/*      $NetBSD: svc_simple.c,v 1.34 2024/01/23 17:24:38 christos Exp $ */

/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *     * Neither the name of the "Oracle America, Inc." nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Copyright (c) 1986-1991 by Sun Microsystems Inc. 
 */

/* #pragma ident        "@(#)svc_simple.c       1.18    94/04/24 SMI" */

/*
 * svc_simple.c
 * Simplified front end to rpc.
 */

/*
 * This interface creates a virtual listener for all the services
 * started thru rpc_reg(). It listens on the same endpoint for
 * all the services and then executes the corresponding service
 * for the given prognum and procnum.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: svc_simple.c,v 1.34 2024/01/23 17:24:38 christos Exp $");
#endif

#include "namespace.h"
#include "reentrant.h"
#include <sys/types.h>
#include <rpc/rpc.h>
#include <rpc/nettype.h>
#include <assert.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "rpc_internal.h"

#ifdef __weak_alias
__weak_alias(rpc_reg,_rpc_reg)
#endif

static void universal(struct svc_req *, SVCXPRT *);

static struct proglst {
        char *(*p_progname)(char *);
        rpcprog_t p_prognum;
        rpcvers_t p_versnum;
        rpcproc_t p_procnum;
        SVCXPRT *p_transp;
        char *p_netid;
        char *p_xdrbuf;
        int p_recvsz;
        xdrproc_t p_inproc, p_outproc;
        struct proglst *p_nxt;
} *proglst;

static const char __reg_err1[] = "can't find appropriate transport";
static const char __reg_err2[] = "can't get protocol info";
static const char __reg_err3[] = "unsupported transport size";
static const char __no_mem_str[] = "out of memory";

/*
 * For simplified, easy to use kind of rpc interfaces.
 * nettype indicates the type of transport on which the service will be
 * listening. Used for conservation of the system resource. Only one
 * handle is created for all the services (actually one of each netid)
 * and same xdrbuf is used for same netid. The size of the arguments
 * is also limited by the recvsize for that transport, even if it is
 * a COTS transport. This may be wrong, but for cases like these, they
 * should not use the simplified interfaces like this.
 */

int
rpc_reg(
        rpcprog_t prognum,              /* program number */
        rpcvers_t versnum,              /* version number */
        rpcproc_t procnum,              /* procedure number */
        char *(*progname)(char *),      /* Server routine */
        xdrproc_t inproc,               /* in XDR procedure */
        xdrproc_t outproc,              /* out XDR procedure */
        char *nettype)                  /* nettype */
{
        struct netconfig *nconf;
        int done = FALSE;
        void *handle;

        if (procnum == NULLPROC) {
                warnx("%s: can't reassign procedure number %u", __func__,
                    NULLPROC);
                return (-1);
        }

        if (nettype == NULL)
                nettype = __UNCONST("netpath"); /* The default behavior */
        if ((handle = __rpc_setconf(nettype)) == NULL) {
                warnx("%s: %s", __func__, __reg_err1);
                return (-1);
        }
/* VARIABLES PROTECTED BY proglst_lock: proglst */
        mutex_lock(&proglst_lock);
        while ((nconf = __rpc_getconf(handle)) != NULL) {
                struct proglst *pl;
                SVCXPRT *svcxprt;
                int madenow;
                u_int recvsz;
                char *xdrbuf;
                char *netid;

                madenow = FALSE;
                svcxprt = NULL;
                recvsz = 0;
                xdrbuf = NULL;
                netid = NULL;
                for (pl = proglst; pl; pl = pl->p_nxt)
                        if (strcmp(pl->p_netid, nconf->nc_netid) == 0) {
                                svcxprt = pl->p_transp;
                                xdrbuf = pl->p_xdrbuf;
                                recvsz = pl->p_recvsz;
                                netid = pl->p_netid;
                                break;
                        }

                if (svcxprt == NULL) {
                        struct __rpc_sockinfo si;

                        svcxprt = svc_tli_create(RPC_ANYFD, nconf, NULL, 0, 0);
                        if (svcxprt == NULL)
                                continue;
                        if (!__rpc_fd2sockinfo(svcxprt->xp_fd, &si)) {
                                warnx("%s: %s", __func__, __reg_err2);
                                SVC_DESTROY(svcxprt);
                                continue;
                        }
                        recvsz = __rpc_get_t_size(si.si_af, si.si_proto, 0);
                        if (recvsz == 0) {
                                warnx("%s: %s", __func__, __reg_err3);
                                SVC_DESTROY(svcxprt);
                                continue;
                        }
                        if (((xdrbuf = mem_alloc((size_t)recvsz)) == NULL) ||
                                ((netid = strdup(nconf->nc_netid)) == NULL)) {
                                warnx("%s: %s", __func__, __no_mem_str);
                                if (xdrbuf != NULL)
                                        free(xdrbuf);
                                if (netid != NULL)
                                        free(netid);
                                SVC_DESTROY(svcxprt);
                                break;
                        }
                        madenow = TRUE;
                }
                /*
                 * Check if this (program, version, netid) had already been
                 * registered.  The check may save a few RPC calls to rpcbind
                 */
                for (pl = proglst; pl; pl = pl->p_nxt)
                        if ((pl->p_prognum == prognum) &&
                                (pl->p_versnum == versnum) &&
                                (strcmp(pl->p_netid, netid) == 0))
                                break;
                if (pl == NULL) { /* Not yet */
                        (void) rpcb_unset(prognum, versnum, nconf);
                } else {
                        /* so that svc_reg does not call rpcb_set() */
                        nconf = NULL;
                }

