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NetBSD/usr.sbin/ypbind/ypbind.c

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/* $NetBSD: ypbind.c,v 1.101 2022/04/11 20:57:37 andvar Exp $ */
/*
* Copyright (c) 1992, 1993 Theo de Raadt <deraadt@fsa.ca>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include <sys/cdefs.h>
#ifndef LINT
__RCSID("$NetBSD: ypbind.c,v 1.101 2022/04/11 20:57:37 andvar Exp $");
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syslog.h>
#include <sys/uio.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <ifaddrs.h>
#include <limits.h>
#include <netdb.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <util.h>
#include <rpc/rpc.h>
#include <rpc/xdr.h>
#include <rpc/pmap_clnt.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_rmt.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#include "pathnames.h"
#define YPSERVERSSUFF ".ypservers"
#define BINDINGDIR (_PATH_VAR_YP "binding")
#ifndef O_SHLOCK
#define O_SHLOCK 0
#endif
int _yp_invalid_domain(const char *); /* XXX libc internal */
////////////////////////////////////////////////////////////
// types and globals
typedef enum {
YPBIND_DIRECT, YPBIND_BROADCAST,
} ypbind_mode_t;
enum domainstates {
DOM_NEW, /* not yet bound */
DOM_ALIVE, /* bound and healthy */
DOM_PINGING, /* ping outstanding */
DOM_LOST, /* binding timed out, looking for a new one */
DOM_DEAD, /* long-term lost, in exponential backoff */
};
struct domain {
struct domain *dom_next;
char dom_name[YPMAXDOMAIN + 1];
struct sockaddr_in dom_server_addr;
long dom_vers;
time_t dom_checktime; /* time of next check/contact */
time_t dom_asktime; /* time we were last DOMAIN'd */
time_t dom_losttime; /* time the binding was lost, or 0 */
unsigned dom_backofftime; /* current backoff period, when DEAD */
int dom_lockfd;
enum domainstates dom_state;
uint32_t dom_xid;
FILE *dom_serversfile; /* /var/yp/binding/foo.ypservers */
int dom_been_ypset; /* ypset been done on this domain? */
ypbind_mode_t dom_ypbindmode; /* broadcast or direct */
};
#define BUFSIZE 1400
/* the list of all domains */
static struct domain *domains;
static int check;
/* option settings */
static ypbind_mode_t default_ypbindmode;
static int allow_local_ypset = 0, allow_any_ypset = 0;
static int insecure;
/* the sockets we use to interact with servers */
static int rpcsock, pingsock;
/* stuff used for manually interacting with servers */
static struct rmtcallargs rmtca;
static struct rmtcallres rmtcr;
static bool_t rmtcr_outval;
static unsigned long rmtcr_port;
/* The ypbind service transports */
static SVCXPRT *udptransp, *tcptransp;
/* set if we get SIGHUP */
static sig_atomic_t hupped;
////////////////////////////////////////////////////////////
// utilities
/*
* Combo of open() and flock().
*/
static int
open_locked(const char *path, int flags, mode_t mode)
{
int fd;
fd = open(path, flags|O_SHLOCK, mode);
if (fd < 0) {
return -1;
}
#if O_SHLOCK == 0
/* dholland 20110522 wouldn't it be better to check this for error? */
(void)flock(fd, LOCK_SH);
#endif
return fd;
}
/*
* Exponential backoff for pinging servers for a dead domain.
*
* We go 10 -> 20 -> 40 -> 60 seconds, then 2 -> 4 -> 8 -> 15 -> 30 ->
* 60 minutes, and stay at 60 minutes. This is overengineered.
*
* With a 60 minute max backoff the response time for when things come
* back is not awful, but we only try (and log) about 60 times even if
* things are down for a whole long weekend. This is an acceptable log
* load, I think.
*/
static void
backoff(unsigned *psecs)
{
unsigned secs;
secs = *psecs;
if (secs < 60) {
secs *= 2;
if (secs > 60) {
secs = 60;
}
} else if (secs < 60 * 15) {
secs *= 2;
if (secs > 60 * 15) {
secs = 60 * 15;
}
} else if (secs < 60 * 60) {
secs *= 2;
}
*psecs = secs;
}
////////////////////////////////////////////////////////////
// logging
#ifdef DEBUG
#define DPRINTF(...) (debug ? (void)printf(__VA_ARGS__) : (void)0)
static int debug;
#else
#define DPRINTF(...)
#endif
static void yp_log(int, const char *, ...) __printflike(2, 3);
/*
* Log some stuff, to syslog or stderr depending on the debug setting.
*/
static void
yp_log(int pri, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
#if defined(DEBUG)
if (debug) {
(void)vprintf(fmt, ap);
(void)printf("\n");
} else
#endif
vsyslog(pri, fmt, ap);
va_end(ap);
}
////////////////////////////////////////////////////////////
// ypservers file
/*
* Get pathname for the ypservers file for a given domain
* (/var/yp/binding/DOMAIN.ypservers)
*/
static const char *
ypservers_filename(const char *domain)
{
static char ret[PATH_MAX];
(void)snprintf(ret, sizeof(ret), "%s/%s%s",
BINDINGDIR, domain, YPSERVERSSUFF);
return ret;
}
////////////////////////////////////////////////////////////
// struct domain
/*
* The state transitions of a domain work as follows:
*
* in state NEW:
* nag_servers every 5 seconds
* upon answer, state is ALIVE
*
* in state ALIVE:
* every 60 seconds, send ping and switch to state PINGING
*
* in state PINGING:
* upon answer, go to state ALIVE
* if no answer in 5 seconds, go to state LOST and do nag_servers
*
* in state LOST:
* do nag_servers every 5 seconds
* upon answer, go to state ALIVE
* if no answer in 60 seconds, go to state DEAD
*
* in state DEAD
* do nag_servers every backofftime seconds (starts at 10)
* upon answer go to state ALIVE
* backofftime doubles (approximately) each try, with a cap of 1 hour
*/
/*
* Look up a domain by the XID we assigned it.
*/
static struct domain *
domain_find(uint32_t xid)
{
struct domain *dom;
for (dom = domains; dom != NULL; dom = dom->dom_next)
if (dom->dom_xid == xid)
break;
return dom;
}
/*
* Pick an XID for a domain.
