ci: do not use 'tail' for skip-file-rwx-check test

Newer versions of 'tail' rely on inotify and after a restore 'tail' is
unhappy with the state of inotify and just stops.

This replaces 'tail' with a minimal test in C which just keeps a file
open to still be able to test how CRIU reacts if the file mode has
changed.

Signed-off-by: Adrian Reber <[email protected]>

test/others/skip-file-rwx-check/.gitignore

@@ -0,0 +1,7 @@
+dump.log
+restore-expected-fail.log
+restore.log
+stats-dump
+stats-restore
+tester
+testfile

test/others/skip-file-rwx-check/Makefile

@@ -1,7 +1,10 @@
 .PHONY: run clean
 
-run:
+tester: tester.c
+	$(CC) -Wall $< -o $@
+
+run: tester
 	./run.sh
 
 clean:
-	rm -rf testfile *.img dump.log restore-expected-fail.log restore.log stats-dump stats-restore
+	rm -rf testfile *.img dump.log restore-expected-fail.log restore.log stats-dump stats-restore tester

test/others/skip-file-rwx-check/run.sh

@@ -8,21 +8,22 @@ set -o xtrace
 source ../env.sh
 
 make clean
+make tester
 touch testfile
 chmod +w testfile
-tail --follow testfile &
-tailpid=$!
-if ! "$criu" dump --tree=$tailpid --shell-job --verbosity=4 --log-file=dump.log
+./tester testfile &
+testpid=$!
+if ! "$criu" dump --tree=$testpid --shell-job --verbosity=4 --log-file=dump.log
 then
-    kill $tailpid
+    kill $testpid
     echo "Failed to dump process as expected"
     echo FAIL
     exit 1
 fi
 chmod -w testfile
 if "$criu" restore --restore-detached --shell-job --verbosity=4 --log-file=restore-expected-fail.log
 then
-    kill $tailpid
+    kill $testpid
     echo "Unexpectedly restored process with reference to a file who's r/w/x perms changed when --skip-file-rwx-check option was not used"
     echo FAIL
     exit 1
@@ -33,5 +34,5 @@ then
     echo FAIL
     exit 1
 fi
-kill $tailpid
+kill $testpid
 echo PASS

test/others/skip-file-rwx-check/tester.c

@@ -0,0 +1,10 @@
+#include <fcntl.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[])
+{
+	open(argv[1], O_RDONLY | O_APPEND);
+
+	while(1)
+		sleep(1);
+}