// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/lockd/svcproc.c
 *
 * Lockd server procedures. We don't implement the NLM_*_RES 
 * procedures because we don't use the async procedures.
 *
 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>
#include <linux/sunrpc/svc_xprt.h>

#define NLMDBG_FACILITY         NLMDBG_CLIENT

#ifdef CONFIG_LOCKD_V4
static __be32
cast_to_nlm(__be32 status, u32 vers)
{
        /* Note: status is assumed to be in network byte order !!! */
        if (vers != 4){
                switch (status) {
                case nlm_granted:
                case nlm_lck_denied:
                case nlm_lck_denied_nolocks:
                case nlm_lck_blocked:
                case nlm_lck_denied_grace_period:
                case nlm_drop_reply:
                        break;
                case nlm4_deadlock:
                        status = nlm_lck_denied;
                        break;
                default:
                        status = nlm_lck_denied_nolocks;
                }
        }

        return (status);
}
#define cast_status(status) (cast_to_nlm(status, rqstp->rq_vers))
#else
#define cast_status(status) (status)
#endif

/*
 * Obtain client and file from arguments
 */
static __be32
nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
                        struct nlm_host **hostp, struct nlm_file **filp)
{
        struct nlm_host         *host = NULL;
        struct nlm_file         *file = NULL;
        struct nlm_lock         *lock = &argp->lock;
        __be32                  error = 0;

        /* nfsd callbacks must have been installed for this procedure */
        if (!nlmsvc_ops)
                return nlm_lck_denied_nolocks;

        /* Obtain host handle */
        if (!(host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len))
         || (argp->monitor && nsm_monitor(host) < 0))
                goto no_locks;
        *hostp = host;

        /* Obtain file pointer. Not used by FREE_ALL call. */
        if (filp != NULL) {
                error = cast_status(nlm_lookup_file(rqstp, &file, &lock->fh));
                if (error != 0)
                        goto no_locks;
                *filp = file;

                /* Set up the missing parts of the file_lock structure */
                lock->fl.fl_file  = file->f_file;
                lock->fl.fl_pid = current->tgid;
                lock->fl.fl_lmops = &nlmsvc_lock_operations;
                nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
                if (!lock->fl.fl_owner) {
                        /* lockowner allocation has failed */
                        nlmsvc_release_host(host);
                        return nlm_lck_denied_nolocks;
                }
        }

        return 0;

no_locks:
        nlmsvc_release_host(host);
        if (error)
                return error;
        return nlm_lck_denied_nolocks;
}

/*
 * NULL: Test for presence of service
 */
static __be32
nlmsvc_proc_null(struct svc_rqst *rqstp)
{
        dprintk("lockd: NULL          called\n");
        return rpc_success;
}

/*
 * TEST: Check for conflicting lock
 */
static __be32
__nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;
        struct nlm_file *file;
        __be32 rc = rpc_success;

        dprintk("lockd: TEST          called\n");
        resp->cookie = argp->cookie;

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

        /* Now check for conflicting locks */
        resp->status = cast_status(nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock, &resp->cookie));
        if (resp->status == nlm_drop_reply)
                rc = rpc_drop_reply;
        else
                dprintk("lockd: TEST          status %d vers %d\n",
                        ntohl(resp->status), rqstp->rq_vers);

        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rc;
}

static __be32
nlmsvc_proc_test(struct svc_rqst *rqstp)
{
        return __nlmsvc_proc_test(rqstp, rqstp->rq_resp);
}

static __be32
__nlmsvc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;
        struct nlm_file *file;
        __be32 rc = rpc_success;

        dprintk("lockd: LOCK          called\n");

        resp->cookie = argp->cookie;

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

#if 0
        /* If supplied state doesn't match current state, we assume it's
         * an old request that time-warped somehow. Any error return would
         * do in this case because it's irrelevant anyway.
         *
         * NB: We don't retrieve the remote host's state yet.
         */
        if (host->h_nsmstate && host->h_nsmstate != argp->state) {
                resp->status = nlm_lck_denied_nolocks;
        } else
#endif

        /* Now try to lock the file */
        resp->status = cast_status(nlmsvc_lock(rqstp, file, host, &argp->lock,
                                               argp->block, &argp->cookie,
                                               argp->reclaim));
        if (resp->status == nlm_drop_reply)
                rc = rpc_drop_reply;
        else
                dprintk("lockd: LOCK         status %d\n", ntohl(resp->status));

