tools/testing/selftests/proc/setns-dcache.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/proc/setns-dcache.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/proc/setns-dcache.c
Extension
.c
Size
2612 bytes
Lines
130
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

if (errno == ENOSYS || errno == EPERM) {
			return 4;
		}
		return 1;
	}
	/* Distinguisher between two otherwise empty net namespaces. */
	if (socket(AF_UNIX, SOCK_STREAM, 0) == -1) {
		return 1;
	}

	if (pipe(fd) == -1) {
		return 1;
	}

	pid = fork();
	if (pid == -1) {
		return 1;
	}

	if (pid == 0) {
		if (unshare(CLONE_NEWNET) == -1) {
			return 1;
		}

		if (write(fd[1], &_, 1) != 1) {
			return 1;
		}

		pause();

		return 0;
	}

	if (read(fd[0], &_, 1) != 1) {
		return 1;
	}

	{
		char buf[64];
		snprintf(buf, sizeof(buf), "/proc/%u/ns/net", pid);
		nsfd = open(buf, O_RDONLY);
		if (nsfd == -1) {
			return 1;
		}
	}

	/* Reliably pin dentry into dcache. */
	(void)open("/proc/net/unix", O_RDONLY);

	if (setns(nsfd, CLONE_NEWNET) == -1) {
		return 1;
	}

	kill(pid, SIGTERM);
	pid = 0;

	{
		char buf[4096];
		ssize_t rv;
		int fd;

		fd = open("/proc/net/unix", O_RDONLY);
		if (fd == -1) {
			return 1;
		}

#define S "Num       RefCount Protocol Flags    Type St Inode Path\n"
		rv = read(fd, buf, sizeof(buf));

		assert(rv == strlen(S));
		assert(memcmp(buf, S, strlen(S)) == 0);
	}

	return 0;
}

Annotation

Implementation Notes