Re: [PATCH v2 3/3] locking: only one instance of iptraf can be run

[Nikola Pajkovsky]

Vitezslav Samel <vitezslav(a)samel.cz&gt; writes:

>  On Tue, Sep 04, 2012 at 04:22:23PM +0200, Nikola Pajkovsky wrote:
> > Signed-off-by: Nikola Pajkovsky <npajkovs(a)redhat.com&gt;
> > ---
> >  src/iptraf.c | 44 +++++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 41 insertions(+), 3 deletions(-)
>
>    Seems like changing location of PID file from the command line
>  will be added later? 
it won't be added at all. Tell me, why it is useful to run iptraf-ng
--pid /tmp/x and iptraf-ng /tmp/xx? Seems to me like nice tool to knock
down system.

while (1)
   iptraf-ng --pid /dev/random


> > diff --git a/src/iptraf.c b/src/iptraf.c
> > index 15789a9..5bb0a00 100644
> > --- a/src/iptraf.c
> > +++ b/src/iptraf.c
> > @@ -34,6 +34,10 @@ An IP Network Statistics Utility
> >  #define WITHALL 1
> >  #define WITHOUTALL 0
> >  
> > +#ifndef IPTRAF_PIDFILE
> > +#define IPTRAF_PIDFILE "/var/run/iptraf-ng.pid"
> > +#endif
> > +
> >  const char *ALLSPEC = "all";
> >  
> >  #define CMD(name, h) { .cmd = #name, .fn = cmd_##name, .help = h }
> > @@ -283,6 +287,29 @@ static struct options iptraf_ng_options[] = {
> >  	OPT_END()
> >  };
> >  
> > +static int create_pidfile(void)
> > +{
> > +	int fd = open(IPTRAF_PIDFILE, O_WRONLY|O_CREAT, 0644);
> > +	if (fd < 0) {
> > +		perror("can not open "IPTRAF_PIDFILE);
> > +		return -1;
> > +	}
> > +
> > +	if (lockf(fd, F_TLOCK, 0) < 0) {
> > +		perror("can not acquire "IPTRAF_PIDFILE);
> > +		return -1;
> > +	}
> > +
> > +	fcntl(fd, F_SETFD, FD_CLOEXEC);
> > +
> > +	char buf[sizeof(long) * 3 + 2];
> > +	int len = sprintf(buf, "%lu\n", (long) getpid());
> > +	write(fd, buf, len);
> > +	ftruncate(fd, len);
> > +	/* we leak opened+locked fd intentionally */
> > +	return 0;
> > +}
> > +
> >  static void sanitize_dir(const char *dir)
> >  {
> >  	/* Check whether LOCKDIR exists (/var/run is on a tmpfs in Ubuntu) */
> > @@ -397,6 +424,12 @@ int main(int argc, char **argv)
> >  
> >  	loadoptions();
> >  
> > +
> > +	if (create_pidfile() < 0)
> > +		goto cleanup;
> > +
> > +	int pidfile_created = 1;
> > +
> >  	/*
> >  	 * If a facility is directly invoked from the command line, check for
> >  	 * a daemonization request
> > @@ -414,9 +447,10 @@ int main(int argc, char **argv)
> >  			options.logging = 1;
> >  			break;
> >  		case -1:	/* error */
> > -			die("Fork error, %s cannot run in background", IPTRAF_NAME);
> > +			error("Fork error, %s cannot run in background", IPTRAF_NAME);
> > +			goto cleanup;
> >  		default:	/* parent */
> > -			exit(0);
> > +			goto cleanup;
> >  		}
> >  	}
> >  
> > @@ -501,5 +535,9 @@ int main(int argc, char **argv)
> >  	doupdate();
> >  	endwin();
> >  
> > -	return (0);
> > +cleanup:
> > +	if (pidfile_created)
> > +		unlink(IPTRAF_PIDFILE);
> > +
> > +	return 0;
> >  }
> > -- 
> > 1.7.11.5 
-- 
Nikola