        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rc;
}

static __be32
nlmsvc_proc_lock(struct svc_rqst *rqstp)
{
        return __nlmsvc_proc_lock(rqstp, rqstp->rq_resp);
}

static __be32
__nlmsvc_proc_cancel(struct svc_rqst *rqstp, struct nlm_res *resp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;
        struct nlm_file *file;
        struct net *net = SVC_NET(rqstp);

        dprintk("lockd: CANCEL        called\n");

        resp->cookie = argp->cookie;

        /* Don't accept requests during grace period */
        if (locks_in_grace(net)) {
                resp->status = nlm_lck_denied_grace_period;
                return rpc_success;
        }

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

        /* Try to cancel request. */
        resp->status = cast_status(nlmsvc_cancel_blocked(net, file, &argp->lock));

        dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rpc_success;
}

static __be32
nlmsvc_proc_cancel(struct svc_rqst *rqstp)
{
        return __nlmsvc_proc_cancel(rqstp, rqstp->rq_resp);
}

/*
 * UNLOCK: release a lock
 */
static __be32
__nlmsvc_proc_unlock(struct svc_rqst *rqstp, struct nlm_res *resp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;
        struct nlm_file *file;
        struct net *net = SVC_NET(rqstp);

        dprintk("lockd: UNLOCK        called\n");

        resp->cookie = argp->cookie;

        /* Don't accept new lock requests during grace period */
        if (locks_in_grace(net)) {
                resp->status = nlm_lck_denied_grace_period;
                return rpc_success;
        }

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

        /* Now try to remove the lock */
        resp->status = cast_status(nlmsvc_unlock(net, file, &argp->lock));

        dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rpc_success;
}

static __be32
nlmsvc_proc_unlock(struct svc_rqst *rqstp)
{
        return __nlmsvc_proc_unlock(rqstp, rqstp->rq_resp);
}

/*
 * GRANTED: A server calls us to tell that a process' lock request
 * was granted
 */
static __be32
__nlmsvc_proc_granted(struct svc_rqst *rqstp, struct nlm_res *resp)
{
        struct nlm_args *argp = rqstp->rq_argp;

        resp->cookie = argp->cookie;

        dprintk("lockd: GRANTED       called\n");
        resp->status = nlmclnt_grant(svc_addr(rqstp), &argp->lock);
        dprintk("lockd: GRANTED       status %d\n", ntohl(resp->status));
        return rpc_success;
}

static __be32
nlmsvc_proc_granted(struct svc_rqst *rqstp)
{
        return __nlmsvc_proc_granted(rqstp, rqstp->rq_resp);
}

/*
 * This is the generic lockd callback for async RPC calls
 */
static void nlmsvc_callback_exit(struct rpc_task *task, void *data)
{
        dprintk("lockd: %5u callback returned %d\n", task->tk_pid,
                        -task->tk_status);
}

void nlmsvc_release_call(struct nlm_rqst *call)
{
        if (!refcount_dec_and_test(&call->a_count))
                return;
        nlmsvc_release_host(call->a_host);
        kfree(call);
}

static void nlmsvc_callback_release(void *data)
{
        nlmsvc_release_call(data);
}

static const struct rpc_call_ops nlmsvc_callback_ops = {
        .rpc_call_done = nlmsvc_callback_exit,
        .rpc_release = nlmsvc_callback_release,
};

/*
 * `Async' versions of the above service routines. They aren't really,
 * because we send the callback before the reply proper. I hope this
 * doesn't break any clients.
 */
static __be32 nlmsvc_callback(struct svc_rqst *rqstp, u32 proc,
                __be32 (*func)(struct svc_rqst *, struct nlm_res *))
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;
        struct nlm_rqst *call;
        __be32 stat;

        host = nlmsvc_lookup_host(rqstp,
                                  argp->lock.caller,
                                  argp->lock.len);
        if (host == NULL)
                return rpc_system_err;

        call = nlm_alloc_call(host);
        nlmsvc_release_host(host);
        if (call == NULL)
                return rpc_system_err;

        stat = func(rqstp, &call->a_res);
        if (stat != 0) {
                nlmsvc_release_call(call);
                return stat;
        }

        call->a_flags = RPC_TASK_ASYNC;
        if (nlm_async_reply(call, proc, &nlmsvc_callback_ops) < 0)
                return rpc_system_err;
        return rpc_success;
}

