1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
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
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
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.
15 */
16
17#define LOG_TAG "BackupHelperDispatcher_native"
18#include <utils/Log.h>
19
20#include "JNIHelp.h"
21#include <android_runtime/AndroidRuntime.h>
22
23#include <sys/types.h>
24#include <sys/uio.h>
25#include <unistd.h>
26
27#include "core_jni_helpers.h"
28
29#define VERSION_1_HEADER 0x01706c48  // 'Hlp'1 little endian
30
31namespace android
32{
33
34struct chunk_header_v1 {
35    int headerSize;
36    int version;
37    int dataSize; // corresponds to Header.chunkSize
38    int nameLength; // not including the NULL terminator, which is not written to the file
39};
40
41static jfieldID s_chunkSizeField = 0;
42static jfieldID s_keyPrefixField = 0;
43
44static jint
45readHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
46{
47    chunk_header_v1 flattenedHeader;
48    ssize_t amt;
49    String8 keyPrefix;
50    char* buf;
51
52    int fd = jniGetFDFromFileDescriptor(env, fdObj);
53
54    amt = read(fd, &flattenedHeader.headerSize, sizeof(flattenedHeader.headerSize));
55    if (amt != sizeof(flattenedHeader.headerSize)) {
56        return (jint) -1;
57    }
58
59    int remainingHeader = flattenedHeader.headerSize - sizeof(flattenedHeader.headerSize);
60
61    if (flattenedHeader.headerSize < (int)sizeof(chunk_header_v1)) {
62        ALOGW("Skipping unknown header: %d bytes", flattenedHeader.headerSize);
63        if (remainingHeader > 0) {
64            lseek(fd, remainingHeader, SEEK_CUR);
65            // >0 means skip this chunk
66            return (jint) 1;
67        }
68    }
69
70    amt = read(fd, &flattenedHeader.version,
71            sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize));
72    if (amt <= 0) {
73        ALOGW("Failed reading chunk header");
74        return (jint) -1;
75    }
76    remainingHeader -= sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize);
77
78    if (flattenedHeader.version != VERSION_1_HEADER) {
79        ALOGW("Skipping unknown header version: 0x%08x, %d bytes", flattenedHeader.version,
80                flattenedHeader.headerSize);
81        if (remainingHeader > 0) {
82            lseek(fd, remainingHeader, SEEK_CUR);
83            // >0 means skip this chunk
84            return (jint) 1;
85        }
86    }
87
88#if 0
89    ALOGD("chunk header:");
90    ALOGD("  headerSize=%d", flattenedHeader.headerSize);
91    ALOGD("  version=0x%08x", flattenedHeader.version);
92    ALOGD("  dataSize=%d", flattenedHeader.dataSize);
93    ALOGD("  nameLength=%d", flattenedHeader.nameLength);
94#endif
95
96    if (flattenedHeader.dataSize < 0 || flattenedHeader.nameLength < 0 ||
97            remainingHeader < flattenedHeader.nameLength) {
98        ALOGW("Malformed V1 header remainingHeader=%d dataSize=%d nameLength=%d", remainingHeader,
99                flattenedHeader.dataSize, flattenedHeader.nameLength);
100        return (jint) -1;
101    }
102
103    buf = keyPrefix.lockBuffer(flattenedHeader.nameLength);
104    if (buf == NULL) {
105        ALOGW("unable to allocate %d bytes", flattenedHeader.nameLength);
106        return (jint) -1;
107    }
108
109    amt = read(fd, buf, flattenedHeader.nameLength);
110    buf[flattenedHeader.nameLength] = 0;
111
112    keyPrefix.unlockBuffer(flattenedHeader.nameLength);
113
114    remainingHeader -= flattenedHeader.nameLength;
115
116    if (remainingHeader > 0) {
117        lseek(fd, remainingHeader, SEEK_CUR);
118    }
119
120    env->SetIntField(headerObj, s_chunkSizeField, flattenedHeader.dataSize);
121    env->SetObjectField(headerObj, s_keyPrefixField, env->NewStringUTF(keyPrefix.string()));
122
123    return (jint) 0;
124}
125
126static jint
127skipChunk_native(JNIEnv* env, jobject clazz, jobject fdObj, jint bytesToSkip)
128{
129    int fd = jniGetFDFromFileDescriptor(env, fdObj);
130
131    lseek(fd, bytesToSkip, SEEK_CUR);
132
133    return (jint) 0;
134}
135
136static int
137padding_len(int len)
138{
139    len = len % 4;
140    return len == 0 ? len : 4 - len;
141}
142
143static jint
144allocateHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
145{
146    int pos;
147    jstring nameObj;
148    int nameLength;
149    int namePadding;
150    int headerSize;
151
152    int fd = jniGetFDFromFileDescriptor(env, fdObj);
153
154    nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
155
156    nameLength = env->GetStringUTFLength(nameObj);
157    namePadding = padding_len(nameLength);
158
159    headerSize = sizeof(chunk_header_v1) + nameLength + namePadding;
160
161    pos = lseek(fd, 0, SEEK_CUR);
162
163    lseek(fd, headerSize, SEEK_CUR);
164
165    return (jint) pos;
166}
167
168static jint
169writeHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj, jint pos)
170{
171    int err;
172    chunk_header_v1 header;
173    int namePadding;
174    int prevPos;
175    jstring nameObj;
176    const char* buf;
177
178    int fd = jniGetFDFromFileDescriptor(env, fdObj);
179    prevPos = lseek(fd, 0, SEEK_CUR);
180
181    nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
182    header.nameLength = env->GetStringUTFLength(nameObj);
183    namePadding = padding_len(header.nameLength);
184
185    header.headerSize = sizeof(chunk_header_v1) + header.nameLength + namePadding;
186    header.version = VERSION_1_HEADER;
187    header.dataSize = prevPos - (pos + header.headerSize);
188
189    lseek(fd, pos, SEEK_SET);
190    err = write(fd, &header, sizeof(chunk_header_v1));
191    if (err != sizeof(chunk_header_v1)) {
192        return (jint) errno;
193    }
194
195    buf = env->GetStringUTFChars(nameObj, NULL);
196    err = write(fd, buf, header.nameLength);
197    env->ReleaseStringUTFChars(nameObj, buf);
198    if (err != header.nameLength) {
199        return (jint) errno;
200    }
201
202    if (namePadding != 0) {
203        int zero = 0;
204        err = write(fd, &zero, namePadding);
205        if (err != namePadding) {
206            return (jint) errno;
207        }
208    }
209
210    lseek(fd, prevPos, SEEK_SET);
211    return (jint) 0;
212}
213
214static const JNINativeMethod g_methods[] = {
215    { "readHeader_native",
216       "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
217       (void*)readHeader_native },
218    { "skipChunk_native",
219        "(Ljava/io/FileDescriptor;I)I",
220        (void*)skipChunk_native },
221    { "allocateHeader_native",
222        "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
223        (void*)allocateHeader_native },
224    { "writeHeader_native",
225       "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;I)I",
226       (void*)writeHeader_native },
227};
228
229int register_android_backup_BackupHelperDispatcher(JNIEnv* env)
230{
231    jclass clazz = FindClassOrDie(env, "android/app/backup/BackupHelperDispatcher$Header");
232    s_chunkSizeField = GetFieldIDOrDie(env, clazz, "chunkSize", "I");
233    s_keyPrefixField = GetFieldIDOrDie(env, clazz, "keyPrefix", "Ljava/lang/String;");
234
235    return RegisterMethodsOrDie(env, "android/app/backup/BackupHelperDispatcher", g_methods,
236                                NELEM(g_methods));
237}
238
239}
240