4 * UID and GID to name mapping for clients.
6 * Copyright (c) 2002 The Regents of the University of Michigan.
9 * Marius Aamodt Eriksen <marius@umich.edu>
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its
21 * contributors may be used to endorse or promote products derived
22 * from this software without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
31 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 #include <linux/types.h>
37 #include <linux/parser.h>
39 #include <linux/nfs_idmap.h>
40 #include <net/net_namespace.h>
41 #include <linux/sunrpc/rpc_pipe_fs.h>
42 #include <linux/nfs_fs.h>
43 #include <linux/nfs_fs_sb.h>
44 #include <linux/key.h>
45 #include <linux/keyctl.h>
46 #include <linux/key-type.h>
47 #include <keys/user-type.h>
48 #include <linux/module.h>
53 #define NFS_UINT_MAXLEN 11
55 static const struct cred
*id_resolver_cache
;
56 static struct key_type key_type_id_resolver_legacy
;
59 struct rpc_pipe
*idmap_pipe
;
60 struct key_construction
*idmap_key_cons
;
61 struct mutex idmap_mutex
;
64 struct idmap_legacy_upcalldata
{
65 struct rpc_pipe_msg pipe_msg
;
66 struct idmap_msg idmap_msg
;
71 * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
72 * @fattr: fully initialised struct nfs_fattr
73 * @owner_name: owner name string cache
74 * @group_name: group name string cache
76 void nfs_fattr_init_names(struct nfs_fattr
*fattr
,
77 struct nfs4_string
*owner_name
,
78 struct nfs4_string
*group_name
)
80 fattr
->owner_name
= owner_name
;
81 fattr
->group_name
= group_name
;
84 static void nfs_fattr_free_owner_name(struct nfs_fattr
*fattr
)
86 fattr
->valid
&= ~NFS_ATTR_FATTR_OWNER_NAME
;
87 kfree(fattr
->owner_name
->data
);
90 static void nfs_fattr_free_group_name(struct nfs_fattr
*fattr
)
92 fattr
->valid
&= ~NFS_ATTR_FATTR_GROUP_NAME
;
93 kfree(fattr
->group_name
->data
);
96 static bool nfs_fattr_map_owner_name(struct nfs_server
*server
, struct nfs_fattr
*fattr
)
98 struct nfs4_string
*owner
= fattr
->owner_name
;
101 if (!(fattr
->valid
& NFS_ATTR_FATTR_OWNER_NAME
))
103 if (nfs_map_name_to_uid(server
, owner
->data
, owner
->len
, &uid
) == 0) {
105 fattr
->valid
|= NFS_ATTR_FATTR_OWNER
;
110 static bool nfs_fattr_map_group_name(struct nfs_server
*server
, struct nfs_fattr
*fattr
)
112 struct nfs4_string
*group
= fattr
->group_name
;
115 if (!(fattr
->valid
& NFS_ATTR_FATTR_GROUP_NAME
))
117 if (nfs_map_group_to_gid(server
, group
->data
, group
->len
, &gid
) == 0) {
119 fattr
->valid
|= NFS_ATTR_FATTR_GROUP
;
125 * nfs_fattr_free_names - free up the NFSv4 owner and group strings
126 * @fattr: a fully initialised nfs_fattr structure
128 void nfs_fattr_free_names(struct nfs_fattr
*fattr
)
130 if (fattr
->valid
& NFS_ATTR_FATTR_OWNER_NAME
)
131 nfs_fattr_free_owner_name(fattr
);
132 if (fattr
->valid
& NFS_ATTR_FATTR_GROUP_NAME
)
133 nfs_fattr_free_group_name(fattr
);
137 * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
138 * @server: pointer to the filesystem nfs_server structure
139 * @fattr: a fully initialised nfs_fattr structure
141 * This helper maps the cached NFSv4 owner/group strings in fattr into
142 * their numeric uid/gid equivalents, and then frees the cached strings.
