1 /*
2 * Copyright (C) 2015 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 #include "file_magic.h"
18
19 #include <fcntl.h>
20 #include <sys/stat.h>
21 #include <sys/types.h>
22
23 #include "base/logging.h"
24 #include "dex_file.h"
25 #include "stringprintf.h"
26
27 namespace art {
28
OpenAndReadMagic(const char * filename,uint32_t * magic,std::string * error_msg)29 ScopedFd OpenAndReadMagic(const char* filename, uint32_t* magic, std::string* error_msg) {
30 CHECK(magic != nullptr);
31 ScopedFd fd(open(filename, O_RDONLY, 0));
32 if (fd.get() == -1) {
33 *error_msg = StringPrintf("Unable to open '%s' : %s", filename, strerror(errno));
34 return ScopedFd();
35 }
36 int n = TEMP_FAILURE_RETRY(read(fd.get(), magic, sizeof(*magic)));
37 if (n != sizeof(*magic)) {
38 *error_msg = StringPrintf("Failed to find magic in '%s'", filename);
39 return ScopedFd();
40 }
41 if (lseek(fd.get(), 0, SEEK_SET) != 0) {
42 *error_msg = StringPrintf("Failed to seek to beginning of file '%s' : %s", filename,
43 strerror(errno));
44 return ScopedFd();
45 }
46 return fd;
47 }
48
IsZipMagic(uint32_t magic)49 bool IsZipMagic(uint32_t magic) {
50 return (('P' == ((magic >> 0) & 0xff)) &&
51 ('K' == ((magic >> 8) & 0xff)));
52 }
53
IsDexMagic(uint32_t magic)54 bool IsDexMagic(uint32_t magic) {
55 return DexFile::IsMagicValid(reinterpret_cast<const uint8_t*>(&magic));
56 }
57
58 } // namespace art
59