M7350/base/core/jni/android_backup_BackupHelperDispatcher.cpp
2024-09-09 08:52:07 +00:00

260 lines
7.8 KiB
C++

/*
* Copyright (C) 2009 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.
*/
#define LOG_TAG "BackupHelperDispatcher_native"
#include <utils/Log.h>
#include "JNIHelp.h"
#include <android_runtime/AndroidRuntime.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#define VERSION_1_HEADER 0x01706c48 // 'Hlp'1 little endian
namespace android
{
struct chunk_header_v1 {
int headerSize;
int version;
int dataSize; // corresponds to Header.chunkSize
int nameLength; // not including the NULL terminator, which is not written to the file
};
// java.io.FileDescriptor
static jfieldID s_descriptorField = 0;
static jfieldID s_chunkSizeField = 0;
static jfieldID s_keyPrefixField = 0;
static int
readHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
{
chunk_header_v1 flattenedHeader;
int fd;
ssize_t amt;
String8 keyPrefix;
char* buf;
fd = env->GetIntField(fdObj, s_descriptorField);
amt = read(fd, &flattenedHeader.headerSize, sizeof(flattenedHeader.headerSize));
if (amt != sizeof(flattenedHeader.headerSize)) {
return -1;
}
int remainingHeader = flattenedHeader.headerSize - sizeof(flattenedHeader.headerSize);
if (flattenedHeader.headerSize < (int)sizeof(chunk_header_v1)) {
LOGW("Skipping unknown header: %d bytes", flattenedHeader.headerSize);
if (remainingHeader > 0) {
lseek(fd, remainingHeader, SEEK_CUR);
// >0 means skip this chunk
return 1;
}
}
amt = read(fd, &flattenedHeader.version,
sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize));
if (amt <= 0) {
LOGW("Failed reading chunk header");
return -1;
}
remainingHeader -= sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize);
if (flattenedHeader.version != VERSION_1_HEADER) {
LOGW("Skipping unknown header version: 0x%08x, %d bytes", flattenedHeader.version,
flattenedHeader.headerSize);
if (remainingHeader > 0) {
lseek(fd, remainingHeader, SEEK_CUR);
// >0 means skip this chunk
return 1;
}
}
#if 0
LOGD("chunk header:");
LOGD(" headerSize=%d", flattenedHeader.headerSize);
LOGD(" version=0x%08x", flattenedHeader.version);
LOGD(" dataSize=%d", flattenedHeader.dataSize);
LOGD(" nameLength=%d", flattenedHeader.nameLength);
#endif
if (flattenedHeader.dataSize < 0 || flattenedHeader.nameLength < 0 ||
remainingHeader < flattenedHeader.nameLength) {
LOGW("Malformed V1 header remainingHeader=%d dataSize=%d nameLength=%d", remainingHeader,
flattenedHeader.dataSize, flattenedHeader.nameLength);
return -1;
}
buf = keyPrefix.lockBuffer(flattenedHeader.nameLength);
if (buf == NULL) {
LOGW("unable to allocate %d bytes", flattenedHeader.nameLength);
return -1;
}
amt = read(fd, buf, flattenedHeader.nameLength);
buf[flattenedHeader.nameLength] = 0;
keyPrefix.unlockBuffer(flattenedHeader.nameLength);
remainingHeader -= flattenedHeader.nameLength;
if (remainingHeader > 0) {
lseek(fd, remainingHeader, SEEK_CUR);
}
env->SetIntField(headerObj, s_chunkSizeField, flattenedHeader.dataSize);
env->SetObjectField(headerObj, s_keyPrefixField, env->NewStringUTF(keyPrefix.string()));
return 0;
}
static int
skipChunk_native(JNIEnv* env, jobject clazz, jobject fdObj, jint bytesToSkip)
{
int fd;
fd = env->GetIntField(fdObj, s_descriptorField);
lseek(fd, bytesToSkip, SEEK_CUR);
return 0;
}
static int
padding_len(int len)
{
len = len % 4;
return len == 0 ? len : 4 - len;
}
static int
allocateHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
{
int pos;
jstring nameObj;
int nameLength;
int namePadding;
int headerSize;
int fd;
fd = env->GetIntField(fdObj, s_descriptorField);
nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
nameLength = env->GetStringUTFLength(nameObj);
namePadding = padding_len(nameLength);
headerSize = sizeof(chunk_header_v1) + nameLength + namePadding;
pos = lseek(fd, 0, SEEK_CUR);
lseek(fd, headerSize, SEEK_CUR);
return pos;
}
static int
writeHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj, jint pos)
{
int err;
chunk_header_v1 header;
int fd;
int namePadding;
int prevPos;
jstring nameObj;
const char* buf;
fd = env->GetIntField(fdObj, s_descriptorField);
prevPos = lseek(fd, 0, SEEK_CUR);
nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
header.nameLength = env->GetStringUTFLength(nameObj);
namePadding = padding_len(header.nameLength);
header.headerSize = sizeof(chunk_header_v1) + header.nameLength + namePadding;
header.version = VERSION_1_HEADER;
header.dataSize = prevPos - (pos + header.headerSize);
lseek(fd, pos, SEEK_SET);
err = write(fd, &header, sizeof(chunk_header_v1));
if (err != sizeof(chunk_header_v1)) {
return errno;
}
buf = env->GetStringUTFChars(nameObj, NULL);
err = write(fd, buf, header.nameLength);
env->ReleaseStringUTFChars(nameObj, buf);
if (err != header.nameLength) {
return errno;
}
if (namePadding != 0) {
int zero = 0;
err = write(fd, &zero, namePadding);
if (err != namePadding) {
return errno;
}
}
lseek(fd, prevPos, SEEK_SET);
return 0;
}
static const JNINativeMethod g_methods[] = {
{ "readHeader_native",
"(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
(void*)readHeader_native },
{ "skipChunk_native",
"(Ljava/io/FileDescriptor;I)I",
(void*)skipChunk_native },
{ "allocateHeader_native",
"(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
(void*)allocateHeader_native },
{ "writeHeader_native",
"(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;I)I",
(void*)writeHeader_native },
};
int register_android_backup_BackupHelperDispatcher(JNIEnv* env)
{
jclass clazz;
clazz = env->FindClass("java/io/FileDescriptor");
LOG_FATAL_IF(clazz == NULL, "Unable to find class java.io.FileDescriptor");
s_descriptorField = env->GetFieldID(clazz, "descriptor", "I");
LOG_FATAL_IF(s_descriptorField == NULL,
"Unable to find descriptor field in java.io.FileDescriptor");
clazz = env->FindClass("android/app/backup/BackupHelperDispatcher$Header");
LOG_FATAL_IF(clazz == NULL,
"Unable to find class android.app.backup.BackupHelperDispatcher.Header");
s_chunkSizeField = env->GetFieldID(clazz, "chunkSize", "I");
LOG_FATAL_IF(s_chunkSizeField == NULL,
"Unable to find chunkSize field in android.app.backup.BackupHelperDispatcher.Header");
s_keyPrefixField = env->GetFieldID(clazz, "keyPrefix", "Ljava/lang/String;");
LOG_FATAL_IF(s_keyPrefixField == NULL,
"Unable to find keyPrefix field in android.app.backup.BackupHelperDispatcher.Header");
return AndroidRuntime::registerNativeMethods(env, "android/app/backup/BackupHelperDispatcher",
g_methods, NELEM(g_methods));
}
}