Fix a bug about the iSCSI DHCP dependency issue.

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

/*\r
 * Copyright (c) 1988, 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_query.c 8.1 (Berkeley) 6/4/93";\r
static char orig_rcsid = "From: Id: res_query.c,v 8.14 1997/06/09 17:47:05 halley Exp $";\r
static char rcsid[] = "$Id: res_query.c,v 1.1.1.1 2003/11/19 01:51:38 kyu3 Exp $";\r
#endif /* LIBC_SCCS and not lint */\r
\r
#include <sys/types.h>\r
#include <sys/param.h>\r
#include <netinet/in.h>\r
#include <arpa/inet.h>\r
#include <arpa/nameser.h>\r
#include <ctype.h>\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
\r
#include "res_config.h"\r
\r
#if PACKETSZ > 1024\r
#define MAXPACKET   PACKETSZ\r
#else\r
#define MAXPACKET   1024\r
#endif\r
\r
/*\r
 * Formulate a normal query, send, and await answer.\r
 * Returned answer is placed in supplied buffer "answer".\r
 * Perform preliminary check of answer, returning success only\r
 * if no error is indicated and the answer count is nonzero.\r
 * Return the size of the response on success, -1 on error.\r
 * Error number is left in h_errno.\r
 *\r
 * Caller must parse answer and determine whether it answers the question.\r
 */\r
int\r
res_query(\r
    const char *name,   /* domain name */\r
    int class,          /* class of query */\r
    int type,           /* type of query */\r
    u_char *answer,     /* buffer to put answer */\r
    int anslen          /* size of answer buffer */\r
    )\r
{\r
    u_char buf[MAXPACKET];\r
    HEADER *hp = (HEADER *) answer;\r
    int n;\r
\r
    hp->rcode = NOERROR;    /* default */\r
\r
    if ((_res.options & RES_INIT) == 0 && res_init() == -1) {\r
        h_errno = NETDB_INTERNAL;\r
        return (-1);\r
    }\r
#ifdef DEBUG\r
    if (_res.options & RES_DEBUG)\r
        printf(";; res_query(%s, %d, %d)\n", name, class, type);\r
#endif\r
\r
    n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,\r
            buf, sizeof(buf));\r
    if (n <= 0) {\r
#ifdef DEBUG\r
        if (_res.options & RES_DEBUG)\r
            printf(";; res_query: mkquery failed\n");\r
#endif\r
        h_errno = NO_RECOVERY;\r
        return (n);\r
    }\r
    n = res_send(buf, n, answer, anslen);\r
    if (n < 0) {\r
#ifdef DEBUG\r
        if (_res.options & RES_DEBUG)\r
            printf(";; res_query: send error\n");\r
#endif\r
        h_errno = TRY_AGAIN;\r
        return (n);\r
    }\r
\r
    if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {\r
#ifdef DEBUG\r
        if (_res.options & RES_DEBUG)\r
            printf(";; rcode = %d, ancount=%d\n", hp->rcode,\r
                ntohs(hp->ancount));\r
#endif\r
        switch (hp->rcode) {\r
        case NXDOMAIN:\r
            h_errno = HOST_NOT_FOUND;\r
            break;\r
        case SERVFAIL:\r
            h_errno = TRY_AGAIN;\r
            break;\r
        case NOERROR:\r
            h_errno = NO_DATA;\r
            break;\r
        case FORMERR:\r
        case NOTIMP:\r
        case REFUSED:\r
        default:\r
            h_errno = NO_RECOVERY;\r
            break;\r
        }\r
        return (-1);\r
    }\r
    return (n);\r
}\r
\r
/*\r
 * Formulate a normal query, send, and retrieve answer in supplied buffer.\r
 * Return the size of the response on success, -1 on error.\r
 * If enabled, implement search rules until answer or unrecoverable failure\r
 * is detected.  Error code, if any, is left in h_errno.\r
 */\r
int\r
res_search(\r
    const char *name,   /* domain name */\r
    int class,          /* class of query */\r
    int type,           /* type of query */\r
    u_char *answer,     /* buffer to put answer */\r
