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

Quoted 8 lines · Subrata Modak

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,

Quoted 3 lines

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 ;)

- Davide

Quoted 11 lines · Davide Libenzi

Quoted 8 lines · Subrata Modak

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,

Quoted 5 lines

Quoted 3 lines

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 ;)

So, here it goes. The following patch integrates this to LTP.

Signed-off-by Subrata Modak <[email protected]>

Original-author-and-copyright-holder: Davide Libenzi <[email protected]>
To: Davide Libenzi <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Ulrich Drepper <[email protected]>
Cc: ltp-list <[email protected]>
---

runtest/syscalls +1 -0

@@ -126,6 +126,7 @@ eventfd01 eventfd01
 
 eventfd2_01 eventfd2_01
 eventfd2_02 eventfd2_02
+eventfd2_03 eventfd2_03
 
 execl01 execl01
 execle01 execle01

testcases/kernel/syscalls/eventfd2/eventfd2_03.c +135 -1

@@ -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 <[email protected]>
+ *  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

Quoted 4 lines

- Davide