i2pd/DaemonLinux.cpp

#include "Daemon.h"

#ifndef _WIN32

#include <signal.h>
#include <stdlib.h>
#include <thread>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>

#include "Config.h"
#include "FS.h"
#include "Log.h"
#include "RouterContext.h"

void handle_signal(int sig)
{
	switch (sig)
	{
		case SIGHUP:
			LogPrint(eLogInfo, "Daemon: Got SIGHUP, reopening log...");
			i2p::log::Logger().Reopen ();
		break;
		case SIGINT:
			if (i2p::context.AcceptsTunnels () && !Daemon.gracefullShutdownInterval)
			{	
				i2p::context.SetAcceptsTunnels (false);
				Daemon.gracefullShutdownInterval = 10*60; // 10 minutes
				LogPrint(eLogInfo, "Graceful shutdown after ", Daemon.gracefullShutdownInterval, " seconds");
			}	
			else
				Daemon.running = 0; 
		break;	
		case SIGABRT:
		case SIGTERM:
			Daemon.running = 0; // Exit loop
		break;
	}
}

namespace i2p
{
	namespace util
	{
		bool DaemonLinux::start()
		{
			if (isDaemon)
			{
				pid_t pid;
				pid = fork();
				if (pid > 0) // parent
					::exit (EXIT_SUCCESS);

				if (pid < 0) // error
				{
					LogPrint(eLogError, "Daemon: could not fork: ", strerror(errno));
					return false;
				}

				// child
				umask(S_IWGRP | S_IRWXO); // 0027
				int sid = setsid();
				if (sid < 0)
				{
					LogPrint(eLogError, "Daemon: could not create process group.");
					return false;
				}
				std::string d = i2p::fs::GetDataDir();
				if (chdir(d.c_str()) != 0)
				{
					LogPrint(eLogError, "Daemon: could not chdir: ", strerror(errno));
					return false;
				}

				// point std{in,out,err} descriptors to /dev/null
#ifndef ANDROID
                stdin  = freopen("/dev/null", "r", stdin);
				stdout = freopen("/dev/null", "w", stdout);
				stderr = freopen("/dev/null", "w", stderr);
#endif
			}

			// Pidfile
			// this code is c-styled and a bit ugly, but we need fd for locking pidfile
			std::string pidfile; i2p::config::GetOption("pidfile", pidfile);
			if (pidfile == "") {
				pidfile = i2p::fs::DataDirPath("i2pd.pid");
			}
			if (pidfile != "") {
				pidFH = open(pidfile.c_str(), O_RDWR | O_CREAT, 0600);
				if (pidFH < 0)
				{
					LogPrint(eLogError, "Daemon: could not create pid file ", pidfile, ": ", strerror(errno));
					return false;
				}
#ifndef ANDROID
				if (lockf(pidFH, F_TLOCK, 0) != 0)
#else
                //TODO ANDROID actually need to read man for this, blindly took a solution from <https://forum.qt.io/topic/27872/qtjsondb-build-failed-for-android/2>. -anon5
                if (fcntl(pidFH, 1, 0) < 0)
#endif
				{
					LogPrint(eLogError, "Daemon: could not lock pid file ", pidfile, ": ", strerror(errno));
					return false;
				}
				char pid[10];
				sprintf(pid, "%d\n", getpid());
				ftruncate(pidFH, 0);
				if (write(pidFH, pid, strlen(pid)) < 0)
				{
					LogPrint(eLogError, "Daemon: could not write pidfile: ", strerror(errno));
					return false;
				}
			}
			gracefullShutdownInterval = 0; // not specified

			// Signal handler
			struct sigaction sa;
			sa.sa_handler = handle_signal;
			sigemptyset(&sa.sa_mask);
			sa.sa_flags = SA_RESTART;
			sigaction(SIGHUP, &sa, 0);
			sigaction(SIGABRT, &sa, 0);
			sigaction(SIGTERM, &sa, 0);
			sigaction(SIGINT, &sa, 0);

			return Daemon_Singleton::start();
		}

		bool DaemonLinux::stop()
		{
			i2p::fs::Remove(pidfile);

			return Daemon_Singleton::stop();			
		}

		void DaemonLinux::run ()
		{
			while (running)
			{
				std::this_thread::sleep_for (std::chrono::seconds(1));
				if (gracefullShutdownInterval)
				{
					gracefullShutdownInterval--; // - 1 second
					if (gracefullShutdownInterval <= 0) 
					{	
						LogPrint(eLogInfo, "Graceful shutdown");
						return;
					}
				}	
			}
		}
	}
}

#endif