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