[mirror_edk2.git] / StdLib / BsdSocketLib / res_send.c

/*\r
 * Copyright (c) 1985, 1989, 1993\r
 *    The Regents of the University of California.  All rights reserved.\r
 *\r
 * Portions copyright (c) 1999, 2000\r
 * Intel Corporation.\r
 * All rights reserved.\r
 *\r
 * Redistribution and use in source and binary forms, with or without\r
 * modification, are permitted provided that the following conditions\r
 * are met:\r
 *\r
 * 1. Redistributions of source code must retain the above copyright\r
 *    notice, this list of conditions and the following disclaimer.\r
 *\r
 * 2. Redistributions in binary form must reproduce the above copyright\r
 *    notice, this list of conditions and the following disclaimer in the\r
 *    documentation and/or other materials provided with the distribution.\r
 *\r
 * 3. All advertising materials mentioning features or use of this software\r
 *    must display the following acknowledgement:\r
 *\r
 *    This product includes software developed by the University of\r
 *    California, Berkeley, Intel Corporation, and its contributors.\r
 *\r
 * 4. Neither the name of University, Intel Corporation, or their respective\r
 *    contributors may be used to endorse or promote products derived from\r
 *    this software without specific prior written permission.\r
 *\r
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND\r
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,\r
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS\r
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS,\r
 * INTEL CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,\r
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT\r
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\r
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY\r
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\r
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF\r
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\r
 *\r
 */\r
\r
/*\r
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.\r
 *\r
 * Permission to use, copy, modify, and distribute this software for any\r
 * purpose with or without fee is hereby granted, provided that the above\r
 * copyright notice and this permission notice appear in all copies, and that\r
 * the name of Digital Equipment Corporation not be used in advertising or\r
 * publicity pertaining to distribution of the document or software without\r
 * specific, written prior permission.\r
 *\r
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL\r
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES\r
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT\r
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL\r
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR\r
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS\r
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS\r
 * SOFTWARE.\r
 */\r
\r
/*\r
 * Portions Copyright (c) 1996 by Internet Software Consortium.\r
 *\r
 * Permission to use, copy, modify, and distribute this software for any\r
 * purpose with or without fee is hereby granted, provided that the above\r
 * copyright notice and this permission notice appear in all copies.\r
 *\r
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS\r
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES\r
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE\r
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL\r
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR\r
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS\r
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS\r
 * SOFTWARE.\r
 */\r
\r
#if defined(LIBC_SCCS) && !defined(lint)\r
static char sccsid[] = "@(#)res_send.c  8.1 (Berkeley) 6/4/93";\r
static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";\r
static char rcsid[] = "$Id: res_send.c,v 1.1.1.1 2003/11/19 01:51:39 kyu3 Exp $";\r
#endif /* LIBC_SCCS and not lint */\r
\r
/*\r
