[linux-cifs-client] Re: REAL fun ;-))

[Jeremy Allison]

On Sat, Jul 15, 2006 at 11:11:47PM -0700, Jeremy Allison wrote:
> On Sun, Jul 16, 2006 at 08:08:07AM +0200, Volker Lendecke wrote:
> > 
> > Sure -- but it's still fun to watch that we still do not
> > properly check all malloc results.
> 
> Don't we always check for failure - then fail
> the logic later ?
> 
> Right now having fun with cifsfs. It doesn't
> understand the difference between fast and
> slow system calls - this is a killer for
> this particular test case (run on a local
> system to see what happens then run on
> a cifsfs mounted file :-).

After my latest checkin (rev 64)
the attached code now runs correctly on
a POSIX locking CIFS mounted share !!

w00t ! :-).

Jeremy.
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#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <string.h>

int fd1;

void alarm_handler(int sig)
{
	write(1,"in handler\n", 11);
	alarm(2);
//	close(fd1);
}

int main(int argc, const char **argv)
{
	struct flock fl;
	pid_t pid;
	struct sigaction sa;

	if ((fd1 = open(argv[1], O_RDWR, 0660)) == -1) {
		fprintf(stderr, "open failed %s\n",
			strerror(errno) );
		return 1;
	}

	fl.l_type = F_WRLCK;
	fl.l_whence = SEEK_SET;
	fl.l_start = 0;
	fl.l_len = 10;

	if (fcntl(fd1, F_SETLK, &fl)==-1) {
		fprintf(stderr, "setlk failed %s\n",
			strerror(errno) );
		return 1;
	}

	pid = fork();
	if (pid == -1) {
		fprintf(stderr, "fork failed %s\n",
			strerror(errno) );
		return 1;
	}

	if (pid != 0) {
		/* Parent - wait for 10 seconds with the lock. */
		sleep(10);
		return 0;
	}

	printf("Child...\n");

	/* Child. */
	memset(&sa, '\0', sizeof(sa));
	sa.sa_handler = alarm_handler;
	sa.sa_flags = SA_RESTART;

	sigaction(SIGALRM, &sa, NULL);

	alarm(2);

	if (fcntl(fd1, F_SETLKW, &fl)==-1) {
		fprintf(stderr, "setlk failed %s\n",
			strerror(errno) );
		return 1;
	}

	printf("setlk succeeded ?\n");
}