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/sched.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
26u32
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 = (struct nlm_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 */
67u32
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); shpp = &share->s_next) {
75		if (share->s_host == host && nlm_cmp_owner(share, oh)) {
76			*shpp = share->s_next;
77			kfree(share);
78			return nlm_granted;
79		}
80	}
81
82	/* X/Open spec says return success even if there was no
83	 * corresponding share. */
84	return nlm_granted;
85}
86
87/*
88 * Traverse all shares for a given file (and host).
89 * NLM_ACT_CHECK is handled by nlmsvc_inspect_file.
90 */
91int
92nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file, int action)
93{
94	struct nlm_share	*share, **shpp;
95
96	shpp = &file->f_shares;
97	while ((share = *shpp) !=  NULL) {
98		if (action == NLM_ACT_MARK)
99			share->s_host->h_inuse = 1;
100		else if (action == NLM_ACT_UNLOCK) {
101			if (host == NULL || host == share->s_host) {
102				*shpp = share->s_next;
103				kfree(share);
104				continue;
105			}
106		}
107		shpp = &share->s_next;
108	}
109
110	return 0;
111}
112