static __be32 nlmsvc_proc_test_msg(struct svc_rqst *rqstp)
{
        dprintk("lockd: TEST_MSG      called\n");
        return nlmsvc_callback(rqstp, NLMPROC_TEST_RES, __nlmsvc_proc_test);
}

static __be32 nlmsvc_proc_lock_msg(struct svc_rqst *rqstp)
{
        dprintk("lockd: LOCK_MSG      called\n");
        return nlmsvc_callback(rqstp, NLMPROC_LOCK_RES, __nlmsvc_proc_lock);
}

static __be32 nlmsvc_proc_cancel_msg(struct svc_rqst *rqstp)
{
        dprintk("lockd: CANCEL_MSG    called\n");
        return nlmsvc_callback(rqstp, NLMPROC_CANCEL_RES, __nlmsvc_proc_cancel);
}

static __be32
nlmsvc_proc_unlock_msg(struct svc_rqst *rqstp)
{
        dprintk("lockd: UNLOCK_MSG    called\n");
        return nlmsvc_callback(rqstp, NLMPROC_UNLOCK_RES, __nlmsvc_proc_unlock);
}

static __be32
nlmsvc_proc_granted_msg(struct svc_rqst *rqstp)
{
        dprintk("lockd: GRANTED_MSG   called\n");
        return nlmsvc_callback(rqstp, NLMPROC_GRANTED_RES, __nlmsvc_proc_granted);
}

/*
 * SHARE: create a DOS share or alter existing share.
 */
static __be32
nlmsvc_proc_share(struct svc_rqst *rqstp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_res *resp = rqstp->rq_resp;
        struct nlm_host *host;
        struct nlm_file *file;

        dprintk("lockd: SHARE         called\n");

        resp->cookie = argp->cookie;

        /* Don't accept new lock requests during grace period */
        if (locks_in_grace(SVC_NET(rqstp)) && !argp->reclaim) {
                resp->status = nlm_lck_denied_grace_period;
                return rpc_success;
        }

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

        /* Now try to create the share */
        resp->status = cast_status(nlmsvc_share_file(host, file, argp));

        dprintk("lockd: SHARE         status %d\n", ntohl(resp->status));
        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rpc_success;
}

/*
 * UNSHARE: Release a DOS share.
 */
static __be32
nlmsvc_proc_unshare(struct svc_rqst *rqstp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_res *resp = rqstp->rq_resp;
        struct nlm_host *host;
        struct nlm_file *file;

        dprintk("lockd: UNSHARE       called\n");

        resp->cookie = argp->cookie;

        /* Don't accept requests during grace period */
        if (locks_in_grace(SVC_NET(rqstp))) {
                resp->status = nlm_lck_denied_grace_period;
                return rpc_success;
        }

        /* Obtain client and file */
        if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
                return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;

        /* Now try to unshare the file */
        resp->status = cast_status(nlmsvc_unshare_file(host, file, argp));

        dprintk("lockd: UNSHARE       status %d\n", ntohl(resp->status));
        nlmsvc_release_lockowner(&argp->lock);
        nlmsvc_release_host(host);
        nlm_release_file(file);
        return rpc_success;
}

/*
 * NM_LOCK: Create an unmonitored lock
 */
static __be32
nlmsvc_proc_nm_lock(struct svc_rqst *rqstp)
{
        struct nlm_args *argp = rqstp->rq_argp;

        dprintk("lockd: NM_LOCK       called\n");

        argp->monitor = 0;              /* just clean the monitor flag */
        return nlmsvc_proc_lock(rqstp);
}

/*
 * FREE_ALL: Release all locks and shares held by client
 */
static __be32
nlmsvc_proc_free_all(struct svc_rqst *rqstp)
{
        struct nlm_args *argp = rqstp->rq_argp;
        struct nlm_host *host;

        /* Obtain client */
        if (nlmsvc_retrieve_args(rqstp, argp, &host, NULL))
                return rpc_success;

        nlmsvc_free_host_resources(host);
        nlmsvc_release_host(host);
        return rpc_success;
}

