freebsd-dev/usr.sbin/ypserv/yp_main.c

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/*
* Copyright (c) 1995
* Bill Paul <wpaul@ctr.columbia.edu>. 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 Bill Paul.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul 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.
*
This commit changes the YPPROC_ALL procecdure so that it handles requests _without_ using fork(). The problem with YPPROC_ALL is that it transmits an entire map through a TCP pipe as the result of a single RPC call. First of all, this requires certain hackery in the XDR filter. Second, if the map being sent is large, the server can end up spending lots of time in the XDR filter sending to just the one client, while requests for other clients will go unanswered. My original solution for this was to fork() the request into a child process which terminates after the map has been transmitted (or the transfer is interrupted due to an error). This leaves the parent free to handle other requests. But this solution is kind of lame: fork() is relatively expensive, and we have to keep a cap on the number of child processes to keep from swamping the system. What we do now is grab control of the service transport handle and XDR handle from the RPC library and send the records one at a time ourselves instead of letting the RPC library do it. We send a record, then go back to the svc_run() loop and select() on the socket. If select() says we can still write data, we send the next record. Then we call svc_getreqset() and handle other RPCs and loop around again. This way, we can handle other RPCs between records. We manage multiple YPPROC_ALL requests using a circular queue. When a request is done, we dequeue it and destroy the handle. We also tag each request with a ttl which is decremented whevever we run the queue and a handle isn't serviced. This lets us nuke requests that have sat idle for too long (if we didn't do this, we might run out of socket descriptors.) Now all I have to do is come up with an async resolver, and ypserv won't need to fork() at all. :) Note: these changes should not go into 2.2 unless they get a very throrough shakedown before the final cutoff date.
1996-11-30 22:38:44 +00:00
* $Id: yp_main.c,v 1.6 1996/05/31 16:01:50 wpaul Exp $
*/
/*
* ypserv startup function.
* We need out own main() since we have to do some additional work
* that rpcgen won't do for us. Most of this file was generated using
* rpcgen.new, and later modified.
*/
#include "yp.h"
#include <stdio.h>
#include <stdlib.h> /* getenv, exit */
#include <rpc/pmap_clnt.h> /* for pmap_unset */
#include <string.h> /* strcmp */
#include <signal.h>
#include <sys/ttycom.h> /* TIOCNOTTY */
#ifdef __cplusplus
#include <sysent.h> /* getdtablesize, open */
#endif /* __cplusplus */
#include <memory.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <syslog.h>
#include <sys/wait.h>
#include "yp_extern.h"
#include <unistd.h>
#include <rpc/rpc.h>
#include <errno.h>
#include <err.h>
#ifndef SIG_PF
#define SIG_PF void(*)(int)
#endif
#define _RPCSVC_CLOSEDOWN 120
#ifndef lint
This commit changes the YPPROC_ALL procecdure so that it handles requests _without_ using fork(). The problem with YPPROC_ALL is that it transmits an entire map through a TCP pipe as the result of a single RPC call. First of all, this requires certain hackery in the XDR filter. Second, if the map being sent is large, the server can end up spending lots of time in the XDR filter sending to just the one client, while requests for other clients will go unanswered. My original solution for this was to fork() the request into a child process which terminates after the map has been transmitted (or the transfer is interrupted due to an error). This leaves the parent free to handle other requests. But this solution is kind of lame: fork() is relatively expensive, and we have to keep a cap on the number of child processes to keep from swamping the system. What we do now is grab control of the service transport handle and XDR handle from the RPC library and send the records one at a time ourselves instead of letting the RPC library do it. We send a record, then go back to the svc_run() loop and select() on the socket. If select() says we can still write data, we send the next record. Then we call svc_getreqset() and handle other RPCs and loop around again. This way, we can handle other RPCs between records. We manage multiple YPPROC_ALL requests using a circular queue. When a request is done, we dequeue it and destroy the handle. We also tag each request with a ttl which is decremented whevever we run the queue and a handle isn't serviced. This lets us nuke requests that have sat idle for too long (if we didn't do this, we might run out of socket descriptors.) Now all I have to do is come up with an async resolver, and ypserv won't need to fork() at all. :) Note: these changes should not go into 2.2 unless they get a very throrough shakedown before the final cutoff date.
