test: Add test-shmem-async test

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

test/Makefile

 SRCS	+= test-counter.c
 SRCS	+= test-rnd-from-file.c
+SRCS	+= test-shmem-async.c
 
 OBJS	:= $(patsubst %.c,%.o,$(SRCS))
 PROGS	:= $(patsubst %.c,%,$(SRCS))

test/test-shmem-async.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <string.h>
+
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+
+#include <sched.h>
+
+static void *map;
+
+int main(int argc, char *argv[])
+{
+	pid_t pid;
+
+	printf("%s pid %d\n", argv[0], getpid());
+
+	map = mmap(NULL, 1024, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+	if (map	== MAP_FAILED) {
+		printf("%6d: mmap failed\n", getpid());
+		return 0;
+	}
+
+	memset(map, '-', 21);
+	((char *)map)[21] = 0;
+
+	printf("%6d: Initial  shmem pattern '%s'\n", getpid(), (char *)map);
+
+	pid = fork();
+	if (pid == -1) {
+		printf("fork failed\n");
+		return 1;
+	}
+
+	if (pid == 0) {
+		int cnt = 0;
+		while(1) {
+			printf("%6d: Observed shmem pattern '%s'\n", getpid(), (char *)map);
+			sprintf(map, "shared-mem-%010d", cnt++);
+			sleep(5);
+		}
+	} else {
+		while(1) {
+			printf("%6d: Observed shmem pattern '%s'\n", getpid(), (char *)map);
+			sleep(3);
+		}
+	}
+
+	return 0;
+}