 * Send query to name server and wait for reply.\r
 */\r
\r
#include <sys/types.h>\r
#include <sys/param.h>\r
#include <sys/select.h>\r
#include <sys/socket.h>\r
#include <sys/time.h>\r
#include <sys/uio.h>\r
\r
#include <netinet/in.h>\r
#include <arpa/nameser.h>\r
#include <arpa/inet.h>\r
\r
#include <errno.h>\r
#include <netdb.h>\r
#include <resolv.h>\r
#include <stdio.h>\r
#include <stdlib.h>\r
#include <string.h>\r
#include <unistd.h>\r
\r
#include "res_config.h"\r
\r
#ifndef _ORG_FREEBSD_\r
#define NOPOLL\r
#endif\r
\r
#ifdef NOPOLL           /* libc_r doesn't wrap poll yet() */\r
#else\r
#include <poll.h>\r
static int use_poll = 1;    /* adapt to poll() syscall availability */\r
                /* 0 = not present, 1 = try it, 2 = exists */\r
#endif\r
\r
static int s = -1;      /* socket used for communications */\r
static int connected = 0;   /* is the socket connected */\r
static int vc = 0;      /* is the socket a virtual circuit? */\r
static res_send_qhook Qhook = NULL;\r
static res_send_rhook Rhook = NULL;\r
\r
\r
#define CAN_RECONNECT 1\r
\r
#ifndef DEBUG\r
#   define Dprint(cond, args) /*empty*/\r
#   define DprintQ(cond, args, query, size) /*empty*/\r
#   define Aerror(file, string, error, address) /*empty*/\r
#   define Perror(file, string, error) /*empty*/\r
#else\r
#   define Dprint(cond, args) if (cond) {fprintf args;} else {}\r
#   define DprintQ(cond, args, query, size) if (cond) {\\r
            fprintf args;\\r
            __fp_nquery(query, size, stdout);\\r
        } else {}\r
\r
static void\r
Aerror(\r
    FILE *file,\r
    char *string,\r
    int error,\r
    struct sockaddr_in address\r
    )\r
{\r
    int save = errno;\r
\r
    if (_res.options & RES_DEBUG) {\r
        fprintf(file, "res_send: %s ([%s].%u): %s\n",\r
            string,\r
            inet_ntoa(address.sin_addr),\r
            ntohs(address.sin_port),\r
            strerror(error));\r
    }\r
    errno = save;\r
}\r
\r
\r
static void\r
Perror(\r
    FILE *file,\r
    char *string,\r
    int error\r
    )\r
{\r
    int save = errno;\r
\r
    if (_res.options & RES_DEBUG) {\r
        fprintf(file, "res_send: %s: %s\n",\r
            string, strerror(error));\r
    }\r
    errno = save;\r
}\r
#endif\r
\r
void\r
res_send_setqhook(\r
    res_send_qhook hook\r
    )\r
{\r
\r
    Qhook = hook;\r
}\r
\r
void\r
res_send_setrhook(\r
    res_send_rhook hook\r
    )\r
{\r
\r
    Rhook = hook;\r
}\r
\r
/* int\r
 * res_isourserver(ina)\r
 *  looks up "ina" in _res.ns_addr_list[]\r
 * returns:\r
 *  0  : not found\r
 *  >0 : found\r
 * author:\r
 *  paul vixie, 29may94\r
 */\r
int\r
res_isourserver(\r
    const struct sockaddr_in *inp\r
    )\r
{\r
    struct sockaddr_in ina;\r
    int ns, ret;\r
\r
    ina = *inp;\r
    ret = 0;\r
    for (ns = 0;  ns < _res.nscount;  ns++) {\r
        const struct sockaddr_in *srv = &_res.nsaddr_list[ns];\r
\r
        if (srv->sin_family == ina.sin_family &&\r
            srv->sin_port == ina.sin_port &&\r
            (srv->sin_addr.s_addr == INADDR_ANY ||\r
             srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {\r
            ret++;\r
            break;\r
        }\r
    }\r
    return (ret);\r
}\r
\r
/* int\r
 * res_nameinquery(name, type, class, buf, eom)\r
 *  look for (name,type,class) in the query section of packet (buf,eom)\r
 * requires:\r
 *  buf + HFIXEDSZ <= eom\r
 * returns:\r
 *  -1 : format error\r
 *  0  : not found\r
 *  >0 : found\r
 * author:\r
 *  paul vixie, 29may94\r
 */\r
int\r
res_nameinquery(\r
    const char *name,\r
    int type,\r
    int class,\r
    const u_char *buf,\r
    const u_char *eom\r
    )\r
{\r
    const u_char *cp = buf + HFIXEDSZ;\r
    int qdcount = ntohs(((HEADER*)buf)->qdcount);\r
\r
    while (qdcount-- > 0) {\r
        char tname[MAXDNAME+1];\r
        int n, ttype, tclass;\r
\r
        n = dn_expand(buf, eom, cp, tname, sizeof tname);\r
        if (n < 0)\r
            return (-1);\r
