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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/lockd/svcshare.c
4 *
5 * Management of DOS shares.
6 *
7 * Copyright (C) 1996 Olaf Kirch <okir@monad.swb.de>
8 */
9
10#include <linux/time.h>
11#include <linux/unistd.h>
12#include <linux/string.h>
13#include <linux/slab.h>
14
15#include <linux/sunrpc/clnt.h>
16#include <linux/sunrpc/svc.h>
17#include <linux/lockd/lockd.h>
18#include <linux/lockd/share.h>
19
20static inline int
21nlm_cmp_owner(struct nlm_share *share, struct xdr_netobj *oh)
22{
23 return share->s_owner.len == oh->len
24 && !memcmp(share->s_owner.data, oh->data, oh->len);
25}
26
27__be32
28nlmsvc_share_file(struct nlm_host *host, struct nlm_file *file,
29 struct nlm_args *argp)
30{
31 struct nlm_share *share;
32 struct xdr_netobj *oh = &argp->lock.oh;
33 u8 *ohdata;
34
35 if (nlmsvc_file_cannot_lock(file))
36 return nlm_lck_denied_nolocks;
37
38 for (share = file->f_shares; share; share = share->s_next) {
39 if (share->s_host == host && nlm_cmp_owner(share, oh))
40 goto update;
41 if ((argp->fsm_access & share->s_mode)
42 || (argp->fsm_mode & share->s_access ))
43 return nlm_lck_denied;
44 }
45
46 share = kmalloc(sizeof(*share) + oh->len,
47 GFP_KERNEL);
48 if (share == NULL)
49 return nlm_lck_denied_nolocks;
50
51 /* Copy owner handle */
52 ohdata = (u8 *) (share + 1);
53 memcpy(ohdata, oh->data, oh->len);
54
55 share->s_file = file;
56 share->s_host = host;
57 share->s_owner.data = ohdata;
58 share->s_owner.len = oh->len;
59 share->s_next = file->f_shares;
60 file->f_shares = share;
61
62update:
63 share->s_access = argp->fsm_access;
64 share->s_mode = argp->fsm_mode;
65 return nlm_granted;
66}
67
68/*
69 * Delete a share.
70 */
71__be32
72nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
73 struct nlm_args *argp)
74{
75 struct nlm_share *share, **shpp;
76 struct xdr_netobj *oh = &argp->lock.oh;
77
78 if (nlmsvc_file_cannot_lock(file))
79 return nlm_lck_denied_nolocks;
80
81 for (shpp = &file->f_shares; (share = *shpp) != NULL;
82 shpp = &share->s_next) {
83 if (share->s_host == host && nlm_cmp_owner(share, oh)) {
84 *shpp = share->s_next;
85 kfree(share);
86 return nlm_granted;
87 }
88 }
89
90 /* X/Open spec says return success even if there was no
91 * corresponding share. */
92 return nlm_granted;
93}
94
95/*
96 * Traverse all shares for a given file, and delete
97 * those owned by the given (type of) host
98 */
99void nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file,
100 nlm_host_match_fn_t match)
101{
102 struct nlm_share *share, **shpp;
103
104 shpp = &file->f_shares;
105 while ((share = *shpp) != NULL) {
106 if (match(share->s_host, host)) {
107 *shpp = share->s_next;
108 kfree(share);
109 continue;
110 }
111 shpp = &share->s_next;
112 }
113}