1996-11-30 22:38:44 +00:00
static const char rcsid[] = "$Id: yp_main.c,v 1.6 1996/05/31 16:01:50 wpaul Exp $";
#endif /* not lint */
int _rpcpmstart; /* Started by a port monitor ? */
static int _rpcfdtype;
/* Whether Stream or Datagram ? */
/* States a server can be in wrt request */
#define _IDLE 0
#define _SERVED 1
#define _SERVING 2
extern void ypprog_1 __P((struct svc_req, register SVCXPRT));
extern void ypprog_2 __P((struct svc_req, register SVCXPRT));
extern int _rpcsvcstate; /* Set when a request is serviced */
char *progname = "ypserv";
char *yp_dir = _PATH_YP;
int debug = 0;
int do_dns = 0;
static
void _msgout(char* msg)
{
if (debug) {
if (_rpcpmstart)
syslog(LOG_ERR, msg);
else
(void) fprintf(stderr, "%s\n", msg);
} else
syslog(LOG_ERR, msg);
}
static void unregister()
{
(void) pmap_unset(YPPROG, YPVERS);
(void) pmap_unset(YPPROG, YPOLDVERS);
}
static void reaper(sig)
int sig;
{
int status;
if (sig == SIGHUP) {
load_securenets();
Performance enhancements (I hope) and new stuff: yp_dblookup.c: - Implement database handle caching. What this means is that instead of opening and closing map databases for each request, we open a database and save the handle (and, if requested, the key index) in an array. This saves a bit of overhead on things like repeated YPPROC_NEXT calls, such as you'd get from getpwent(). Normally, each YPPROC_NEXT would require open()ing the database, seeking to the location supplied by the caller (which is time consuming with hash databases as the R_CURSOR flag doesn't work), reading the data, close()ing the database and then shipping the data off to the caller. The system call overhead is prohibitive, especially with very large maps. By caching the handle to an open database, we elimitate at least the open()/close() system calls, as well as the associated DB setup and tear-down operations, for a large percentage of the time. This improves performance substantially at the cost of consuming a little more memory than before. Note that all the caching support is surrounded by #ifdef DB_CACHE so that this same source module can still be used by other programs that don't need it. - Make yp_open_db() call yp_validdomain(). Doing it here saves cycles when caching is enabled since a hit on the map cache list by definition means that the domain being referenced is valid. - Also make yp_open_db() check for exhaustion of file descriptors, just in case. yp_server.c: - Reorganize things a little to take advantage of the database handle caching. Add a call to yp_flush_all() in ypproc_clear_2_svc(). - Remove calls to yp_validdomain() from some of the service procedures. yp_validdomain() is called inside yp_open_db() now, so procedures that call into the database package don't need to use yp_validdomain() themselves. - Fix a bogosity in ypproc_maplist_2_svc(): don't summarily initiallize the result.maps pointer to NULL. This causes yp_maplist_free() to fail and leaks memory. - Make ypproc_master_2_svc() copy the string it gets from the database package into a private static buffer before trying to NUL terminate it. This is necessary with the DB handle caching: stuffing a NUL into the data returned by DB package will goof it up internally. yp_main.c: - Stuff for DB handle caching: call yp_init_dbs() to clear the handle array and add call to yp_flush_all() to the SIGHUP signal handler. Makefile.yp: - Reorganize to deal with database caching. yp_mkdb(8) can now be used to send a YPPROC_CLEAR signal to ypserv(8). Call it after each map is created to refresh ypserv's cache. - Add support for mail.alias map. Contributed by Mike Murphy (mrm@sceard.com). - Make default location for the netgroups source file be /var/yp/netgroup instead of /etc/netgroup. mkaliases: - New file: script to generate mail.alias map. Contributed by Mike Murphy (mrm@sceard.com). Makefile: - Install Makefile.yp as /var/yp/Makefile.dist and link it to /var/yp/Makefile only if /var/yp/Makefile doesn't already exist. Suggested by Peter Wemm. - Install new mkaliases script in /usr/libexec along with mknetid. - Use somewhat saner approach to generating rpcgen-dependent files as suggested by Garrett Wollman.
