posix_acl.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3  File: linux/posix_acl.h
  4
  5  (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
  6*/
  7
  8
  9#ifndef __LINUX_POSIX_ACL_H
 10#define __LINUX_POSIX_ACL_H
 11
 12#include <linux/bug.h>
 13#include <linux/slab.h>
 14#include <linux/rcupdate.h>
 15#include <linux/refcount.h>
 16#include <uapi/linux/posix_acl.h>
 17
 18struct user_namespace;
 19
 20struct posix_acl_entry {
 21	short			e_tag;
 22	unsigned short		e_perm;
 23	union {
 24		kuid_t		e_uid;
 25		kgid_t		e_gid;
 26	};
 27};
 28
 29struct posix_acl {
 30	/* New members MUST be added within the struct_group() macro below. */
 31	struct_group_tagged(posix_acl_hdr, hdr,
 32		refcount_t		a_refcount;
 33		unsigned int		a_count;
 34		struct rcu_head		a_rcu;
 35	);
 36	struct posix_acl_entry	a_entries[] __counted_by(a_count);
 37};
 38static_assert(offsetof(struct posix_acl, a_entries) == sizeof(struct posix_acl_hdr),
 39	      "struct member likely outside of struct_group_tagged()");
 40
 41#define FOREACH_ACL_ENTRY(pa, acl, pe) \
 42	for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
 43
 44
 45/*
 46 * Duplicate an ACL handle.
 47 */
 48static inline struct posix_acl *
 49posix_acl_dup(struct posix_acl *acl)
 50{
 51	if (acl)
 52		refcount_inc(&acl->a_refcount);
 53	return acl;
 54}
 55
 56/*
 57 * Free an ACL handle.
 58 */
 59static inline void
 60posix_acl_release(struct posix_acl *acl)
 61{
 62	if (acl && refcount_dec_and_test(&acl->a_refcount))
 63		kfree_rcu(acl, a_rcu);
 64}
 65
 66
 67/* posix_acl.c */
 68
 69extern void posix_acl_init(struct posix_acl *, int);
 70extern struct posix_acl *posix_acl_alloc(unsigned int count, gfp_t flags);
 71extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
 72extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
 73extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
 74extern int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
 75
 76extern struct posix_acl *get_posix_acl(struct inode *, int);
 77int set_posix_acl(struct mnt_idmap *, struct dentry *, int,
 78		  struct posix_acl *);
 79
 80struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
 81struct posix_acl *posix_acl_clone(const struct posix_acl *acl, gfp_t flags);
 82
 83#ifdef CONFIG_FS_POSIX_ACL
 84int posix_acl_chmod(struct mnt_idmap *, struct dentry *, umode_t);
 85extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
 86		struct posix_acl **);
 87int posix_acl_update_mode(struct mnt_idmap *, struct inode *, umode_t *,
 88			  struct posix_acl **);
 89
 90int simple_set_acl(struct mnt_idmap *, struct dentry *,
 91		   struct posix_acl *, int);
 92extern int simple_acl_create(struct inode *, struct inode *);
 93
 94struct posix_acl *get_cached_acl(struct inode *inode, int type);
 95void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
 96void forget_cached_acl(struct inode *inode, int type);
 97void forget_all_cached_acls(struct inode *inode);
 98int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
 99int posix_acl_permission(struct mnt_idmap *, struct inode *,
100			 const struct posix_acl *, int);
101
102static inline void cache_no_acl(struct inode *inode)
103{
104	inode->i_acl = NULL;
105	inode->i_default_acl = NULL;
106}
107
108int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
109		const char *acl_name, struct posix_acl *kacl);
110struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
111			      struct dentry *dentry, const char *acl_name);
112int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
113		   const char *acl_name);
114int posix_acl_listxattr(struct inode *inode, char **buffer,
115			ssize_t *remaining_size);
116#else
117static inline int posix_acl_chmod(struct mnt_idmap *idmap,
118				  struct dentry *dentry, umode_t mode)
119{
120	return 0;
121}
122
123#define simple_set_acl		NULL
124
125static inline int simple_acl_create(struct inode *dir, struct inode *inode)
126{
127	return 0;
128}
129static inline void cache_no_acl(struct inode *inode)
130{
131}
132
133static inline int posix_acl_create(struct inode *inode, umode_t *mode,
134		struct posix_acl **default_acl, struct posix_acl **acl)
135{
136	*default_acl = *acl = NULL;
137	return 0;
138}
139
140static inline void forget_all_cached_acls(struct inode *inode)
141{
142}
143
144static inline int vfs_set_acl(struct mnt_idmap *idmap,
145			      struct dentry *dentry, const char *name,
146			      struct posix_acl *acl)
147{
148	return -EOPNOTSUPP;
149}
150
151static inline struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
152					    struct dentry *dentry,
153					    const char *acl_name)
154{
155	return ERR_PTR(-EOPNOTSUPP);
156}
157
158static inline int vfs_remove_acl(struct mnt_idmap *idmap,
159				 struct dentry *dentry, const char *acl_name)
160{
161	return -EOPNOTSUPP;
162}
163static inline int posix_acl_listxattr(struct inode *inode, char **buffer,
164				      ssize_t *remaining_size)
165{
166	return 0;
167}
168#endif /* CONFIG_FS_POSIX_ACL */
169
170struct posix_acl *get_inode_acl(struct inode *inode, int type);
171
172#endif  /* __LINUX_POSIX_ACL_H */