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 "android-base/stringprintf.h" 24 25 #include "base/logging.h" 26 #include "base/unix_file/fd_file.h" 27 #include "dex_file.h" 28 29 namespace art { 30 31 using android::base::StringPrintf; 32 33 File OpenAndReadMagic(const char* filename, uint32_t* magic, std::string* error_msg) { 34 CHECK(magic != nullptr); 35 File fd(filename, O_RDONLY, /* check_usage */ false); 36 if (fd.Fd() == -1) { 37 *error_msg = StringPrintf("Unable to open '%s' : %s", filename, strerror(errno)); 38 return File(); 39 } 40 int n = TEMP_FAILURE_RETRY(read(fd.Fd(), magic, sizeof(*magic))); 41 if (n != sizeof(*magic)) { 42 *error_msg = StringPrintf("Failed to find magic in '%s'", filename); 43 return File(); 44 } 45 if (lseek(fd.Fd(), 0, SEEK_SET) != 0) { 46 *error_msg = StringPrintf("Failed to seek to beginning of file '%s' : %s", filename, 47 strerror(errno)); 48 return File(); 49 } 50 return fd; 51 } 52 53 bool IsZipMagic(uint32_t magic) { 54 return (('P' == ((magic >> 0) & 0xff)) && 55 ('K' == ((magic >> 8) & 0xff))); 56 } 57 58 bool IsDexMagic(uint32_t magic) { 59 return DexFile::IsMagicValid(reinterpret_cast<const uint8_t*>(&magic)); 60 } 61 62 } // namespace art 63
