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

[Vitezslav Samel]

  See comments in the code.

	Vita

On Mon, Sep 03, 2012 at 02:06:13PM +0200, Nikola Pajkovsky wrote:
>  Signed-off-by: Nikola Pajkovsky <npajkovs(a)redhat.com&gt;
>  ---
>   src/iptraf.c | 43 ++++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 40 insertions(+), 3 deletions(-)
>  
>  diff --git a/src/iptraf.c b/src/iptraf.c
>  index 15789a9..9fe7138 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
>  + 
  Could you, please, make it configurable from the command line?

>   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 lock file "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; 
   ^^^^^^^^
  change this to tabs!

>  +}
>  +
>   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();
>    
  The next part should go somewhere to the line 371 after this one:

	if (help_opt)
		parse_usage_and_die(iptraf_ng_usage, iptraf_ng_options);

>  +
>  +	if (create_pidfile() < 0)
>  +		goto cleanup; 
    This is before ncurses initialization. Should only remove pidfile.

>  +
>  +	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;
>   		}
>   	}
>   
>  @@ -496,10 +530,13 @@ int main(int argc, char **argv)
>   	else
>   		program_interface();
>    
 This cleanup should go after ncurses finalization.

>  +cleanup:
>  +	if (pidfile_created)
>  +		unlink(IPTRAF_PIDFILE);
>   	erase();
>   	update_panels();
>   	doupdate();
>   	endwin(); 
  Here.

>   
>  -	return (0);
>  +	return 0;
>   }
>  -- 
>  1.7.11.5