fs/xfs/xfs_attr.h

   1 /*
   2  * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_ATTR_H__
  19 #define __XFS_ATTR_H__
  20
  21 /*
  22  * xfs_attr.h
  23  *
  24  * Large attribute lists are structured around Btrees where all the data
  25  * elements are in the leaf nodes.  Attribute names are hashed into an int,
  26  * then that int is used as the index into the Btree.  Since the hashval
  27  * of an attribute name may not be unique, we may have duplicate keys.
  28  * The internal links in the Btree are logical block offsets into the file.
  29  *
  30  * Small attribute lists use a different format and are packed as tightly
  31  * as possible so as to fit into the literal area of the inode.
  32  */
  33
  34 /*========================================================================
  35  * External interfaces
  36  *========================================================================*/
  37
  38 struct cred;
  39 struct vnode;
  40
  41 typedef int (*attrset_t)(struct vnode *, char *, void *, size_t, int);
  42 typedef int (*attrget_t)(struct vnode *, char *, void *, size_t, int);
  43 typedef int (*attrremove_t)(struct vnode *, char *, int);
  44 typedef int (*attrexists_t)(struct vnode *);
  45 typedef int (*attrcapable_t)(struct vnode *, struct cred *);
  46
  47 typedef struct attrnames {
  48         char *          attr_name;
  49         unsigned int    attr_namelen;
  50         unsigned int    attr_flag;
  51         attrget_t       attr_get;
  52         attrset_t       attr_set;
  53         attrremove_t    attr_remove;
  54         attrexists_t    attr_exists;
  55         attrcapable_t   attr_capable;
  56 } attrnames_t;
  57
  58 #define ATTR_NAMECOUNT  4
  59 extern struct attrnames attr_user;
  60 extern struct attrnames attr_secure;
  61 extern struct attrnames attr_system;
  62 extern struct attrnames attr_trusted;
  63 extern struct attrnames *attr_namespaces[ATTR_NAMECOUNT];
  64
  65 extern attrnames_t *attr_lookup_namespace(char *, attrnames_t **, int);
  66 extern int attr_generic_list(struct vnode *, void *, size_t, int, ssize_t *);
  67
  68 #define ATTR_DONTFOLLOW 0x0001  /* -- unused, from IRIX -- */
  69 #define ATTR_ROOT       0x0002  /* use attrs in root (trusted) namespace */
  70 #define ATTR_TRUST      0x0004  /* -- unused, from IRIX -- */
  71 #define ATTR_SECURE     0x0008  /* use attrs in security namespace */
  72 #define ATTR_CREATE     0x0010  /* pure create: fail if attr already exists */
  73 #define ATTR_REPLACE    0x0020  /* pure set: fail if attr does not exist */
  74 #define ATTR_SYSTEM     0x0100  /* use attrs in system (pseudo) namespace */
  75
  76 #define ATTR_KERNACCESS 0x0400  /* [kernel] iaccess, inode held io-locked */
  77 #define ATTR_KERNOTIME  0x1000  /* [kernel] don't update inode timestamps */
  78 #define ATTR_KERNOVAL   0x2000  /* [kernel] get attr size only, not value */
  79 #define ATTR_KERNAMELS  0x4000  /* [kernel] list attr names (simple list) */
  80
  81 #define ATTR_KERNORMALS 0x0800  /* [kernel] normal attr list: user+secure */
  82 #define ATTR_KERNROOTLS 0x8000  /* [kernel] include root in the attr list */
  83 #define ATTR_KERNFULLS  (ATTR_KERNORMALS|ATTR_KERNROOTLS)
  84
  85 /*
  86  * The maximum size (into the kernel or returned from the kernel) of an
  87  * attribute value or the buffer used for an attr_list() call.  Larger
  88  * sizes will result in an ERANGE return code.
  89  */
  90 #define ATTR_MAX_VALUELEN       (64*1024)       /* max length of a value */
  91
  92 /*
  93  * Define how lists of attribute names are returned to the user from
  94  * the attr_list() call.  A large, 32bit aligned, buffer is passed in
  95  * along with its size.  We put an array of offsets at the top that each
  96  * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
  97  */
  98 typedef struct attrlist {
  99         __s32   al_count;       /* number of entries in attrlist */
 100         __s32   al_more;        /* T/F: more attrs (do call again) */
 101         __s32   al_offset[1];   /* byte offsets of attrs [var-sized] */
 102 } attrlist_t;
 103
 104 /*
 105  * Show the interesting info about one attribute.  This is what the
 106  * al_offset[i] entry points to.
 107  */
 108 typedef struct attrlist_ent {   /* data from attr_list() */
 109         __u32   a_valuelen;     /* number bytes in value of attr */
 110         char    a_name[1];      /* attr name (NULL terminated) */
 111 } attrlist_ent_t;
 112
 113 /*
 114  * Given a pointer to the (char*) buffer containing the attr_list() result,
 115  * and an index, return a pointer to the indicated attribute in the buffer.
 116  */
 117 #define ATTR_ENTRY(buffer, index)               \
 118         ((attrlist_ent_t *)                     \
 119          &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
 120
 121 /*
 122  * Multi-attribute operation vector.
 123  */
 124 typedef struct attr_multiop {
 125         int     am_opcode;      /* operation to perform (ATTR_OP_GET, etc.) */
 126         int     am_error;       /* [out arg] result of this sub-op (an errno) */
 127         char    *am_attrname;   /* attribute name to work with */
 128         char    *am_attrvalue;  /* [in/out arg] attribute value (raw bytes) */
 129         int     am_length;      /* [in/out arg] length of value */
 130         int     am_flags;       /* bitwise OR of attr API flags defined above */
 131 } attr_multiop_t;
 132
 133 #define ATTR_OP_GET     1       /* return the indicated attr's value */
 134 #define ATTR_OP_SET     2       /* set/create the indicated attr/value pair */
 135 #define ATTR_OP_REMOVE  3       /* remove the indicated attr */
 136
 137 /*
 138  * Kernel-internal version of the attrlist cursor.
 139  */
 140 typedef struct attrlist_cursor_kern {
 141         __u32   hashval;        /* hash value of next entry to add */
 142         __u32   blkno;          /* block containing entry (suggestion) */
 143         __u32   offset;         /* offset in list of equal-hashvals */
 144         __u16   pad1;           /* padding to match user-level */
 145         __u8    pad2;           /* padding to match user-level */
 146         __u8    initted;        /* T/F: cursor has been initialized */
 147 } attrlist_cursor_kern_t;
 148
 149
 150 /*========================================================================
 151  * Function prototypes for the kernel.
 152  *========================================================================*/
 153
 154 struct xfs_inode;
 155 struct attrlist_cursor_kern;
 156 struct xfs_da_args;
 157
 158 /*
 159  * Overall external interface routines.
 160  */
 161 int xfs_attr_get(bhv_desc_t *, const char *, char *, int *, int, struct cred *);
 162 int xfs_attr_set(bhv_desc_t *, const char *, char *, int, int, struct cred *);
 163 int xfs_attr_remove(bhv_desc_t *, const char *, int, struct cred *);
 164 int xfs_attr_list(bhv_desc_t *, char *, int, int,
 165                          struct attrlist_cursor_kern *, struct cred *);
 166 int xfs_attr_inactive(struct xfs_inode *dp);
 167
 168 int xfs_attr_shortform_getvalue(struct xfs_da_args *);
 169 int xfs_attr_fetch(struct xfs_inode *, const char *, int,
 170                         char *, int *, int, struct cred *);
 171
 172 #endif  /* __XFS_ATTR_H__ */