144 void nfs_fattr_map_and_free_names(struct nfs_server
*server
, struct nfs_fattr
*fattr
)
146 if (nfs_fattr_map_owner_name(server
, fattr
))
147 nfs_fattr_free_owner_name(fattr
);
148 if (nfs_fattr_map_group_name(server
, fattr
))
149 nfs_fattr_free_group_name(fattr
);
152 static int nfs_map_string_to_numeric(const char *name
, size_t namelen
, __u32
*res
)
157 if (memchr(name
, '@', namelen
) != NULL
|| namelen
>= sizeof(buf
))
159 memcpy(buf
, name
, namelen
);
161 if (strict_strtoul(buf
, 0, &val
) != 0)
167 static int nfs_map_numeric_to_string(__u32 id
, char *buf
, size_t buflen
)
169 return snprintf(buf
, buflen
, "%u", id
);
172 static struct key_type key_type_id_resolver
= {
173 .name
= "id_resolver",
174 .instantiate
= user_instantiate
,
176 .revoke
= user_revoke
,
177 .destroy
= user_destroy
,
178 .describe
= user_describe
,
182 static int nfs_idmap_init_keyring(void)
188 printk(KERN_NOTICE
"NFS: Registering the %s key type\n",
189 key_type_id_resolver
.name
);
191 cred
= prepare_kernel_cred(NULL
);
195 keyring
= key_alloc(&key_type_keyring
, ".id_resolver", 0, 0, cred
,
196 (KEY_POS_ALL
& ~KEY_POS_SETATTR
) |
197 KEY_USR_VIEW
| KEY_USR_READ
,
198 KEY_ALLOC_NOT_IN_QUOTA
);
199 if (IS_ERR(keyring
)) {
200 ret
= PTR_ERR(keyring
);
201 goto failed_put_cred
;
204 ret
= key_instantiate_and_link(keyring
, NULL
, 0, NULL
, NULL
);
208 ret
= register_key_type(&key_type_id_resolver
);
212 ret
= register_key_type(&key_type_id_resolver_legacy
);
214 goto failed_reg_legacy
;
216 set_bit(KEY_FLAG_ROOT_CAN_CLEAR
, &keyring
->flags
);
217 cred
->thread_keyring
= keyring
;
218 cred
->jit_keyring
= KEY_REQKEY_DEFL_THREAD_KEYRING
;
219 id_resolver_cache
= cred
;
223 unregister_key_type(&key_type_id_resolver
);
231 static void nfs_idmap_quit_keyring(void)
233 key_revoke(id_resolver_cache
->thread_keyring
);
234 unregister_key_type(&key_type_id_resolver
);
235 unregister_key_type(&key_type_id_resolver_legacy
);
236 put_cred(id_resolver_cache
);
240 * Assemble the description to pass to request_key()
241 * This function will allocate a new string and update dest to point
242 * at it. The caller is responsible for freeing dest.
244 * On error 0 is returned. Otherwise, the length of dest is returned.
