add directory gnu
This commit is contained in:
gohigh
268
gnu/glibc/glibc-1.03/inet/bsd/res_query.c
Normal file
268
gnu/glibc/glibc-1.03/inet/bsd/res_query.c
Normal file
@@ -0,0 +1,268 @@
|
||||
/*
|
||||
* Copyright (c) 1988 Regents of the University of California.
|
||||
* All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms are permitted
|
||||
* provided that: (1) source distributions retain this entire copyright
|
||||
* notice and comment, and (2) distributions including binaries display
|
||||
* the following acknowledgement: ``This product includes software
|
||||
* developed by the University of California, Berkeley and its contributors''
|
||||
* in the documentation or other materials provided with the distribution
|
||||
* and in all advertising materials mentioning features or use of this
|
||||
* software. Neither the name of the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
|
||||
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
|
||||
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
||||
*/
|
||||
|
||||
#if defined(LIBC_SCCS) && !defined(lint)
|
||||
static char sccsid[] = "@(#)res_query.c 5.7 (Berkeley) 6/1/90";
|
||||
#endif /* LIBC_SCCS and not lint */
|
||||
|
||||
#include <sys/param.h>
|
||||
#include <sys/socket.h>
|
||||
#include <netinet/in.h>
|
||||
#include <ctype.h>
|
||||
#include <netdb.h>
|
||||
#include <stdio.h>
|
||||
#include <errno.h>
|
||||
#include <string.h>
|
||||
#include <arpa/inet.h>
|
||||
#include <arpa/nameser.h>
|
||||
#include <resolv.h>
|
||||
|
||||
#if PACKETSZ > 1024
|
||||
#define MAXPACKET PACKETSZ
|
||||
#else
|
||||
#define MAXPACKET 1024
|
||||
#endif
|
||||
|
||||
extern int errno;
|
||||
int h_errno;
|
||||
|
||||
/*
|
||||
* Formulate a normal query, send, and await answer.
|
||||
* Returned answer is placed in supplied buffer "answer".
|
||||
* Perform preliminary check of answer, returning success only
|
||||
* if no error is indicated and the answer count is nonzero.
|
||||
* Return the size of the response on success, -1 on error.
|
||||
* Error number is left in h_errno.
|
||||
* Caller must parse answer and determine whether it answers the question.
|
||||
*/
|
||||
res_query(name, class, type, answer, anslen)
|
||||
char *name; /* domain name */
|
||||
int class, type; /* class and type of query */
|
||||
u_char *answer; /* buffer to put answer */
|
||||
int anslen; /* size of answer buffer */
|
||||
{
|
||||
char buf[MAXPACKET];
|
||||
HEADER *hp;
|
||||
int n;
|
||||
|
||||
if ((_res.options & RES_INIT) == 0 && res_init() == -1)
|
||||
return (-1);
|
||||
#ifdef DEBUG
|
||||
if (_res.options & RES_DEBUG)
|
||||
printf("res_query(%s, %d, %d)\n", name, class, type);
|
||||
#endif
|
||||
n = res_mkquery(QUERY, name, class, type, (char *)NULL, 0, NULL,
|
||||
buf, sizeof(buf));
|
||||
|
||||
if (n <= 0) {
|
||||
#ifdef DEBUG
|
||||
if (_res.options & RES_DEBUG)
|
||||
printf("res_query: mkquery failed\n");
|
||||
#endif
|
||||
h_errno = NO_RECOVERY;
|
||||
return (n);
|
||||
}
|
||||
n = res_send(buf, n, answer, anslen);
|
||||
if (n < 0) {
|
||||
#ifdef DEBUG
|
||||
if (_res.options & RES_DEBUG)
|
||||
printf("res_query: send error\n");
|
||||
#endif
|
||||
h_errno = TRY_AGAIN;
|
||||
return(n);
|
||||
}
|
||||
|
||||
hp = (HEADER *) answer;
|
||||
if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
|
||||
#ifdef DEBUG
|
||||
if (_res.options & RES_DEBUG)
|
||||
printf("rcode = %d, ancount=%d\n", hp->rcode,
|
||||
ntohs(hp->ancount));
|
||||
#endif
|
||||
switch (hp->rcode) {
|
||||
case NXDOMAIN:
|
||||
h_errno = HOST_NOT_FOUND;
|
||||
break;
|
||||
case SERVFAIL:
|
||||
h_errno = TRY_AGAIN;
|
||||
break;
|
||||
case NOERROR:
|
||||
h_errno = NO_DATA;
|
||||
break;
|
||||
case FORMERR:
|
||||
case NOTIMP:
|
||||
case REFUSED:
|
||||
default:
|
||||
h_errno = NO_RECOVERY;
|
||||
break;
|
||||
}
|
||||
return (-1);
|
||||
}
|
||||
return(n);
|
||||
}
|
||||
|
||||
/*
|
||||
* Formulate a normal query, send, and retrieve answer in supplied buffer.
|
||||
* Return the size of the response on success, -1 on error.
|
||||
* If enabled, implement search rules until answer or unrecoverable failure
|
||||
* is detected. Error number is left in h_errno.
|
||||
* Only useful for queries in the same name hierarchy as the local host
|
||||
* (not, for example, for host address-to-name lookups in domain in-addr.arpa).
|
||||
*/
|
||||
res_search(name, class, type, answer, anslen)
|
||||
char *name; /* domain name */
|
||||
int class, type; /* class and type of query */
|
||||
u_char *answer; /* buffer to put answer */
|
||||
int anslen; /* size of answer */
|
||||
{
|
||||
register char *cp, **domain;
|
||||
int n, ret, got_nodata = 0;
|
||||
char *hostalias();
|
||||
|
||||
if ((_res.options & RES_INIT) == 0 && res_init() == -1)
|
||||
return (-1);
|
||||
|
||||
errno = 0;
|
||||
h_errno = HOST_NOT_FOUND; /* default, if we never query */
|
||||
for (cp = name, n = 0; *cp; cp++)
|
||||
if (*cp == '.')