1996-04-28 04:38:52 +00:00
#ifdef DB_CACHE
yp_flush_all();
#endif
return;
}
if (sig == SIGCHLD) {
while (wait3(&status, WNOHANG, NULL) > 0)
children--;
} else {
unregister();
exit(0);
}
}
static void usage()
{
fprintf(stderr, "Usage: %s [-h] [-d] [-n] [-p path]\n", progname);
exit(1);
}
static void
closedown(int sig)
{
if (_rpcsvcstate == _IDLE) {
extern fd_set svc_fdset;
static int size;
int i, openfd;
if (_rpcfdtype == SOCK_DGRAM) {
unregister();
exit(0);
}
if (size == 0) {
size = getdtablesize();
}
for (i = 0, openfd = 0; i < size && openfd < 2; i++)
if (FD_ISSET(i, &svc_fdset))
openfd++;
if (openfd <= 1) {
unregister();
exit(0);
}
}
if (_rpcsvcstate == _SERVED)
_rpcsvcstate = _IDLE;
(void) signal(SIGALRM, (SIG_PF) closedown);
(void) alarm(_RPCSVC_CLOSEDOWN/2);
}
main(argc, argv)
int argc;
char *argv[];
{
register SVCXPRT *transp = NULL;
int sock;
int proto = 0;
struct sockaddr_in saddr;
int asize = sizeof (saddr);
int ch;
while ((ch = getopt(argc, argv, "hdnp:")) != EOF) {
switch(ch) {
case 'd':
debug = ypdb_debug = 1;
break;
case 'n':
do_dns = 1;
break;
case 'p':
yp_dir = optarg;
break;
case 'h':
default:
usage();
}
}
load_securenets();
This commit changes the YPPROC_ALL procecdure so that it handles requests _without_ using fork(). The problem with YPPROC_ALL is that it transmits an entire map through a TCP pipe as the result of a single RPC call. First of all, this requires certain hackery in the XDR filter. Second, if the map being sent is large, the server can end up spending lots of time in the XDR filter sending to just the one client, while requests for other clients will go unanswered. My original solution for this was to fork() the request into a child process which terminates after the map has been transmitted (or the transfer is interrupted due to an error). This leaves the parent free to handle other requests. But this solution is kind of lame: fork() is relatively expensive, and we have to keep a cap on the number of child processes to keep from swamping the system. What we do now is grab control of the service transport handle and XDR handle from the RPC library and send the records one at a time ourselves instead of letting the RPC library do it. We send a record, then go back to the svc_run() loop and select() on the socket. If select() says we can still write data, we send the next record. Then we call svc_getreqset() and handle other RPCs and loop around again. This way, we can handle other RPCs between records. We manage multiple YPPROC_ALL requests using a circular queue. When a request is done, we dequeue it and destroy the handle. We also tag each request with a ttl which is decremented whevever we run the queue and a handle isn't serviced. This lets us nuke requests that have sat idle for too long (if we didn't do this, we might run out of socket descriptors.) Now all I have to do is come up with an async resolver, and ypserv won't need to fork() at all. :) Note: these changes should not go into 2.2 unless they get a very throrough shakedown before the final cutoff date.
1996-11-30 22:38:44 +00:00
yp_init_async();
Performance enhancements (I hope) and new stuff: yp_dblookup.c: - Implement database handle caching. What this means is that instead of opening and closing map databases for each request, we open a database and save the handle (and, if requested, the key index) in an array. This saves a bit of overhead on things like repeated YPPROC_NEXT calls, such as you'd get from getpwent(). Normally, each YPPROC_NEXT would require open()ing the database, seeking to the location supplied by the caller (which is time consuming with hash databases as the R_CURSOR flag doesn't work), reading the data, close()ing the database and then shipping the data off to the caller. The system call overhead is prohibitive, especially with very large maps. By caching the handle to an open database, we elimitate at least the open()/close() system calls, as well as the associated DB setup and tear-down operations, for a large percentage of the time. This improves performance substantially at the cost of consuming a little more memory than before. Note that all the caching