svcshare.c

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/*
 * linux/fs/lockd/svcshare.c
 *
 * Management of DOS shares.
 *
 * Copyright (C) 1996 Olaf Kirch <[email protected]>
 */

#include <linux/time.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/slab.h>

#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>

static inline int
nlm_cmp_owner(struct nlm_share *share, struct xdr_netobj *oh)
{
    return share->s_owner.len == oh->len
        && !memcmp(share->s_owner.data, oh->data, oh->len);
}

__be32
nlmsvc_share_file(struct nlm_host *host, struct nlm_file *file,
            struct nlm_args *argp)
{
    struct nlm_share    *share;
    struct xdr_netobj   *oh = &argp->lock.oh;
    u8          *ohdata;

    for (share = file->f_shares; share; share = share->s_next) {
        if (share->s_host == host && nlm_cmp_owner(share, oh))
            goto update;
        if ((argp->fsm_access & share->s_mode)
         || (argp->fsm_mode   & share->s_access ))
            return nlm_lck_denied;
    }

    share = kmalloc(sizeof(*share) + oh->len,
                        GFP_KERNEL);
    if (share == NULL)
        return nlm_lck_denied_nolocks;

    /* Copy owner handle */
    ohdata = (u8 *) (share + 1);
    memcpy(ohdata, oh->data, oh->len);

    share->s_file       = file;
    share->s_host       = host;
    share->s_owner.data = ohdata;
    share->s_owner.len  = oh->len;
    share->s_next       = file->f_shares;
    file->f_shares      = share;

update:
    share->s_access = argp->fsm_access;
    share->s_mode   = argp->fsm_mode;
    return nlm_granted;
}

/*
 * Delete a share.
 */
__be32
nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
            struct nlm_args *argp)
{
    struct nlm_share    *share, **shpp;
    struct xdr_netobj   *oh = &argp->lock.oh;

    for (shpp = &file->f_shares; (share = *shpp) != NULL;
                    shpp = &share->s_next) {
        if (share->s_host == host && nlm_cmp_owner(share, oh)) {
            *shpp = share->s_next;
            kfree(share);
            return nlm_granted;
        }
    }

    /* X/Open spec says return success even if there was no
     * corresponding share. */
    return nlm_granted;
}

/*
 * Traverse all shares for a given file, and delete
 * those owned by the given (type of) host
 */
void nlmsvc_traverse_shares(struct nlm_host *host, struct nlm_file *file,
        nlm_host_match_fn_t match)
{
    struct nlm_share    *share, **shpp;

    shpp = &file->f_shares;
    while ((share = *shpp) !=  NULL) {
        if (match(share->s_host, host)) {
            *shpp = share->s_next;
            kfree(share);
            continue;
        }
        shpp = &share->s_next;
    }
}