                if (!svc_reg(svcxprt, prognum, versnum, universal, nconf)) {
                        warnx("%s: couldn't register prog %u vers %u for %s",
                            __func__, (unsigned)prognum,
                            (unsigned)versnum, netid);
                        if (madenow) {
                                SVC_DESTROY(svcxprt);
                                free(xdrbuf);
                                free(netid);
                        }
                        continue;
                }

                pl = malloc(sizeof(*pl));
                if (pl == NULL) {
                        warn("%s: %s", __func__, __no_mem_str);
                        if (madenow) {
                                SVC_DESTROY(svcxprt);
                                free(xdrbuf);
                                free(netid);
                        }
                        break;
                }
                pl->p_progname = progname;
                pl->p_prognum = prognum;
                pl->p_versnum = versnum;
                pl->p_procnum = procnum;
                pl->p_inproc = inproc;
                pl->p_outproc = outproc;
                pl->p_transp = svcxprt;
                pl->p_xdrbuf = xdrbuf;
                pl->p_recvsz = recvsz;
                pl->p_netid = netid;
                pl->p_nxt = proglst;
                proglst = pl;
                done = TRUE;
        }
        __rpc_endconf(handle);
        mutex_unlock(&proglst_lock);

        if (done == FALSE) {
                warnx("%s: can't find suitable transport for %s",
                    __func__, nettype);
                return (-1);
        }
        return (0);
}

/*
 * The universal handler for the services registered using registerrpc.
 * It handles both the connectionless and the connection oriented cases.
 */

static void
universal(struct svc_req *rqstp, SVCXPRT *transp)
{
        rpcprog_t prog;
        rpcvers_t vers;
        rpcproc_t proc;
        char *outdata;
        char *xdrbuf;
        struct proglst *pl;

        _DIAGASSERT(rqstp != NULL);
        _DIAGASSERT(transp != NULL);

        /*
         * enforce "procnum 0 is echo" convention
         */
        if (rqstp->rq_proc == NULLPROC) {
                if (svc_sendreply(transp, (xdrproc_t) xdr_void, NULL) ==
                    FALSE) {
                        warnx("%s: svc_sendreply failed", __func__);
                }
                return;
        }
        prog = rqstp->rq_prog;
        vers = rqstp->rq_vers;
        proc = rqstp->rq_proc;
        mutex_lock(&proglst_lock);
        for (pl = proglst; pl; pl = pl->p_nxt)
                if (pl->p_prognum == prog && pl->p_procnum == proc &&
                        pl->p_versnum == vers &&
                        (strcmp(pl->p_netid, transp->xp_netid) == 0)) {
                        /* decode arguments into a CLEAN buffer */
                        xdrbuf = pl->p_xdrbuf;
                        /* Zero the arguments: reqd ! */
                        (void) memset(xdrbuf, 0, (size_t)pl->p_recvsz);
                        /*
                         * Assuming that sizeof (xdrbuf) would be enough
                         * for the arguments; if not then the program
                         * may bomb. BEWARE!
                         */
                        if (!svc_getargs(transp, pl->p_inproc, xdrbuf)) {
                                svcerr_decode(transp);
                                mutex_unlock(&proglst_lock);
                                return;
                        }
                        outdata = (*(pl->p_progname))(xdrbuf);
                        if (outdata == NULL &&
                                pl->p_outproc != (xdrproc_t) xdr_void){
                                /* there was an error */
                                mutex_unlock(&proglst_lock);
                                return;
                        }
                        if (!svc_sendreply(transp, pl->p_outproc, outdata)) {
                                warnx("%s: trouble replying to prog %u vers %u",
                                    __func__, (unsigned)prog, (unsigned)vers);
                                mutex_unlock(&proglst_lock);
                                return;
                        }
                        /* free the decoded arguments */
                        (void) svc_freeargs(transp, pl->p_inproc, xdrbuf);
                        mutex_unlock(&proglst_lock);
                        return;
                }
        mutex_unlock(&proglst_lock);
        /* This should never happen */
        warnx("%s: never registered prog %u vers %u", __func__,
            (unsigned)prog, (unsigned)vers);
        return;
}