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