Root/fs/lockd/svcshare.c

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

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