/*
 * SM_NOTIFY: private callback from statd (not part of official NLM proto)
 */
static __be32
nlmsvc_proc_sm_notify(struct svc_rqst *rqstp)
{
        struct nlm_reboot *argp = rqstp->rq_argp;

        dprintk("lockd: SM_NOTIFY     called\n");

        if (!nlm_privileged_requester(rqstp)) {
                char buf[RPC_MAX_ADDRBUFLEN];
                printk(KERN_WARNING "lockd: rejected NSM callback from %s\n",
                                svc_print_addr(rqstp, buf, sizeof(buf)));
                return rpc_system_err;
        }

        nlm_host_rebooted(SVC_NET(rqstp), argp);
        return rpc_success;
}

/*
 * client sent a GRANTED_RES, let's remove the associated block
 */
static __be32
nlmsvc_proc_granted_res(struct svc_rqst *rqstp)
{
        struct nlm_res *argp = rqstp->rq_argp;

        if (!nlmsvc_ops)
                return rpc_success;

        dprintk("lockd: GRANTED_RES   called\n");

        nlmsvc_grant_reply(&argp->cookie, argp->status);
        return rpc_success;
}

/*
 * NLM Server procedures.
 */

#define nlmsvc_encode_norep     nlmsvc_encode_void
#define nlmsvc_decode_norep     nlmsvc_decode_void
#define nlmsvc_decode_testres   nlmsvc_decode_void
#define nlmsvc_decode_lockres   nlmsvc_decode_void
#define nlmsvc_decode_unlockres nlmsvc_decode_void
#define nlmsvc_decode_cancelres nlmsvc_decode_void
#define nlmsvc_decode_grantedres        nlmsvc_decode_void

#define nlmsvc_proc_none        nlmsvc_proc_null
#define nlmsvc_proc_test_res    nlmsvc_proc_null
#define nlmsvc_proc_lock_res    nlmsvc_proc_null
#define nlmsvc_proc_cancel_res  nlmsvc_proc_null
#define nlmsvc_proc_unlock_res  nlmsvc_proc_null

struct nlm_void                 { int dummy; };

#define PROC(name, xargt, xrest, argt, rest, respsize)  \
 { .pc_func     = nlmsvc_proc_##name,                   \
   .pc_decode   = nlmsvc_decode_##xargt,                \
   .pc_encode   = nlmsvc_encode_##xrest,                \
   .pc_release  = NULL,                                 \
   .pc_argsize  = sizeof(struct nlm_##argt),            \
   .pc_ressize  = sizeof(struct nlm_##rest),            \
   .pc_xdrressize = respsize,                           \
 }

#define Ck      (1+XDR_QUADLEN(NLM_MAXCOOKIELEN))       /* cookie */
#define St      1                               /* status */
#define No      (1+1024/4)                      /* Net Obj */
#define Rg      2                               /* range - offset + size */

const struct svc_procedure nlmsvc_procedures[] = {
  PROC(null,            void,           void,           void,   void, 1),
  PROC(test,            testargs,       testres,        args,   res, Ck+St+2+No+Rg),
  PROC(lock,            lockargs,       res,            args,   res, Ck+St),
  PROC(cancel,          cancargs,       res,            args,   res, Ck+St),
  PROC(unlock,          unlockargs,     res,            args,   res, Ck+St),
  PROC(granted,         testargs,       res,            args,   res, Ck+St),
  PROC(test_msg,        testargs,       norep,          args,   void, 1),
  PROC(lock_msg,        lockargs,       norep,          args,   void, 1),
  PROC(cancel_msg,      cancargs,       norep,          args,   void, 1),
  PROC(unlock_msg,      unlockargs,     norep,          args,   void, 1),
  PROC(granted_msg,     testargs,       norep,          args,   void, 1),
  PROC(test_res,        testres,        norep,          res,    void, 1),
  PROC(lock_res,        lockres,        norep,          res,    void, 1),
  PROC(cancel_res,      cancelres,      norep,          res,    void, 1),
  PROC(unlock_res,      unlockres,      norep,          res,    void, 1),
  PROC(granted_res,     res,            norep,          res,    void, 1),
  /* statd callback */
  PROC(sm_notify,       reboot,         void,           reboot, void, 1),
  PROC(none,            void,           void,           void,   void, 1),
  PROC(none,            void,           void,           void,   void, 1),
  PROC(none,            void,           void,           void,   void, 1),
  PROC(share,           shareargs,      shareres,       args,   res, Ck+St+1),
  PROC(unshare,         shareargs,      shareres,       args,   res, Ck+St+1),
  PROC(nm_lock,         lockargs,       res,            args,   res, Ck+St),
  PROC(free_all,        notify,         void,           args,   void, 0),

};