1 /*
2 * Copyright (C) 2007 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 //
18 // Misc zip/gzip utility functions.
19 //
20
21 #define LOG_TAG "ziputil"
22
23 #include "android-base/file.h"
24 #include <androidfw/ZipUtils.h>
25 #include <utils/Log.h>
26 #include <utils/Compat.h>
27 #include <ziparchive/zip_archive.h>
28
29 #include <stdlib.h>
30 #include <string.h>
31 #include <assert.h>
32
33 #include <zlib.h>
34
35 using namespace android;
36
37 // TODO: This can go away once the only remaining usage in aapt goes away.
38 class FileReader : public zip_archive::Reader {
39 public:
FileReader(FILE * fp)40 explicit FileReader(FILE* fp) : Reader(), mFp(fp), mCurrentOffset(0) {
41 }
42
ReadAtOffset(uint8_t * buf,size_t len,off64_t offset) const43 bool ReadAtOffset(uint8_t* buf, size_t len, off64_t offset) const {
44 // Data is usually requested sequentially, so this helps avoid pointless
45 // fseeks every time we perform a read. There's an impedence mismatch
46 // here because the original API was designed around pread and pwrite.
47 if (offset != mCurrentOffset) {
48 if (fseek(mFp, offset, SEEK_SET) != 0) {
49 return false;
50 }
51
52 mCurrentOffset = offset;
53 }
54
55 size_t read = fread(buf, 1, len, mFp);
56 if (read != len) {
57 return false;
58 }
59
60 mCurrentOffset += read;
61 return true;
62 }
63
64 private:
65 FILE* mFp;
66 mutable off64_t mCurrentOffset;
67 };
68
69 class FdReader : public zip_archive::Reader {
70 public:
FdReader(int fd)71 explicit FdReader(int fd) : mFd(fd) {
72 }
73
ReadAtOffset(uint8_t * buf,size_t len,off64_t offset) const74 bool ReadAtOffset(uint8_t* buf, size_t len, off64_t offset) const {
75 return android::base::ReadFullyAtOffset(mFd, buf, len, offset);
76 }
77
78 private:
79 const int mFd;
80 };
81
82 class BufferReader : public zip_archive::Reader {
83 public:
BufferReader(const void * input,size_t inputSize)84 BufferReader(const void* input, size_t inputSize) : Reader(),
85 mInput(reinterpret_cast<const uint8_t*>(input)),
86 mInputSize(inputSize) {
87 }
88
ReadAtOffset(uint8_t * buf,size_t len,off64_t offset) const89 bool ReadAtOffset(uint8_t* buf, size_t len, off64_t offset) const {
90 if (mInputSize < len || offset > mInputSize - len) {
91 return false;
92 }
93
94 memcpy(buf, mInput + offset, len);
95 return true;
96 }
97
98 private:
99 const uint8_t* mInput;
100 const size_t mInputSize;
101 };
102
103 class BufferWriter : public zip_archive::Writer {
104 public:
BufferWriter(void * output,size_t outputSize)105 BufferWriter(void* output, size_t outputSize) : Writer(),
106 mOutput(reinterpret_cast<uint8_t*>(output)), mOutputSize(outputSize), mBytesWritten(0) {
107 }
108
Append(uint8_t * buf,size_t bufSize)109 bool Append(uint8_t* buf, size_t bufSize) override {
110 if (mBytesWritten + bufSize > mOutputSize) {
111 return false;
112 }
113
114 memcpy(mOutput + mBytesWritten, buf, bufSize);
115 mBytesWritten += bufSize;
116 return true;
117 }
118
119 private:
120 uint8_t* const mOutput;
121 const size_t mOutputSize;
122 size_t mBytesWritten;
123 };
124
inflateToBuffer(FILE * fp,void * buf,long uncompressedLen,long compressedLen)125 /*static*/ bool ZipUtils::inflateToBuffer(FILE* fp, void* buf,
126 long uncompressedLen, long compressedLen)
127 {
128 FileReader reader(fp);
129 BufferWriter writer(buf, uncompressedLen);
130 return (zip_archive::Inflate(reader, compressedLen, uncompressedLen, &writer, nullptr) == 0);
131 }
132
inflateToBuffer(int fd,void * buf,long uncompressedLen,long compressedLen)133 /*static*/ bool ZipUtils::inflateToBuffer(int fd, void* buf,
134 long uncompressedLen, long compressedLen)
135 {
136 FdReader reader(fd);
137 BufferWriter writer(buf, uncompressedLen);
138 return (zip_archive::Inflate(reader, compressedLen, uncompressedLen, &writer, nullptr) == 0);
139 }
140
inflateToBuffer(const void * in,void * buf,long uncompressedLen,long compressedLen)141 /*static*/ bool ZipUtils::inflateToBuffer(const void* in, void* buf,
142 long uncompressedLen, long compressedLen)
143 {
144 BufferReader reader(in, compressedLen);
145 BufferWriter writer(buf, uncompressedLen);
146 return (zip_archive::Inflate(reader, compressedLen, uncompressedLen, &writer, nullptr) == 0);
147 }
148
get4LE(const unsigned char * buf)149 static inline unsigned long get4LE(const unsigned char* buf) {
150 return buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
151 }
152
153 /*
154 * Look at the contents of a gzip archive. We want to know where the
155 * data starts, and how long it will be after it is uncompressed.