*
* XXX: this should just generate a random number.
*/
static uint32_t
unique_xid(struct domain *dom)
{
uint32_t tmp_xid;
tmp_xid = ((uint32_t)(unsigned long)dom) & 0xffffffff;
while (domain_find(tmp_xid) != NULL)
tmp_xid++;
return tmp_xid;
}
/*
* Construct a new domain. Adds it to the global linked list of all
* domains.
*/
static struct domain *
domain_create(const char *name)
{
struct domain *dom;
const char *pathname;
struct stat st;
dom = malloc(sizeof *dom);
if (dom == NULL) {
yp_log(LOG_ERR, "domain_create: Out of memory");
return NULL;
}
dom->dom_next = NULL;
(void)strlcpy(dom->dom_name, name, sizeof(dom->dom_name));
(void)memset(&dom->dom_server_addr, 0, sizeof(dom->dom_server_addr));
dom->dom_vers = YPVERS;
dom->dom_checktime = 0;
dom->dom_asktime = 0;
dom->dom_losttime = 0;
dom->dom_backofftime = 10;
dom->dom_lockfd = -1;
dom->dom_state = DOM_NEW;
dom->dom_xid = unique_xid(dom);
dom->dom_been_ypset = 0;
dom->dom_serversfile = NULL;
/*
* Per traditional ypbind(8) semantics, if a ypservers
* file does not exist, we revert to broadcast mode.
*
* The sysadmin can force broadcast mode by passing the
* -broadcast flag. There is currently no way to fail and
* reject domains for which there is no ypservers file.
*/
dom->dom_ypbindmode = default_ypbindmode;
if (dom->dom_ypbindmode == YPBIND_DIRECT) {
pathname = ypservers_filename(dom->dom_name);
if (stat(pathname, &st) < 0) {
/* XXX syslog a warning here? */
DPRINTF("%s does not exist, defaulting to broadcast\n",
pathname);
dom->dom_ypbindmode = YPBIND_BROADCAST;
}
}
/* add to global list */
dom->dom_next = domains;
domains = dom;
return dom;
}
////////////////////////////////////////////////////////////
// locks
/*
* Open a new binding file. Does not write the contents out; the
* caller (there's only one) does that.
*/
static int
makelock(struct domain *dom)
{
int fd;
char path[MAXPATHLEN];
(void)snprintf(path, sizeof(path), "%s/%s.%ld", BINDINGDIR,
dom->dom_name, dom->dom_vers);
fd = open_locked(path, O_CREAT|O_RDWR|O_TRUNC, 0644);
if (fd == -1) {
(void)mkdir(BINDINGDIR, 0755);
fd = open_locked(path, O_CREAT|O_RDWR|O_TRUNC, 0644);
if (fd == -1) {
return -1;
}
}
return fd;
}
/*
* Remove a binding file.
*/
static void
removelock(struct domain *dom)
{
char path[MAXPATHLEN];
(void)snprintf(path, sizeof(path), "%s/%s.%ld",
BINDINGDIR, dom->dom_name, dom->dom_vers);
(void)unlink(path);
}
/*
* purge_bindingdir: remove old binding files (i.e. "rm *.[0-9]" in BINDINGDIR)
*
* The local YP functions [e.g. yp_master()] will fail without even
* talking to ypbind if there is a stale (non-flock'd) binding file
* present.
*
* We have to remove all binding files in BINDINGDIR, not just the one
* for the default domain.
*/
static int
purge_bindingdir(const char *dirpath)
{
DIR *dirp;
int unlinkedfiles, l;
struct dirent *dp;
char pathname[MAXPATHLEN];
if ((dirp = opendir(dirpath)) == NULL)
return(-1); /* at this point, shouldn't ever happen */
do {
unlinkedfiles = 0;
while ((dp = readdir(dirp)) != NULL) {
l = dp->d_namlen;
/* 'rm *.[0-9]' */
if (l > 2 && dp->d_name[l-2] == '.' &&
dp->d_name[l-1] >= '0' && dp->d_name[l-1] <= '9') {
(void)snprintf(pathname, sizeof(pathname),
"%s/%s", dirpath, dp->d_name);
if (unlink(pathname) < 0 && errno != ENOENT)
return(-1);
unlinkedfiles++;
}
}
/* rescan dir if we removed it */
if (unlinkedfiles)
rewinddir(dirp);
} while (unlinkedfiles);
closedir(dirp);
return(0);
}
////////////////////////////////////////////////////////////
// sunrpc twaddle
/*
* Check if the info coming in is (at least somewhat) valid.
*/
static int
rpc_is_valid_response(char *name, struct sockaddr_in *addr)
{
if (name == NULL) {
return 0;
}
if (_yp_invalid_domain(name)) {
return 0;
}
/* don't support insecure servers by default */
if (!insecure && ntohs(addr->sin_port) >= IPPORT_RESERVED) {
return 0;
}
return 1;
}
/*
* Take note of the fact that we've received a reply from a ypserver.
* Or, in the case of being ypset, that we've been ypset, which
* functions much the same.
*
* Note that FORCE is set if and only if IS_YPSET is set.
*
* This function has also for the past 20+ years carried the annotation
*
* LOOPBACK IS MORE IMPORTANT: PUT IN HACK
*
* whose meaning isn't entirely clear.
*/
static int
rpc_received(char *dom_name, struct sockaddr_in *raddrp, int force,
int is_ypset)
{
struct domain *dom;
struct iovec iov[2];
struct ypbind_resp ybr;
ssize_t result;
int fd;
DPRINTF("returned from %s about %s\n",
inet_ntoa(raddrp->sin_addr), dom_name);
/* validate some stuff */
if (!rpc_is_valid_response(dom_name, raddrp)) {
return 0;
}
/* look for the domain */
for (dom = domains; dom != NULL; dom = dom->dom_next)
if (!strcmp(dom->dom_name, dom_name))
break;
/* if not found, create it, but only if FORCE; otherwise ignore */
if (dom == NULL) {
if (force == 0)
return 0;
dom = domain_create(dom_name);
if (dom == NULL)
return 0;
}
/* the domain needs to know if it's been explicitly ypset */
if (is_ypset) {
dom->dom_been_ypset = 1;
}
/*
* If the domain is alive and we aren't being called by ypset,
* we shouldn't be getting a response at all. Log it, as it
* might be hostile.
