl.h>
 #include <sys/stat.h>
 #include <string.h>
 #include <unistd.h>
 #include <string>
 #include <nativehelper/JNIHelp.h>
 #include <nativehelper/ScopedLocalRef.h>
 #include <nativehelper/ScopedUtfChars.h>
 #include <nativehelper/ScopedPrimitiveArray.h>

 #include "jni.h"
 #include "utils/Log.h"
 #include "utils/misc.h"

 // Defined in ravenwood_os_constants.cpp
 void register_android_system_OsConstants(JNIEnv* env);

 // ---- Exception related ----

 static void throwErrnoException(JNIEnv* env, const char* functionName) {
     int error = errno;
     jniThrowErrnoException(env, functionName, error);
 }

 template <typename rc_t>
 static rc_t throwIfMinusOne(JNIEnv* env, const char* name, rc_t rc) {
     if (rc == rc_t(-1)) {
         throwErrnoException(env, name);
     }
     return rc;
 }

 // ---- Helper functions ---

 static jclass g_StructStat;
 static jclass g_StructTimespecClass;

 // We have to explicitly decode the string to real UTF-8, because when using GetStringUTFChars
 // we only get modified UTF-8, which is not the platform string type used in host JVM.
 struct ScopedRealUtf8Chars {
     ScopedRealUtf8Chars(JNIEnv* env, jstring s) : valid_(false) {
         if (s == nullptr) {
             jniThrowNullPointerException(env);
             return;
         }
         jclass clazz = env->GetObjectClass(s);
         jmethodID getBytes = env->GetMethodID(clazz, "getBytes", "(Ljava/lang/String;)[B");

         ScopedLocalRef<jstring> utf8(env, env->NewStringUTF("UTF-8"));
         ScopedLocalRef<jbyteArray> jbytes(env,
             (jbyteArray) env->CallObjectMethod(s, getBytes, utf8.get()));

         ScopedByteArrayRO bytes(env, jbytes.get());
         string_.append((const char *) bytes.get(), bytes.size());
         valid_ = true;
     }

     const char* c_str() const {
         return valid_ ? string_.c_str() : nullptr;
     }

     size_t size() const {
         return string_.size();
     }

     const char& operator[](size_t n) const {
         return string_[n];
     }

 private:
     std::string string_;
     bool valid_;
 };

 static jclass findClass(JNIEnv* env, const char* name) {
     ScopedLocalRef<jclass> localClass(env, env->FindClass(name));
     jclass result = reinterpret_cast<jclass>(env->NewGlobalRef(localClass.get()));
     if (result == NULL) {
         ALOGE("failed to find class '%s'", name);
         abort();
     }
     return result;
 }

 static jobject makeStructTimespec(JNIEnv* env, const struct timespec& ts) {
     static jmethodID ctor = env->GetMethodID(g_StructTimespecClass, "<init>",
             "(JJ)V");
     if (ctor == NULL) {
         return NULL;
     }
     return env->NewObject(g_StructTimespecClass, ctor,
             static_cast<jlong>(ts.tv_sec), static_cast<jlong>(ts.tv_nsec));
 }

 static jobject makeStructStat(JNIEnv* env, const struct stat64& sb) {
     static jmethodID ctor = env->GetMethodID(g_StructStat, "<init>",
             "(JJIJIIJJLandroid/system/StructTimespec;Landroid/system/StructTimespec;Landroid/system/StructTimespec;JJ)V");
     if (ctor == NULL) {
         return NULL;
     }

     jobject atim_timespec = makeStructTimespec(env, sb.st_atim);
     if (atim_timespec == NULL) {
         return NULL;
     }
     jobject mtim_timespec = makeStructTimespec(env, sb.st_mtim);
     if (mtim_timespec == NULL) {
         return NULL;
     }
     jobject ctim_timespec = makeStructTimespec(env, sb.st_ctim);
     if (ctim_timespec == NULL) {
         return NULL;
     }

     return env->NewObject(g_StructStat, ctor,
             static_cast<jlong>(sb.st_dev), static_cast<jlong>(sb.st_ino),
             static_cast<jint>(sb.st_mode), static_cast<jlong>(sb.st_nlink),
             static_cast<jint>(sb.st_uid), static_cast<jint>(sb.st_gid),
             static_cast<jlong>(sb.st_rdev), static_cast<jlong>(sb.st_size),
             atim_timespec, mtim_timespec, ctim_timespec,
             static_cast<jlong>(sb.st_blksize), static_cast<jlong>(sb.st_blocks));
 }

 static jobject doStat(JNIEnv* env, jstring javaPath, bool isLstat) {
     ScopedRealUtf8Chars path(env, javaPath);
     if (path.c_str() == NULL) {
         return NULL;
     }
     struct stat64 sb;
     int rc = isLstat ? TEMP_FAILURE_RETRY(lstat64(path.c_str(), &sb))
                      : TEMP_FAILURE_RETRY(stat64(path.c_str(), &sb));
     if (rc == -1) {
         throwErrnoException(env, isLstat ? "lstat" : "stat");
         return NULL;
     }
     return makeStructStat(env, sb);
 }