    int anslen          /* size of answer */\r
    )\r
{\r
    const char *cp, * const *domain;\r
    HEADER *hp = (HEADER *) answer;\r
    u_int dots;\r
    int trailing_dot, ret, saved_herrno;\r
    int got_nodata = 0, got_servfail = 0, tried_as_is = 0;\r
\r
    if ((_res.options & RES_INIT) == 0 && res_init() == -1) {\r
        h_errno = NETDB_INTERNAL;\r
        return (-1);\r
    }\r
    errno = 0;\r
    h_errno = HOST_NOT_FOUND;   /* default, if we never query */\r
    dots = 0;\r
    for (cp = name; *cp; cp++)\r
        dots += (*cp == '.');\r
    trailing_dot = 0;\r
    if (cp > name && *--cp == '.')\r
        trailing_dot++;\r
\r
    /* If there aren't any dots, it could be a user-level alias */\r
    if (!dots && (cp = hostalias(name)) != NULL)\r
        return (res_query(cp, class, type, answer, anslen));\r
\r
    /*\r
     * If there are dots in the name already, let's just give it a try\r
     * 'as is'.  The threshold can be set with the "ndots" option.\r
     */\r
    saved_herrno = -1;\r
    if (dots >= _res.ndots) {\r
        ret = res_querydomain(name, NULL, class, type, answer, anslen);\r
        if (ret > 0)\r
            return (ret);\r
        saved_herrno = h_errno;\r
        tried_as_is++;\r
    }\r
\r
    /*\r
     * We do at least one level of search if\r
     *  - there is no dot and RES_DEFNAME is set, or\r
     *  - there is at least one dot, there is no trailing dot,\r
     *    and RES_DNSRCH is set.\r
     */\r
    if ((!dots && (_res.options & RES_DEFNAMES)) ||\r
        (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {\r
        int done = 0;\r
\r
        for (domain = (const char * const *)_res.dnsrch;\r
             *domain && !done;\r
             domain++) {\r
\r
            ret = res_querydomain(name, *domain, class, type,\r
                          answer, anslen);\r
            if (ret > 0)\r
                return (ret);\r
\r
            /*\r
             * If no server present, give up.\r
             * If name isn't found in this domain,\r
             * keep trying higher domains in the search list\r
             * (if that's enabled).\r
             * On a NO_DATA error, keep trying, otherwise\r
             * a wildcard entry of another type could keep us\r
             * from finding this entry higher in the domain.\r
             * If we get some other error (negative answer or\r
             * server failure), then stop searching up,\r
             * but try the input name below in case it's\r
             * fully-qualified.\r
             */\r
            if (errno == ECONNREFUSED) {\r
                h_errno = TRY_AGAIN;\r
                return (-1);\r
            }\r
\r
            switch (h_errno) {\r
            case NO_DATA:\r
                got_nodata++;\r
                /* FALLTHROUGH */\r
            case HOST_NOT_FOUND:\r
                /* keep trying */\r
                break;\r
            case TRY_AGAIN:\r
                if (hp->rcode == SERVFAIL) {\r
                    /* try next search element, if any */\r
                    got_servfail++;\r
                    break;\r
                }\r
                /* FALLTHROUGH */\r
            default:\r
                /* anything else implies that we're done */\r
                done++;\r
            }\r
\r
            /* if we got here for some reason other than DNSRCH,\r
             * we only wanted one iteration of the loop, so stop.\r
             */\r
            if (!(_res.options & RES_DNSRCH))\r
                done++;\r
        }\r
    }\r
\r
    /*\r
     * If we have not already tried the name "as is", do that now.\r