*/
if (dom->dom_state == DOM_ALIVE && force == 0) {
if (!memcmp(&dom->dom_server_addr, raddrp,
sizeof(dom->dom_server_addr))) {
yp_log(LOG_WARNING,
"Unexpected reply from server %s for domain %s",
inet_ntoa(dom->dom_server_addr.sin_addr),
dom->dom_name);
} else {
yp_log(LOG_WARNING,
"Falsified reply from %s for domain %s",
inet_ntoa(dom->dom_server_addr.sin_addr),
dom->dom_name);
}
return 0;
}
/*
* If we're expected a ping response, and we've got it
* (meaning we aren't being called by ypset), we don't need to
* do anything.
*/
if (dom->dom_state == DOM_PINGING && force == 0) {
/*
* If the reply came from the server we expect, set
* dom_state back to ALIVE and ping again in 60
* seconds.
*
* If it came from somewhere else, log it.
*/
if (!memcmp(&dom->dom_server_addr, raddrp,
sizeof(dom->dom_server_addr))) {
dom->dom_state = DOM_ALIVE;
/* recheck binding in 60 sec */
dom->dom_checktime = time(NULL) + 60;
} else {
yp_log(LOG_WARNING,
"Falsified reply from %s for domain %s",
inet_ntoa(dom->dom_server_addr.sin_addr),
dom->dom_name);
}
return 0;
}
#ifdef HEURISTIC
/*
* If transitioning to the alive state from a non-alive state,
* clear dom_asktime. This will help prevent any requests that
* are still coming in from triggering unnecessary pings via
* the HEURISTIC code.
*
* XXX: this may not be an adequate measure; we may need to
* keep more state so we can disable the HEURISTIC code for
* the first few seconds after rebinding.
*/
if (dom->dom_state == DOM_NEW ||
dom->dom_state == DOM_LOST ||
dom->dom_state == DOM_DEAD) {
dom->dom_asktime = 0;
}
#endif
/*
* Take the address we got the message from (or in the case of
* ypset, the explicit address we were given) as the server
* address for this domain, mark the domain alive, and we'll
* check it again in 60 seconds.
*
* XXX: it looks like if we get a random unsolicited reply
* from somewhere, we'll silently switch to that server
* address, regardless of merit.
*
* 1. If we have a foo.ypservers file the address should be
* checked against it and rejected if it's not one of the
* addresses of one of the listed hostnames. Note that it
* might not be the same address we sent to; even fairly smart
* UDP daemons don't always handle multihomed hosts correctly
* and we can't expect sunrpc code to do anything intelligent
* at all.
*
* 2. If we're in broadcast mode the address should be
* checked against the local addresses and netmasks so we
* don't accept responses from Mars.
*
* 2a. If we're in broadcast mode and we've been ypset, we
* should not accept anything else until we drop the ypset
* state for not responding.
*
* 3. Either way we should not accept a response from an
* arbitrary host unless we don't currently have a binding.
* (This is now fixed above.)
*
* Note that for a random unsolicited reply to work it has to
* carry the XID of one of the domains we know about; but
* those values are predictable.
*/
(void)memcpy(&dom->dom_server_addr, raddrp,
sizeof(dom->dom_server_addr));
/* recheck binding in 60 seconds */
dom->dom_checktime = time(NULL) + 60;
dom->dom_state = DOM_ALIVE;
/* Clear the dead/backoff state. */
dom->dom_losttime = 0;
dom->dom_backofftime = 10;
if (is_ypset == 0) {
yp_log(LOG_NOTICE, "Domain %s is alive; server %s",
dom->dom_name,
inet_ntoa(dom->dom_server_addr.sin_addr));
}
/*
* Generate a new binding file. If this fails, forget about it.
* (But we keep the binding and we'll report it to anyone who
* asks via the ypbind service.) XXX: this will interact badly,
* maybe very badly, with the code in HEURISTIC.
*
* Note that makelock() doesn't log on failure.
*/
if (dom->dom_lockfd != -1)
(void)close(dom->dom_lockfd);
if ((fd = makelock(dom)) == -1)
return 0;
dom->dom_lockfd = fd;
iov[0].iov_base = &(udptransp->xp_port);
iov[0].iov_len = sizeof udptransp->xp_port;
iov[1].iov_base = &ybr;
iov[1].iov_len = sizeof ybr;
(void)memset(&ybr, 0, sizeof ybr);
ybr.ypbind_status = YPBIND_SUCC_VAL;
ybr.ypbind_respbody.ypbind_bindinfo.ypbind_binding_addr =
raddrp->sin_addr;
ybr.ypbind_respbody.ypbind_bindinfo.ypbind_binding_port =
raddrp->sin_port;
result = writev(dom->dom_lockfd, iov, 2);
if (result < 0 || (size_t)result != iov[0].iov_len + iov[1].iov_len) {
if (result < 0)
yp_log(LOG_WARNING, "writev: %s", strerror(errno));
else
yp_log(LOG_WARNING, "writev: short count");
(void)close(dom->dom_lockfd);
removelock(dom);
dom->dom_lockfd = -1;
return 0;
}
return 1;
}
/*
* The NULL call: do nothing. This is obliged to exist because of
* sunrpc silliness.
*/
static void *
/*ARGSUSED*/
ypbindproc_null_2(SVCXPRT *transp, void *argp)
{
static char res;
DPRINTF("ypbindproc_null_2\n");
(void)memset(&res, 0, sizeof(res));
return (void *)&res;
}
/*
* The DOMAIN call: look up the ypserver for a specified domain.
*/
static void *
/*ARGSUSED*/
ypbindproc_domain_2(SVCXPRT *transp, void *argp)
{
static struct ypbind_resp res;
struct domain *dom;
char *arg = *(char **) argp;
time_t now;
int count;
DPRINTF("ypbindproc_domain_2 %s\n", arg);
(void)memset(&res, 0, sizeof res);
res.ypbind_status = YPBIND_FAIL_VAL;
/* Reject invalid domains. */
if (_yp_invalid_domain(arg)) {
res.ypbind_respbody.ypbind_error = YPBIND_ERR_NOSERV;
return &res;
}
/*
* Look for the domain. XXX: Behave erratically if we have
* more than 100 domains. The intent here is to avoid allowing
* arbitrary incoming requests to create more than 100
* domains; but this logic means that if we legitimately have
* more than 100 (e.g. via ypset) we'll only actually bind the
* first 100 and the rest will fail. The test on 'count' should
* be moved further down.