 // ---- JNI methods ----

 typedef void (*FreeFunction)(void*);

 static void nApplyFreeFunction(JNIEnv*, jclass, jlong freeFunction, jlong ptr) {
     void* nativePtr = reinterpret_cast<void*>(static_cast<uintptr_t>(ptr));
     FreeFunction nativeFreeFunction
         = reinterpret_cast<FreeFunction>(static_cast<uintptr_t>(freeFunction));
     nativeFreeFunction(nativePtr);
 }

 static jint nFcntlInt(JNIEnv* env, jclass, jint fd, jint cmd, jint arg) {
     return throwIfMinusOne(env, "fcntl", TEMP_FAILURE_RETRY(fcntl(fd, cmd, arg)));
 }

 static jlong nLseek(JNIEnv* env, jclass, jint fd, jlong offset, jint whence) {
     return throwIfMinusOne(env, "lseek", TEMP_FAILURE_RETRY(lseek(fd, offset, whence)));
 }

 static jintArray nPipe2(JNIEnv* env, jclass, jint flags) {
     int fds[2];
     throwIfMinusOne(env, "pipe2", TEMP_FAILURE_RETRY(pipe2(fds, flags)));

     jintArray result;
     result = env->NewIntArray(2);
     if (result == NULL) {
         return NULL; /* out of memory error thrown */
     }
     env->SetIntArrayRegion(result, 0, 2, fds);
     return result;
 }

 static jlong nDup(JNIEnv* env, jclass, jint fd) {
     return throwIfMinusOne(env, "fcntl", TEMP_FAILURE_RETRY(fcntl(fd, F_DUPFD_CLOEXEC, 0)));
 }

 static jobject nFstat(JNIEnv* env, jobject, jint fd) {
     struct stat64 sb;
     int rc = TEMP_FAILURE_RETRY(fstat64(fd, &sb));
     if (rc == -1) {
         throwErrnoException(env, "fstat");
         return NULL;
     }
     return makeStructStat(env, sb);
 }

 static jobject Linux_lstat(JNIEnv* env, jobject, jstring javaPath) {
     return doStat(env, javaPath, true);
 }

 static jobject Linux_stat(JNIEnv* env, jobject, jstring javaPath) {
     return doStat(env, javaPath, false);
 }

 static jint Linux_open(JNIEnv* env, jobject, jstring javaPath, jint flags, jint mode) {
     ScopedRealUtf8Chars path(env, javaPath);
     if (path.c_str() == NULL) {
         return -1;
     }
     return throwIfMinusOne(env, "open", TEMP_FAILURE_RETRY(open(path.c_str(), flags, mode)));
 }

 // ---- Registration ----

 static const JNINativeMethod sMethods[] =
 {
     { "applyFreeFunction", "(JJ)V", (void*)nApplyFreeFunction },
     { "nFcntlInt", "(III)I", (void*)nFcntlInt },
     { "nLseek", "(IJI)J", (void*)nLseek },
     { "nPipe2", "(I)[I", (void*)nPipe2 },
     { "nDup", "(I)I", (void*)nDup },
     { "nFstat", "(I)Landroid/system/StructStat;", (void*)nFstat },
     { "lstat", "(Ljava/lang/String;)Landroid/system/StructStat;", (void*)Linux_lstat },
     { "stat", "(Ljava/lang/String;)Landroid/system/StructStat;", (void*)Linux_stat },
     { "nOpen", "(Ljava/lang/String;II)I", (void*)Linux_open },
 };

 extern "C" jint JNI_OnLoad(JavaVM* vm, void* /* reserved */)
 {
     JNIEnv* env = NULL;
     jint result = -1;

     if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
         ALOGE("GetEnv failed!");
         return result;
     }
     ALOG_ASSERT(env, "Could not retrieve the env!");

     ALOGI("%s: JNI_OnLoad", __FILE__);

     g_StructStat = findClass(env, "android/system/StructStat");
     g_StructTimespecClass = findClass(env, "android/system/StructTimespec");

     jint res = jniRegisterNativeMethods(env, "com/android/ravenwood/common/RavenwoodRuntimeNative",
             sMethods, NELEM(sMethods));
     if (res < 0) {
         return res;
     }

     register_android_system_OsConstants(env);

     return JNI_VERSION_1_4;
 }
	/*
	* Copyright (C) 2024 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 <fcntl.h>
	#include <sys/stat.h>
	#include <string.h>
	#include <unistd.h>
	#include <string>
	#include <nativehelper/JNIHelp.h>
	#include <nativehelper/ScopedLocalRef.h>
	#include <nativehelper/ScopedUtfChars.h>
	#include <nativehelper/ScopedPrimitiveArray.h>

