LXR linux/fs/lockd/svcshare.c

   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