246 static ssize_t
nfs_idmap_get_desc(const char *name
, size_t namelen
,
247 const char *type
, size_t typelen
, char **desc
)
250 size_t desclen
= typelen
+ namelen
+ 2;
252 *desc
= kmalloc(desclen
, GFP_KERNEL
);
257 memcpy(cp
, type
, typelen
);
261 memcpy(cp
, name
, namelen
);
267 static ssize_t
nfs_idmap_request_key(struct key_type
*key_type
,
268 const char *name
, size_t namelen
,
269 const char *type
, void *data
,
270 size_t data_size
, struct idmap
*idmap
)
272 const struct cred
*saved_cred
;
275 struct user_key_payload
*payload
;
278 ret
= nfs_idmap_get_desc(name
, namelen
, type
, strlen(type
), &desc
);
282 saved_cred
= override_creds(id_resolver_cache
);
284 rkey
= request_key_with_auxdata(key_type
, desc
, "", 0, idmap
);
286 rkey
= request_key(&key_type_id_resolver
, desc
, "");
287 revert_creds(saved_cred
);
296 rkey
->perm
|= KEY_USR_VIEW
;
298 ret
= key_validate(rkey
);
302 payload
= rcu_dereference(rkey
->payload
.data
);
303 if (IS_ERR_OR_NULL(payload
)) {
304 ret
= PTR_ERR(payload
);
308 ret
= payload
->datalen
;
309 if (ret
> 0 && ret
<= data_size
)
310 memcpy(data
, payload
->data
, ret
);
321 static ssize_t
nfs_idmap_get_key(const char *name
, size_t namelen
,
322 const char *type
, void *data
,
323 size_t data_size
, struct idmap
*idmap
)
325 ssize_t ret
= nfs_idmap_request_key(&key_type_id_resolver
,
326 name
, namelen
, type
, data
,
329 mutex_lock(&idmap
->idmap_mutex
);
330 ret
= nfs_idmap_request_key(&key_type_id_resolver_legacy
,
331 name
, namelen
, type
, data
,
333 idmap
->idmap_key_cons
= NULL
;
334 mutex_unlock(&idmap
->idmap_mutex
);
340 static ssize_t
nfs_idmap_lookup_name(__u32 id
, const char *type
, char *buf
,
341 size_t buflen
, struct idmap
*idmap
)
343 char id_str
[NFS_UINT_MAXLEN
];
347 id_len
= snprintf(id_str
, sizeof(id_str
), "%u", id
);
348 ret
= nfs_idmap_get_key(id_str
, id_len
, type
, buf
, buflen
, idmap
);
355 static int nfs_idmap_lookup_id(const char *name
, size_t namelen
, const char *type
,
356 __u32
*id
, struct idmap
*idmap
)
358 char id_str
[NFS_UINT_MAXLEN
];
363 data_size
= nfs_idmap_get_key(name
, namelen
, type
, id_str
, NFS_UINT_MAXLEN
, idmap
);
364 if (data_size
<= 0) {
367 ret
= strict_strtol(id_str
, 10, &id_long
);
368 *id
= (__u32
)id_long
;
373 /* idmap classic begins here */
376 Opt_find_uid
, Opt_find_gid
, Opt_find_user
, Opt_find_group
, Opt_find_err
379 static const match_table_t nfs_idmap_tokens
= {
380 { Opt_find_uid
, "uid:%s" },
381 { Opt_find_gid
, "gid:%s" },
382 { Opt_find_user
, "user:%s" },
383 { Opt_find_group
, "group:%s" },
384 { Opt_find_err
, NULL
}
387 static int nfs_idmap_legacy_upcall(struct key_construction
*, const char *, void *);
388 static ssize_t
idmap_pipe_downcall(struct file
*, const char __user
*,
390 static void idmap_release_pipe(struct inode
*);
391 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg
*);
393 static const struct rpc_pipe_ops idmap_upcall_ops
= {
394 .upcall
= rpc_pipe_generic_upcall
,
395 .downcall
= idmap_pipe_downcall
,
396 .release_pipe
= idmap_release_pipe
,
397 .destroy_msg
= idmap_pipe_destroy_msg
,
400 static struct key_type key_type_id_resolver_legacy
= {
402 .instantiate
= user_instantiate
,
404 .revoke
= user_revoke
,
405 .destroy
= user_destroy
,
406 .describe
= user_describe
