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 <nativehelper/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
31 namespace android
32 {
33
34 struct 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
41 static jfieldID s_chunkSizeField = 0;
42 static jfieldID s_keyPrefixField = 0;
43
44 static jint
readHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj)45 readHeader_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
126 static jint
skipChunk_native(JNIEnv * env,jobject clazz,jobject fdObj,jint bytesToSkip)127 skipChunk_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
136 static int
padding_len(int len)137 padding_len(int len)
138 {
139 len = len % 4;
140 return len == 0 ? len : 4 - len;
141 }
142
143 static jint
allocateHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj)144 allocateHeader_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
168 static jint
writeHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj,jint pos)169 writeHeader_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
214 static 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$Header;Ljava/io/FileDescriptor;I)I",
226 (void*)writeHeader_native },
227 };
228
register_android_backup_BackupHelperDispatcher(JNIEnv * env)229 int register_android_backup_BackupHelperDispatcher(JNIEnv* env)
230 {
231 jclass clazz = FindClassOrDie(env, "android/app/backup/BackupHelperDispatcher$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