98 lines
1.6 KiB
C++
98 lines
1.6 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#ifndef MPD_PID_FILE_HXX
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#define MPD_PID_FILE_HXX
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#include "lib/fmt/PathFormatter.hxx"
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#include "fs/FileSystem.hxx"
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#include "fs/AllocatedPath.hxx"
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#include "lib/fmt/SystemError.hxx"
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#include "lib/fmt/ToBuffer.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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throw FmtErrno("Failed to create pid file \"{}\"",
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path);
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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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const auto s = FmtBuffer<64>("{}\n", pid);
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write(fd, s.c_str(), strlen(s.c_str()));
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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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[[gnu::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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