        cp += n;\r
        if (cp + 2 * INT16SZ > eom)\r
            return (-1);\r
        ttype = ns_get16(cp); cp += INT16SZ;\r
        tclass = ns_get16(cp); cp += INT16SZ;\r
        if (ttype == type &&\r
            tclass == class &&\r
            strcasecmp(tname, name) == 0)\r
            return (1);\r
    }\r
    return (0);\r
}\r
\r
/* int\r
 * res_queriesmatch(buf1, eom1, buf2, eom2)\r
 *  is there a 1:1 mapping of (name,type,class)\r
 *  in (buf1,eom1) and (buf2,eom2)?\r
 * returns:\r
 *  -1 : format error\r
 *  0  : not a 1:1 mapping\r
 *  >0 : is a 1:1 mapping\r
 * author:\r
 *  paul vixie, 29may94\r
 */\r
int\r
res_queriesmatch(\r
    const u_char *buf1,\r
    const u_char *eom1,\r
    const u_char *buf2,\r
    const u_char *eom2\r
    )\r
{\r
    const u_char *cp = buf1 + HFIXEDSZ;\r
    int qdcount = ntohs(((HEADER*)buf1)->qdcount);\r
\r
    if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)\r
        return (-1);\r
\r
    /*\r
     * Only header section present in replies to\r
     * dynamic update packets.\r
     */\r
    if ( (((HEADER *)buf1)->opcode == ns_o_update) &&\r
         (((HEADER *)buf2)->opcode == ns_o_update) )\r
        return (1);\r
\r
    if (qdcount != ntohs(((HEADER*)buf2)->qdcount))\r
        return (0);\r
    while (qdcount-- > 0) {\r
        char tname[MAXDNAME+1];\r
        int n, ttype, tclass;\r
\r
        n = dn_expand(buf1, eom1, cp, tname, sizeof tname);\r
        if (n < 0)\r
            return (-1);\r
        cp += n;\r
        if (cp + 2 * INT16SZ > eom1)\r
            return (-1);\r
        ttype = ns_get16(cp);   cp += INT16SZ;\r
        tclass = ns_get16(cp); cp += INT16SZ;\r
        if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))\r
            return (0);\r
    }\r
    return (1);\r
}\r
\r
int\r
res_send(\r
    const u_char *buf,\r
    int buflen,\r
    u_char *ans,\r
    int anssiz\r
    )\r
{\r
    HEADER *hp = (HEADER *) buf;\r
    HEADER *anhp = (HEADER *) ans;\r
    int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;\r
    ssize_t n;\r
    u_int32_t badns;    /* XXX NSMAX can't exceed #/bits in this variable */\r
\r
    if ((_res.options & RES_INIT) == 0 && res_init() == -1) {\r
        /* errno should have been set by res_init() in this case. */\r
        return (-1);\r
    }\r
    if (anssiz < HFIXEDSZ) {\r
        errno = EINVAL;\r
        return (-1);\r
    }\r
    DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),\r
        (stdout, ";; res_send()\n"), buf, buflen);\r
    v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;\r
    gotsomewhere = 0;\r
    connreset = 0;\r
    terrno = ETIMEDOUT;\r
    badns = 0;\r
\r
    /*\r
     * Send request, RETRY times, or until successful\r
     */\r
    for (try = 0; try < _res.retry; try++) {\r
        for (ns = 0; ns < _res.nscount; ns++) {\r
        struct sockaddr_in *nsap = &_res.nsaddr_list[ns];\r
    same_ns:\r
        if (badns & (1 << ns)) {\r
            res_close();\r
            goto next_ns;\r
        }\r
\r
        if (Qhook) {\r
            int done = 0, loops = 0;\r
\r
            do {\r
                res_sendhookact act;\r
\r
                act = (*Qhook)(&nsap, &buf, &buflen,\r
                           ans, anssiz, &resplen);\r
                switch (act) {\r
                case res_goahead:\r
                    done = 1;\r
                    break;\r
                case res_nextns:\r
                    res_close();\r
                    goto next_ns;\r
                case res_done:\r
                    return (resplen);\r
                case res_modified:\r
                    /* give the hook another try */\r
                    if (++loops < 42) /*doug adams*/\r
                        break;\r
                    /*FALLTHROUGH*/\r
                case res_error:\r
                    /*FALLTHROUGH*/\r
                default:\r
                    return (-1);\r
                }\r
