tools/testing/selftests/cgroup/test_core.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/cgroup/test_core.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/cgroup/test_core.c
Extension
.c
Size
19964 bytes
Lines
960
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct lesser_ns_open_thread_arg {
	const char	*path;
	int		fd;
	int		err;
};

static int lesser_ns_open_thread_fn(void *arg)
{
	struct lesser_ns_open_thread_arg *targ = arg;

	targ->fd = open(targ->path, O_RDWR);
	targ->err = errno;
	return 0;
}

/*
 * cgroup migration permission check should be performed based on the cgroup
 * namespace at the time of open instead of write.
 */
static int test_cgcore_lesser_ns_open(const char *root)
{
	static char stack[65536];
	const uid_t test_euid = 65534;	/* usually nobody, any !root is fine */
	int ret = KSFT_FAIL;
	char *cg_test_a = NULL, *cg_test_b = NULL;
	char *cg_test_a_procs = NULL, *cg_test_b_procs = NULL;
	int cg_test_b_procs_fd = -1;
	struct lesser_ns_open_thread_arg targ = { .fd = -1 };
	pid_t pid;
	int status;

	if (!nsdelegate)
		return KSFT_SKIP;

	cg_test_a = cg_name(root, "cg_test_a");
	cg_test_b = cg_name(root, "cg_test_b");

	if (!cg_test_a || !cg_test_b)
		goto cleanup;

	cg_test_a_procs = cg_name(cg_test_a, "cgroup.procs");
	cg_test_b_procs = cg_name(cg_test_b, "cgroup.procs");

	if (!cg_test_a_procs || !cg_test_b_procs)
		goto cleanup;

	if (cg_create(cg_test_a) || cg_create(cg_test_b))
		goto cleanup;

	if (cg_enter_current(cg_test_b))
		goto cleanup;

	if (chown(cg_test_a_procs, test_euid, -1) ||
	    chown(cg_test_b_procs, test_euid, -1))
		goto cleanup;

	targ.path = cg_test_b_procs;
	pid = clone(lesser_ns_open_thread_fn, stack + sizeof(stack),
		    CLONE_NEWCGROUP | CLONE_FILES | CLONE_VM | SIGCHLD,
		    &targ);
	if (pid < 0)
		goto cleanup;

	if (waitpid(pid, &status, 0) < 0)
		goto cleanup;

	if (!WIFEXITED(status))
		goto cleanup;

	cg_test_b_procs_fd = targ.fd;
	if (cg_test_b_procs_fd < 0)
		goto cleanup;

	if (cg_enter_current(cg_test_a))
		goto cleanup;

	if ((status = write(cg_test_b_procs_fd, "0", 1)) >= 0 || errno != ENOENT)
		goto cleanup;

	ret = KSFT_PASS;

cleanup:
	cg_enter_current(root);
	if (cg_test_b_procs_fd >= 0)
		close(cg_test_b_procs_fd);
	if (cg_test_b)
		cg_destroy(cg_test_b);
	if (cg_test_a)
		cg_destroy(cg_test_a);
	free(cg_test_b_procs);

Annotation

Implementation Notes