,
408 .request_key
= nfs_idmap_legacy_upcall
,
411 static void __nfs_idmap_unregister(struct rpc_pipe
*pipe
)
414 rpc_unlink(pipe
->dentry
);
417 static int __nfs_idmap_register(struct dentry
*dir
,
419 struct rpc_pipe
*pipe
)
421 struct dentry
*dentry
;
423 dentry
= rpc_mkpipe_dentry(dir
, "idmap", idmap
, pipe
);
425 return PTR_ERR(dentry
);
426 pipe
->dentry
= dentry
;
430 static void nfs_idmap_unregister(struct nfs_client
*clp
,
431 struct rpc_pipe
*pipe
)
433 struct net
*net
= clp
->cl_net
;
434 struct super_block
*pipefs_sb
;
436 pipefs_sb
= rpc_get_sb_net(net
);
438 __nfs_idmap_unregister(pipe
);
443 static int nfs_idmap_register(struct nfs_client
*clp
,
445 struct rpc_pipe
*pipe
)
447 struct net
*net
= clp
->cl_net
;
448 struct super_block
*pipefs_sb
;
451 pipefs_sb
= rpc_get_sb_net(net
);
453 if (clp
->cl_rpcclient
->cl_dentry
)
454 err
= __nfs_idmap_register(clp
->cl_rpcclient
->cl_dentry
,
462 nfs_idmap_new(struct nfs_client
*clp
)
465 struct rpc_pipe
*pipe
;
468 BUG_ON(clp
->cl_idmap
!= NULL
);
470 idmap
= kzalloc(sizeof(*idmap
), GFP_KERNEL
);
474 pipe
= rpc_mkpipe_data(&idmap_upcall_ops
, 0);
476 error
= PTR_ERR(pipe
);
480 error
= nfs_idmap_register(clp
, idmap
, pipe
);
482 rpc_destroy_pipe_data(pipe
);
486 idmap
->idmap_pipe
= pipe
;
487 mutex_init(&idmap
->idmap_mutex
);
489 clp
->cl_idmap
= idmap
;
494 nfs_idmap_delete(struct nfs_client
*clp
)
496 struct idmap
*idmap
= clp
->cl_idmap
;
500 nfs_idmap_unregister(clp
, idmap
->idmap_pipe
);
501 rpc_destroy_pipe_data(idmap
->idmap_pipe
);
502 clp
->cl_idmap
= NULL
;
506 static int __rpc_pipefs_event(struct nfs_client
*clp
, unsigned long event
,
507 struct super_block
*sb
)
512 case RPC_PIPEFS_MOUNT
:
513 BUG_ON(clp
->cl_rpcclient
->cl_dentry
== NULL
);
514 err
= __nfs_idmap_register(clp
->cl_rpcclient
->cl_dentry
,
516 clp
->cl_idmap
->idmap_pipe
);
518 case RPC_PIPEFS_UMOUNT
:
519 if (clp
->cl_idmap
->idmap_pipe
) {
520 struct dentry
*parent
;
522 parent
= clp
->cl_idmap
->idmap_pipe
->dentry
->d_parent
;
523 __nfs_idmap_unregister(clp
->cl_idmap
->idmap_pipe
);
525 * Note: This is a dirty hack. SUNRPC hook has been
526 * called already but simple_rmdir() call for the
527 * directory returned with error because of idmap pipe
528 * inside. Thus now we have to remove this directory
531 if (rpc_rmdir(parent
))
532 printk(KERN_ERR
"NFS: %s: failed to remove "
533 "clnt dir!\n", __func__
);
537 printk(KERN_ERR
"NFS: %s: unknown event: %ld\n", __func__
,
544 static struct nfs_client
*nfs_get_client_for_event(struct net
*net
, int event
)
546 struct nfs_net
*nn
= net_generic(net
, nfs_net_id
);
547 struct dentry
*cl_dentry
;
548 struct nfs_client
*clp
;
552 spin_lock(&nn
->nfs_client_lock
);
553 list_for_each_entry(clp
, &nn
->nfs_client_list
, cl_share_link
) {
554 /* Wait for initialisation to finish */
555 if (clp
->cl_cons_state
== NFS_CS_INITING
) {
556 atomic_inc(&clp
->cl_count
);
557 spin_unlock(&nn
->nfs_client_lock
);
558 err
= nfs_wait_client_init_complete(clp
);
564 /* Skip nfs_clients that failed to initialise */
565 if (clp
->cl_cons_state
< 0)
568 if (clp
->rpc_ops
!= &nfs_v4_clientops
)
570 cl_dentry
= clp
->cl_idmap
->idmap_pipe
->dentry
;
571 if (((event
== RPC_PIPEFS_MOUNT
) && cl_dentry
) ||
572 ((event
== RPC_PIPEFS_UMOUNT
