linux/include/linux/projid.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PROJID_H
#define _LINUX_PROJID_H

/*
 * A set of types for the internal kernel types representing project ids.
 *
 * The types defined in this header allow distinguishing which project ids in
 * the kernel are values used by userspace and which project id values are
 * the internal kernel values.  With the addition of user namespaces the values
 * can be different.  Using the type system makes it possible for the compiler
 * to detect when we overlook these differences.
 *
 */
#include <linux/types.h>

struct user_namespace;
extern struct user_namespace init_user_ns;

projid_t;

kprojid_t;

static inline projid_t __kprojid_val(kprojid_t projid)
{ … }

#define KPROJIDT_INIT(value) …

#define INVALID_PROJID …
#define OVERFLOW_PROJID …

static inline bool projid_eq(kprojid_t left, kprojid_t right)
{ … }

static inline bool projid_lt(kprojid_t left, kprojid_t right)
{ … }

static inline bool projid_valid(kprojid_t projid)
{ … }

#ifdef CONFIG_USER_NS

extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);

extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);

static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
{ … }

#else

static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
{
	return KPROJIDT_INIT(projid);
}

static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
{
	return __kprojid_val(kprojid);
}

static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
{
	projid_t projid = from_kprojid(to, kprojid);
	if (projid == (projid_t)-1)
		projid = OVERFLOW_PROJID;
	return projid;
}

static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
{
	return true;
}

#endif /* CONFIG_USER_NS */

#endif /* _LINUX_PROJID_H */