kernel/nsproxy.c

File Facts

System

Linux kernel

Corpus path

kernel/nsproxy.c

Extension

.c

Size

13794 bytes

Lines

614

Domain

Core OS

Bucket

Scheduler, Processes, Timers, Sync, And Syscalls

Inferred role

Core OS: syscall or user/kernel boundary

Status

core implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Defines or participates in a user/kernel boundary; inspect argument validation, copy_from_user/copy_to_user, credentials, and dispatch target.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/slab.h
• linux/export.h
• linux/nsproxy.h
• linux/ns/ns_common_types.h
• linux/init_task.h
• linux/mnt_namespace.h
• linux/utsname.h
• linux/pid_namespace.h
• net/net_namespace.h
• linux/ipc_namespace.h
• linux/time_namespace.h
• linux/fs_struct.h
• linux/proc_fs.h
• linux/proc_ns.h
• linux/file.h
• linux/syscalls.h
• linux/cgroup.h
• linux/perf_event.h
• linux/nstree.h

Detected Declarations

• syscall setns
• function nsproxy_free
• function deactivate_nsproxy
• function copy_namespaces
• function unshare_nsproxy_namespaces
• function switch_task_namespaces
• function exit_nsproxy_namespaces
• function switch_cred_namespaces
• function get_cred_namespaces
• function exit_cred_namespaces
• function exec_task_namespaces
• function check_setns_flags
• function put_nsset
• function prepare_nsset
• function validate_ns
• function unshare
• function commit_nsset
• function nsproxy_cache_init

Annotated Snippet

SYSCALL_DEFINE2(setns, int, fd, int, flags)
{
	CLASS(fd, f)(fd);
	struct ns_common *ns = NULL;
	struct nsset nsset = {};
	int err = 0;

	if (fd_empty(f))
		return -EBADF;

	if (proc_ns_file(fd_file(f))) {
		ns = get_proc_ns(file_inode(fd_file(f)));
		if (flags && (ns->ns_type != flags))
			err = -EINVAL;
		flags = ns->ns_type;
	} else if (!IS_ERR(pidfd_pid(fd_file(f)))) {
		err = check_setns_flags(flags);
	} else {
		err = -EINVAL;
	}
	if (err)
		goto out;

	err = prepare_nsset(flags, &nsset);
	if (err)
		goto out;

	if (proc_ns_file(fd_file(f)))
		err = validate_ns(&nsset, ns);
	else
		err = validate_nsset(&nsset, pidfd_pid(fd_file(f)));
	if (!err) {
		commit_nsset(&nsset);
		perf_event_namespaces(current);
	}
	put_nsset(&nsset);
out:
	return err;
}

int __init nsproxy_cache_init(void)
{
	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
	return 0;
}

Annotation

• Immediate include surface: `linux/slab.h`, `linux/export.h`, `linux/nsproxy.h`, `linux/ns/ns_common_types.h`, `linux/init_task.h`, `linux/mnt_namespace.h`, `linux/utsname.h`, `linux/pid_namespace.h`.
• Detected declarations: `syscall setns`, `function nsproxy_free`, `function deactivate_nsproxy`, `function copy_namespaces`, `function unshare_nsproxy_namespaces`, `function switch_task_namespaces`, `function exit_nsproxy_namespaces`, `function switch_cred_namespaces`, `function get_cred_namespaces`, `function exit_cred_namespaces`.
• Atlas domain: Core OS / Scheduler, Processes, Timers, Sync, And Syscalls.
• Implementation status: core implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.