freebsd-dev/lib/libc/net/getservent.c
Bill Paul 217ae63218 Improve NIS performace of getservbyname() and getservbyport(). Both these
functions are implimented as wrappers around getservent(), which means it's
up to getservent() to do all the work. The NIS support in getservent()
only allows it to scan through the services.byname map one entry at a
time until it finds the requested service name/port. This can be painfully
slow due to the overhead involved (lots and lots of successive RPCs).

To fix this, we allow getservbyname() and getservbyport() to signal
getservent() that if NIS is turned on (there's a '+' in /etc/services),
the usual yp_first()/yp_next() linear search should be abandoned and
yp_match() used instead. This causes getservent() to immediately
locate the requested entry instead of wasting time groping through the
whole map.

The downside is that this trick is accomplished by exporting a couple of
pointers from getservent.c which getservbyname.c and getservbyport.c can
preset in order to tell getservent() what to do. If all three functions
were in the same source module, then the extra cruft could be delcared
static to avoid poluting the global symbol space. Maybe they should be
combined anyway. For now I've settled on prepending lots of underscores.
1996-06-01 04:40:42 +00:00

277 lines
6.5 KiB
C

/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 BY THE REGENTS 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 REGENTS 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getservent.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef YP
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
static int serv_stepping_yp = 0;
#endif
#define MAXALIASES 35
static FILE *servf = NULL;
static char line[BUFSIZ+1];
static struct servent serv;
static char *serv_aliases[MAXALIASES];
int _serv_stayopen;
#ifdef YP
char *___getservbyname_yp = NULL;
char *___getservbyproto_yp = NULL;
int ___getservbyport_yp = 0;
static char *yp_domain = NULL;
static int
_getservbyport_yp(line)
char *line;
{
char *result;
int resultlen;
char buf[YPMAXRECORD];
int rv;
snprintf(buf, sizeof(buf), "%d/%s", ntohs(___getservbyport_yp),
___getservbyproto_yp);
___getservbyport_yp = 0;
___getservbyproto_yp = NULL;
if(!yp_domain) {
if(yp_get_default_domain(&yp_domain))
return (0);
}
/*
* We have to be a little flexible here. Ideally you're supposed
* to have both a services.byname and a services.byport map, but
* some systems have only services.byname. FreeBSD cheats a little
* by putting the services.byport information in the same map as
* services.byname so that either case will work. We allow for both
* possibilities here: if there is no services.byport map, we try
* services.byname instead.
*/
if ((rv = yp_match(yp_domain, "services.byport", buf, strlen(buf),
&result, &resultlen))) {
if (rv == YPERR_MAP) {
if (yp_match(yp_domain, "services.byname", buf,
strlen(buf), &result, &resultlen))
return(0);
} else
return(0);
}
/* getservent() expects lines terminated with \n -- make it happy */
snprintf(line, BUFSIZ, "%.*s\n", resultlen, result);
free(result);
return(1);
}
static int
_getservbyname_yp(line)
char *line;
{
char *result;
int resultlen;
char buf[YPMAXRECORD];
if(!yp_domain) {
if(yp_get_default_domain(&yp_domain))
return (0);
}
snprintf(buf, sizeof(buf), "%s/%s", ___getservbyname_yp,
___getservbyproto_yp);
___getservbyname_yp = 0;
___getservbyproto_yp = NULL;
if (yp_match(yp_domain, "services.byname", buf, strlen(buf),
&result, &resultlen)) {
return(0);
}
/* getservent() expects lines terminated with \n -- make it happy */
snprintf(line, BUFSIZ, "%.*s\n", resultlen, result);
free(result);
return(1);
}
static int
_getservent_yp(line)
char *line;
{
static char *key = NULL;
static int keylen;
char *lastkey, *result;
int resultlen;
int rv;
if(!yp_domain) {
if(yp_get_default_domain(&yp_domain))
return (0);
}
if (!serv_stepping_yp) {
if (key)
free(key);
if ((rv = yp_first(yp_domain, "services.byname", &key, &keylen,
&result, &resultlen))) {
serv_stepping_yp = 0;
return(0);
}
serv_stepping_yp = 1;
} else {
lastkey = key;
rv = yp_next(yp_domain, "services.byname", key, keylen, &key,
&keylen, &result, &resultlen);
free(lastkey);
if (rv) {
serv_stepping_yp = 0;
return (0);
}
}
/* getservent() expects lines terminated with \n -- make it happy */
snprintf(line, BUFSIZ, "%.*s\n", resultlen, result);
free(result);
return(1);
}
#endif
void
setservent(f)
int f;
{
if (servf == NULL)
servf = fopen(_PATH_SERVICES, "r" );
else
rewind(servf);
_serv_stayopen |= f;
}
void
endservent()
{
if (servf) {
fclose(servf);
servf = NULL;
}
_serv_stayopen = 0;
}
struct servent *
getservent()
{
char *p;
register char *cp, **q;
#ifdef YP
if (serv_stepping_yp && _getservent_yp(line)) {
p = (char *)&line;
goto unpack;
}
tryagain:
#endif
if (servf == NULL && (servf = fopen(_PATH_SERVICES, "r" )) == NULL)
return (NULL);
again:
if ((p = fgets(line, BUFSIZ, servf)) == NULL)
return (NULL);
#ifdef YP
if (*p == '+' && _yp_check(NULL)) {
if (___getservbyname_yp != NULL) {
if (!_getservbyname_yp(&line))
goto tryagain;
}
else if (___getservbyport_yp != 0) {
if (!_getservbyport_yp(&line))
goto tryagain;
}
else if (!_getservent_yp(&line))
goto tryagain;
}
unpack:
#endif
if (*p == '#')
goto again;
cp = strpbrk(p, "#\n");
if (cp == NULL)
goto again;
*cp = '\0';
serv.s_name = p;
p = strpbrk(p, " \t");
if (p == NULL)
goto again;
*p++ = '\0';
while (*p == ' ' || *p == '\t')
p++;
cp = strpbrk(p, ",/");
if (cp == NULL)
goto again;
*cp++ = '\0';
serv.s_port = htons((u_short)atoi(p));
serv.s_proto = cp;
q = serv.s_aliases = serv_aliases;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (q < &serv_aliases[MAXALIASES - 1])
*q++ = cp;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
}
*q = NULL;
return (&serv);
}