115 lines
2.3 KiB
C++
115 lines
2.3 KiB
C++
/*
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* Copyright 2003-2021 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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#ifndef MPD_PID_FILE_HXX
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#define MPD_PID_FILE_HXX
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#include "fs/FileSystem.hxx"
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#include "fs/AllocatedPath.hxx"
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#include "system/Error.hxx"
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#include <cassert>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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class PidFile {
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int fd;
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public:
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PidFile(const AllocatedPath &path):fd(-1) {
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if (path.IsNull())
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return;
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fd = OpenFile(path, O_WRONLY|O_CREAT|O_TRUNC, 0666).Steal();
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if (fd < 0) {
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const std::string utf8 = path.ToUTF8();
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throw FormatErrno("Failed to create pid file \"%s\"",
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utf8.c_str());
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}
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}
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PidFile(const PidFile &) = delete;
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void Close() noexcept {
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if (fd < 0)
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return;
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close(fd);
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}
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void Delete(const AllocatedPath &path) noexcept {
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if (fd < 0) {
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assert(path.IsNull());
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return;
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}
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assert(!path.IsNull());
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close(fd);
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unlink(path.c_str());
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}
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void Write(pid_t pid) noexcept {
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if (fd < 0)
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return;
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char buffer[64];
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sprintf(buffer, "%lu\n", (unsigned long)pid);
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write(fd, buffer, strlen(buffer));
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close(fd);
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}
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void Write() noexcept {
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if (fd < 0)
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return;
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Write(getpid());
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}
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};
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gcc_pure
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static inline pid_t
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ReadPidFile(Path path) noexcept
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{
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auto fd = OpenFile(path, O_RDONLY, 0);
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if (!fd.IsDefined())
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return -1;
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pid_t pid = -1;
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char buffer[32];
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auto nbytes = fd.Read(buffer, sizeof(buffer) - 1);
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if (nbytes > 0) {
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buffer[nbytes] = 0;
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char *endptr;
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auto value = strtoul(buffer, &endptr, 10);
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if (endptr > buffer)
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pid = value;
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}
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return pid;
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}
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#endif
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