uFTP/library/daemon.c

/*
 * The MIT License
 *
 * Copyright 2018 Ugo Cirmignani.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */


#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <syslog.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>

#include "fileManagement.h"

#define LOCKFILE "/var/run/uFTP.pid"
#define LOCKMODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)
#define MAXIMUM_IDLE_TIME			60

static int WatchDogTime = 0, WatchDogTimerTimeOut = MAXIMUM_IDLE_TIME;

int isProcessAlreadyRunning(void)
{
    int fd;
    int returnCode;
    char buf[101];
    memset(buf, 0,101);
    fd = open(LOCKFILE, O_RDWR|O_CREAT, LOCKMODE);
    if (fd < 0) 
    {
        syslog(LOG_ERR, "can’t open %s: %s", LOCKFILE, strerror(errno));
        exit(1);
    }
    //printf("\nFile pid opened.");
    
    if ((returnCode = FILE_LockFile(fd)) < 0) 
    {
        if (errno == EACCES || errno == EAGAIN) 
        {
        close(fd);
        return(1);
        }
        syslog(LOG_ERR, "can’t lock %s: %s", LOCKFILE, strerror(errno));
        exit(1);
    }
    
    //printf("\nFILE_LockFile returnCode = %d", returnCode);    
    ftruncate(fd, 0);
    returnCode = snprintf(buf, 100, "%ld", (long)getpid());
    returnCode = write(fd, buf, strlen(buf)+1);
    return 0;
}

void daemonize(const char *cmd)
	{
    int
    i, fd0, fd1, fd2;
    pid_t pid;
    struct rlimit rl;
    struct sigaction sa;
    
    /*
    * Clear file creation mask.
    */
    umask(0);
    
    /*
    * Get maximum number of file descriptors.
    */
    if (getrlimit(RLIMIT_NOFILE, &rl) < 0)
    printf("%s: can’t get file limit", cmd);
    
    /*
    * Become a session leader to lose controlling TTY.
    */
    if ((pid = fork()) < 0)
        printf("%s: can’t fork", cmd);
    else if (pid != 0) /* parent */
        exit(0);
    
    setsid();
    
    /*
    * Ensure future opens won’t allocate controlling TTYs.
    */
    sa.sa_handler = SIG_IGN;
    sigemptyset(&sa.sa_mask);
    
    sa.sa_flags = 0;
    if (sigaction(SIGHUP, &sa, NULL) < 0)
        printf("%s: can’t ignore SIGHUP", cmd);
    if ((pid = fork()) < 0)
        printf("%s: can’t fork", cmd);
    else if (pid != 0) /* parent */
    exit(0);
    /*
    * Change the current working directory to the root so
    * we won’t prevent file systems from being unmounted.
    */
    if (chdir("/") < 0)
        printf("%s: can’t change directory to /", cmd);
    /*
    * Close all open file descriptors.
    */
    if (rl.rlim_max == RLIM_INFINITY)
        rl.rlim_max = 1024;
    for (i = 0; i < rl.rlim_max; i++)
        close(i);
    /*
    * Attach file descriptors 0, 1, and 2 to /dev/null.
    */
    fd0 = open("/dev/null", O_RDWR);
    fd1 = dup(0);
    fd2 = dup(0);
    }

void respawnProcess(void)
	{
	  pid_t spawnedProcess;

	  //Respawn
	  while(1)
			{
			spawnedProcess = fork();

			if (spawnedProcess == 0)
				{
				//is child, exit from the loop
				printf("\nRespawn mode is active");
				break;
				}
			else
				{
				int returnStatus;
				waitpid(spawnedProcess, &returnStatus, 0);
				printf("\nwaitpid done with status: %d", returnStatus);

				if (WIFEXITED(returnStatus))
					{
					if (WEXITSTATUS(returnStatus) == 99)
						{
						printf("\nWIFEXITED verified the respawn is now disabled with return code %d.", WEXITSTATUS(returnStatus));
						exit(3);
						}
					}
				sleep(1);
				}
			}
		return;
	}

void *watchDog(void * arg)
{
	WatchDogTime = (int)time(NULL);

	while(1)
	{
		//Check if the time is expired
		if ((int)time(NULL) - WatchDogTime > WatchDogTimerTimeOut)
		{
			printf("\nWatchDog Time Expired");
			exit(98);
		}

		//printf("\nWatchDog Time ok %d, %d", (int)time(NULL), WatchDogTime);

		sleep(5);
	}
}

void setWatchDogTimeout(int theTime)
{
	WatchDogTimerTimeOut = theTime;
}

void updateWatchDogTime(int theTime)
{
	WatchDogTime = theTime;
}