*/
for (count = 0, dom = domains;
dom != NULL;
dom = dom->dom_next, count++) {
if (count > 100) {
res.ypbind_respbody.ypbind_error = YPBIND_ERR_RESC;
return &res; /* prevent denial of service */
}
if (!strcmp(dom->dom_name, arg))
break;
}
/*
* If the domain doesn't exist, create it, then fail the call
* because we have no information yet.
*
* Set "check" so that checkwork() will run and look for a
* server.
*
* XXX: like during startup there's a spurious call to
* removelock() after domain_create().
*/
if (dom == NULL) {
dom = domain_create(arg);
if (dom != NULL) {
removelock(dom);
check++;
DPRINTF("unknown domain %s\n", arg);
res.ypbind_respbody.ypbind_error = YPBIND_ERR_NOSERV;
} else {
res.ypbind_respbody.ypbind_error = YPBIND_ERR_RESC;
}
return &res;
}
if (dom->dom_state == DOM_NEW) {
DPRINTF("new domain %s\n", arg);
res.ypbind_respbody.ypbind_error = YPBIND_ERR_NOSERV;
return &res;
}
#ifdef HEURISTIC
/*
* Keep track of the last time we were explicitly asked about
* this domain. If it happens a lot, force a ping. This works
* (or "works") because we only get asked specifically when
* things aren't going; otherwise the client code in libc and
* elsewhere uses the binding file.
*
* Note: HEURISTIC is enabled by default.
*
* dholland 20140609: I think this is part of the mechanism
* that causes ypbind to spam. I'm changing this logic so it
* only triggers when the state is DOM_ALIVE: if the domain
* is new, lost, or dead we shouldn't send more requests than
* the ones already scheduled, and if we're already in the
* middle of pinging there's no point doing it again.
*/
(void)time(&now);
if (dom->dom_state == DOM_ALIVE && now < dom->dom_asktime + 5) {
/*
* Hmm. More than 2 requests in 5 seconds have indicated
* that my binding is possibly incorrect.
* Ok, do an immediate poll of the server.
*/
if (dom->dom_checktime >= now) {
/* don't flood it */
dom->dom_checktime = 0;
check++;
}
}
dom->dom_asktime = now;
#endif
res.ypbind_status = YPBIND_SUCC_VAL;
res.ypbind_respbody.ypbind_bindinfo.ypbind_binding_addr.s_addr =
dom->dom_server_addr.sin_addr.s_addr;
res.ypbind_respbody.ypbind_bindinfo.ypbind_binding_port =
dom->dom_server_addr.sin_port;
DPRINTF("domain %s at %s/%d\n", dom->dom_name,
inet_ntoa(dom->dom_server_addr.sin_addr),
ntohs(dom->dom_server_addr.sin_port));
return &res;
}
/*
* The SETDOM call: ypset.
*
* Unless -ypsetme was given on the command line, this is rejected;
* even then it's only allowed from localhost unless -ypset was
* given on the command line.
*
* Allowing anyone anywhere to ypset you (and therefore provide your
* password file and such) is a horrible thing and it isn't clear to
* me why this functionality even exists.
*
* ypset from localhost has some but limited utility.
*/
static void *
ypbindproc_setdom_2(SVCXPRT *transp, void *argp)
{
struct ypbind_setdom *sd = argp;
struct sockaddr_in *fromsin, bindsin;
static bool_t res;
(void)memset(&res, 0, sizeof(res));
fromsin = svc_getcaller(transp);
DPRINTF("ypbindproc_setdom_2 from %s\n", inet_ntoa(fromsin->sin_addr));
/*
* Reject unless enabled.
*/
if (allow_any_ypset) {
/* nothing */
} else if (allow_local_ypset) {
if (fromsin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
DPRINTF("ypset denied from %s\n",
inet_ntoa(fromsin->sin_addr));
return NULL;
}
} else {
DPRINTF("ypset denied\n");
return NULL;
}
/* Make a "security" check. */
if (ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
DPRINTF("ypset from unprivileged port denied\n");
return &res;
}
/* Ignore requests we don't understand. */
if (sd->ypsetdom_vers != YPVERS) {
DPRINTF("ypset with wrong version denied\n");
return &res;
}
/*
* Fetch the arguments out of the xdr-decoded blob and call
* rpc_received(), setting FORCE so that the domain will be
* created if we don't already know about it, and also saying
* that it's actually a ypset.
*
* Effectively we're telilng rpc_received() that we got an
* RPC response from the server specified by ypset.
*/
(void)memset(&bindsin, 0, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_len = sizeof(bindsin);
bindsin.sin_addr = sd->ypsetdom_addr;
bindsin.sin_port = sd->ypsetdom_port;
if (rpc_received(sd->ypsetdom_domain, &bindsin, 1, 1)) {
DPRINTF("ypset to %s for domain %s succeeded\n",
inet_ntoa(bindsin.sin_addr), sd->ypsetdom_domain);
res = 1;
}
return &res;
}
/*
* Dispatcher for the ypbind service.
*
* There are three calls: NULL, which does nothing, DOMAIN, which
* gets the binding for a particular domain, and SETDOM, which
* does ypset.
