Re: [LTP] [PATCH] Add eventfd2_03 test for eventfd2() syscall [Earlier Subject: (testing)improve support for semaphore-like behavior]

[Subrata Modak <subrata@linux.vnet.ibm.com>]

On Fri, 2009-06-12 at 18:51 +0530, Subrata Modak wrote: 
> >On Thu, 2009-06-11 at 19:50 -0700, Davide Libenzi wrote:
> >On Fri, 12 Jun 2009, Subrata Modak wrote:
> > 
> > > Hi Davide,
> > > 
> > > Your had introduced an improvement to support for semaphore-like
> > > behavior in eventfd for linux-2.6.30. And also have a small test program
> > > envisaged through:
> > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=bcd0b235bf3808dec5115c381cd55568f63b85f0,
> > > http://www.xmailserver.org/eventfd-sem.c,
> > > 
> > > Would you be willing to share this test program for inclusion in Linux
> > > Test Project (http://ltp.sourceforge.net/) under GPLv2 ? If affirmative,
> > > can you confirm by replying to this mail with your consent/Sign-off.
> > 
> > Sure, it's all yours ;)

Thanks David.

Regards--
Subrata

> 
> So, here it goes. The following patch integrates this to LTP.
> 
> Signed-off-by: Subrata Modak <subrata@linux.vnet.ibm.com> 
> Original-author-and-copyright-holder: Davide Libenzi <davidel@xmailserver.org>
> To: Davide Libenzi <davidel@xmailserver.org>
> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> Cc: Ulrich Drepper <drepper@redhat.com>
> Cc: ltp-list <ltp-list@lists.sf.net>
> ---
> 
> --- ltp-full-20090531.orig/runtest/syscalls	2009-06-12 17:03:15.000000000 +0530
> +++ ltp-full-20090531/runtest/syscalls	2009-06-12 18:13:49.000000000 +0530
> @@ -126,6 +126,7 @@ eventfd01 eventfd01
> 
>  eventfd2_01 eventfd2_01
>  eventfd2_02 eventfd2_02
> +eventfd2_03 eventfd2_03
> 
>  execl01 execl01
>  execle01 execle01
> --- ltp-full-20090531.orig/testcases/kernel/syscalls/eventfd2/eventfd2_03.c	1970-01-01 05:30:00.000000000 +0530
> +++ ltp-full-20090531/testcases/kernel/syscalls/eventfd2/eventfd2_03.c	2009-06-12 18:17:49.000000000 +0530
> @@ -0,0 +1,135 @@
> +/*
> + *  eventfd-sem by Davide Libenzi (Simple test for eventfd sempahore)
> + *  Copyright (C) 2009  Davide Libenzi
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, write to the Free Software
> + *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + *  Davide Libenzi <davidel@xmailserver.org>
> + *  Reference: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=bcd0b235bf3808dec5115c381cd55568f63b85f0
> + *  Reference: http://www.xmailserver.org/eventfd-sem.c
> + *  eventfd: testing improved support for semaphore-like behavior in linux-2.6.30
> + *
> + */
> +
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <errno.h>
> +
> +char *TCID = "eventfd2_02";     /* test program identifier*/
> +
> +#ifndef EFD_SEMLIKE
> +#define EFD_SEMLIKE (1 << 0)
> +#endif
> +
> +#ifndef __NR_eventfd2
> +#if defined(__x86_64__)
> +#define __NR_eventfd2 290
> +#elif defined(__i386__)
> +#define __NR_eventfd2 328
> +#else
> +#error Cannot detect your architecture!
> +#endif
> +#endif
> +
> +
> +static int eventfd2(int count, int flags) {
> +	return syscall(__NR_eventfd2, count, flags);
> +}
> +
> +static void xsem_wait(int fd) {
> +	u_int64_t cntr;
> +
> +	if (read(fd, &cntr, sizeof(cntr)) != sizeof(cntr)) {
> +		perror("reading eventfd");
> +		exit(1);
> +	}
> +	fprintf(stdout, "[%u] wait completed on %d: count=%llu\n",
> +		getpid(), fd, cntr);
> +}
> +
> +static void xsem_post(int fd, int count) {
> +	u_int64_t cntr = count;
> +
> +	if (write(fd, &cntr, sizeof(cntr)) != sizeof(cntr)) {
> +		perror("writing eventfd");
> +		exit(1);
> +	}
> +}
> +
> +static void sem_player(int fd1, int fd2) {
> +	fprintf(stdout, "[%u] posting 1 on %d\n", getpid(), fd1);
> +	xsem_post(fd1, 1);
> +
> +	fprintf(stdout, "[%u] waiting on %d\n", getpid(), fd2);
> +	xsem_wait(fd2);
> +
> +	fprintf(stdout, "[%u] posting 1 on %d\n", getpid(), fd1);
> +	xsem_post(fd1, 1);
> +
> +	fprintf(stdout, "[%u] waiting on %d\n", getpid(), fd2);
> +	xsem_wait(fd2);
> +
> +	fprintf(stdout, "[%u] posting 5 on %d\n", getpid(), fd1);
> +	xsem_post(fd1, 5);
> +
> +	fprintf(stdout, "[%u] waiting 5 times on %d\n", getpid(), fd2);
> +	xsem_wait(fd2);
> +	xsem_wait(fd2);
> +	xsem_wait(fd2);
> +	xsem_wait(fd2);
> +	xsem_wait(fd2);
> +}
> +
> +static void usage(char const *prg) {
> +	fprintf(stderr, "use: %s [-h]\n", prg);
> +}
> +
> +int main (int argc, char **argv) {
> +	int c, fd1, fd2, status;
> +	pid_t cpid_poster, cpid_waiter;
> +
> +	while ((c = getopt(argc, argv, "h")) != -1) {
> +		switch (c) {
> +		default:
> +			usage(argv[0]);
> +			return 1;
> +		}
> +	}
> +	if ((fd1 = eventfd2(0, EFD_SEMLIKE)) == -1 ||
> +	    (fd2 = eventfd2(0, EFD_SEMLIKE)) == -1) {
> +		perror("eventfd2");
> +		return 1;
> +	}
> +	if ((cpid_poster = fork()) == 0) {
> +		sem_player(fd1, fd2);
> +		exit(0);
> +	}
> +	if ((cpid_waiter = fork()) == 0) {
> +		sem_player(fd2, fd1);
> +		exit(0);
> +	}
> +	waitpid(cpid_poster, &status, 0);
> +	waitpid(cpid_waiter, &status, 0);
> +
> +	return 0;
> +}
> +
> +
> 
> ---
> Regards--
> Subrata
> 
> > 
> > - Davide
> > 
> > 


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