zdtm: Make cgroup00 test check several tasks and sub-cgroup

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

test/zdtm/live/static/cgroup00.c

@@ -4,6 +4,7 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/mount.h>
+#include <stdlib.h>
 #include "zdtmtst.h"
 
 const char *test_doc	= "Check that cgroups layout is preserved";
@@ -13,6 +14,7 @@ char *dirname;
 TEST_OPTION(dirname, string, "cgroup directory name", 1);
 static const char *cgname = "zdtmtst";
 #define SUBNAME	"subcg"
+#define SUBNAME2 SUBNAME"/subsubcg"
 
 static int cg_move(char *name)
 {
@@ -79,9 +81,22 @@ static void cg_cleanup(void)
 int main(int argc, char **argv)
 {
 	char aux[64];
+	int p1[2], p2[2], pr[2], status;
 
 	test_init(argc, argv);
 
+	/*
+	 * Pipes to talk to two kids.
+	 * First, they report that they are ready (int),
+	 * then they report the restore status (int).
+	 */
+
+	pipe(p1);
+	pipe(p2);
+
+	/* "Restore happened" pipe */
+	pipe(pr);
+
 	if (mkdir(dirname, 0700) < 0) {
 		err("Can't make dir");
 		goto out;
@@ -96,14 +111,92 @@ int main(int argc, char **argv)
 	if (cg_move(SUBNAME))
 		goto out_rs;
 
+	if (fork() == 0) {
+		if (fork() == 0) {
+			/*
+			 * 2nd level kid -- moves into its own
+			 * cgroup and triggers slow-path cg_set
+			 * restore in criu
+			 */
+
+			close(p1[0]);
+			close(p1[1]);
+			close(p2[0]);
+			close(pr[1]);
+
+			status = cg_move(SUBNAME2);
+			write(p2[1], &status, sizeof(status));
+
+			if (status == 0) {
+				read(pr[0], &status, sizeof(status));
+
+				status = cg_check(SUBNAME2);
+				write(p2[1], &status, sizeof(status));
+			}
+
+			exit(0);
+		}
+
+		/*
+		 * 1st level kid -- inherits cgroup from
+		 * parent and triggers fast-path cg_set
+		 * restore in criu
+		 */
+
+		close(p1[0]);
+		close(p2[0]);
+		close(p2[1]);
+		close(pr[1]);
+
+		status = 0;
+		write(p1[1], &status, sizeof(status));
+
+		read(pr[0], &status, sizeof(status));
+
+		status = cg_check(SUBNAME);
+		write(p1[1], &status, sizeof(status));
+
+		exit(0);
+	}
+
+	close(p1[1]);
+	close(p2[1]);
+	close(pr[0]);
+
+	status = -1;
+	read(p1[0], &status, sizeof(status));
+	if (status != 0)
+		goto out_ks;
+
+	status = -1;
+	read(p2[0], &status, sizeof(status));
+	if (status != 0)
+		goto out_ks;
+
 	test_daemon();
 	test_waitsig();
 
+	close(pr[1]);
+
 	if (cg_check(SUBNAME)) {
 		fail("Top level task cg changed");
 		goto out_rs;
 	}
 
+	status = -1;
+	read(p1[0], &status, sizeof(status));
+	if (status != 0) {
+		fail("1st level task cg changed");
+		goto out_rs;
+	}
+
+	status = -1;
+	read(p2[0], &status, sizeof(status));
+	if (status != 0) {
+		fail("2nd level task cg changed");
+		goto out_rs;
+	}
+
 	pass();
 
 out_rs:
@@ -113,4 +206,9 @@ out_rd:
 	rmdir(dirname);
 out:
 	return 0;
+
+out_ks:
+	err("Error moving into cgroups");
+	close(pr[0]);
+	goto out_rs;
 }