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128 lines
2.6 KiB
128 lines
2.6 KiB
// Copyright 2015 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "bsdiff/file.h"
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#include <errno.h>
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#include <fcntl.h>
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#ifdef __linux__
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#include <linux/fs.h>
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#endif // __linux__
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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// TEMP_FAILURE_RETRY is defined by some versions of <unistd.h>.
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#ifndef TEMP_FAILURE_RETRY
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#include <utils/Compat.h>
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#endif
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#include <algorithm>
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namespace bsdiff {
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std::unique_ptr<File> File::FOpen(const char* pathname, int flags) {
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int fd = TEMP_FAILURE_RETRY(open(pathname, flags, 0644));
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if (fd < 0)
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return std::unique_ptr<File>();
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return std::unique_ptr<File>(new File(fd));
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}
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File::~File() {
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Close();
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}
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bool File::Read(void* buf, size_t count, size_t* bytes_read) {
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if (fd_ < 0) {
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errno = EBADF;
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return false;
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}
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ssize_t rc = TEMP_FAILURE_RETRY(read(fd_, buf, count));
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if (rc == -1)
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return false;
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*bytes_read = static_cast<size_t>(rc);
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return true;
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}
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bool File::Write(const void* buf, size_t count, size_t* bytes_written) {
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if (fd_ < 0) {
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errno = EBADF;
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return false;
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}
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ssize_t rc = TEMP_FAILURE_RETRY(write(fd_, buf, count));
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if (rc == -1)
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return false;
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*bytes_written = static_cast<size_t>(rc);
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return true;
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}
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bool File::Seek(off_t pos) {
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if (fd_ < 0) {
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errno = EBADF;
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return false;
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}
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off_t newpos = lseek(fd_, pos, SEEK_SET);
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if (newpos < 0)
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return false;
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if (newpos != pos) {
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errno = EINVAL;
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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 File::Close() {
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if (fd_ < 0) {
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errno = EBADF;
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return false;
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}
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bool success = close(fd_) == 0;
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if (!success && errno == EINTR)
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success = true;
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fd_ = -1;
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return success;
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}
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bool File::GetSize(uint64_t* size) {
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struct stat stbuf;
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if (fstat(fd_, &stbuf) == -1)
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return false;
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if (S_ISREG(stbuf.st_mode)) {
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*size = stbuf.st_size;
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return true;
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}
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if (S_ISBLK(stbuf.st_mode)) {
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#if defined(BLKGETSIZE64)
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return ioctl(fd_, BLKGETSIZE64, size);
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#elif defined(DKIOCGETBLOCKCOUNT)
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uint64_t sectors = 0;
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if (ioctl(fd_, DKIOCGETBLOCKCOUNT, §ors) == 0) {
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*size = sectors << 9;
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return true;
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}
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return false;
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#else
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// Fall back to doing seeks to know the EOF.
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off_t pos = lseek(fd_, 0, SEEK_CUR);
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if (pos == -1)
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return false;
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off_t end_pos = lseek(fd_, 0, SEEK_END);
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if (end_pos == -1)
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return false;
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*size = end_pos;
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lseek(fd_, 0, SEEK_END);
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return true;
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#endif
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}
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return false;
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}
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File::File(int fd)
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: fd_(fd) {}
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} // namespace bsdiff
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