support is surrounded by #ifdef DB_CACHE so that this same source module can still be used by other programs that don't need it. - Make yp_open_db() call yp_validdomain(). Doing it here saves cycles when caching is enabled since a hit on the map cache list by definition means that the domain being referenced is valid. - Also make yp_open_db() check for exhaustion of file descriptors, just in case. yp_server.c: - Reorganize things a little to take advantage of the database handle caching. Add a call to yp_flush_all() in ypproc_clear_2_svc(). - Remove calls to yp_validdomain() from some of the service procedures. yp_validdomain() is called inside yp_open_db() now, so procedures that call into the database package don't need to use yp_validdomain() themselves. - Fix a bogosity in ypproc_maplist_2_svc(): don't summarily initiallize the result.maps pointer to NULL. This causes yp_maplist_free() to fail and leaks memory. - Make ypproc_master_2_svc() copy the string it gets from the database package into a private static buffer before trying to NUL terminate it. This is necessary with the DB handle caching: stuffing a NUL into the data returned by DB package will goof it up internally. yp_main.c: - Stuff for DB handle caching: call yp_init_dbs() to clear the handle array and add call to yp_flush_all() to the SIGHUP signal handler. Makefile.yp: - Reorganize to deal with database caching. yp_mkdb(8) can now be used to send a YPPROC_CLEAR signal to ypserv(8). Call it after each map is created to refresh ypserv's cache. - Add support for mail.alias map. Contributed by Mike Murphy (mrm@sceard.com). - Make default location for the netgroups source file be /var/yp/netgroup instead of /etc/netgroup. mkaliases: - New file: script to generate mail.alias map. Contributed by Mike Murphy (mrm@sceard.com). Makefile: - Install Makefile.yp as /var/yp/Makefile.dist and link it to /var/yp/Makefile only if /var/yp/Makefile doesn't already exist. Suggested by Peter Wemm. - Install new mkaliases script in /usr/libexec along with mknetid. - Use somewhat saner approach to generating rpcgen-dependent files as suggested by Garrett Wollman.
1996-04-28 04:38:52 +00:00
#ifdef DB_CACHE
yp_init_dbs();
#endif
if (getsockname(0, (struct sockaddr *)&saddr, &asize) == 0) {
int ssize = sizeof (int);
if (saddr.sin_family != AF_INET)
exit(1);
if (getsockopt(0, SOL_SOCKET, SO_TYPE,
(char *)&_rpcfdtype, &ssize) == -1)
exit(1);
sock = 0;
_rpcpmstart = 1;
proto = 0;
openlog(progname, LOG_PID, LOG_DAEMON);
} else {
if (!debug) {
if (daemon(0,0)) {
err(1,"cannot fork");
}
openlog(progname, LOG_PID, LOG_DAEMON);
}
sock = RPC_ANYSOCK;
(void) pmap_unset(YPPROG, YPVERS);
(void) pmap_unset(YPPROG, 1);
}
if ((_rpcfdtype == 0) || (_rpcfdtype == SOCK_DGRAM)) {
transp = svcudp_create(sock);
if (transp == NULL) {
_msgout("cannot create udp service.");
exit(1);
}
if (!_rpcpmstart)
proto = IPPROTO_UDP;
if (!svc_register(transp, YPPROG, YPOLDVERS, ypprog_1, proto)) {
_msgout("unable to register (YPPROG, YPOLDVERS, udp).");
exit(1);
}
if (!svc_register(transp, YPPROG, YPVERS, ypprog_2, proto)) {
_msgout("unable to register (YPPROG, YPVERS, udp).");
exit(1);
}
}
if ((_rpcfdtype == 0) || (_rpcfdtype == SOCK_STREAM)) {
transp = svctcp_create(sock, 0, 0);
if (transp == NULL) {
_msgout("cannot create tcp service.");
exit(1);
}
if (!_rpcpmstart)
proto = IPPROTO_TCP;
if (!svc_register(transp, YPPROG, YPOLDVERS, ypprog_1, proto)) {
_msgout("unable to register (YPPROG, YPOLDVERS, tcp).");
exit(1);
}
if (!svc_register(transp, YPPROG, YPVERS, ypprog_2, proto)) {
_msgout("unable to register (YPPROG, YPVERS, tcp).");
exit(1);
}
}
if (transp == (SVCXPRT *)NULL) {
_msgout("could not create a handle");
exit(1);
}
if (_rpcpmstart) {
(void) signal(SIGALRM, (SIG_PF) closedown);
(void) alarm(_RPCSVC_CLOSEDOWN/2);
}
/*
* Make sure SIGPIPE doesn't blow us away while servicing TCP
* connections.
*/
(void) signal(SIGPIPE, SIG_IGN);
(void) signal(SIGCHLD, (SIG_PF) reaper);
(void) signal(SIGTERM, (SIG_PF) reaper);
(void) signal(SIGINT, (SIG_PF) reaper);
(void) signal(SIGHUP, (SIG_PF) reaper);
yp_svc_run();
_msgout("svc_run returned");
exit(1);
/* NOTREACHED */
}