Shared memory pthread sync primitive test

Signed-off-by: Keith Packard <keithp@keithp.com>

2 files changed, 108 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index e77f938..bdfb0cb 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CFLAGS=-Wall -O0 -g $(shell pkg-config --cflags xcb-shm xcb-aux xcb-dri3 xcb-present xshmfence)
-LIBS=$(shell pkg-config --libs xcb-shm xcb-aux xcb-dri3 xcb-present xshmfence)
+LIBS=$(shell pkg-config --libs xcb-shm xcb-aux xcb-dri3 xcb-present xshmfence xcb-sync xcb-xfixes)
 
-all: shmfd dri3 futex xfence present pipefence shmtest
+all: shmfd dri3 futex xfence present pipefence shmtest condtest
 
 SHMFD_OBJS=shmfd.o
 
@@ -38,6 +38,11 @@ SHMTEST_OBJS=shmtest.o
 shmtest: $(SHMTEST_OBJS)
 	$(CC) $(CFLAGS) -o $@ $(SHMTEST_OBJS)
 
+CONDTEST_OBJS=condtest.o
+
+condtest: $(CONDTEST_OBJS)
+	$(CC) $(CFLAGS) -o $@ $(CONDTEST_OBJS) -lpthread
+
 clean:
 	rm -f shmfd $(SHMFD_OBJS)
 	rm -f dri3 $(DRI3_OBJS)
diff --git a/condtest.c b/condtest.c
new file mode 100644
index 0000000..4b8b868
--- /dev/null
+++ b/condtest.c
@@ -0,0 +1,101 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <values.h>
+#include <pthread.h>
+
+struct xshmfence {
+	pthread_mutex_t lock;
+	pthread_cond_t	cond;
+	int 		value;
+};
+
+struct xshmfence *
+map_shm(int fd)
+{
+	struct xshmfence *addr;
+	addr = mmap (NULL, sizeof (struct xshmfence) , PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		close (fd);
+		return 0;
+	}
+	return addr;
+}
+
+void
+unmap_shm(struct xshmfence *f)
+{
+        munmap(f, sizeof (struct xshmfence));
+}
+
+int
+alloc_shm(void)
+{
+	char	template[] = "/run/shm/shmfd-XXXXXX";
+	int	fd;
+	struct xshmfence *f;
+	pthread_condattr_t attr;
+
+#ifdef O_TMPFILE
+	fd = open(SHMDIR, O_TMPFILE|O_RDWR|O_CLOEXEC|O_EXCL, 0666);
+	if (fd < 0)
+#endif
+        {
+            fd = mkstemp(template);
+            if (fd < 0)
+		return fd;
+            unlink(template);
+        }
+	ftruncate(fd, sizeof (struct xshmfence));
+	f = map_shm(fd);
+	pthread_condattr_init(&attr);
+	pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+	pthread_cond_init(&f->cond, &attr);
+	return fd;
+}
+
+void *
+thread(void *arg)
+{
+	int *fdp = arg;
+	int fd = *fdp;
+	struct xshmfence *f = map_shm(fd);
+
+	printf ("thread starting\n");
+	pthread_mutex_lock(&f->lock);
+	pthread_cond_wait(&f->cond, &f->lock);
+	pthread_mutex_unlock(&f->lock);
+	printf ("thread done\n");
+	pthread_exit(0);
+}
+
+int
+main(int argc, char **argv)
+{
+	pthread_t	child;
+	void		*ret;
+	int		fd;
+	struct xshmfence	*f;
+
+	fd = alloc_shm();
+	pthread_create (&child, NULL, thread, &fd);
+
+	f = map_shm(fd);
+	sleep(1);
+	printf ("parent starting\n");
+	pthread_mutex_lock(&f->lock);
+	pthread_cond_broadcast(&f->cond);
+	printf ("parent done\n");
+	pthread_mutex_unlock(&f->lock);
+	pthread_join(child, &ret);
+	printf ("finished\n");
+	exit(0);
+}