            } while (!done);\r
        }\r
\r
        Dprint(_res.options & RES_DEBUG,\r
               (stdout, ";; Querying server (# %d) address = %s\n",\r
            ns + 1, inet_ntoa(nsap->sin_addr)));\r
\r
        if (v_circuit) {\r
            int truncated;\r
            struct iovec iov[2];\r
            u_short len;\r
            u_char *cp;\r
\r
            /*\r
             * Use virtual circuit;\r
             * at most one attempt per server.\r
             */\r
            try = _res.retry;\r
            truncated = 0;\r
            if (s < 0 || !vc || hp->opcode == ns_o_update) {\r
                if (s >= 0)\r
                    res_close();\r
\r
                s = socket(PF_INET, SOCK_STREAM, 0);\r
                if (s < 0) {\r
                    terrno = errno;\r
                    Perror(stderr, "socket(vc)", errno);\r
                    return (-1);\r
                }\r
                errno = 0;\r
                nsap->sin_len = sizeof ( *nsap );\r
                if (connect(s, (struct sockaddr *)nsap,\r
                        sizeof *nsap) < 0) {\r
                    terrno = errno;\r
                    Aerror(stderr, "connect/vc",\r
                           errno, *nsap);\r
                    badns |= (1 << ns);\r
                    res_close();\r
                    goto next_ns;\r
                }\r
                vc = 1;\r
            }\r
            /*\r
             * Send length & message\r
             */\r
            putshort((u_short)buflen, (u_char*)&len);\r
            iov[0].iov_base = (caddr_t)&len;\r
            iov[0].iov_len = INT16SZ;\r
            iov[1].iov_base = (caddr_t)buf;\r
            iov[1].iov_len = buflen;\r
            if (writev(s, iov, 2) != (INT16SZ + buflen)) {\r
                terrno = errno;\r
                Perror(stderr, "write failed", errno);\r
                badns |= (1 << ns);\r
                res_close();\r
                goto next_ns;\r
            }\r
            /*\r
             * Receive length & response\r
             */\r
read_len:\r
            cp = ans;\r
            len = INT16SZ;\r
            while ((n = read(s, (char *)cp, (int)len)) > 0) {\r
                cp += n;\r
                len = (u_short)( len - n );\r
                if (len <= 0)\r
                    break;\r
            }\r
            if (n <= 0) {\r
                terrno = errno;\r
                Perror(stderr, "read failed", errno);\r
                res_close();\r
                /*\r
                 * A long running process might get its TCP\r
                 * connection reset if the remote server was\r
                 * restarted.  Requery the server instead of\r
                 * trying a new one.  When there is only one\r
                 * server, this means that a query might work\r
                 * instead of failing.  We only allow one reset\r
                 * per query to prevent looping.\r
                 */\r
                if (terrno == ECONNRESET && !connreset) {\r
                    connreset = 1;\r
                    res_close();\r
                    goto same_ns;\r
                }\r
                res_close();\r
                goto next_ns;\r
            }\r
            resplen = ns_get16(ans);\r
            if (resplen > anssiz) {\r
                Dprint(_res.options & RES_DEBUG,\r
                       (stdout, ";; response truncated\n")\r
                       );\r
                truncated = 1;\r
                len = (ushort)anssiz;\r
            } else\r
                len = (ushort)resplen;\r
            if (len < HFIXEDSZ) {\r
                /*\r
                 * Undersized message.\r
                 */\r
                Dprint(_res.options & RES_DEBUG,\r
                       (stdout, ";; undersized: %d\n", len));\r
                terrno = EMSGSIZE;\r
                badns |= (1 << ns);\r
                res_close();\r