) && !cl_dentry
))
574 atomic_inc(&clp
->cl_count
);
575 spin_unlock(&nn
->nfs_client_lock
);
578 spin_unlock(&nn
->nfs_client_lock
);
582 static int rpc_pipefs_event(struct notifier_block
*nb
, unsigned long event
,
585 struct super_block
*sb
= ptr
;
586 struct nfs_client
*clp
;
589 if (!try_module_get(THIS_MODULE
))
592 while ((clp
= nfs_get_client_for_event(sb
->s_fs_info
, event
))) {
593 error
= __rpc_pipefs_event(clp
, event
, sb
);
598 module_put(THIS_MODULE
);
602 #define PIPEFS_NFS_PRIO 1
604 static struct notifier_block nfs_idmap_block
= {
605 .notifier_call
= rpc_pipefs_event
,
606 .priority
= SUNRPC_PIPEFS_NFS_PRIO
,
609 int nfs_idmap_init(void)
612 ret
= nfs_idmap_init_keyring();
615 ret
= rpc_pipefs_notifier_register(&nfs_idmap_block
);
617 nfs_idmap_quit_keyring();
622 void nfs_idmap_quit(void)
624 rpc_pipefs_notifier_unregister(&nfs_idmap_block
);
625 nfs_idmap_quit_keyring();
628 static int nfs_idmap_prepare_message(char *desc
, struct idmap
*idmap
,
629 struct idmap_msg
*im
,
630 struct rpc_pipe_msg
*msg
)
635 memset(im
, 0, sizeof(*im
));
636 memset(msg
, 0, sizeof(*msg
));
638 im
->im_type
= IDMAP_TYPE_GROUP
;
639 token
= match_token(desc
, nfs_idmap_tokens
, &substr
);
643 im
->im_type
= IDMAP_TYPE_USER
;
645 im
->im_conv
= IDMAP_CONV_NAMETOID
;
646 ret
= match_strlcpy(im
->im_name
, &substr
, IDMAP_NAMESZ
);
650 im
->im_type
= IDMAP_TYPE_USER
;
652 im
->im_conv
= IDMAP_CONV_IDTONAME
;
653 ret
= match_int(&substr
, &im
->im_id
);
662 msg
->len
= sizeof(struct idmap_msg
);
668 static int nfs_idmap_legacy_upcall(struct key_construction
*cons
,
672 struct idmap_legacy_upcalldata
*data
;
673 struct rpc_pipe_msg
*msg
;
674 struct idmap_msg
*im
;
675 struct idmap
*idmap
= (struct idmap
*)aux
;
676 struct key
*key
= cons
->key
;
679 /* msg and im are freed in idmap_pipe_destroy_msg */
680 data
= kmalloc(sizeof(*data
), GFP_KERNEL
);
684 msg
= &data
->pipe_msg
;
685 im
= &data
->idmap_msg
;
688 ret
= nfs_idmap_prepare_message(key
->description
, idmap
, im
, msg
);
692 BUG_ON(idmap
->idmap_key_cons
!= NULL
);
693 idmap
->idmap_key_cons
= cons
;
695 ret
= rpc_queue_upcall(idmap
->idmap_pipe
, msg
);
702 idmap
->idmap_key_cons
= NULL
;
706 complete_request_key(cons
, ret
);
710 static int nfs_idmap_instantiate(struct key
*key
, struct key
*authkey
, char *data
)
712 return key_instantiate_and_link(key
, data
, strlen(data
) + 1,
713 id_resolver_cache
->thread_keyring
,
717 static int nfs_idmap_read_message(struct idmap_msg
*im
, struct key
*key
, struct key
*authkey
)
719 char id_str
[NFS_UINT_MAXLEN
];
722 switch (im
->im_conv
) {
723 case IDMAP_CONV_NAMETOID
:
724 sprintf(id_str
, "%d", im
->im_id
);
725 ret
= nfs_idmap_instantiate(key
, authkey
, id_str
);
727 case IDMAP_CONV_IDTONAME
:
728 ret
= nfs_idmap_instantiate(key
, authkey
, im
->im_name
);
736 idmap_pipe_downcall(struct file
*filp
, const char __user
*src
, size_t mlen
)
738 struct rpc_inode
*rpci
= RPC_I(filp
->f_path
.dentry
->d_inode
);
739 struct idmap
*idmap
= (struct idmap
*)rpci
->private;
740 struct key_construction
*cons
;
745 /* If instantiation is successful, anyone waiting for key construction
746 * will have been woken up and someone else may now have used
747 * idmap_key_cons - so after this point we may no longer touch it.
