118 lines
2.6 KiB
C++
118 lines
2.6 KiB
C++
/*
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* Copyright (C) Roland Jax 2014 <roland.jax@liwest.at>
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*
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* This file is part of ebus-daemon.
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*
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* ebus-daemon 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 3 of the License, or
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* (at your option) any later version.
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*
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* ebus-daemon 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
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* along with ebus-daemon. If not, see http://www.gnu.org/licenses/.
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*/
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#include "daemon.h"
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#include <iostream>
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#include <cstring>
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#include <cstdio>
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#include <cstdlib>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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Daemon& Daemon::Instance()
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{
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static Daemon instance;
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return instance;
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}
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void Daemon::run(const char* file)
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{
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m_status = false;
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m_pidfile = file;
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m_pidfd = 0;
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pid_t pid;
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// fork off the parent process
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pid = fork();
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if (pid < 0) {
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std::cerr << "ebusd fork() failed." << std::endl;
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exit(EXIT_FAILURE);
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}
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// If we got a good PID, then we can exit the parent process
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if (pid > 0) {
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// printf("Child process created: %d\n", pid);
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exit(EXIT_SUCCESS);
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}
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// At this point we are executing as the child process
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// Set file permissions 750
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umask(027);
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// Create a new SID for the child process and
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// detach the process from the parent (normally a shell)
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if (setsid() < 0) {
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std::cerr << "ebusd setsid() failed." << std::endl;
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exit(EXIT_FAILURE);
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}
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// Change the current working directory. This prevents the current
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// directory from being locked; hence not being able to remove it.
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if (chdir("/tmp") < 0) { //DAEMON_WORKDIR
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std::cerr << "ebusd chdir() failed." << std::endl;
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exit(EXIT_FAILURE);
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}
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// Close stdin, stdout and stderr
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close(STDIN_FILENO);
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close(STDOUT_FILENO);
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close(STDERR_FILENO);
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// write pidfile and try to lock it
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if (pidfile_open() == false) {
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std::cerr << "can't open pidfile: %s" << m_pidfile << std::endl;
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exit(EXIT_FAILURE);
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}
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m_status = true;
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}
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bool Daemon::pidfile_open()
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{
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char pid[10];
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m_pidfd = open(m_pidfile, O_RDWR|O_CREAT, 0600);
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if (m_pidfd < 0)
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return false;
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if (lockf(m_pidfd, F_TLOCK, 0) < 0)
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return false;
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sprintf(pid, "%d\n", getpid());
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if (write(m_pidfd, pid, strlen(pid)) < 0)
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return false;
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return true;
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}
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bool Daemon::pidfile_close()
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{
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if (close(m_pidfd) < 0)
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return false;
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if (remove(m_pidfile) < 0)
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return false;
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return true;
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}
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