check/zdtm: Introduce fine-grained feature testing

Right now we state that CRIU works on 3.11 and above kernels and, at the
same time, have support for a couple of new features like aio, tun, timerfd
etc. available in later kernels. Since these new features do not break
generic operations we do not require them in the kernel strictly.

However, in the zdtm tests it's very important to know exactly what can
and what cannot be tested. Right now this is done in a tough manner -- if
the kernel is not 3.11 or criu check fails for _any_ reason we treat the
kernel as being "bad" and throw out a set of tests.

I propose to test some individual features and form the list of tests
in a more fine-grained manner.

This patch only fixes the AIO, mnt_id, tun and posix-timers tests. Next
I will add checks and fixes for user-namespaces tests.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Andrew Vagin <avagin@parallels.com>

cr-check.c

@@ -675,6 +675,8 @@ static int check_aio_remap(void)
 	return 0;
 }
 
+static int (*chk_feature)(void);
+
 int cr_check(void)
 {
 	struct ns_id ns = { .pid = getpid(), .nd = &mnt_ns_desc };
@@ -700,6 +702,11 @@ int cr_check(void)
 	if (mntinfo == NULL)
 		return -1;
 
+	if (chk_feature) {
+		ret = chk_feature();
+		goto out;
+	}
+
 	ret |= check_map_files();
 	ret |= check_sock_diag();
 	ret |= check_ns_last_pid();
@@ -718,13 +725,43 @@ int cr_check(void)
 	ret |= check_ptrace_peeksiginfo();
 	ret |= check_mem_dirty_track();
 	ret |= check_posix_timers();
-	ret |= check_tun();
+	ret |= check_tun_cr(0);
 	ret |= check_timerfd();
 	ret |= check_mnt_id();
 	ret |= check_aio_remap();
 
+out:
 	if (!ret)
 		pr_msg("Looks good.\n");
 
 	return ret;
 }
+
+static int check_tun(void)
+{
+	/*
+	 * In case there's no TUN support at all we
+	 * should report error. Unlike this plain criu
+	 * check would report "Looks good" in this case
+	 * since C/R effectively works, just not for TUN.
+	 */
+	return check_tun_cr(-1);
+}
+
+int check_add_feature(char *feat)
+{
+	if (!strcmp(feat, "mnt_id"))
+		chk_feature = check_mnt_id;
+	else if (!strcmp(feat, "aio_remap"))
+		chk_feature = check_aio_remap;
+	else if (!strcmp(feat, "timerfd"))
+		chk_feature = check_timerfd;
+	else if (!strcmp(feat, "tun"))
+		chk_feature = check_tun;
+	else {
+		pr_err("Unknown feature %s\n", feat);
+		return -1;
+	}
+
+	return 0;
+}

crtools.c

@@ -191,6 +191,7 @@ int main(int argc, char *argv[], char *envp[])
 		{ "manage-cgroups", no_argument, 0, 1060},
 		{ "cgroup-root", required_argument, 0, 1061},
 		{ "inherit-fd", required_argument, 0, 1062},
+		{ "feature", required_argument, 0, 1063},
 		{ },
 	};
 
@@ -400,6 +401,10 @@ int main(int argc, char *argv[], char *envp[])
 			if (inherit_fd_add(optarg) < 0)
 				return 1;
 			break;
+		case 1063:
+			if (check_add_feature(optarg) < 0)
+				return 1;
+			break;
 		case 'M':
 			{
 				char *aux;

include/crtools.h

@@ -30,5 +30,6 @@ extern bool may_dump(struct proc_status_creds *);
 struct _CredsEntry;
 extern bool may_restore(struct _CredsEntry *);
 extern bool cr_user_is_root(void);
+extern int check_add_feature(char *arg);
 
 #endif /* __CR_CRTOOLS_H__ */

include/tun.h

@@ -11,6 +11,6 @@ extern const struct fdtype_ops tunfile_dump_ops;
 extern int dump_tun_link(NetDeviceEntry *nde, struct cr_imgset *fds);
 extern int restore_one_tun(NetDeviceEntry *nde, int nlsk);
 extern struct collect_image_info tunfile_cinfo;
-extern int check_tun(void);
+extern int check_tun_cr(int no_tun_err);
 
 #endif /* __CR_TUN_H__ */

test/zdtm.sh

@@ -11,6 +11,8 @@ ARCH=`uname -m | sed			\
 
 ZP="zdtm/live"
 
+source $(readlink -f `dirname $0`/env.sh) || exit 1
+
 TEST_LIST="
 static/pipe00
 static/pipe01
@@ -178,7 +180,6 @@ static/shm
 static/msgque
 static/sem
 transition/ipc
-ns/static/tun
 static/netns-nf
 static/netns
 static/cgroup00
@@ -189,14 +190,9 @@ static/remap_dead_pid
 "
 
 TEST_CR_KERNEL="
-ns/static/tun
-static/timerfd
-static/aio00
 "
 
-cat /proc/self/fdinfo/1 | grep -q mnt_id
-if [ $? -eq 0 ]; then
-	TEST_LIST="$TEST_LIST
+TEST_MNTNS="
 ns/static/mntns_open
 ns/static/mntns_link_remap
 ns/static/mntns_link_ghost
@@ -204,10 +200,41 @@ ns/static/mntns_shared_bind
 ns/static/mntns_shared_bind02
 ns/static/mntns_root_bind
 "
+
+TEST_AIO="
+static/aio00
+"
+
+TEST_TIMERFD="
+static/timerfd
+"
+
+TEST_TUN="
+ns/static/tun
+"
+
+$CRIU check --feature "mnt_id"
+if [ $? -eq 0 ]; then
+	TEST_LIST="$TEST_LIST$TEST_MNTNS"
 else
 	export ZDTM_NOSUBNS=1
 fi
 
+$CRIU check --feature "aio_remap"
+if [ $? -eq 0 ]; then
+	TEST_LIST="$TEST_LIST$TEST_AIO"
+fi
+
+$CRIU check --feature "timerfd"
+if [ $? -eq 0 ]; then
+	TEST_LIST="$TEST_LIST$TEST_TIMERFD"
+fi
+
+$CRIU check --feature "tun"
+if [ $? -eq 0 ]; then
+	TEST_LIST="$TEST_LIST$TEST_TUN"
+fi
+
 BLACKLIST_FOR_USERNS="
 ns/static/maps01
 ns/static/mlock_setuid
@@ -257,8 +284,6 @@ ns/static/mntns_shared_bind02
 ns/static/mntns_root_bind
 "
 
-source $(readlink -f `dirname $0`/env.sh) || exit 1
-
 can_cr_userns() {
 	[ ! -f /proc/self/ns/user ] && return 1
 	$CRIU check | fgrep -q 'PR_SET_MM_MAP is not supported' && return 1

tun.c

@@ -50,7 +50,7 @@
 
 #define TUN_DEV_GEN_PATH	"/dev/net/tun"
 
-int check_tun(void)
+int check_tun_cr(int no_tun_err)
 {
 	int fd, idx = 13, ret;
 
@@ -62,7 +62,7 @@ int check_tun(void)
 	fd = open(TUN_DEV_GEN_PATH, O_RDWR);
 	if (fd < 0) {
 		pr_perror("Can't check tun support");
-		return 0;
+		return no_tun_err;
 	}
 
 	ret = ioctl(fd, TUNSETIFINDEX, &idx);