include/linux/mnt_idmapping.h

Source file repositories/reference/linux-study-clean/include/linux/mnt_idmapping.h

File Facts

System
Linux kernel
Corpus path
include/linux/mnt_idmapping.h
Extension
.h
Size
7186 bytes
Lines
254
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

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

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _LINUX_MNT_IDMAPPING_H
#define _LINUX_MNT_IDMAPPING_H

#include <linux/types.h>
#include <linux/uidgid.h>

struct mnt_idmap;
struct user_namespace;

extern struct mnt_idmap nop_mnt_idmap;
extern struct mnt_idmap invalid_mnt_idmap;
extern struct user_namespace init_user_ns;

typedef struct {
	uid_t val;
} vfsuid_t;

typedef struct {
	gid_t val;
} vfsgid_t;

static_assert(sizeof(vfsuid_t) == sizeof(kuid_t));
static_assert(sizeof(vfsgid_t) == sizeof(kgid_t));
static_assert(offsetof(vfsuid_t, val) == offsetof(kuid_t, val));
static_assert(offsetof(vfsgid_t, val) == offsetof(kgid_t, val));

static inline bool is_valid_mnt_idmap(const struct mnt_idmap *idmap)
{
	return idmap != &nop_mnt_idmap && idmap != &invalid_mnt_idmap;
}

#ifdef CONFIG_MULTIUSER
static inline uid_t __vfsuid_val(vfsuid_t uid)
{
	return uid.val;
}

static inline gid_t __vfsgid_val(vfsgid_t gid)
{
	return gid.val;
}
#else
static inline uid_t __vfsuid_val(vfsuid_t uid)
{
	return 0;
}

static inline gid_t __vfsgid_val(vfsgid_t gid)
{
	return 0;
}
#endif

static inline bool vfsuid_valid(vfsuid_t uid)
{
	return __vfsuid_val(uid) != (uid_t)-1;
}

static inline bool vfsgid_valid(vfsgid_t gid)
{
	return __vfsgid_val(gid) != (gid_t)-1;
}

static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right)
{
	return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right);
}

static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right)
{
	return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right);
}

/**
 * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value
 * @vfsuid: the vfsuid to compare
 * @kuid: the kuid to compare
 *
 * Check whether @vfsuid and @kuid have the same values.
 *
 * Return: true if @vfsuid and @kuid have the same value, false if not.
 * Comparison between two invalid uids returns false.
 */
static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid)
{
	return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid);
}

/**
 * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value

Annotation

Implementation Notes