zdtm: Basic test for mount points in mount namespace

Test with sysfs and proc as no other fs-s are currently supported.
Will be fixed later.

Note, that the original /proc mount is kept as the dumping code requires
it for reading pagemap file with RSS info. Worth fixing it some day?
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -53,6 +53,10 @@ transition/fork
 static/file_fown
 "
 
+MNT_TEST_LIST="
+static/mountpoints
+"
+
 # These ones are in pidns
 TEST_LIST="$TEST_LIST
 pidns/static/session00
@@ -230,11 +234,14 @@ if [ $# -eq 0 ]; then
 	for t in $UTS_TEST_LIST; do
 		run_test $t -n uts || case_error $t
 	done
+	for t in $MNT_TEST_LIST; do
+		run_test $t -n mnt || case_error $t
+	done
 	for t in $IPC_TEST_LIST; do
 		run_test $t -n ipc || case_error $t
 	done
 elif [ "$1" == "-l" ]; then
-	echo $TEST_LIST $UTS_TEST_LIST $IPC_TEST_LIST | tr ' ' '\n'
+	echo $TEST_LIST $UTS_TEST_LIST $MNT_TEST_LIST $IPC_TEST_LIST | tr ' ' '\n'
 elif [ "$1" == "-h" ]; then
 	cat >&2 <<EOF
 This script is used for executing unit tests.
@@ -248,6 +255,8 @@ EOF
 else
 	if echo $UTS_TEST_LIST | fgrep -qw $1; then
 		run_test $1 -n uts || case_error $1
+	elif echo $MNT_TEST_LIST | fgrep -qw $1; then
+		run_test $1 -n mnt || case_error $1
 	elif echo $IPC_TEST_LIST | fgrep -qw $1; then
 		run_test $1 -n ipc || case_error $1
 	else

test/zdtm/live/static/Makefile

@@ -50,6 +50,7 @@ TST_NOFILE	=				\
 		session00			\
 		pty00				\
 		tty00				\
+		mountpoints			\
 #		jobctl00			\
 
 TST_FILE	=				\

test/zdtm/live/static/mountpoints.c

+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Check that mountpoints (in mount namespace) are supported";
+const char *test_author	= "Pavel Emelianov <xemul@parallels.com>";
+
+#define MPTS_ROOT	"/zdtm_mpts/"
+
+static char buf[1024];
+
+static int test_fn(int argc, char **argv)
+{
+	FILE *f;
+	unsigned fs_cnt, fs_cnt_last = 0;
+
+again:
+	fs_cnt = 0;
+	f = fopen("/proc/self/mountinfo", "r");
+	if (!f) {
+		fail("Can't open mountinfo");
+		return -1;
+	}
+
+	while (fgets(buf, sizeof(buf), f) != NULL) {
+		char *mp = buf, *end;
+
+		mp = strchr(mp, ' ') + 1;
+		mp = strchr(mp, ' ') + 1;
+		mp = strchr(mp, ' ') + 1;
+		mp = strchr(mp, ' ') + 1;
+		end = strchr(mp, ' ');
+		*end = '\0';
+
+		if (!strcmp(mp, "/"))
+			continue;
+		if (!strcmp(mp, "/proc"))
+			continue;
+
+		umount(mp);
+		fs_cnt++;
+	}
+
+	fclose(f);
+
+	if (fs_cnt == 0)
+		goto done;
+
+	if (fs_cnt != fs_cnt_last) {
+		fs_cnt_last = fs_cnt;
+		goto again;
+	}
+
+	fail("Can't umount all the filesystems");
+	return -1;
+
+done:
+	close(0);
+	close(1);
+	close(2);
+	rmdir(MPTS_ROOT);
+	if (mkdir(MPTS_ROOT, 0600) < 0) {
+		fail("Can't make zdtm_sys");
+		return 1;
+	}
+
+	if (mount("none", MPTS_ROOT, "sysfs", 0, "") < 0) {
+		fail("Can't mount sysfs");
+		return 1;
+	}
+
+	if (mount("none", MPTS_ROOT"/kernel/debug", "proc", 0, "") < 0) {
+		fail("Can't mount proc");
+		return 1;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	/* this checks both -- sys and proc presence */
+	if (access(MPTS_ROOT"/kernel/debug/slabinfo", F_OK)) {
+		fail("No proc after restore");
+		return 1;
+	}
+
+	pass();
+	return 0;
+}
+
+#define CLONE_NEWNS     0x00020000
+
+int main(int argc, char **argv)
+{
+	test_init_ns(argc, argv, CLONE_NEWNS, test_fn);
+	return 0;
+}