linux/fs/lockd/svcshare.c
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   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
  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
  26__be32
  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 = 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 */
  67__be32
  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) != 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 */
  92void 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}
 107
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