cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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svcshare.c (2459B)

      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}