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 bhv_vnode;
  40 struct xfs_attr_list_context;
  41
  42 typedef int (*attrset_t)(struct bhv_vnode *, char *, void *, size_t, int);
  43 typedef int (*attrget_t)(struct bhv_vnode *, char *, void *, size_t, int);
  44 typedef int (*attrremove_t)(struct bhv_vnode *, char *, int);
  45 typedef int (*attrexists_t)(struct bhv_vnode *);
  46 typedef int (*attrcapable_t)(struct bhv_vnode *, struct cred *);
  47
  48 typedef struct attrnames {
  49         char *          attr_name;
  50         unsigned int    attr_namelen;
  51         unsigned int    attr_flag;
  52         attrget_t       attr_get;
  53         attrset_t       attr_set;
  54         attrremove_t    attr_remove;
  55         attrexists_t    attr_exists;
  56         attrcapable_t   attr_capable;
  57 } attrnames_t;
  58
  59 #define ATTR_NAMECOUNT  4
  60 extern struct attrnames attr_user;
  61 extern struct attrnames attr_secure;
  62 extern struct attrnames attr_system;
  63 extern struct attrnames attr_trusted;
  64 extern struct attrnames *attr_namespaces[ATTR_NAMECOUNT];
  65
  66 extern attrnames_t *attr_lookup_namespace(char *, attrnames_t **, int);
  67 extern int attr_generic_list(struct bhv_vnode *, void *, size_t, int, ssize_t *);
  68
  69 #define ATTR_DONTFOLLOW 0x0001  /* -- unused, from IRIX -- */
  70 #define ATTR_ROOT       0x0002  /* use attrs in root (trusted) namespace */
  71 #define ATTR_TRUST      0x0004  /* -- unused, from IRIX -- */
  72 #define ATTR_SECURE     0x0008  /* use attrs in security namespace */
  73 #define ATTR_CREATE     0x0010  /* pure create: fail if attr already exists */
  74 #define ATTR_REPLACE    0x0020  /* pure set: fail if attr does not exist */
  75 #define ATTR_SYSTEM     0x0100  /* use attrs in system (pseudo) namespace */
  76
  77 #define ATTR_KERNACCESS 0x0400  /* [kernel] iaccess, inode held io-locked */
  78 #define ATTR_KERNOTIME  0x1000  /* [kernel] don't update inode timestamps */
  79 #define ATTR_KERNOVAL   0x2000  /* [kernel] get attr size only, not value */
  80 #define ATTR_KERNAMELS  0x4000  /* [kernel] list attr names (simple list) */
  81
  82 #define ATTR_KERNORMALS 0x0800  /* [kernel] normal attr list: user+secure */
  83 #define ATTR_KERNROOTLS 0x8000  /* [kernel] include root in the attr list */
  84 #define ATTR_KERNFULLS  (ATTR_KERNORMALS|ATTR_KERNROOTLS)
  85
  86 /*
  87  * The maximum size (into the kernel or returned from the kernel) of an
  88  * attribute value or the buffer used for an attr_list() call.  Larger
  89  * sizes will result in an ERANGE return code.
  90  */
  91 #define ATTR_MAX_VALUELEN       (64*1024)       /* max length of a value */
  92
  93 /*
  94  * Define how lists of attribute names are returned to the user from
  95  * the attr_list() call.  A large, 32bit aligned, buffer is passed in
  96  * along with its size.  We put an array of offsets at the top that each
  97  * reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
  98  */
  99 typedef struct attrlist {
 100         __s32   al_count;       /* number of entries in attrlist */
 101         __s32   al_more;        /* T/F: more attrs (do call again) */
 102         __s32   al_offset[1];   /* byte offsets of attrs [var-sized] */
 103 } attrlist_t;
 104
 105 /*
 106  * Show the interesting info about one attribute.  This is what the
 107  * al_offset[i] entry points to.
 108  */
 109 typedef struct attrlist_ent {   /* data from attr_list() */
 110         __u32   a_valuelen;     /* number bytes in value of attr */
 111         char    a_name[1];      /* attr name (NULL terminated) */
 112 } attrlist_ent_t;
 113
 114 /*
 115  * Given a pointer to the (char*) buffer containing the attr_list() result,
 116  * and an index, return a pointer to the indicated attribute in the buffer.
 117  */
 118 #define ATTR_ENTRY(buffer, index)               \
 119         ((attrlist_ent_t *)                     \
 120          &((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
 121
 122 /*
 123  * Multi-attribute operation vector.
 124  */
 125 typedef struct attr_multiop {
 126         int     am_opcode;      /* operation to perform (ATTR_OP_GET, etc.) */
 127         int     am_error;       /* [out arg] result of this sub-op (an errno) */
 128         char    *am_attrname;   /* attribute name to work with */
 129         char    *am_attrvalue;  /* [in/out arg] attribute value (raw bytes) */
 130         int     am_length;      /* [in/out arg] length of value */
 131         int     am_flags;       /* bitwise OR of attr API flags defined above */
 132 } attr_multiop_t;
 133
 134 #define ATTR_OP_GET     1       /* return the indicated attr's value */
 135 #define ATTR_OP_SET     2       /* set/create the indicated attr/value pair */
 136 #define ATTR_OP_REMOVE  3       /* remove the indicated attr */
 137
 138 /*
 139  * Kernel-internal version of the attrlist cursor.
 140  */
 141 typedef struct attrlist_cursor_kern {
 142         __u32   hashval;        /* hash value of next entry to add */
 143         __u32   blkno;          /* block containing entry (suggestion) */
 144         __u32   offset;         /* offset in list of equal-hashvals */
 145         __u16   pad1;           /* padding to match user-level */
 146         __u8    pad2;           /* padding to match user-level */
 147         __u8    initted;        /* T/F: cursor has been initialized */
 148 } attrlist_cursor_kern_t;
 149
 150
 151 /*========================================================================
 152  * Function prototypes for the kernel.
 153  *========================================================================*/
 154
 155 struct xfs_inode;
 156 struct attrlist_cursor_kern;
 157 struct xfs_da_args;
 158
 159 /*
 160  * Overall external interface routines.
 161  */
 162 int xfs_attr_get(bhv_desc_t *, const char *, char *, int *, int, struct cred *);
 163 int xfs_attr_set(bhv_desc_t *, const char *, char *, int, int, struct cred *);
 164 int xfs_attr_set_int(struct xfs_inode *, const char *, int, char *, int, int);
 165 int xfs_attr_remove(bhv_desc_t *, const char *, int, struct cred *);
 166 int xfs_attr_remove_int(struct xfs_inode *, const char *, int, int);
 167 int xfs_attr_list(bhv_desc_t *, char *, int, int, struct attrlist_cursor_kern *, struct cred *);
 168 int xfs_attr_list_int(struct xfs_attr_list_context *);
 169 int xfs_attr_inactive(struct xfs_inode *dp);
 170
 171 int xfs_attr_shortform_getvalue(struct xfs_da_args *);
 172 int xfs_attr_fetch(struct xfs_inode *, const char *, int,
 173                         char *, int *, int, struct cred *);
 174 int xfs_attr_rmtval_get(struct xfs_da_args *args);
 175
 176 #endif  /* __XFS_ATTR_H__ */