749 cons
= ACCESS_ONCE(idmap
->idmap_key_cons
);
750 idmap
->idmap_key_cons
= NULL
;
752 if (mlen
!= sizeof(im
)) {
757 if (copy_from_user(&im
, src
, mlen
) != 0) {
762 if (!(im
.im_status
& IDMAP_STATUS_SUCCESS
)) {
764 complete_request_key(cons
, -ENOKEY
);
768 namelen_in
= strnlen(im
.im_name
, IDMAP_NAMESZ
);
769 if (namelen_in
== 0 || namelen_in
== IDMAP_NAMESZ
) {
774 ret
= nfs_idmap_read_message(&im
, cons
->key
, cons
->authkey
);
776 key_set_timeout(cons
->key
, nfs_idmap_cache_timeout
);
781 complete_request_key(cons
, ret
);
787 idmap_pipe_destroy_msg(struct rpc_pipe_msg
*msg
)
789 struct idmap_legacy_upcalldata
*data
= container_of(msg
,
790 struct idmap_legacy_upcalldata
,
792 struct idmap
*idmap
= data
->idmap
;
793 struct key_construction
*cons
;
795 cons
= ACCESS_ONCE(idmap
->idmap_key_cons
);
796 idmap
->idmap_key_cons
= NULL
;
797 complete_request_key(cons
, msg
->errno
);
799 /* Free memory allocated in nfs_idmap_legacy_upcall() */
804 idmap_release_pipe(struct inode
*inode
)
806 struct rpc_inode
*rpci
= RPC_I(inode
);
807 struct idmap
*idmap
= (struct idmap
*)rpci
->private;
808 idmap
->idmap_key_cons
= NULL
;
811 int nfs_map_name_to_uid(const struct nfs_server
*server
, const char *name
, size_t namelen
, __u32
*uid
)
813 struct idmap
*idmap
= server
->nfs_client
->cl_idmap
;
815 if (nfs_map_string_to_numeric(name
, namelen
, uid
))
817 return nfs_idmap_lookup_id(name
, namelen
, "uid", uid
, idmap
);
820 int nfs_map_group_to_gid(const struct nfs_server
*server
, const char *name
, size_t namelen
, __u32
*gid
)
822 struct idmap
*idmap
= server
->nfs_client
->cl_idmap
;
824 if (nfs_map_string_to_numeric(name
, namelen
, gid
))
826 return nfs_idmap_lookup_id(name
, namelen
, "gid", gid
, idmap
);
829 int nfs_map_uid_to_name(const struct nfs_server
*server
, __u32 uid
, char *buf
, size_t buflen
)
831 struct idmap
*idmap
= server
->nfs_client
->cl_idmap
;
834 if (!(server
->caps
& NFS_CAP_UIDGID_NOMAP
))
835 ret
= nfs_idmap_lookup_name(uid
, "user", buf
, buflen
, idmap
);
837 ret
= nfs_map_numeric_to_string(uid
, buf
, buflen
);
840 int nfs_map_gid_to_group(const struct nfs_server
*server
, __u32 gid
, char *buf
, size_t buflen
)
842 struct idmap
*idmap
= server
->nfs_client
->cl_idmap
;
845 if (!(server
->caps
& NFS_CAP_UIDGID_NOMAP
))
846 ret
= nfs_idmap_lookup_name(gid
, "group", buf
, buflen
, idmap
);
848 ret
= nfs_map_numeric_to_string(gid
, buf
, buflen
);