	#include "jni.h"
	#include "utils/Log.h"
	#include "utils/misc.h"

	// Defined in ravenwood_os_constants.cpp
	void register_android_system_OsConstants(JNIEnv* env);

	// ---- Exception related ----

	static void throwErrnoException(JNIEnv* env, const char* functionName) {
	int error = errno;
	jniThrowErrnoException(env, functionName, error);
	}

	template <typename rc_t>
	static rc_t throwIfMinusOne(JNIEnv* env, const char* name, rc_t rc) {
	if (rc == rc_t(-1)) {
	throwErrnoException(env, name);
	}
	return rc;
	}

	// ---- Helper functions ---

	static jclass g_StructStat;
	static jclass g_StructTimespecClass;

	// We have to explicitly decode the string to real UTF-8, because when using GetStringUTFChars
	// we only get modified UTF-8, which is not the platform string type used in host JVM.
	struct ScopedRealUtf8Chars {
	ScopedRealUtf8Chars(JNIEnv* env, jstring s) : valid_(false) {
	if (s == nullptr) {
	jniThrowNullPointerException(env);
	return;
	}
	jclass clazz = env->GetObjectClass(s);
	jmethodID getBytes = env->GetMethodID(clazz, "getBytes", "(Ljava/lang/String;)[B");

	ScopedLocalRef<jstring> utf8(env, env->NewStringUTF("UTF-8"));
	ScopedLocalRef<jbyteArray> jbytes(env,
	(jbyteArray) env->CallObjectMethod(s, getBytes, utf8.get()));

	ScopedByteArrayRO bytes(env, jbytes.get());
	string_.append((const char *) bytes.get(), bytes.size());
	valid_ = true;
	}

	const char* c_str() const {
	return valid_ ? string_.c_str() : nullptr;
	}

	size_t size() const {
	return string_.size();
	}

	const char& operator[](size_t n) const {
	return string_[n];
	}

	private:
	std::string string_;
	bool valid_;
	};

	static jclass findClass(JNIEnv* env, const char* name) {
	ScopedLocalRef<jclass> localClass(env, env->FindClass(name));
	jclass result = reinterpret_cast<jclass>(env->NewGlobalRef(localClass.get()));
	if (result == NULL) {
	ALOGE("failed to find class '%s'", name);
	abort();
	}
	return result;
	}

	static jobject makeStructTimespec(JNIEnv* env, const struct timespec& ts) {
	static jmethodID ctor = env->GetMethodID(g_StructTimespecClass, "<init>",
	"(JJ)V");
	if (ctor == NULL) {
	return NULL;
	}
	return env->NewObject(g_StructTimespecClass, ctor,
	static_cast<jlong>(ts.tv_sec), static_cast<jlong>(ts.tv_nsec));
	}

	static jobject makeStructStat(JNIEnv* env, const struct stat64& sb) {
	static jmethodID ctor = env->GetMethodID(g_StructStat, "<init>",
	"(JJIJIIJJLandroid/system/StructTimespec;Landroid/system/StructTimespec;Landroid/system/StructTimespec;JJ)V");
	if (ctor == NULL) {
	return NULL;
	}

	jobject atim_timespec = makeStructTimespec(env, sb.st_atim);
	if (atim_timespec == NULL) {
	return NULL;
	}
	jobject mtim_timespec = makeStructTimespec(env, sb.st_mtim);
	if (mtim_timespec == NULL) {
	return NULL;
	}
	jobject ctim_timespec = makeStructTimespec(env, sb.st_ctim);
	if (ctim_timespec == NULL) {
	return NULL;
	}

	return env->NewObject(g_StructStat, ctor,
	static_cast<jlong>(sb.st_dev), static_cast<jlong>(sb.st_ino),
	static_cast<jint>(sb.st_mode), static_cast<jlong>(sb.st_nlink),
	static_cast<jint>(sb.st_uid), static_cast<jint>(sb.st_gid),
	static_cast<jlong>(sb.st_rdev), static_cast<jlong>(sb.st_size),
	atim_timespec, mtim_timespec, ctim_timespec,
	static_cast<jlong>(sb.st_blksize), static_cast<jlong>(sb.st_blocks));
	}

	static jobject doStat(JNIEnv* env, jstring javaPath, bool isLstat) {
	ScopedRealUtf8Chars path(env, javaPath);
	if (path.c_str() == NULL) {
	return NULL;
	}
	struct stat64 sb;
	int rc = isLstat ? TEMP_FAILURE_RETRY(lstat64(path.c_str(), &sb))
	: TEMP_FAILURE_RETRY(stat64(path.c_str(), &sb));
	if (rc == -1) {
	throwErrnoException(env, isLstat ? "lstat" : "stat");
	return NULL;
	}
	return makeStructStat(env, sb);
	}

