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
  20 static inline int
  21 nlm_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
  28 nlmsvc_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
  59 update:
  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
  69 nlmsvc_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  */
  93 void 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 }