*/
static void
ypbindprog_2(struct svc_req *rqstp, register SVCXPRT *transp)
{
union {
char ypbindproc_domain_2_arg[YPMAXDOMAIN + 1];
struct ypbind_setdom ypbindproc_setdom_2_arg;
void *alignment;
} argument;
struct authunix_parms *creds;
char *result;
xdrproc_t xdr_argument, xdr_result;
void *(*local)(SVCXPRT *, void *);
switch (rqstp->rq_proc) {
case YPBINDPROC_NULL:
xdr_argument = (xdrproc_t)xdr_void;
xdr_result = (xdrproc_t)xdr_void;
local = ypbindproc_null_2;
break;
case YPBINDPROC_DOMAIN:
xdr_argument = (xdrproc_t)xdr_ypdomain_wrap_string;
xdr_result = (xdrproc_t)xdr_ypbind_resp;
local = ypbindproc_domain_2;
break;
case YPBINDPROC_SETDOM:
switch (rqstp->rq_cred.oa_flavor) {
case AUTH_UNIX:
creds = (struct authunix_parms *)rqstp->rq_clntcred;
if (creds->aup_uid != 0) {
svcerr_auth(transp, AUTH_BADCRED);
return;
}
break;
default:
svcerr_auth(transp, AUTH_TOOWEAK);
return;
}
xdr_argument = (xdrproc_t)xdr_ypbind_setdom;
xdr_result = (xdrproc_t)xdr_void;
local = ypbindproc_setdom_2;
break;
default:
svcerr_noproc(transp);
return;
}
(void)memset(&argument, 0, sizeof(argument));
if (!svc_getargs(transp, xdr_argument, (caddr_t)(void *)&argument)) {
svcerr_decode(transp);
return;
}
result = (*local)(transp, &argument);
if (result != NULL && !svc_sendreply(transp, xdr_result, result)) {
svcerr_systemerr(transp);
}
return;
}
/*
* Set up sunrpc stuff.
*
* This sets up the ypbind service (both TCP and UDP) and also opens
* the sockets we use for talking to ypservers.
*/
static void
sunrpc_setup(void)
{
int one;
(void)pmap_unset(YPBINDPROG, YPBINDVERS);
udptransp = svcudp_create(RPC_ANYSOCK);
if (udptransp == NULL)
errx(1, "Cannot create udp service.");
if (!svc_register(udptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
IPPROTO_UDP))
errx(1, "Unable to register (YPBINDPROG, YPBINDVERS, udp).");
tcptransp = svctcp_create(RPC_ANYSOCK, 0, 0);
if (tcptransp == NULL)
errx(1, "Cannot create tcp service.");
if (!svc_register(tcptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
IPPROTO_TCP))
errx(1, "Unable to register (YPBINDPROG, YPBINDVERS, tcp).");
/* XXX use SOCK_STREAM for direct queries? */
if ((rpcsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
err(1, "rpc socket");
if ((pingsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
err(1, "ping socket");
(void)fcntl(rpcsock, F_SETFL, fcntl(rpcsock, F_GETFL, 0) | FNDELAY);
(void)fcntl(pingsock, F_SETFL, fcntl(pingsock, F_GETFL, 0) | FNDELAY);
one = 1;
(void)setsockopt(rpcsock, SOL_SOCKET, SO_BROADCAST, &one,
(socklen_t)sizeof(one));
rmtca.prog = YPPROG;
rmtca.vers = YPVERS;
rmtca.proc = YPPROC_DOMAIN_NONACK;
rmtca.xdr_args = NULL; /* set at call time */
rmtca.args_ptr = NULL; /* set at call time */
rmtcr.port_ptr = &rmtcr_port;
rmtcr.xdr_results = (xdrproc_t)xdr_bool;
rmtcr.results_ptr = (caddr_t)(void *)&rmtcr_outval;
}
////////////////////////////////////////////////////////////
// operational logic
/*
* Broadcast an RPC packet to hopefully contact some servers for a
* domain.
*/
static int
broadcast(char *buf, int outlen)
{
struct ifaddrs *ifap, *ifa;
struct sockaddr_in bindsin;
struct in_addr in;
(void)memset(&bindsin, 0, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_len = sizeof(bindsin);
bindsin.sin_port = htons(PMAPPORT);
if (getifaddrs(&ifap) != 0) {
yp_log(LOG_WARNING, "broadcast: getifaddrs: %s",
strerror(errno));
return (-1);
}
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
if ((ifa->ifa_flags & IFF_UP) == 0)
continue;
switch (ifa->ifa_flags & (IFF_LOOPBACK | IFF_BROADCAST)) {
case IFF_BROADCAST:
if (!ifa->ifa_broadaddr)
continue;
if (ifa->ifa_broadaddr->sa_family != AF_INET)
continue;
in = ((struct sockaddr_in *)(void *)ifa->ifa_broadaddr)->sin_addr;
break;
case IFF_LOOPBACK:
in = ((struct sockaddr_in *)(void *)ifa->ifa_addr)->sin_addr;
break;
default:
continue;
}
bindsin.sin_addr = in;
DPRINTF("broadcast %x\n", bindsin.sin_addr.s_addr);
if (sendto(rpcsock, buf, outlen, 0,
(struct sockaddr *)(void *)&bindsin,
(socklen_t)bindsin.sin_len) == -1)
yp_log(LOG_WARNING, "broadcast: sendto: %s",
strerror(errno));
}
freeifaddrs(ifap);
return (0);
}
/*
* Send an RPC packet to all the configured (in /var/yp/foo.ypservers)
* servers for a domain.
*
* XXX: we should read and parse the file up front and reread it only
* if it changes.
*/
static int
direct(char *buf, int outlen, struct domain *dom)
{
const char *path;
char line[_POSIX2_LINE_MAX];
char *p;
struct hostent *hp;
struct sockaddr_in bindsin;
int i, count = 0;
/*
* XXX what happens if someone's editor unlinks and replaces
* the servers file?
*/
if (dom->dom_serversfile != NULL) {
rewind(dom->dom_serversfile);
} else {
path = ypservers_filename(dom->dom_name);
dom->dom_serversfile = fopen(path, "r");
if (dom->dom_serversfile == NULL) {
/*
* XXX there should be a time restriction on
* this (and/or on trying the open) so we
* don't flood the log. Or should we fall back
* to broadcast mode?
