2 * Copyright (C) 2009 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #define LOG_TAG "backup_data"
23 #include <androidfw/BackupHelpers.h>
25 #include <utils/ByteOrder.h>
29 static const bool kIsDebug = false;
34 * All ints are stored little-endian.
36 * - An app_header_v1 struct.
37 * - The name of the package, utf-8, null terminated, padded to 4-byte boundary.
38 * - A sequence of zero or more key/value paires (entities), each with
39 * - A entity_header_v1 struct
40 * - The key, utf-8, null terminated, padded to 4-byte boundary.
41 * - The value, padded to 4 byte boundary
44 const static int ROUND_UP[4] = { 0, 3, 2, 1 };
47 padding_extra(size_t n)
49 return ROUND_UP[n % 4];
52 BackupDataWriter::BackupDataWriter(int fd)
57 m_pos = (ssize_t) lseek(fd, 0, SEEK_CUR);
58 if (kIsDebug) ALOGI("BackupDataWriter(%d) @ %ld", fd, (long)m_pos);
61 BackupDataWriter::~BackupDataWriter()
65 // Pad out anything they've previously written to the next 4 byte boundary.
67 BackupDataWriter::write_padding_for(int n)
72 paddingSize = padding_extra(n);
73 if (paddingSize > 0) {
74 uint32_t padding = 0xbcbcbcbc;
75 if (kIsDebug) ALOGI("writing %zd padding bytes for %d", paddingSize, n);
76 amt = write(m_fd, &padding, paddingSize);
77 if (amt != paddingSize) {
87 BackupDataWriter::WriteEntityHeader(const String8& key, size_t dataSize)
89 if (m_status != NO_ERROR) {
95 amt = write_padding_for(m_pos);
101 if (m_keyPrefix.length() > 0) {
109 ALOGD("Writing header: prefix='%s' key='%s' dataSize=%zu", m_keyPrefix.string(),
110 key.string(), dataSize);
113 entity_header_v1 header;
118 header.type = tolel(BACKUP_HEADER_ENTITY_V1);
119 header.keyLen = tolel(keyLen);
120 header.dataSize = tolel(dataSize);
122 if (kIsDebug) ALOGI("writing entity header, %zu bytes", sizeof(entity_header_v1));
123 amt = write(m_fd, &header, sizeof(entity_header_v1));
124 if (amt != sizeof(entity_header_v1)) {
130 if (kIsDebug) ALOGI("writing entity header key, %zd bytes", keyLen+1);
131 amt = write(m_fd, k.string(), keyLen+1);
132 if (amt != keyLen+1) {
138 amt = write_padding_for(keyLen+1);
146 BackupDataWriter::WriteEntityData(const void* data, size_t size)
148 if (kIsDebug) ALOGD("Writing data: size=%lu", (unsigned long) size);
150 if (m_status != NO_ERROR) {
152 ALOGD("Not writing data - stream in error state %d (%s)", m_status, strerror(m_status));
157 // We don't write padding here, because they're allowed to call this several
158 // times with smaller buffers. We write it at the end of WriteEntityHeader
160 ssize_t amt = write(m_fd, data, size);
161 if (amt != (ssize_t)size) {
163 if (kIsDebug) ALOGD("write returned error %d (%s)", m_status, strerror(m_status));
171 BackupDataWriter::SetKeyPrefix(const String8& keyPrefix)
173 m_keyPrefix = keyPrefix;
177 BackupDataReader::BackupDataReader(int fd)
183 memset(&m_header, 0, sizeof(m_header));
184 m_pos = (ssize_t) lseek(fd, 0, SEEK_CUR);
185 if (kIsDebug) ALOGI("BackupDataReader(%d) @ %ld", fd, (long)m_pos);
188 BackupDataReader::~BackupDataReader()
193 BackupDataReader::Status()
198 #define CHECK_SIZE(actual, expected) \
200 if ((actual) != (expected)) { \
201 if ((actual) == 0) { \
206 ALOGD("CHECK_SIZE(a=%ld e=%ld) failed at line %d m_status='%s'", \
207 long(actual), long(expected), __LINE__, strerror(m_status)); \
212 #define SKIP_PADDING() \
214 status_t err = skip_padding(); \
215 if (err != NO_ERROR) { \
216 ALOGD("SKIP_PADDING FAILED at line %d", __LINE__); \
223 BackupDataReader::ReadNextHeader(bool* done, int* type)
226 if (m_status != NO_ERROR) {
232 amt = skip_padding();
234 *done = m_done = true;
237 else if (amt != NO_ERROR) {
240 amt = read(m_fd, &m_header, sizeof(m_header));
241 *done = m_done = (amt == 0);
245 CHECK_SIZE(amt, sizeof(m_header));
246 m_pos += sizeof(m_header);
248 *type = m_header.type;
251 // validate and fix up the fields.
252 m_header.type = fromlel(m_header.type);
253 switch (m_header.type)
255 case BACKUP_HEADER_ENTITY_V1:
257 m_header.entity.keyLen = fromlel(m_header.entity.keyLen);
258 if (m_header.entity.keyLen <= 0) {
259 ALOGD("Entity header at %d has keyLen<=0: 0x%08x\n", (int)m_pos,
260 (int)m_header.entity.keyLen);
263 m_header.entity.dataSize = fromlel(m_header.entity.dataSize);
266 // read the rest of the header (filename)
267 size_t size = m_header.entity.keyLen;
268 char* buf = m_key.lockBuffer(size);
273 int amt = read(m_fd, buf, size+1);
274 CHECK_SIZE(amt, (int)size+1);
275 m_key.unlockBuffer(size);
278 m_dataEndPos = m_pos + m_header.entity.dataSize;
283 ALOGD("Chunk header at %d has invalid type: 0x%08x",
284 (int)(m_pos - sizeof(m_header)), (int)m_header.type);
292 BackupDataReader::HasEntities()
294 return m_status == NO_ERROR && m_header.type == BACKUP_HEADER_ENTITY_V1;
298 BackupDataReader::ReadEntityHeader(String8* key, size_t* dataSize)
300 if (m_status != NO_ERROR) {
303 if (m_header.type != BACKUP_HEADER_ENTITY_V1) {
307 *dataSize = m_header.entity.dataSize;
312 BackupDataReader::SkipEntityData()
314 if (m_status != NO_ERROR) {
317 if (m_header.type != BACKUP_HEADER_ENTITY_V1) {
320 if (m_header.entity.dataSize > 0) {
321 int pos = lseek(m_fd, m_dataEndPos, SEEK_SET);
332 BackupDataReader::ReadEntityData(void* data, size_t size)
334 if (m_status != NO_ERROR) {
337 int remaining = m_dataEndPos - m_pos;
339 ALOGD("ReadEntityData size=%zu m_pos=0x%zx m_dataEndPos=0x%zx remaining=%d\n",
340 size, m_pos, m_dataEndPos, remaining);
342 if (remaining <= 0) {
345 if (((int)size) > remaining) {
349 ALOGD(" reading %zu bytes", size);
351 int amt = read(m_fd, data, size);
365 BackupDataReader::skip_padding()
370 paddingSize = padding_extra(m_pos);
371 if (paddingSize > 0) {
373 amt = read(m_fd, &padding, paddingSize);
374 CHECK_SIZE(amt, paddingSize);
381 } // namespace android