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	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
59update:
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
69nlmsvc_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 */
93void 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