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
20 static inline int
nlm_cmp_owner(struct nlm_share * share,struct xdr_netobj * oh)21 nlm_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
nlmsvc_share_file(struct nlm_host * host,struct nlm_file * file,struct nlm_args * argp)28 nlmsvc_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 for (share = file->f_shares; share; share = share->s_next) {
36 if (share->s_host == host && nlm_cmp_owner(share, oh))
37 goto update;
38 if ((argp->fsm_access & share->s_mode)
39 || (argp->fsm_mode & share->s_access ))
40 return nlm_lck_denied;
41 }
42
43 share = kmalloc(sizeof(*share) + oh->len,
44 GFP_KERNEL);
45 if (share == NULL)
46 return nlm_lck_denied_nolocks;
47
48 /* Copy owner handle */
49 ohdata = (u8 *) (share + 1);
50 memcpy(ohdata, oh->data, oh->len);
51
52 share->s_file = file;
53 share->s_host = host;
54 share->s_owner.data = ohdata;
55 share->s_owner.len = oh->len;
56 share->s_next = file->f_shares;
57 file->f_shares = share;
58
59 update:
60 share->s_access = argp->fsm_access;
61 share->s_mode = argp->fsm_mode;
62 return nlm_granted;
63 }
64
65 /*
66 * Delete a share.
67 */
68 __be32
nlmsvc_unshare_file(struct nlm_host * host,struct nlm_file * file,struct nlm_args * argp)69 nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
70 struct nlm_args *argp)
71 {
72 struct nlm_share *share, **shpp;
73 struct xdr_netobj *oh = &argp->lock.oh;
74
75 for (shpp = &file->f_shares; (share = *shpp) != NULL;
76 shpp = &share->s_next) {
77 if (share->s_host == host && nlm_cmp_owner(share, oh)) {
78 *shpp = share->s_next;
79 kfree(share);
80 return nlm_granted;
81 }
82 }
83
84 /* X/Open spec says return success even if there was no
85 * corresponding share. */
86 return nlm_granted;
87 }
88
89 /*
90 * Traverse all shares for a given file, and delete
91 * those owned by the given (type of) host
92 */
nlmsvc_traverse_shares(struct nlm_host * host,struct nlm_file * file,nlm_host_match_fn_t match)93 void nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file,
94 nlm_host_match_fn_t match)
95 {
96 struct nlm_share *share, **shpp;
97
98 shpp = &file->f_shares;
99 while ((share = *shpp) != NULL) {
100 if (match(share->s_host, host)) {
101 *shpp = share->s_next;
102 kfree(share);
103 continue;
104 }
105 shpp = &share->s_next;
106 }
107 }
108