tests: fix builds on alpine and centos

Install sudo, create test user with ID 1000, install bash,
fix pidfile creation and pidfile chmod.

v2:
 * use sleep to give the criu daemon some time to start up

v3:
 * Andrei is of course right and sleep is not good solution.
   After adding --status-fd support to criu service, this
   is how we now detect that criu is ready.

v4:
 * This was much more complicated than expected which is related
   to the different versions of the tools on the different travis
   test targets. There seems to be a bug in bash on Ubuntu
    https://lists.gnu.org/archive/html/bug-bash/2017-07/msg00039.html
   which prevents using 'read -n1' on Ubuntu. As a workaround
   the result from CRIU's status FD is now read via python.

   Another problem was discovered on alpine with the loop restore test.
   CRIU says to use setsid even if the process is already using setsid.
   As a workaround, still with setsid, this process is now using
   shell-job true for checkpoint and restore.

Parts of v2 have been committed before. So the changes from this commit
are partially already in another commit.
Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

scripts/build/Dockerfile.centos

@@ -40,4 +40,8 @@ WORKDIR /criu
 ENV CCACHE_DIR=/tmp/.ccache CCACHE_NOCOMPRESS=1 $ENV1=yes
 RUN mv .ccache /tmp && make mrproper && ccache -sz  && \
 	date && make -j $(nproc) CC="$CC" && date && ccache -s
+
+# The rpc test cases are running as user #1000, let's add the user
+RUN adduser -u 1000 test
+
 RUN make -C test/zdtm -j $(nproc)

test/others/rpc/Makefile

@@ -4,13 +4,22 @@ all: test-c rpc_pb2.py criu
 CFLAGS += -g -Werror -Wall -I.
 LDLIBS +=  -lprotobuf-c
 
+PYTHON ?= python
+
 run: all
 	mkdir -p build
 	chmod a+rwx build
-	@# need to start the criu daemon here to access the pidfile
-	sudo -g '#1000' -u '#1000' ./criu service -v4 -W build -o service.log --address criu_service.socket -d --pidfile pidfile
-	# Give the criu daemon some time to start up
-	sleep 0.5
+	rm -f build/status
+	sudo -g '#1000' -u '#1000' mkfifo build/status
+	@# Need to start the criu daemon here to access the pidfile.
+	@# The script read.py is used to wait until 'criu service'
+	@# is ready. As 'read -n 1' in some releases has a bug and does
+	@# not read correctly a \0, using python is a workaround.
+	sudo -g '#1000' -u '#1000' -- bash -c "exec 200<>build/status; \
+		./criu service -v4 -W build --address criu_service.socket \
+		-d --pidfile pidfile -o service.log --status-fd 200; \
+		$(PYTHON) read.py build/status"
+	rm -f build/status
 	chmod a+rw build/pidfile
 	sudo -g '#1000' -u '#1000' ./run.sh
 	sudo -g '#1000' -u '#1000' ./version.py

test/others/rpc/read.py

+# This script is used to read a single character from CRIU's status FD.
+# That way we know when the CRIU service is ready. CRIU writes a \0 to
+# the status FD.
+# In theory this could be easily done using 'read -n 1' from bash, but
+# but the bash version on Ubuntu has probably the following bug:
+# https://lists.gnu.org/archive/html/bug-bash/2017-07/msg00039.html
+
+import os
+import sys
+
+
+f=open(sys.argv[1])
+r = f.read(1)
+
+if r == '\0':
+	sys.exit(0)
+
+sys.exit(-1)

test/others/rpc/restore-loop.py

@@ -19,6 +19,11 @@ s.connect(args['socket'])
 req			= rpc.criu_req()
 req.type		= rpc.RESTORE
 req.opts.images_dir_fd	= os.open(args['dir'], os.O_DIRECTORY)
+# As the dumped process is running with setsid this should not
+# be necessary. There seems to be a problem for this testcase
+# in combination with alpine's setsid.
+# The dump is now done with -j and the restore also.
+req.opts.shell_job      = True
 
 # Send request
 s.send(req.SerializeToString())

test/others/rpc/run.sh

@@ -50,7 +50,9 @@ function test_restore_loop {
 	echo "pid ${P}"
 
 	title_print "Dump loop.sh"
-	${CRIU} dump -v4 -o dump-loop.log -D build/imgs_loop -t ${P}
+	# So theoretically '-j' (--shell-job) should not be necessary, but on alpine
+	# this test fails without it.
+	${CRIU} dump -j -v4 -o dump-loop.log -D build/imgs_loop -t ${P}
 
 	title_print "Run restore-loop"
 	./restore-loop.py build/criu_service.socket build/imgs_loop