zdtm/static: check that cgroup layout of threads is preserved

Co-developed-by: Stepan Pieshkin <stepanpieshkin@google.com>
Signed-off-by: Stepan Pieshkin <stepanpieshkin@google.com>
Signed-off-by: Michal Clapinski <mclapinski@google.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

test/zdtm/static/Makefile

@@ -402,6 +402,7 @@ TST_DIR		=				\
 		cgroup_ignore			\
 		cgroup_stray			\
 		cgroup_yard			\
+		cgroup_threads			\
 		unlink_fstat04			\
 		unlink_fstat041			\
 		mntns_remap			\
@@ -684,6 +685,8 @@ s390x_gs_threads:	LDFLAGS += -pthread
 
 thread_different_uid_gid:	LDLIBS += -pthread -lcap
 
+cgroup_threads:		LDFLAGS += -pthread
+
 bpf_hash:		LDLIBS += -lbpf
 bpf_array:		LDLIBS += -lbpf
 

test/zdtm/static/cgroup_threads.c

@@ -0,0 +1,184 @@
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include "zdtmtst.h"
+
+const char *test_doc = "Check that cgroup layout of threads is preserved";
+const char *test_author = "Michał Cłapiński <mclapinski@google.com>";
+
+char *dirname;
+TEST_OPTION(dirname, string, "cgroup directory name", 1);
+static const char *cgname = "zdtmtst";
+#define SUBNAME	 "subcg_threads"
+#define SUBNAME2 SUBNAME "/subsubcg"
+
+#define exit_group(code) syscall(__NR_exit_group, code)
+
+static int cg_move(char *name)
+{
+	int cgfd, l;
+	char paux[256];
+
+	sprintf(paux, "%s/%s", dirname, name);
+	if (mkdir(paux, 0600)) {
+		pr_perror("Can't create %s", paux);
+		return -1;
+	}
+
+	sprintf(paux, "%s/%s/tasks", dirname, name);
+
+	cgfd = open(paux, O_WRONLY);
+	if (cgfd < 0) {
+		pr_perror("Can't open tasks");
+		return -1;
+	}
+
+	l = write(cgfd, "0", 2);
+	close(cgfd);
+
+	if (l < 0) {
+		pr_perror("Can't move self to subcg");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int cg_check(char *name)
+{
+	int found = 0;
+	FILE *cgf;
+	char paux[256], aux[128];
+
+	cgf = fopen("/proc/thread-self/cgroup", "r");
+	if (cgf == NULL)
+		return -1;
+
+	sprintf(aux, "name=%s:/%s", cgname, name);
+	while (fgets(paux, sizeof(paux), cgf)) {
+		char *s;
+
+		s = strchr(paux, ':') + 1;
+		s[strlen(s) - 1] = '\0';
+		test_msg("CMP [%s] vs [%s]\n", s, aux);
+		if (!strcmp(s, aux)) {
+			found = 1;
+			break;
+		}
+	}
+
+	fclose(cgf);
+
+	return found ? 0 : -1;
+}
+
+int th_sync[2], rst_sync[2];
+
+void *thread_fn(void *args)
+{
+	int status = cg_move(SUBNAME2);
+
+	if (write(th_sync[1], &status, sizeof(status)) != sizeof(status)) {
+		pr_perror("write");
+		exit_group(1);
+	}
+
+	if (status == 0) {
+		if (read(rst_sync[0], &status, sizeof(status)) < 0) {
+			pr_perror("read");
+			exit_group(1);
+		}
+
+		status = cg_check(SUBNAME2);
+		if (write(th_sync[1], &status, sizeof(status)) != sizeof(status)) {
+			pr_perror("write");
+			exit_group(1);
+		}
+	}
+
+	pthread_exit(0);
+}
+
+int main(int argc, char **argv)
+{
+	int status, exit_code = 1;
+	pthread_t thread;
+	char aux[64];
+
+	test_init(argc, argv);
+
+	/*
+	 * Pipe to talk to the kid.
+	 * First, it reports that it's ready (int),
+	 * then it reports the restore status (int).
+	 */
+
+	if (pipe(th_sync)) {
+		pr_perror("pipe");
+		return 1;
+	}
+
+	/* "Restore happened" pipe */
+	if (pipe(rst_sync)) {
+		pr_perror("pipe");
+		return 1;
+	}
+
+	if (mkdir(dirname, 0700) < 0) {
+		pr_perror("Can't make dir");
+		goto out;
+	}
+
+	sprintf(aux, "none,name=%s", cgname);
+	if (mount("none", dirname, "cgroup", 0, aux)) {
+		pr_perror("Can't mount cgroups");
+		goto out_rd;
+	}
+
+	if (cg_move(SUBNAME))
+		goto out_rs;
+
+	if (pthread_create(&thread, NULL, thread_fn, NULL)) {
+		pr_perror("Can't create a new thread");
+		goto out_rs;
+	}
+
+	status = -1;
+	read(th_sync[0], &status, sizeof(status));
+	if (status != 0) {
+		pr_perror("Error moving into cgroups");
+		close(rst_sync[0]);
+		goto out_rs;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	close(rst_sync[1]);
+
+	status = -1;
+	if (read(th_sync[0], &status, sizeof(status)) < 0) {
+		pr_perror("read");
+		goto out_rs;
+	}
+	if (status != 0) {
+		fail("child cg changed");
+		goto out_rs;
+	}
+
+	pass();
+	exit_code = 0;
+
+out_rs:
+	umount(dirname);
+out_rd:
+	rmdir(dirname);
+out:
+	return exit_code;
+}

test/zdtm/static/cgroup_threads.desc

@@ -0,0 +1 @@
+{'flavor': 'h', 'flags': 'suid', 'opts': '--manage-cgroups'}

test/zdtm/static/cgroup_threads.hook

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -e
+
+[ "$1" == "--clean" -o "$1" == "--pre-restore" ] || exit 0
+
+tname=$(mktemp -d cgclean.XXXXXX)
+trap 'rmdir "${tname}"' EXIT
+
+mount -t cgroup none $tname -o "none,name=zdtmtst"
+trap 'umount "${tname}"; rmdir "${tname}"' EXIT
+
+echo "Cleaning $tname"
+
+rmdir "$tname/subcg_threads/subsubcg/" || true
+rmdir "$tname/subcg_threads/" || true
+
+echo "Left there is:"
+ls "$tname"