172 lines
3.9 KiB
C
172 lines
3.9 KiB
C
/*
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File: linux/posix_acl.h
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(C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
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*/
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#ifndef __LINUX_POSIX_ACL_H
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#define __LINUX_POSIX_ACL_H
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#include <linux/slab.h>
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#include <linux/rcupdate.h>
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#define ACL_UNDEFINED_ID (-1)
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/* a_type field in acl_user_posix_entry_t */
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#define ACL_TYPE_ACCESS (0x8000)
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#define ACL_TYPE_DEFAULT (0x4000)
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/* e_tag entry in struct posix_acl_entry */
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#define ACL_USER_OBJ (0x01)
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#define ACL_USER (0x02)
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#define ACL_GROUP_OBJ (0x04)
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#define ACL_GROUP (0x08)
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#define ACL_MASK (0x10)
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#define ACL_OTHER (0x20)
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/* permissions in the e_perm field */
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#define ACL_READ (0x04)
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#define ACL_WRITE (0x02)
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#define ACL_EXECUTE (0x01)
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//#define ACL_ADD (0x08)
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//#define ACL_DELETE (0x10)
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struct posix_acl_entry {
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short e_tag;
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unsigned short e_perm;
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unsigned int e_id;
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};
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struct posix_acl {
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union {
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atomic_t a_refcount;
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struct rcu_head a_rcu;
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};
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unsigned int a_count;
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struct posix_acl_entry a_entries[0];
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};
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#define FOREACH_ACL_ENTRY(pa, acl, pe) \
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for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
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/*
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* Duplicate an ACL handle.
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*/
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static inline struct posix_acl *
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posix_acl_dup(struct posix_acl *acl)
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{
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if (acl)
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atomic_inc(&acl->a_refcount);
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return acl;
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}
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/*
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* Free an ACL handle.
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*/
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static inline void
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posix_acl_release(struct posix_acl *acl)
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{
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if (acl && atomic_dec_and_test(&acl->a_refcount))
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kfree_rcu(acl, a_rcu);
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}
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/* posix_acl.c */
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extern void posix_acl_init(struct posix_acl *, int);
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extern struct posix_acl *posix_acl_alloc(int, gfp_t);
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extern int posix_acl_valid(const struct posix_acl *);
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extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
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extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
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extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
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extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
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extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
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extern struct posix_acl *get_posix_acl(struct inode *, int);
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extern int set_posix_acl(struct inode *, int, struct posix_acl *);
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#ifdef CONFIG_FS_POSIX_ACL
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static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
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{
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switch (type) {
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case ACL_TYPE_ACCESS:
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return &inode->i_acl;
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case ACL_TYPE_DEFAULT:
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return &inode->i_default_acl;
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default:
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BUG();
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}
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}
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static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *acl = ACCESS_ONCE(*p);
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if (acl) {
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spin_lock(&inode->i_lock);
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acl = *p;
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if (acl != ACL_NOT_CACHED)
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acl = posix_acl_dup(acl);
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spin_unlock(&inode->i_lock);
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}
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return acl;
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}
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static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
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{
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return rcu_dereference(*acl_by_type(inode, type));
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}
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static inline void set_cached_acl(struct inode *inode,
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int type,
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struct posix_acl *acl)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *old;
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spin_lock(&inode->i_lock);
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old = *p;
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rcu_assign_pointer(*p, posix_acl_dup(acl));
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spin_unlock(&inode->i_lock);
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if (old != ACL_NOT_CACHED)
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posix_acl_release(old);
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}
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static inline void forget_cached_acl(struct inode *inode, int type)
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{
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struct posix_acl **p = acl_by_type(inode, type);
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struct posix_acl *old;
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spin_lock(&inode->i_lock);
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old = *p;
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*p = ACL_NOT_CACHED;
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spin_unlock(&inode->i_lock);
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if (old != ACL_NOT_CACHED)
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posix_acl_release(old);
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}
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static inline void forget_all_cached_acls(struct inode *inode)
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{
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struct posix_acl *old_access, *old_default;
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spin_lock(&inode->i_lock);
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old_access = inode->i_acl;
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old_default = inode->i_default_acl;
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inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
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spin_unlock(&inode->i_lock);
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if (old_access != ACL_NOT_CACHED)
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posix_acl_release(old_access);
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if (old_default != ACL_NOT_CACHED)
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posix_acl_release(old_default);
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}
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#endif
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static inline void cache_no_acl(struct inode *inode)
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{
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#ifdef CONFIG_FS_POSIX_ACL
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inode->i_acl = NULL;
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inode->i_default_acl = NULL;
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#endif
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}
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#endif /* __LINUX_POSIX_ACL_H */
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