                goto next_ns;\r
            }\r
            cp = ans;\r
            while (len != 0 &&\r
                   (n = read(s, (char *)cp, (int)len)) > 0) {\r
                cp += n;\r
                len = (u_short)( len - n );\r
            }\r
            if (n <= 0) {\r
                terrno = errno;\r
                Perror(stderr, "read(vc)", errno);\r
                res_close();\r
                goto next_ns;\r
            }\r
            if (truncated) {\r
                /*\r
                 * Flush rest of answer\r
                 * so connection stays in synch.\r
                 */\r
                anhp->tc = 1;\r
                len = (ushort)( resplen - anssiz );\r
                while (len != 0) {\r
                    char junk[PACKETSZ];\r
\r
                    n = (len > sizeof(junk)\r
                         ? sizeof(junk)\r
                         : len);\r
                    if ((n = read(s, junk, n)) > 0)\r
                        len = (u_short)( len - n );\r
                    else\r
                        break;\r
                }\r
            }\r
            /*\r
             * The calling applicating has bailed out of\r
             * a previous call and failed to arrange to have\r
             * the circuit closed or the server has got\r
             * itself confused. Anyway drop the packet and\r
             * wait for the correct one.\r
             */\r
            if (hp->id != anhp->id) {\r
                DprintQ((_res.options & RES_DEBUG) ||\r
                    (_res.pfcode & RES_PRF_REPLY),\r
                    (stdout, ";; old answer (unexpected):\n"),\r
                    ans, (resplen>anssiz)?anssiz:resplen);\r
                goto read_len;\r
            }\r
        } else {\r
            /*\r
             * Use datagrams.\r
             */\r
#ifndef NOPOLL\r
            struct pollfd pfd;\r
            int msec;\r
#endif\r
            struct timeval timeout;\r
            fd_set dsmask, *dsmaskp;\r
            int dsmasklen;\r
            struct sockaddr_in from;\r
            int fromlen;\r
\r
            if ((s < 0) || vc) {\r
                if (vc)\r
                    res_close();\r
                s = socket(PF_INET, SOCK_DGRAM, 0);\r
                if (s < 0) {\r
#ifndef CAN_RECONNECT\r
 bad_dg_sock:\r
#endif\r
                    terrno = errno;\r
                    Perror(stderr, "socket(dg)", errno);\r
                    return (-1);\r
                }\r
                connected = 0;\r
            }\r
#ifndef CANNOT_CONNECT_DGRAM\r
            /*\r
             * On a 4.3BSD+ machine (client and server,\r
             * actually), sending to a nameserver datagram\r
             * port with no nameserver will cause an\r
             * ICMP port unreachable message to be returned.\r
             * If our datagram socket is "connected" to the\r
             * server, we get an ECONNREFUSED error on the next\r
             * socket operation, and select returns if the\r
             * error message is received.  We can thus detect\r
             * the absence of a nameserver without timing out.\r
             * If we have sent queries to at least two servers,\r
             * however, we don't want to remain connected,\r
             * as we wish to receive answers from the first\r
             * server to respond.\r
             */\r
            if (_res.nscount == 1 || (try == 0 && ns == 0)) {\r
                /*\r
                 * Connect only if we are sure we won't\r
                 * receive a response from another server.\r
                 */\r
                if (!connected) {\r
                    nsap->sin_len = sizeof ( *nsap );\r
                    if (connect(s, (struct sockaddr *)nsap,\r
                            sizeof *nsap\r
                            ) < 0) {\r
                        Aerror(stderr,\r
                               "connect(dg)",\r