*/
yp_log(LOG_ERR, "%s: %s", path,
strerror(errno));
return -1;
}
}
(void)memset(&bindsin, 0, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_len = sizeof(bindsin);
bindsin.sin_port = htons(PMAPPORT);
while (fgets(line, (int)sizeof(line), dom->dom_serversfile) != NULL) {
/* skip lines that are too big */
p = strchr(line, '\n');
if (p == NULL) {
int c;
while ((c = getc(dom->dom_serversfile)) != '\n' && c != EOF)
;
continue;
}
*p = '\0';
p = line;
while (isspace((unsigned char)*p))
p++;
if (*p == '#')
continue;
hp = gethostbyname(p);
if (!hp) {
yp_log(LOG_WARNING, "%s: %s", p, hstrerror(h_errno));
continue;
}
/* step through all addresses in case first is unavailable */
for (i = 0; hp->h_addr_list[i]; i++) {
(void)memcpy(&bindsin.sin_addr, hp->h_addr_list[0],
hp->h_length);
if (sendto(rpcsock, buf, outlen, 0,
(struct sockaddr *)(void *)&bindsin,
(socklen_t)sizeof(bindsin)) < 0) {
yp_log(LOG_WARNING, "direct: sendto: %s",
strerror(errno));
continue;
} else
count++;
}
}
if (!count) {
yp_log(LOG_WARNING, "No contactable servers found in %s",
ypservers_filename(dom->dom_name));
return -1;
}
return 0;
}
/*
* Send an RPC packet to the server that's been selected with ypset.
* (This is only used when in broadcast mode and when ypset is
* allowed.)
*/
static int
direct_set(char *buf, int outlen, struct domain *dom)
{
struct sockaddr_in bindsin;
char path[MAXPATHLEN];
struct iovec iov[2];
struct ypbind_resp ybr;
SVCXPRT dummy_svc;
int fd;
ssize_t bytes;
/*
* Gack, we lose if binding file went away. We reset
* "been_set" if this happens, otherwise we'll never
* bind again.
*/
(void)snprintf(path, sizeof(path), "%s/%s.%ld", BINDINGDIR,
dom->dom_name, dom->dom_vers);
fd = open_locked(path, O_RDONLY, 0644);
if (fd == -1) {
yp_log(LOG_WARNING, "%s: %s", path, strerror(errno));
dom->dom_been_ypset = 0;
return -1;
}
/* Read the binding file... */
iov[0].iov_base = &(dummy_svc.xp_port);
iov[0].iov_len = sizeof(dummy_svc.xp_port);
iov[1].iov_base = &ybr;
iov[1].iov_len = sizeof(ybr);
bytes = readv(fd, iov, 2);
(void)close(fd);
if (bytes <0 || (size_t)bytes != (iov[0].iov_len + iov[1].iov_len)) {
/* Binding file corrupt? */
if (bytes < 0)
yp_log(LOG_WARNING, "%s: %s", path, strerror(errno));
else
yp_log(LOG_WARNING, "%s: short read", path);
dom->dom_been_ypset = 0;
return -1;
}
bindsin.sin_addr =
ybr.ypbind_respbody.ypbind_bindinfo.ypbind_binding_addr;
if (sendto(rpcsock, buf, outlen, 0,
(struct sockaddr *)(void *)&bindsin,
(socklen_t)sizeof(bindsin)) < 0) {
yp_log(LOG_WARNING, "direct_set: sendto: %s", strerror(errno));
return -1;
}
return 0;
}
/*
* Receive and dispatch packets on the general RPC socket.
*/
static enum clnt_stat
handle_replies(void)
{
char buf[BUFSIZE];
socklen_t fromlen;
ssize_t inlen;
struct domain *dom;
struct sockaddr_in raddr;
struct rpc_msg msg;
XDR xdr;
recv_again:
DPRINTF("handle_replies receiving\n");
(void)memset(&xdr, 0, sizeof(xdr));
(void)memset(&msg, 0, sizeof(msg));
msg.acpted_rply.ar_verf = _null_auth;
msg.acpted_rply.ar_results.where = (caddr_t)(void *)&rmtcr;
msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_rmtcallres;
try_again:
fromlen = sizeof(struct sockaddr);
inlen = recvfrom(rpcsock, buf, sizeof buf, 0,
(struct sockaddr *)(void *)&raddr, &fromlen);
if (inlen < 0) {
if (errno == EINTR)
goto try_again;
DPRINTF("handle_replies: recvfrom failed (%s)\n",
strerror(errno));
return RPC_CANTRECV;
}
if ((size_t)inlen < sizeof(uint32_t))
goto recv_again;
/*
* see if reply transaction id matches sent id.
* If so, decode the results.
*/
xdrmem_create(&xdr, buf, (unsigned)inlen, XDR_DECODE);
if (xdr_replymsg(&xdr, &msg)) {
if ((msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
(msg.acpted_rply.ar_stat == SUCCESS)) {
raddr.sin_port = htons((uint16_t)rmtcr_port);
dom = domain_find(msg.rm_xid);
if (dom != NULL)
(void)rpc_received(dom->dom_name, &raddr, 0, 0);
}
}
xdr.x_op = XDR_FREE;
msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
xdr_destroy(&xdr);
return RPC_SUCCESS;
}
/*
* Receive and dispatch packets on the ping socket.
*/
static enum clnt_stat
handle_ping(void)
{
char buf[BUFSIZE];
socklen_t fromlen;
ssize_t inlen;
struct domain *dom;
struct sockaddr_in raddr;
struct rpc_msg msg;
XDR xdr;
bool_t res;
recv_again:
DPRINTF("handle_ping receiving\n");
(void)memset(&xdr, 0, sizeof(xdr));
(void)memset(&msg, 0, sizeof(msg));
msg.acpted_rply.ar_verf = _null_auth;
msg.acpted_rply.ar_results.where = (caddr_t)(void *)&res;
msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_bool;
try_again:
fromlen = sizeof (struct sockaddr);
inlen = recvfrom(pingsock, buf, sizeof buf, 0,
(struct sockaddr *)(void *)&raddr, &fromlen);
if (inlen < 0) {
if (errno == EINTR)
goto try_again;
DPRINTF("handle_ping: recvfrom failed (%s)\n",
strerror(errno));
return RPC_CANTRECV;
}
if ((size_t)inlen < sizeof(uint32_t))
goto recv_again;
/*
* see if reply transaction id matches sent id.
* If so, decode the results.
*/
xdrmem_create(&xdr, buf, (unsigned)inlen, XDR_DECODE);
if (xdr_replymsg(&xdr, &msg)) {
if ((msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
(msg.acpted_rply.ar_stat == SUCCESS)) {
dom = domain_find(msg.rm_xid);
if (dom != NULL)
(void)rpc_received(dom->dom_name, &raddr, 0, 0);
}
}
xdr.x_op = XDR_FREE;
msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
xdr_destroy(&xdr);
return RPC_SUCCESS;
}
/*
* Contact all known servers for a domain in the hopes that one of
* them's awake. Also, if we previously had a binding but it timed
* out, try the portmapper on that host in case ypserv moved ports for
* some reason.
