[CRIU] [RFC][PATCH] zdtm: Check that files from alien mnt ns are handled

[Pavel Emelyanov]

Check that files opened before switching to new mount namespace
remain in it after restore. Right now this is not so :( Andrey is
fixing the issue.

Christopher, can you check whether the ns_child's call to system()
works in your minimal set-ups (it launches cat and awk). If not,
then I should rewrite this routine in pure C.

Signed-off-by: Pavel Emelyanov <xemul at parallels.com>

---

diff --git a/test/zdtm.sh b/test/zdtm.sh
index eccbfaf..b5e7ff5 100755
--- a/test/zdtm.sh
+++ b/test/zdtm.sh
@@ -207,6 +207,7 @@ cgroup00
 cgroup01
 clean_mntns
 deleted_dev
+mntns_open
 "
 
 source $(readlink -f `dirname $0`/env.sh) || exit 1
diff --git a/test/zdtm/live/static/Makefile b/test/zdtm/live/static/Makefile
index d3d42a1..e444b11 100644
--- a/test/zdtm/live/static/Makefile
+++ b/test/zdtm/live/static/Makefile
@@ -91,6 +91,7 @@ TST_NOFILE	=				\
 		tty02				\
 		tty03				\
 		mountpoints			\
+		mntns_open			\
 		netns				\
 		session01			\
 		session02			\
diff --git a/test/zdtm/live/static/mntns_open.c b/test/zdtm/live/static/mntns_open.c
new file mode 100644
index 0000000..292895b
--- /dev/null
+++ b/test/zdtm/live/static/mntns_open.c
@@ -0,0 +1,190 @@
+#define _GNU_SOURCE
+#include <stdbool.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sched.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+
+#include "zdtmtst.h"
+
+#ifndef CLONE_NEWNS
+#define CLONE_NEWNS     0x00020000
+#endif
+
+const char *test_doc	= "Check that mnt_id is repsected";
+const char *test_author	= "Pavel Emelianov <xemul at parallels.com>";
+
+#define MPTS_ROOT	"/zdtm_mpts/"
+#define MPTS_FILE	"F"
+
+static char buf[1024];
+
+#define NS_STACK_SIZE	4096
+/* All arguments should be above stack, because it grows down */
+struct ns_exec_args {
+	char stack[NS_STACK_SIZE];
+	char stack_ptr[0];
+	int fd;
+};
+
+#define AWK_OK		13
+#define AWK_FAIL	42
+#define AWK_BS		57
+
+#define _S(X)	#X
+#define S(X)	_S(X)
+
+int ns_child(void *_arg)
+{
+	struct ns_exec_args *args = _arg;
+	int fd2, ret;
+	char *cmd_pat = "cat /proc/self/fdinfo/%d /proc/self/fdinfo/%d |"
+			" awk 'BEGIN{p=0}/mnt_id:/{"
+			" if (p == 0) { p = $2; } "
+			" else if (p != $2) { exit " S(AWK_OK) " } "
+			" else { exit " S(AWK_FAIL) " } }'";
+
+	fd2 = open(MPTS_ROOT MPTS_FILE, O_RDWR);
+	test_waitsig();
+
+	sprintf(buf, cmd_pat, args->fd, fd2);
+	ret = system(buf);
+	close(fd2);
+
+	if (WIFEXITED(ret))
+		ret = WEXITSTATUS(ret);
+	else
+		ret = AWK_BS;
+
+	test_msg("AWK exited %d\n", ret);
+	exit(ret);
+}
+
+static int test_fn(int argc, char **argv)
+{
+	FILE *f;
+	unsigned fs_cnt, fs_cnt_last = 0;
+	struct ns_exec_args args;
+	bool private = false;
+	pid_t pid = -1;
+
+	if (!getenv("ZDTM_REEXEC")) {
+		setenv("ZDTM_REEXEC", "1", 0);
+		return execv(argv[0], argv);
+	}
+
+	test_init(argc, argv);
+	close(0); /* /dev/null */
+again:
+	fs_cnt = 0;
+	f = fopen("/proc/self/mountinfo", "r");
+	if (!f) {
+		fail("Can't open mountinfo");
+		return -1;
+	}
+
+	if (mount(NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL)) {
+		err("Can't remount / with MS_PRIVATE");
+		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;
+
+		if (umount(mp))
+			test_msg("umount(`%s') failed: %m\n", mp);
+
+		fs_cnt++;
+	}
+
+	fclose(f);
+
+	if (!private) {
+		private = true;
+		goto again;
+	}
+
+	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:
+	rmdir(MPTS_ROOT);
+	if (mkdir(MPTS_ROOT, 0600) < 0) {
+		fail("Can't make zdtm_sys");
+		return 1;
+	}
+
+	if (getenv("ZDTM_NOSUBNS") == NULL) {
+		args.fd = open(MPTS_ROOT MPTS_FILE, O_CREAT | O_RDWR, 0600);
+		if (args.fd < 0) {
+			fail("Can't open file");
+			return 1;
+		}
+
+		pid = clone(ns_child, args.stack_ptr, CLONE_NEWNS | SIGCHLD, &args);
+		if (pid < 0) {
+			err("Unable to fork child");
+			return 1;
+		}
+
+		close(args.fd);
+	}
+
+	test_daemon();
+	test_waitsig();
+
+
+	if (pid > 0) {
+		kill(pid, SIGTERM);
+		int status = 1;
+		wait(&status);
+		if (WIFEXITED(status)) {
+			if (WEXITSTATUS(status) == AWK_OK)
+				pass();
+			else if (WEXITSTATUS(status) == AWK_FAIL)
+				fail("Mount ID not restored");
+			else
+				fail("Failed to check mount IDs (%d)", WEXITSTATUS(status));
+		} else
+			fail("Test died");
+	}
+
+	unlink(MPTS_ROOT MPTS_FILE);
+	rmdir(MPTS_ROOT);
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	if (getenv("ZDTM_REEXEC"))
+		return test_fn(argc, argv);
+
+	test_init_ns(argc, argv, CLONE_NEWNS, test_fn);
+	return 0;
+}