156 *
157 * We expect to find the CRC and length as the last 8 bytes on the file.
158 * This is a pretty reasonable thing to expect for locally-compressed
159 * files, but there's a small chance that some extra padding got thrown
160 * on (the man page talks about compressed data written to tape). We
161 * don't currently deal with that here. If "gzip -l" whines, we're going
162 * to fail too.
163 *
164 * On exit, "fp" is pointing at the start of the compressed data.
165 */
examineGzip(FILE * fp,int * pCompressionMethod,long * pUncompressedLen,long * pCompressedLen,unsigned long * pCRC32)166 /*static*/ bool ZipUtils::examineGzip(FILE* fp, int* pCompressionMethod,
167 long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32)
168 {
169 enum { // flags
170 FTEXT = 0x01,
171 FHCRC = 0x02,
172 FEXTRA = 0x04,
173 FNAME = 0x08,
174 FCOMMENT = 0x10,
175 };
176 int ic;
177 int method, flags;
178 int i;
179
180 ic = getc(fp);
181 if (ic != 0x1f || getc(fp) != 0x8b)
182 return false; // not gzip
183 method = getc(fp);
184 flags = getc(fp);
185
186 /* quick sanity checks */
187 if (method == EOF || flags == EOF)
188 return false;
189 if (method != kCompressDeflated)
190 return false;
191
192 /* skip over 4 bytes of mod time, 1 byte XFL, 1 byte OS */
193 for (i = 0; i < 6; i++)
194 (void) getc(fp);
195 /* consume "extra" field, if present */
196 if ((flags & FEXTRA) != 0) {
197 int len;
198
199 len = getc(fp);
200 len |= getc(fp) << 8;
201 while (len-- && getc(fp) != EOF)
202 ;
203 }
204 /* consume filename, if present */
205 if ((flags & FNAME) != 0) {
206 do {
207 ic = getc(fp);
208 } while (ic != 0 && ic != EOF);
209 }
210 /* consume comment, if present */
211 if ((flags & FCOMMENT) != 0) {
212 do {
213 ic = getc(fp);
214 } while (ic != 0 && ic != EOF);
215 }
216 /* consume 16-bit header CRC, if present */
217 if ((flags & FHCRC) != 0) {
218 (void) getc(fp);
219 (void) getc(fp);
220 }
221
222 if (feof(fp) || ferror(fp))
223 return false;
224
225 /* seek to the end; CRC and length are in the last 8 bytes */
226 long curPosn = ftell(fp);
227 unsigned char buf[8];
228 fseek(fp, -8, SEEK_END);
229 *pCompressedLen = ftell(fp) - curPosn;
230
231 if (fread(buf, 1, 8, fp) != 8)
232 return false;
233 /* seek back to start of compressed data */
234 fseek(fp, curPosn, SEEK_SET);
235
236 *pCompressionMethod = method;
237 *pCRC32 = get4LE(&buf[0]);
238 *pUncompressedLen = get4LE(&buf[4]);
239
240 return true;
241 }
242