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
27namespace art {
28
29ScopedFd 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
49bool IsZipMagic(uint32_t magic) {
50  return (('P' == ((magic >> 0) & 0xff)) &&
51          ('K' == ((magic >> 8) & 0xff)));
52}
53
54bool IsDexMagic(uint32_t magic) {
55  return DexFile::IsMagicValid(reinterpret_cast<const uint8_t*>(&magic));
56}
57
58}  // namespace art
59