zdtm: add a new test case, which create processes in a loop

and this processes live a short period of time. This test case is needed
for testing snapshots.

https://bugzilla.openvz.org/show_bug.cgi?id=2636
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/transition/Makefile

@@ -10,6 +10,7 @@ TST_NOFILE	=	\
 		ptrace		\
 		epoll		\
 		fork		\
+		fork2		\
 
 TST_FILE	=	\
 		file_read 	\
@@ -59,6 +60,7 @@ $(TST):	$(LIB)
 ptrace.o:	override CFLAGS += -pthread
 ptrace:		override LDFLAGS += -pthread
 ipc:		override CFLAGS += -DNEW_IPC_NS
+fork2:		override CFLAGS += -D FORK2
 
 %: %.sh
 	cp $< $@

test/zdtm/live/transition/fork.c

@@ -29,8 +29,12 @@ int main(int argc, char **argv)
 			goto out;
 		}
 
-		if (pid == 0)
+		if (pid == 0) {
+#ifdef FORK2
+			usleep(10000);
+#endif
 			exit(0);
+		}
 
 		while ((wpid = wait(&status)) == -1 && errno == EINTR);
 

test/zdtm/live/transition/fork2.c

@@ -0,0 +1 @@
+fork.c