     * note that we do this regardless of how many dots were in the\r
     * name or whether it ends with a dot unless NOTLDQUERY is set.\r
     */\r
    if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {\r
        ret = res_querydomain(name, NULL, class, type, answer, anslen);\r
        if (ret > 0)\r
            return (ret);\r
    }\r
\r
    /* if we got here, we didn't satisfy the search.\r
     * if we did an initial full query, return that query's h_errno\r
     * (note that we wouldn't be here if that query had succeeded).\r
     * else if we ever got a nodata, send that back as the reason.\r
     * else send back meaningless h_errno, that being the one from\r
     * the last DNSRCH we did.\r
     */\r
    if (saved_herrno != -1)\r
        h_errno = saved_herrno;\r
    else if (got_nodata)\r
        h_errno = NO_DATA;\r
    else if (got_servfail)\r
        h_errno = TRY_AGAIN;\r
    return (-1);\r
}\r
\r
/*\r
 * Perform a call on res_query on the concatenation of name and domain,\r
 * removing a trailing dot from name if domain is NULL.\r
 */\r
int\r
res_querydomain(\r
    const char *name,\r
    const char *domain,\r
    int class,      /* class of query */\r
    int type,       /* type of query */\r
    u_char *answer, /* buffer to put answer */\r
    int anslen      /* size of answer */\r
    )\r
{\r
    char nbuf[MAXDNAME];\r
    const char *longname = nbuf;\r
    int n, d;\r
\r
    if ((_res.options & RES_INIT) == 0 && res_init() == -1) {\r
        h_errno = NETDB_INTERNAL;\r
        return (-1);\r
    }\r
#ifdef DEBUG\r
    if (_res.options & RES_DEBUG)\r
        printf(";; res_querydomain(%s, %s, %d, %d)\n",\r
               name, domain?domain:"<Nil>", class, type);\r
#endif\r
    if (domain == NULL) {\r
        /*\r
         * Check for trailing '.';\r
         * copy without '.' if present.\r
         */\r
        n = (int)strlen(name);\r
        if (n >= MAXDNAME) {\r
            h_errno = NO_RECOVERY;\r
            return (-1);\r
        }\r
        n--;\r
        if (n >= 0 && name[n] == '.') {\r
            strncpy(nbuf, name, n);\r
            nbuf[n] = '\0';\r
        } else\r
            longname = name;\r
    } else {\r
        n = (int)strlen(name);\r
        d = (int)strlen(domain);\r
        if (n + d + 1 >= MAXDNAME) {\r
            h_errno = NO_RECOVERY;\r
            return (-1);\r
        }\r
        sprintf(nbuf, "%s.%s", name, domain);\r
    }\r
    return (res_query(longname, class, type, answer, anslen));\r
}\r
\r
const char *\r
hostalias(\r
    const char *name\r
    )\r
{\r
    register char *cp1, *cp2;\r
    FILE *fp;\r
    char *file;\r
    char buf[BUFSIZ];\r
    static char abuf[MAXDNAME];\r
\r
    if (_res.options & RES_NOALIASES)\r
        return (NULL);\r
#ifdef _ORG_FREEBSD_\r
    if (issetugid())\r
        return (NULL);\r
#endif\r
    file = getenv("HOSTALIASES");\r
    if (file == NULL || (fp = fopen(file, "r")) == NULL)\r
        return (NULL);\r
    setbuf(fp, NULL);\r
    buf[sizeof(buf) - 1] = '\0';\r
    while (fgets(buf, sizeof(buf), fp)) {\r
        for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)\r
            ;\r
        if (!*cp1)\r
            break;\r
        *cp1 = '\0';\r
        if (!strcasecmp(buf, name)) {\r
            while (isspace(*++cp1))\r
                ;\r
            if (!*cp1)\r
                break;\r
            for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)\r
                ;\r
            abuf[sizeof(abuf) - 1] = *cp2 = '\0';\r
            strncpy(abuf, cp1, sizeof(abuf) - 1);\r
            fclose(fp);\r
            return (abuf);\r
        }\r
    }\r
    fclose(fp);\r
    return (NULL);\r
}\r