release/src-rt-6.x.4708/linux/linux-2.6.36/fs/lockd/svcshare.c

   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
  19 static inline int
  20 nlm_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
  27 nlmsvc_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
  58 update:
  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
  68 nlmsvc_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  */
  92 void 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 }