tools/testing/selftests/filesystems/utils.h

File Facts

System

Linux kernel

Corpus path

tools/testing/selftests/filesystems/utils.h

Extension

.h

Size

1103 bytes

Lines

52

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.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.

Dependency Surface

• errno.h
• linux/types.h
• sched.h
• signal.h
• stdbool.h
• stdio.h
• stdlib.h
• string.h
• syscall.h
• sys/capability.h
• sys/fsuid.h
• sys/types.h
• unistd.h

Detected Declarations

• function switch_userns

Annotated Snippet

#ifndef __IDMAP_UTILS_H
#define __IDMAP_UTILS_H

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <errno.h>
#include <linux/types.h>
#include <sched.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/capability.h>
#include <sys/fsuid.h>
#include <sys/types.h>
#include <unistd.h>

extern int get_userns_fd(unsigned long nsid, unsigned long hostid,
			 unsigned long range);

extern int caps_down(void);
extern int cap_down(cap_value_t down);

extern bool switch_ids(uid_t uid, gid_t gid);
extern int setup_userns(void);
extern int enter_userns(void);

static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)
{
	if (setns(fd, CLONE_NEWUSER))
		return false;

	if (!switch_ids(uid, gid))
		return false;

	if (drop_caps && !caps_down())
		return false;

	return true;
}

extern int wait_for_pid(pid_t pid);
extern int write_file(const char *path, const char *val);
extern uint64_t get_unique_mnt_id(const char *path);

#endif /* __IDMAP_UTILS_H */

Annotation

• Immediate include surface: `errno.h`, `linux/types.h`, `sched.h`, `signal.h`, `stdbool.h`, `stdio.h`, `stdlib.h`, `string.h`.
• Detected declarations: `function switch_userns`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

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.