69 lines
2.0 KiB
C++
69 lines
2.0 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "file_magic.h"
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <android-base/logging.h>
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#include <android-base/stringprintf.h>
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#include "unix_file/fd_file.h"
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namespace art {
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using android::base::StringPrintf;
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File OpenAndReadMagic(const char* filename, uint32_t* magic, std::string* error_msg) {
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CHECK(magic != nullptr);
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File fd(filename, O_RDONLY, /* check_usage= */ false);
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if (fd.Fd() == -1) {
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*error_msg = StringPrintf("Unable to open '%s' : %s", filename, strerror(errno));
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return File();
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}
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if (!ReadMagicAndReset(fd.Fd(), magic, error_msg)) {
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StringPrintf("Error in reading magic from file %s: %s", filename, error_msg->c_str());
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return File();
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}
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return fd;
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}
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bool ReadMagicAndReset(int fd, uint32_t* magic, std::string* error_msg) {
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if (lseek(fd, 0, SEEK_SET) != 0) {
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*error_msg = StringPrintf("Failed to seek to beginning of file : %s", strerror(errno));
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return false;
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}
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int n = TEMP_FAILURE_RETRY(read(fd, magic, sizeof(*magic)));
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if (n != sizeof(*magic)) {
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*error_msg = StringPrintf("Failed to find magic");
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return false;
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}
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if (lseek(fd, 0, SEEK_SET) != 0) {
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*error_msg = StringPrintf("Failed to seek to beginning of file : %s", strerror(errno));
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return false;
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}
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return true;
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}
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bool IsZipMagic(uint32_t magic) {
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return (('P' == ((magic >> 0) & 0xff)) &&
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('K' == ((magic >> 8) & 0xff)));
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}
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} // namespace art
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