zdtm: Sanitize cgroup00 test

Prepare it for multiple tasks by moving cg creation and
checking code into helpers.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/static/cgroup00.c

@@ -12,83 +12,105 @@ const char *test_author	= "Pavel Emelianov <xemul@parallels.com>";
 char *dirname;
 TEST_OPTION(dirname, string, "cgroup directory name", 1);
 static const char *cgname = "zdtmtst";
-static const char *subname = "subcg";
+#define SUBNAME	"subcg"
 
-int main(int argc, char **argv)
+static int cg_move(char *name)
 {
-	int cgfd, l, ret = 1;
-	char aux[32], paux[1024];
-	FILE *cgf;
-
-	test_init(argc, argv);
-
-	if (mkdir(dirname, 0700) < 0) {
-		err("Can't make dir");
-		goto out;
-	}
-
-	sprintf(aux, "none,name=%s", cgname);
-	if (mount("none", dirname, "cgroup", 0, aux)) {
-		err("Can't mount cgroups");
-		goto out_rd;
-	}
+	int cgfd, l;
+	char paux[256];
 
-	sprintf(paux, "%s/%s", dirname, subname);
+	sprintf(paux, "%s/%s", dirname, name);
 	mkdir(paux, 0600);
 
-	l = sprintf(aux, "%d", getpid());
-	sprintf(paux, "%s/%s/tasks", dirname, subname);
+	sprintf(paux, "%s/%s/tasks", dirname, name);
 
 	cgfd = open(paux, O_WRONLY);
 	if (cgfd < 0) {
 		err("Can't open tasks");
-		goto out_rs;
+		return -1;
 	}
 
-	l = write(cgfd, aux, l);
+	l = write(cgfd, "0", 2);
 	close(cgfd);
 
 	if (l < 0) {
 		err("Can't move self to subcg");
-		goto out_rs;
+		return -1;
 	}
 
-	close(cgfd);
+	return 0;
+}
 
-	test_daemon();
-	test_waitsig();
+static int cg_check(char *name)
+{
+	int found = 0;
+	FILE *cgf;
+	char paux[256], aux[128];
 
 	cgf = fopen("/proc/self/cgroup", "r");
-	if (cgf == NULL) {
-		fail("No cgroups file");
-		goto out_rs;
-	}
+	if (cgf == NULL)
+		return -1;
 
-	sprintf(aux, "name=%s:/%s\n", cgname, subname);
+	sprintf(aux, "name=%s:/%s\n", cgname, name);
 	while (fgets(paux, sizeof(paux), cgf)) {
 		char *s;
 
 		s = strchr(paux, ':') + 1;
 		test_msg("CMP [%s] vs [%s]\n", s, aux);
 		if (!strcmp(s, aux)) {
-			ret = 0;
+			found = 1;
 			break;
 		}
 	}
 
 	fclose(cgf);
 
-	if (!ret)
+	return found ? 0 : -1;
+}
+
+static void cg_cleanup(void)
+{
+	char paux[256];
+
+	sprintf(paux, "%s/%s", dirname, SUBNAME);
+	rmdir(paux);
+}
+
+int main(int argc, char **argv)
+{
+	char aux[64];
+
+	test_init(argc, argv);
+
+	if (mkdir(dirname, 0700) < 0) {
+		err("Can't make dir");
+		goto out;
+	}
+
+	sprintf(aux, "none,name=%s", cgname);
+	if (mount("none", dirname, "cgroup", 0, aux)) {
+		err("Can't mount cgroups");
+		goto out_rd;
+	}
+
+	if (cg_move(SUBNAME))
+		goto out_rs;
+
+	test_daemon();
+	test_waitsig();
+
+	if (cg_check(SUBNAME)) {
+		fail("Top level task cg changed");
+		goto out_rs;
+	}
+
 	pass();
-	else
-		fail("Task is not in subgroups");
 
 out_rs:
-	sprintf(paux, "%s/%s", dirname, subname);
-	rmdir(paux);
+	cg_cleanup();
 	umount(dirname);
 out_rd:
 	rmdir(dirname);
 out:
-	return ret;
+	return 0;
 }