                               errno, *nsap);\r
                        badns |= (1 << ns);\r
                        res_close();\r
                        goto next_ns;\r
                    }\r
                    connected = 1;\r
                }\r
                if (send(s, (char*)buf, buflen, 0) != buflen) {\r
                    Perror(stderr, "send", errno);\r
                    badns |= (1 << ns);\r
                    res_close();\r
                    goto next_ns;\r
                }\r
            } else {\r
                /*\r
                 * Disconnect if we want to listen\r
                 * for responses from more than one server.\r
                 */\r
                if (connected) {\r
#ifdef CAN_RECONNECT\r
                    struct sockaddr_in no_addr;\r
\r
                    no_addr.sin_family = AF_INET;\r
                    no_addr.sin_addr.s_addr = INADDR_ANY;\r
                    no_addr.sin_port = 0;\r
                    (void) connect(s,\r
                               (struct sockaddr *)\r
                                &no_addr,\r
                               sizeof no_addr);\r
#else\r
                    int s1 = socket(PF_INET, SOCK_DGRAM,0);\r
                    if (s1 < 0)\r
                        goto bad_dg_sock;\r
                    (void) dup2(s1, s);\r
                    (void) close(s1);\r
                    Dprint(_res.options & RES_DEBUG,\r
                        (stdout, ";; new DG socket\n"))\r
#endif /* CAN_RECONNECT */\r
                    connected = 0;\r
                    errno = 0;\r
                }\r
#endif /* !CANNOT_CONNECT_DGRAM */\r
                if (sendto(s, (char*)buf, buflen, 0,\r
                       (struct sockaddr *)nsap,\r
                       sizeof *nsap)\r
                    != buflen) {\r
                    Aerror(stderr, "sendto", errno, *nsap);\r
                    badns |= (1 << ns);\r
                    res_close();\r
                    goto next_ns;\r
                }\r
#ifndef CANNOT_CONNECT_DGRAM\r
            }\r
#endif /* !CANNOT_CONNECT_DGRAM */\r
\r
            /*\r
             * Wait for reply\r
             */\r
#ifndef NOPOLL\r
    othersyscall:\r
            if (use_poll) {\r
                msec = (_res.retrans << try) * 1000;\r
                if (try > 0)\r
                    msec /= _res.nscount;\r
                if (msec <= 0)\r
                    msec = 1000;\r
            } else {\r
#endif\r
                timeout.tv_sec = (_res.retrans << try);\r
                if (try > 0)\r
                    timeout.tv_sec /= _res.nscount;\r
                if ((long) timeout.tv_sec <= 0)\r
                    timeout.tv_sec = 1;\r
                timeout.tv_usec = 0;\r
#ifndef NOPOLL\r
            }\r
#endif\r
    wait:\r
            if (s < 0) {\r
                Perror(stderr, "s out-of-bounds", EMFILE);\r
                res_close();\r
                goto next_ns;\r
            }\r
#ifndef NOPOLL\r
            if (use_poll) {\r
                struct sigaction sa, osa;\r
                int sigsys_installed = 0;\r
\r
                pfd.fd = s;\r
                pfd.events = POLLIN;\r
                if (use_poll == 1) {\r
                    bzero(&sa, sizeof(sa));\r
                    sa.sa_handler = SIG_IGN;\r
                    if (sigaction(SIGSYS, &sa, &osa) >= 0)\r
                        sigsys_installed = 1;\r
                }\r
                n = poll(&pfd, 1, msec);\r
                if (sigsys_installed == 1) {\r
                    int oerrno = errno;\r
                    sigaction(SIGSYS, &osa, NULL);\r
                    errno = oerrno;\r
                }\r
                /* XXX why does nosys() return EINVAL? */\r
                if (n < 0 && (errno == ENOSYS ||\r
                    errno == EINVAL)) {\r
                    use_poll = 0;\r
                    goto othersyscall;\r
                } else if (use_poll == 1)\r