*
* As a side effect, wipe out any existing binding file.
*/
static int
nag_servers(struct domain *dom)
{
char *dom_name = dom->dom_name;
struct rpc_msg msg;
char buf[BUFSIZE];
enum clnt_stat st;
int outlen;
AUTH *rpcua;
XDR xdr;
DPRINTF("nag_servers\n");
rmtca.xdr_args = (xdrproc_t)xdr_ypdomain_wrap_string;
rmtca.args_ptr = (caddr_t)(void *)&dom_name;
(void)memset(&xdr, 0, sizeof xdr);
(void)memset(&msg, 0, sizeof msg);
rpcua = authunix_create_default();
if (rpcua == NULL) {
DPRINTF("cannot get unix auth\n");
return RPC_SYSTEMERROR;
}
msg.rm_direction = CALL;
msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
msg.rm_call.cb_prog = PMAPPROG;
msg.rm_call.cb_vers = PMAPVERS;
msg.rm_call.cb_proc = PMAPPROC_CALLIT;
msg.rm_call.cb_cred = rpcua->ah_cred;
msg.rm_call.cb_verf = rpcua->ah_verf;
msg.rm_xid = dom->dom_xid;
xdrmem_create(&xdr, buf, (unsigned)sizeof(buf), XDR_ENCODE);
if (!xdr_callmsg(&xdr, &msg)) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
if (!xdr_rmtcall_args(&xdr, &rmtca)) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
outlen = (int)xdr_getpos(&xdr);
xdr_destroy(&xdr);
if (outlen < 1) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
AUTH_DESTROY(rpcua);
if (dom->dom_lockfd != -1) {
(void)close(dom->dom_lockfd);
dom->dom_lockfd = -1;
removelock(dom);
}
if (dom->dom_state == DOM_PINGING || dom->dom_state == DOM_LOST) {
/*
* This resolves the following situation:
* ypserver on other subnet was once bound,
* but rebooted and is now using a different port
*/
struct sockaddr_in bindsin;
(void)memset(&bindsin, 0, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_len = sizeof(bindsin);
bindsin.sin_port = htons(PMAPPORT);
bindsin.sin_addr = dom->dom_server_addr.sin_addr;
if (sendto(rpcsock, buf, outlen, 0,
(struct sockaddr *)(void *)&bindsin,
(socklen_t)sizeof bindsin) == -1)
yp_log(LOG_WARNING, "nag_servers: sendto: %s",
strerror(errno));
}
switch (dom->dom_ypbindmode) {
case YPBIND_BROADCAST:
if (dom->dom_been_ypset) {
return direct_set(buf, outlen, dom);
}
return broadcast(buf, outlen);
case YPBIND_DIRECT:
return direct(buf, outlen, dom);
}
/*NOTREACHED*/
return -1;
}
/*
* Send a ping message to a domain's current ypserver.
*/
static int
ping(struct domain *dom)
{
char *dom_name = dom->dom_name;
struct rpc_msg msg;
char buf[BUFSIZE];
enum clnt_stat st;
int outlen;
AUTH *rpcua;
XDR xdr;
(void)memset(&xdr, 0, sizeof xdr);
(void)memset(&msg, 0, sizeof msg);
rpcua = authunix_create_default();
if (rpcua == NULL) {
DPRINTF("cannot get unix auth\n");
return RPC_SYSTEMERROR;
}
msg.rm_direction = CALL;
msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
msg.rm_call.cb_prog = YPPROG;
msg.rm_call.cb_vers = YPVERS;
msg.rm_call.cb_proc = YPPROC_DOMAIN_NONACK;
msg.rm_call.cb_cred = rpcua->ah_cred;
msg.rm_call.cb_verf = rpcua->ah_verf;
msg.rm_xid = dom->dom_xid;
xdrmem_create(&xdr, buf, (unsigned)sizeof(buf), XDR_ENCODE);
if (!xdr_callmsg(&xdr, &msg)) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
if (!xdr_ypdomain_wrap_string(&xdr, &dom_name)) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
outlen = (int)xdr_getpos(&xdr);
xdr_destroy(&xdr);
if (outlen < 1) {
st = RPC_CANTENCODEARGS;
AUTH_DESTROY(rpcua);
return st;
}
AUTH_DESTROY(rpcua);
DPRINTF("ping %x\n", dom->dom_server_addr.sin_addr.s_addr);
if (sendto(pingsock, buf, outlen, 0,
(struct sockaddr *)(void *)&dom->dom_server_addr,
(socklen_t)(sizeof dom->dom_server_addr)) == -1)
yp_log(LOG_WARNING, "ping: sendto: %s", strerror(errno));
return 0;
}
/*
* Scan for timer-based work to do.
*
* If the domain is currently alive, ping the server we're currently
* bound to. Otherwise, try all known servers and/or broadcast for a
* server via nag_servers.
*
* Try again in five seconds.
*
* If we get back here and the state is still DOM_PINGING, it means
* we didn't receive a ping response within five seconds. Declare the
* binding lost. If the binding is already lost, and it's been lost
* for 60 seconds, switch to DOM_DEAD and begin exponential backoff.
* The exponential backoff starts at 10 seconds and tops out at one
* hour; see above.
*/
static void
checkwork(void)
{
struct domain *dom;
time_t t;
check = 0;
(void)time(&t);
for (dom = domains; dom != NULL; dom = dom->dom_next) {
if (dom->dom_checktime >= t) {
continue;
}
switch (dom->dom_state) {
case DOM_NEW:
/* XXX should be a timeout for this state */
dom->dom_checktime = t + 5;
(void)nag_servers(dom);
break;
case DOM_ALIVE:
dom->dom_state = DOM_PINGING;
dom->dom_checktime = t + 5;
(void)ping(dom);
break;
case DOM_PINGING:
dom->dom_state = DOM_LOST;
dom->dom_losttime = t;
dom->dom_checktime = t + 5;
yp_log(LOG_NOTICE, "Domain %s lost its binding to "
"server %s", dom->dom_name,
inet_ntoa(dom->dom_server_addr.sin_addr));
(void)nag_servers(dom);
break;
case DOM_LOST:
if (t > dom->dom_losttime + 60) {
dom->dom_state = DOM_DEAD;
dom->dom_backofftime = 10;
yp_log(LOG_NOTICE, "Domain %s dead; "
"going to exponential backoff",
dom->dom_name);
}
dom->dom_checktime = t + 5;
(void)nag_servers(dom);
break;
case DOM_DEAD:
dom->dom_checktime = t + dom->dom_backofftime;
backoff(&dom->dom_backofftime);
(void)nag_servers(dom);
break;
}
/* re-fetch the time in case we hung sending packets */
(void)time(&t);
}
}
/*
* Process a hangup signal.