|
||||
n++;
|
||||
if (n == 0 && (cp = hostalias(name)))
|
||||
return (res_query(cp, class, type, answer, anslen));
|
||||
|
||||
/*
|
||||
* We do at least one level of search if
|
||||
* - there is no dot and RES_DEFNAME is set, or
|
||||
* - there is at least one dot, there is no trailing dot,
|
||||
* and RES_DNSRCH is set.
|
||||
*/
|
||||
if ((n == 0 && _res.options & RES_DEFNAMES) ||
|
||||
(n != 0 && *--cp != '.' && _res.options & RES_DNSRCH))
|
||||
for (domain = _res.dnsrch; *domain; domain++) {
|
||||
ret = res_querydomain(name, *domain, class, type,
|
||||
answer, anslen);
|
||||
if (ret > 0)
|
||||
return (ret);
|
||||
/*
|
||||
* If no server present, give up.
|
||||
* If name isn't found in this domain,
|
||||
* keep trying higher domains in the search list
|
||||
* (if that's enabled).
|
||||
* On a NO_DATA error, keep trying, otherwise
|
||||
* a wildcard entry of another type could keep us
|
||||
* from finding this entry higher in the domain.
|
||||
* If we get some other error (negative answer or
|
||||
* server failure), then stop searching up,
|
||||
* but try the input name below in case it's fully-qualified.
|
||||
*/
|
||||
if (errno == ECONNREFUSED) {
|
||||
h_errno = TRY_AGAIN;
|
||||
return (-1);
|
||||
}
|
||||
if (h_errno == NO_DATA)
|
||||
got_nodata++;
|
||||
if ((h_errno != HOST_NOT_FOUND && h_errno != NO_DATA) ||
|
||||
(_res.options & RES_DNSRCH) == 0)
|
||||
break;
|
||||
}
|
||||
/*
|
||||
* If the search/default failed, try the name as fully-qualified,
|
||||
* but only if it contained at least one dot (even trailing).
|
||||
* This is purely a heuristic; we assume that any reasonable query
|
||||
* about a top-level domain (for servers, SOA, etc) will not use
|
||||
* res_search.
|
||||
*/
|
||||
if (n && (ret = res_querydomain(name, (char *)NULL, class, type,
|
||||
answer, anslen)) > 0)
|
||||
return (ret);
|
||||
if (got_nodata)
|
||||
h_errno = NO_DATA;
|
||||
return (-1);
|
||||
}
|
||||
|
||||
/*
|
||||
* Perform a call on res_query on the concatenation of name and domain,
|
||||
* removing a trailing dot from name if domain is NULL.
|
||||
*/
|
||||
res_querydomain(name, domain, class, type, answer, anslen)
|
||||
char *name, *domain;
|
||||
int class, type; /* class and type of query */
|
||||
u_char *answer; /* buffer to put answer */
|
||||
int anslen; /* size of answer */
|
||||
{
|
||||
char nbuf[2*MAXDNAME+2];
|
||||
char *longname = nbuf;
|
||||
int n;
|
||||
|
||||
#ifdef DEBUG
|
||||
if (_res.options & RES_DEBUG)
|
||||
printf("res_querydomain(%s, %s, %d, %d)\n",
|
||||
name, domain, class, type);
|
||||
#endif
|
||||
if (domain == NULL) {
|
||||
/*
|
||||
* Check for trailing '.';
|
||||
* copy without '.' if present.
|
||||
*/
|
||||
n = strlen(name) - 1;
|
||||
if (name[n] == '.' && n < sizeof(nbuf) - 1) {
|
||||
bcopy(name, nbuf, n);
|
||||
nbuf[n] = '\0';
|
||||
} else
|
||||
longname = name;
|
||||
} else
|
||||
(void)sprintf(nbuf, "%.*s.%.*s",
|
||||
MAXDNAME, name, MAXDNAME, domain);
|
||||
|
||||
return (res_query(longname, class, type, answer, anslen));
|
||||
}
|
||||
|
||||
char *
|
||||
hostalias(name)
|
||||
register char *name;
|
||||
{
|
||||
register char *C1, *C2;
|
||||
FILE *fp;
|
||||
char *file, *getenv(), *strcpy(), *strncpy();
|
||||
char buf[BUFSIZ];
|
||||
static char abuf[MAXDNAME];
|
||||
|
||||
file = getenv("HOSTALIASES");
|
||||
if (file == NULL || (fp = fopen(file, "r")) == NULL)
|
||||
return (NULL);
|
||||
buf[sizeof(buf) - 1] = '\0';
|
||||
while (fgets(buf, sizeof(buf), fp)) {
|
||||
for (C1 = buf; *C1 && !isspace(*C1); ++C1);
|
||||
if (!*C1)
|
||||
break;
|
||||
*C1 = '\0';
|
||||
if (!strcasecmp(buf, name)) {
|
||||
while (isspace(*++C1));
|
||||
if (!*C1)
|
||||
break;
|
||||
for (C2 = C1 + 1; *C2 && !isspace(*C2); ++C2);
|
||||
abuf[sizeof(abuf) - 1] = *C2 = '\0';
|
||||
(void)strncpy(abuf, C1, sizeof(abuf) - 1);
|
||||
fclose(fp);
|
||||
return (abuf);
|
||||
}
|
||||
}
|
||||
fclose(fp);
|
||||
return (NULL);
|
||||
}
|
||||
Reference in New Issue
Block a user