1.1 --- a/tools/blktap/drivers/blktapctrl.c	Wed Dec 13 11:13:08 2006 +0000
     1.2 +++ b/tools/blktap/drivers/blktapctrl.c	Wed Dec 13 11:23:01 2006 +0000
     1.3 @@ -57,6 +57,8 @@
     1.4  #include "blktapctrl.h"
     1.5  #include "tapdisk.h"
     1.6  
     1.7 +#define PIDFILE "/var/run/blktapctrl.pid"
     1.8 +
     1.9  #define NUM_POLL_FDS 2
    1.10  #define MSG_SIZE 4096
    1.11  #define MAX_TIMEOUT 10
    1.12 @@ -622,6 +624,29 @@ static void print_drivers(void)
    1.13  		DPRINTF("Found driver: [%s]\n",dtypes[i]->name);
    1.14  } 
    1.15  
    1.16 +static void write_pidfile(long pid)
    1.17 +{
    1.18 +	char buf[100];
    1.19 +	int len;
    1.20 +	int fd;
    1.21 +
    1.22 +	fd = open(PIDFILE, O_RDWR | O_CREAT, 0600);
    1.23 +	if (fd == -1) {
    1.24 +		DPRINTF("Opening pid file failed (%d)\n", errno);
    1.25 +		exit(1);
    1.26 +	}
    1.27 +
    1.28 +	/* We exit silently if daemon already running. */
    1.29 +	if (lockf(fd, F_TLOCK, 0) == -1)
    1.30 +		exit(0);
    1.31 +
    1.32 +	len = sprintf(buf, "%ld\n", pid);
    1.33 +	if (write(fd, buf, len) != len) {
    1.34 +		DPRINTF("Writing pid file failed (%d)\n", errno);
    1.35 +		exit(1);
    1.36 +	}
    1.37 +}
    1.38 +
    1.39  int main(int argc, char *argv[])
    1.40  {
    1.41  	char *devname;
    1.42 @@ -681,6 +706,7 @@ int main(int argc, char *argv[])
    1.43  	ioctl(ctlfd, BLKTAP_IOCTL_SETMODE, BLKTAP_MODE_INTERPOSE );
    1.44  
    1.45  	process = getpid();
    1.46 +	write_pidfile(process);
    1.47  	ret = ioctl(ctlfd, BLKTAP_IOCTL_SENDPID, process );
    1.48  
    1.49  	/*Static pollhooks*/
    1.50 @@ -716,3 +742,13 @@ int main(int argc, char *argv[])
    1.51  	closelog();
    1.52  	return -1;
    1.53  }
    1.54 +
    1.55 +/*
    1.56 + * Local variables:
    1.57 + *  c-file-style: "linux"
    1.58 + *  indent-tabs-mode: t
    1.59 + *  c-indent-level: 8
    1.60 + *  c-basic-offset: 8
    1.61 + *  tab-width: 8
    1.62 + * End:
    1.63 + */