*
* Do an extra nag_servers() for any domains that are DEAD. This way
* if you know things are back up you can restore service by sending
* ypbind a SIGHUP rather than waiting for the timeout period.
*/
static void
dohup(void)
{
struct domain *dom;
hupped = 0;
for (dom = domains; dom != NULL; dom = dom->dom_next) {
if (dom->dom_state == DOM_DEAD) {
(void)nag_servers(dom);
}
}
}
/*
* Receive a hangup signal.
*/
static void
hup(int __unused sig)
{
hupped = 1;
}
/*
* Initialize hangup processing.
*/
static void
starthup(void)
{
struct sigaction sa;
sa.sa_handler = hup;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGHUP, &sa, NULL) == -1) {
err(1, "sigaction");
}
}
////////////////////////////////////////////////////////////
// main
/*
* Usage message.
*/
__dead static void
usage(void)
{
const char *opt = "";
#ifdef DEBUG
opt = " [-d]";
#endif
(void)fprintf(stderr,
"Usage: %s [-broadcast] [-insecure] [-ypset] [-ypsetme]%s\n",
getprogname(), opt);
exit(1);
}
/*
* Main.
*/
int
main(int argc, char *argv[])
{
struct timeval tv;
fd_set fdsr;
int width, lockfd;
int started = 0;
char *domainname;
setprogname(argv[0]);
/*
* Process arguments.
*/
default_ypbindmode = YPBIND_DIRECT;
while (--argc) {
++argv;
if (!strcmp("-insecure", *argv)) {
insecure = 1;
} else if (!strcmp("-ypset", *argv)) {
allow_any_ypset = 1;
allow_local_ypset = 1;
} else if (!strcmp("-ypsetme", *argv)) {
allow_any_ypset = 0;
allow_local_ypset = 1;
} else if (!strcmp("-broadcast", *argv)) {
default_ypbindmode = YPBIND_BROADCAST;
#ifdef DEBUG
} else if (!strcmp("-d", *argv)) {
debug = 1;
#endif
} else {
usage();
}
}
/*
* Look up the name of the default domain.
*/
(void)yp_get_default_domain(&domainname);
if (domainname[0] == '\0')
errx(1, "Domainname not set. Aborting.");
if (_yp_invalid_domain(domainname))
errx(1, "Invalid domainname: %s", domainname);
/*
* Start things up.
*/
/* Open the system log. */
openlog("ypbind", LOG_PERROR | LOG_PID, LOG_DAEMON);
/* Acquire /var/run/ypbind.lock. */
lockfd = open_locked(_PATH_YPBIND_LOCK, O_CREAT|O_RDWR|O_TRUNC, 0644);
if (lockfd == -1)
err(1, "Cannot create %s", _PATH_YPBIND_LOCK);
/* Accept hangups. */
starthup();
/* Initialize sunrpc stuff. */
sunrpc_setup();
/* Clean out BINDINGDIR, deleting all existing (now stale) bindings */
if (purge_bindingdir(BINDINGDIR) < 0)
errx(1, "Unable to purge old bindings from %s", BINDINGDIR);
/*
* We start with one binding, for the default domain. It starts
* out "unsuccessful".
*/
if (domain_create(domainname) == NULL)
err(1, "initial domain binding failed");
/*
* Delete the lock for the default domain again, just in case something
* magically caused it to appear since purge_bindingdir() was called.
* XXX: this is useless and redundant; remove it.
*/
removelock(domains);
/*
* Main loop. Wake up at least once a second and check for
* timer-based work to do (checkwork) and also handle incoming
* responses from ypservers and any RPCs made to the ypbind
* service.
*
* There are two sockets used for ypserver traffic: one for
* pings and one for everything else. These call XDR manually
* for encoding and are *not* dispatched via the sunrpc
* libraries.
*
* The ypbind service *is* dispatched via the sunrpc libraries.
* svc_getreqset() does whatever internal muck and ultimately
* ypbind service calls arrive at ypbindprog_2().
*/
checkwork();
for (;;) {
width = svc_maxfd;
if (rpcsock > width)
width = rpcsock;
if (pingsock > width)
width = pingsock;
width++;
fdsr = svc_fdset;
FD_SET(rpcsock, &fdsr);
FD_SET(pingsock, &fdsr);
tv.tv_sec = 1;
tv.tv_usec = 0;
switch (select(width, &fdsr, NULL, NULL, &tv)) {
case 0:
/* select timed out - check for timer-based work */
if (hupped) {
dohup();
}
checkwork();
break;
case -1:
if (hupped) {
dohup();
}
if (errno != EINTR) {
yp_log(LOG_WARNING, "select: %s",
strerror(errno));
}
break;
default:
if (hupped) {
dohup();
}
/* incoming of our own; read it */
if (FD_ISSET(rpcsock, &fdsr))
(void)handle_replies();
if (FD_ISSET(pingsock, &fdsr))
(void)handle_ping();
/* read any incoming packets for the ypbind service */
svc_getreqset(&fdsr);
/*
* Only check for timer-based work if
* something in the incoming RPC logic said
* to. This might be just a hack to avoid
* scanning the list unnecessarily, but I
* suspect it's also a hack to cover wrong
* state logic. - dholland 20140609
*/
if (check)
checkwork();
break;
}
/*
* Defer daemonizing until the default domain binds
* successfully. XXX: there seems to be no timeout
* on this, which means that if the default domain
* is dead upstream boot will hang indefinitely.
*/
if (!started && domains->dom_state == DOM_ALIVE) {
started = 1;
#ifdef DEBUG
if (!debug)
#endif
(void)daemon(0, 0);
(void)pidfile(NULL);
}
}
}
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