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#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <stdlib.h>
#include <syslog.h>
volatile sig_atomic_t get_info = 0;
volatile sig_atomic_t signal_counter = 0;
void handler(int s)
{
signal(SIGUSR1, handler);
signal(SIGALRM, handler);
switch(s) {
case SIGUSR1:
get_info = 1;
++signal_counter;
break;
case SIGALRM:
get_info = 1;
alarm(300);
}
}
int main()
{
int fd, pid;
char *path = "/tmp/ordinary_daemon.log";
FILE *file;
time_t start, end;
double dif;
signal(SIGUSR1, handler);
signal(SIGALRM, handler);
close(0);
close(1);
close(2);
open("/dev/null", O_RDONLY);
open("/dev/null", O_WRONLY);
open("/dev/null", O_WRONLY);
chdir("/");
pid = fork();
if(pid > 0)
exit(0);
setsid();
pid = fork();
if(pid > 0)
exit(0);
fd = open(path, O_CREAT | O_WRONLY | O_TRUNC, 0666);
file = fdopen(fd, "w");
if(fd == -1) {
perror("can't open file");
exit(1);
}
openlog("ordinary daemon", 0, LOG_USER);
syslog(LOG_INFO, "daemon started");
alarm(300);
pid = getpid();
time(&start);
while(1) {
pause();
if(get_info) {
time(&end);
dif = difftime(end, start);
fprintf(file, "time spent (in sec): %.2f pid: %u SIGUSR1: %u\n",
dif, pid, signal_counter);
syslog(LOG_INFO, "time spent (in sec): %.2f pid: %u SIGUSR1: %u",
dif, pid, signal_counter);
fflush(file);
get_info = 0;
}
}
closelog();
close(fd);
return 0;
}
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