test/others: refactor loop process

There are several problems with the loop.sh script. First, the code is
duplicated across tests in the so-called 'othres' category. Second, we
need to run it with the 'setsid' utility to make sure that it runs in
a new session. Third, we have to redirect the standard file descriptors
and use the '&' operator to make it run in the background. Finally,
obtaining the PID of the 'loop.sh' process resulted in race condition.

In this patch we replace the loop.sh script with a program that would
address all problems mentioned above. The requirements for this program
are as follows.
- It must be reusable across tests
- It must start a process that is detached from the current shell
- It must wait for the process to start and output its PID

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

3 files changed, 2 insertions, 6 deletions

diff --git a/test/others/crit/Makefile b/test/others/crit/Makefile
index 75d09b66c..ca296e333 100644
--- a/test/others/crit/Makefile
+++ b/test/others/crit/Makefile
@@ -1,4 +1,5 @@
 run: clean
+	@make -C .. loop
 	./test.sh
 
 clean:
diff --git a/test/others/crit/loop.sh b/test/others/crit/loop.sh
deleted file mode 100755
index 0ab34ce96..000000000
--- a/test/others/crit/loop.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/bin/bash
-while :; do
-	sleep 1
-done
diff --git a/test/others/crit/test.sh b/test/others/crit/test.sh
index 345f8ce04..0d38043d7 100755
--- a/test/others/crit/test.sh
+++ b/test/others/crit/test.sh
@@ -8,8 +8,7 @@ source ../env.sh
 images_list=""
 
 function gen_imgs {
-	setsid ./loop.sh < /dev/null &> /dev/null &
-	PID=$!
+	PID=$(../loop)
 	if ! $CRIU dump -v4 -o dump.log -D ./ -t "$PID"; then
 		echo "Failed to checkpoint process $PID"
 		cat dump.log