tools/testing/selftests/filesystems/nsfs/pidns.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/filesystems/nsfs/pidns.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/filesystems/nsfs/pidns.c
Extension
.c
Size
1820 bytes
Lines
80
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 cr_clone_arg {
	char stack[128] __stack_aligned__;
	char stack_ptr[];
};

static int child(void *args)
{
	prctl(PR_SET_PDEATHSIG, SIGKILL);
	while (1)
		sleep(1);
	exit(0);
}

int main(int argc, char *argv[])
{
	char *ns_strs[] = {"pid", "user"};
	char path[] = "/proc/0123456789/ns/pid";
	struct cr_clone_arg ca;
	struct stat st1, st2;
	int ns, pns, i;
	pid_t pid;

	pid = clone(child, ca.stack_ptr, CLONE_NEWUSER | CLONE_NEWPID | SIGCHLD, NULL);
	if (pid < 0)
		return pr_err("clone");

	for (i = 0; i < 2; i++) {
		snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, ns_strs[i]);
		ns = open(path, O_RDONLY);
		if (ns < 0)
			return pr_err("Unable to open %s", path);

		pns = ioctl(ns, NS_GET_PARENT);
		if (pns < 0)
			return pr_err("Unable to get a parent pidns");

		snprintf(path, sizeof(path), "/proc/self/ns/%s", ns_strs[i]);
		if (stat(path, &st2))
			return pr_err("Unable to stat %s", path);
		if (fstat(pns, &st1))
			return pr_err("Unable to stat the parent pidns");
		if (st1.st_ino != st2.st_ino)
			return pr_err("NS_GET_PARENT returned a wrong namespace");

		if (ioctl(pns, NS_GET_PARENT) >= 0 || errno != EPERM)
			return pr_err("Don't get EPERM");
	}

	kill(pid, SIGKILL);
	wait(NULL);
	return 0;
}

Annotation

Implementation Notes