                    use_poll = 2;\r
                if (n < 0) {\r
                    if (errno == EINTR)\r
                        goto wait;\r
                    Perror(stderr, "poll", errno);\r
                    res_close();\r
                    goto next_ns;\r
                }\r
            } else {\r
#endif\r
                dsmasklen = howmany(s + 1, NFDBITS) *\r
                        sizeof(fd_mask);\r
                if (dsmasklen > sizeof(fd_set)) {\r
                    dsmaskp = (fd_set *)malloc(dsmasklen);\r
                    if (dsmaskp == NULL) {\r
                        res_close();\r
                        goto next_ns;\r
                    }\r
                } else\r
                    dsmaskp = &dsmask;\r
                /* only zero what we need */\r
                memset((char *)dsmaskp, 0, dsmasklen);\r
                FD_SET(s, dsmaskp);\r
                n = select(s + 1, dsmaskp, (fd_set *)NULL,\r
                       (fd_set *)NULL, &timeout);\r
                if (dsmaskp != &dsmask)\r
                    free(dsmaskp);\r
                if (n < 0) {\r
                    if (errno == EINTR)\r
                        goto wait;\r
                    Perror(stderr, "select", errno);\r
                    res_close();\r
                    goto next_ns;\r
                }\r
#ifndef NOPOLL\r
            }\r
#endif\r
\r
            if (n == 0) {\r
                /*\r
                 * timeout\r
                 */\r
                Dprint(_res.options & RES_DEBUG,\r
                       (stdout, ";; timeout\n"));\r
                gotsomewhere = 1;\r
                res_close();\r
                goto next_ns;\r
            }\r
            errno = 0;\r
            fromlen = sizeof(struct sockaddr_in);\r
            resplen = (int)recvfrom(s, (char*)ans, anssiz, 0,\r
                       (struct sockaddr *)&from, (socklen_t *)&fromlen);\r
            if (resplen <= 0) {\r
                Perror(stderr, "recvfrom", errno);\r
                res_close();\r
                goto next_ns;\r
            }\r
            gotsomewhere = 1;\r
            if (resplen < HFIXEDSZ) {\r
                /*\r
                 * Undersized message.\r
                 */\r
                Dprint(_res.options & RES_DEBUG,\r
                       (stdout, ";; undersized: %d\n",\r
                    resplen));\r
                terrno = EMSGSIZE;\r
                badns |= (1 << ns);\r
                res_close();\r
                goto next_ns;\r
            }\r
            if (hp->id != anhp->id) {\r
                /*\r
                 * response from old query, ignore it.\r
                 * XXX - potential security hazard could\r
                 *   be detected here.\r
                 */\r
                DprintQ((_res.options & RES_DEBUG) ||\r
                    (_res.pfcode & RES_PRF_REPLY),\r
                    (stdout, ";; old answer:\n"),\r
                    ans, (resplen>anssiz)?anssiz:resplen);\r
                goto wait;\r
            }\r
#ifdef CHECK_SRVR_ADDR\r
            if (!(_res.options & RES_INSECURE1) &&\r
                !res_isourserver(&from)) {\r
                /*\r
                 * response from wrong server? ignore it.\r
                 * XXX - potential security hazard could\r
                 *   be detected here.\r
                 */\r
                DprintQ((_res.options & RES_DEBUG) ||\r
                    (_res.pfcode & RES_PRF_REPLY),\r
                    (stdout, ";; not our server:\n"),\r
                    ans, (resplen>anssiz)?anssiz:resplen);\r
                goto wait;\r
            }\r
#endif\r
            if (!(_res.options & RES_INSECURE2) &&\r
                !res_queriesmatch(buf, buf + buflen,\r
                          ans, ans + anssiz)) {\r
                /*\r
                 * response contains wrong query? ignore it.\r