	// ---- JNI methods ----

	typedef void (FreeFunction)(void);

	static void nApplyFreeFunction(JNIEnv*, jclass, jlong freeFunction, jlong ptr) {
	void* nativePtr = reinterpret_cast<void*>(static_cast<uintptr_t>(ptr));
	FreeFunction nativeFreeFunction
	= reinterpret_cast<FreeFunction>(static_cast<uintptr_t>(freeFunction));
	nativeFreeFunction(nativePtr);
	}

	static jint nFcntlInt(JNIEnv* env, jclass, jint fd, jint cmd, jint arg) {
	return throwIfMinusOne(env, "fcntl", TEMP_FAILURE_RETRY(fcntl(fd, cmd, arg)));
	}

	static jlong nLseek(JNIEnv* env, jclass, jint fd, jlong offset, jint whence) {
	return throwIfMinusOne(env, "lseek", TEMP_FAILURE_RETRY(lseek(fd, offset, whence)));
	}

	static jintArray nPipe2(JNIEnv* env, jclass, jint flags) {
	int fds[2];
	throwIfMinusOne(env, "pipe2", TEMP_FAILURE_RETRY(pipe2(fds, flags)));

	jintArray result;
	result = env->NewIntArray(2);
	if (result == NULL) {
	return NULL; /* out of memory error thrown */
	}
	env->SetIntArrayRegion(result, 0, 2, fds);
	return result;
	}

	static jlong nDup(JNIEnv* env, jclass, jint fd) {
	return throwIfMinusOne(env, "fcntl", TEMP_FAILURE_RETRY(fcntl(fd, F_DUPFD_CLOEXEC, 0)));
	}

	static jobject nFstat(JNIEnv* env, jobject, jint fd) {
	struct stat64 sb;
	int rc = TEMP_FAILURE_RETRY(fstat64(fd, &sb));
	if (rc == -1) {
	throwErrnoException(env, "fstat");
	return NULL;
	}
	return makeStructStat(env, sb);
	}

	static jobject Linux_lstat(JNIEnv* env, jobject, jstring javaPath) {
	return doStat(env, javaPath, true);
	}

	static jobject Linux_stat(JNIEnv* env, jobject, jstring javaPath) {
	return doStat(env, javaPath, false);
	}

	static jint Linux_open(JNIEnv* env, jobject, jstring javaPath, jint flags, jint mode) {
	ScopedRealUtf8Chars path(env, javaPath);
	if (path.c_str() == NULL) {
	return -1;
	}
	return throwIfMinusOne(env, "open", TEMP_FAILURE_RETRY(open(path.c_str(), flags, mode)));
	}

	// ---- Registration ----

	static const JNINativeMethod sMethods[] =
	{
	{ "applyFreeFunction", "(JJ)V", (void*)nApplyFreeFunction },
	{ "nFcntlInt", "(III)I", (void*)nFcntlInt },
	{ "nLseek", "(IJI)J", (void*)nLseek },
	{ "nPipe2", "(I)[I", (void*)nPipe2 },
	{ "nDup", "(I)I", (void*)nDup },
	{ "nFstat", "(I)Landroid/system/StructStat;", (void*)nFstat },
	{ "lstat", "(Ljava/lang/String;)Landroid/system/StructStat;", (void*)Linux_lstat },
	{ "stat", "(Ljava/lang/String;)Landroid/system/StructStat;", (void*)Linux_stat },
	{ "nOpen", "(Ljava/lang/String;II)I", (void*)Linux_open },
	};

	extern "C" jint JNI_OnLoad(JavaVM* vm, void* /* reserved */)
	{
	JNIEnv* env = NULL;
	jint result = -1;

	if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
	ALOGE("GetEnv failed!");
	return result;
	}
	ALOG_ASSERT(env, "Could not retrieve the env!");

	ALOGI("%s: JNI_OnLoad", __FILE__);

	g_StructStat = findClass(env, "android/system/StructStat");
	g_StructTimespecClass = findClass(env, "android/system/StructTimespec");

	jint res = jniRegisterNativeMethods(env, "com/android/ravenwood/common/RavenwoodRuntimeNative",
	sMethods, NELEM(sMethods));
	if (res < 0) {
	return res;
	}

	register_android_system_OsConstants(env);

	return JNI_VERSION_1_4;
	}