199 lines
4.1 KiB
C++
199 lines
4.1 KiB
C++
/*
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* Copyright (C) 2003-2015 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include "FileOutputStream.hxx"
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#include "fs/FileSystem.hxx"
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#include "util/Error.hxx"
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FileOutputStream *
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FileOutputStream::Create(Path path, Error &error)
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{
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FileOutputStream *f = new FileOutputStream(path, error);
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if (!f->IsDefined()) {
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delete f;
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f = nullptr;
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}
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return f;
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}
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#ifdef WIN32
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FileOutputStream::FileOutputStream(Path _path, Error &error)
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:path(_path),
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handle(CreateFile(path.c_str(), GENERIC_WRITE, 0, nullptr,
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TRUNCATE_EXISTING,
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FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH,
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nullptr))
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{
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if (handle == INVALID_HANDLE_VALUE)
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error.FormatLastError("Failed to create %s", path.c_str());
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}
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bool
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FileOutputStream::Write(const void *data, size_t size, Error &error)
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{
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assert(IsDefined());
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DWORD nbytes;
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if (!WriteFile(handle, data, size, &nbytes, nullptr)) {
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error.FormatLastError("Failed to write to %s", path.c_str());
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return false;
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}
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if (size_t(nbytes) != size) {
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error.FormatLastError(ERROR_DISK_FULL,
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"Failed to write to %s", path.c_str());
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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
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FileOutputStream::Commit(gcc_unused Error &error)
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{
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assert(IsDefined());
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CloseHandle(handle);
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return true;
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}
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void
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FileOutputStream::Cancel()
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{
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assert(IsDefined());
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CloseHandle(handle);
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RemoveFile(path);
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}
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#else
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#ifdef HAVE_LINKAT
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#ifndef O_TMPFILE
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/* supported since Linux 3.11 */
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#define __O_TMPFILE 020000000
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#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
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#include <stdio.h>
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#endif
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/**
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* Open a file using Linux's O_TMPFILE for writing the given file.
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*/
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static int
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OpenTempFile(Path path)
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{
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const auto directory = path.GetDirectoryName();
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if (directory.IsNull())
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return -1;
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return OpenFile(directory, O_TMPFILE|O_WRONLY, 0666);
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}
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#endif /* HAVE_LINKAT */
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FileOutputStream::FileOutputStream(Path _path, Error &error)
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:path(_path)
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{
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#ifdef HAVE_LINKAT
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/* try Linux's O_TMPFILE first */
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fd = OpenTempFile(path);
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is_tmpfile = fd >= 0;
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if (!is_tmpfile) {
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#endif
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/* fall back to plain POSIX */
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fd = OpenFile(path,
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O_WRONLY|O_CREAT|O_TRUNC,
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0666);
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if (fd < 0)
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error.FormatErrno("Failed to create %s", path.c_str());
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#ifdef HAVE_LINKAT
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}
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#endif
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}
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bool
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FileOutputStream::Write(const void *data, size_t size, Error &error)
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{
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assert(IsDefined());
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ssize_t nbytes = write(fd, data, size);
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if (nbytes < 0) {
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error.FormatErrno("Failed to write to %s", path.c_str());
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return false;
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} else if ((size_t)nbytes < size) {
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error.FormatErrno(ENOSPC,
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"Failed to write to %s", path.c_str());
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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
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FileOutputStream::Commit(Error &error)
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{
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assert(IsDefined());
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#if HAVE_LINKAT
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if (is_tmpfile) {
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RemoveFile(path);
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/* hard-link the temporary file to the final path */
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char fd_path[64];
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snprintf(fd_path, sizeof(fd_path), "/proc/self/fd/%d", fd);
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if (linkat(AT_FDCWD, fd_path, AT_FDCWD, path.c_str(),
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AT_SYMLINK_FOLLOW) < 0) {
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error.FormatErrno("Failed to commit %s", path.c_str());
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close(fd);
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return false;
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}
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}
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#endif
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bool success = close(fd) == 0;
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fd = -1;
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if (!success)
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error.FormatErrno("Failed to commit %s", path.c_str());
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return success;
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}
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void
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FileOutputStream::Cancel()
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{
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assert(IsDefined());
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close(fd);
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fd = -1;
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#ifdef HAVE_LINKAT
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if (!is_tmpfile)
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#endif
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RemoveFile(path);
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}
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#endif
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