                 * XXX - potential security hazard could\r
                 *   be detected here.\r
                 */\r
                DprintQ((_res.options & RES_DEBUG) ||\r
                    (_res.pfcode & RES_PRF_REPLY),\r
                    (stdout, ";; wrong query name:\n"),\r
                    ans, (resplen>anssiz)?anssiz:resplen);\r
                goto wait;\r
            }\r
            if (anhp->rcode == SERVFAIL ||\r
                anhp->rcode == NOTIMP ||\r
                anhp->rcode == REFUSED) {\r
                DprintQ(_res.options & RES_DEBUG,\r
                    (stdout, "server rejected query:\n"),\r
                    ans, (resplen>anssiz)?anssiz:resplen);\r
                badns |= (1 << ns);\r
                res_close();\r
                /* don't retry if called from dig */\r
                if (!_res.pfcode)\r
                    goto next_ns;\r
            }\r
            if (!(_res.options & RES_IGNTC) && anhp->tc) {\r
                /*\r
                 * get rest of answer;\r
                 * use TCP with same server.\r
                 */\r
                Dprint(_res.options & RES_DEBUG,\r
                       (stdout, ";; truncated answer\n"));\r
                v_circuit = 1;\r
                res_close();\r
                goto same_ns;\r
            }\r
        } /*if vc/dg*/\r
        Dprint((_res.options & RES_DEBUG) ||\r
               ((_res.pfcode & RES_PRF_REPLY) &&\r
            (_res.pfcode & RES_PRF_HEAD1)),\r
               (stdout, ";; got answer:\n"));\r
        if((_res.options & RES_DEBUG) ||\r
            (_res.pfcode & RES_PRF_REPLY)) {\r
            __fp_nquery(ans, (resplen>anssiz)?anssiz:resplen, stdout);\r
        }\r
        /*\r
         * If using virtual circuits, we assume that the first server\r
         * is preferred over the rest (i.e. it is on the local\r
         * machine) and only keep that one open.\r
         * If we have temporarily opened a virtual circuit,\r
         * or if we haven't been asked to keep a socket open,\r
         * close the socket.\r
         */\r
        if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||\r
            !(_res.options & RES_STAYOPEN)) {\r
            res_close();\r
        }\r
        if (Rhook) {\r
            int done = 0, loops = 0;\r
\r
            do {\r
                res_sendhookact act;\r
\r
                act = (*Rhook)(nsap, buf, buflen,\r
                           ans, anssiz, &resplen);\r
                switch (act) {\r
                case res_goahead:\r
                case res_done:\r
                    done = 1;\r
                    break;\r
                case res_nextns:\r
                    res_close();\r
                    goto next_ns;\r
                case res_modified:\r
                    /* give the hook another try */\r
                    if (++loops < 42) /*doug adams*/\r
                        break;\r
                    /*FALLTHROUGH*/\r
                case res_error:\r
                    /*FALLTHROUGH*/\r
                default:\r
                    return (-1);\r
                }\r
            } while (!done);\r
\r
        }\r
        return (resplen);\r
    next_ns: ;\r
       } /*foreach ns*/\r
    } /*foreach retry*/\r
    res_close();\r
    if (!v_circuit) {\r
        if (!gotsomewhere)\r
            errno = ECONNREFUSED;   /* no nameservers found */\r
        else\r
            errno = ETIMEDOUT;  /* no answer obtained */\r
    } else\r
        errno = terrno;\r
    return (-1);\r
}\r
\r
/*\r
 * This routine is for closing the socket if a virtual circuit is used and\r
 * the program wants to close it.  This provides support for endhostent()\r
 * which expects to close the socket.\r
 *\r
 * This routine is not expected to be user visible.\r
 */\r
void\r
res_close()\r
{\r
    if (s >= 0) {\r
        (void) close(s);\r
        s = -1;\r
        connected = 0;\r
        vc = 0;\r
    }\r
}\r