*** /dev/null Fri May 3 13:52:11 2024
--- - Fri May 3 13:52:34 2024
***************
*** 0 ****
--- 1,723 ----
+ /*
+ * event.c
+ * - event loop core
+ * - TCP connection management
+ * - user-visible check/wait and event-loop-related functions
+ */
+ /*
+ * This file is
+ * Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
+ *
+ * It is part of adns, which is
+ * Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
+ * Copyright (C) 1999 Tony Finch <dot@dotat.at>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+ #include <errno.h>
+ #include <stdlib.h>
+ #include <unistd.h>
+
+ #include <sys/types.h>
+ #include <sys/time.h>
+ #include <netdb.h>
+ #include <sys/socket.h>
+ #include <netinet/in.h>
+ #include <arpa/inet.h>
+
+ #include "internal.h"
+ #include "tvarith.h"
+
+ /* TCP connection management. */
+
+ static void tcp_close(adns_state ads) {
+ int serv;
+
+ serv= ads->tcpserver;
+ close(ads->tcpsocket);
+ ads->tcpsocket= -1;
+ ads->tcprecv.used= ads->tcprecv_skip= ads->tcpsend.used= 0;
+ }
+
+ void adns__tcp_broken(adns_state ads, const char *what, const char *why) {
+ int serv;
+ adns_query qu;
+
+ assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok);
+ serv= ads->tcpserver;
+ if (what) adns__warn(ads,serv,0,"TCP connection failed: %s: %s",what,why);
+
+ if (ads->tcpstate == server_connecting) {
+ /* Counts as a retry for all the queries waiting for TCP. */
+ for (qu= ads->tcpw.head; qu; qu= qu->next)
+ qu->retries++;
+ }
+
+ tcp_close(ads);
+ ads->tcpstate= server_broken;
+ ads->tcpserver= (serv+1)%ads->nservers;
+ }
+
+ static void tcp_connected(adns_state ads, struct timeval now) {
+ adns_query qu, nqu;
+
+ adns__debug(ads,ads->tcpserver,0,"TCP connected");
+ ads->tcpstate= server_ok;
+ for (qu= ads->tcpw.head; qu && ads->tcpstate == server_ok; qu= nqu) {
+ nqu= qu->next;
+ assert(qu->state == query_tcpw);
+ adns__querysend_tcp(qu,now);
+ }
+ }
+
+ void adns__tcp_tryconnect(adns_state ads, struct timeval now) {
+ int r, fd, tries;
+ struct sockaddr_in addr;
+ struct protoent *proto;
+
+ for (tries=0; tries<ads->nservers; tries++) {
+ switch (ads->tcpstate) {
+ case server_connecting:
+ case server_ok:
+ case server_broken:
+ return;
+ case server_disconnected:
+ break;
+ default:
+ abort();
+ }
+
+ assert(!ads->tcpsend.used);
+ assert(!ads->tcprecv.used);
+ assert(!ads->tcprecv_skip);
+
+ proto= getprotobyname("tcp");
+ if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; }
+ fd= socket(AF_INET,SOCK_STREAM,proto->p_proto);
+ if (fd<0) {
+ adns__diag(ads,-1,0,"cannot create TCP socket: %s",strerror(errno));
+ return;
+ }
+ r= adns__setnonblock(ads,fd);
+ if (r) {
+ adns__diag(ads,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r));
+ close(fd);
+ return;
+ }
+ memset(&addr,0,sizeof(addr));
+ addr.sin_family= AF_INET;
+ addr.sin_port= htons(DNS_PORT);
+ addr.sin_addr= ads->servers[ads->tcpserver].addr;
+ r= connect(fd,(const struct sockaddr*)&addr,sizeof(addr));
+ ads->tcpsocket= fd;
+ ads->tcpstate= server_connecting;
+ if (r==0) { tcp_connected(ads,now); return; }
+ if (errno == EWOULDBLOCK || errno == EINPROGRESS) {
+ ads->tcptimeout= now;
+ timevaladd(&ads->tcptimeout,TCPCONNMS);
+ return;
+ }
+ adns__tcp_broken(ads,"connect",strerror(errno));
+ ads->tcpstate= server_disconnected;
+ }
+ }
+
+ /* Timeout handling functions. */
+
+ void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io,
+ struct timeval *tv_buf) {
+ const struct timeval *now;
+ int r;
+
+ now= *now_io;
+ if (now) return;
+ r= gettimeofday(tv_buf,0); if (!r) { *now_io= tv_buf; return; }
+ adns__diag(ads,-1,0,"gettimeofday failed: %s",strerror(errno));
+ adns_globalsystemfailure(ads);
+ return;
+ }
+
+ static void inter_immed(struct timeval **tv_io, struct timeval *tvbuf) {
+ struct timeval *rbuf;
+
+ if (!tv_io) return;
+
+ rbuf= *tv_io;
+ if (!rbuf) { *tv_io= rbuf= tvbuf; }
+
+ timerclear(rbuf);
+ }
+
+ static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval maxto) {
+ struct timeval *rbuf;
+
+ if (!tv_io) return;
+ rbuf= *tv_io;
+ if (!rbuf) {
+ *tvbuf= maxto; *tv_io= tvbuf;
+ } else {
+ if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
+ }
+ /*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n",
+ maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);*/
+ }
+
+ static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now, struct timeval maxtime) {
+ /* tv_io may be 0 */
+ ldiv_t dr;
+
+ /*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n",
+ now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);*/
+ if (!tv_io) return;
+ maxtime.tv_sec -= (now.tv_sec+2);
+ maxtime.tv_usec -= (now.tv_usec-2000000);
+ dr= ldiv(maxtime.tv_usec,1000000);
+ maxtime.tv_sec += dr.quot;
+ maxtime.tv_usec -= dr.quot*1000000;
+ if (maxtime.tv_sec<0) timerclear(&maxtime);
+ inter_maxto(tv_io,tvbuf,maxtime);
+ }
+
+ static void timeouts_queue(adns_state ads, int act,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now, struct query_queue *queue) {
+ adns_query qu, nqu;
+
+ for (qu= queue->head; qu; qu= nqu) {
+ nqu= qu->next;
+ if (!timercmp(&now,&qu->timeout,>)) {
+ inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+ } else {
+ if (!act) { inter_immed(tv_io,tvbuf); return; }
+ LIST_UNLINK(*queue,qu);
+ if (qu->state != query_tosend) {
+ adns__query_fail(qu,adns_s_timeout);
+ } else {
+ adns__query_send(qu,now);
+ }
+ nqu= queue->head;
+ }
+ }
+ }
+
+ static void tcp_events(adns_state ads, int act,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now) {
+ adns_query qu, nqu;
+
+ for (;;) {
+ switch (ads->tcpstate) {
+ case server_broken:
+ if (!act) { inter_immed(tv_io,tvbuf); return; }
+ for (qu= ads->tcpw.head; qu; qu= nqu) {
+ nqu= qu->next;
+ assert(qu->state == query_tcpw);
+ if (qu->retries > ads->nservers) {
+ LIST_UNLINK(ads->tcpw,qu);
+ adns__query_fail(qu,adns_s_allservfail);
+ }
+ }
+ ads->tcpstate= server_disconnected;
+ case server_disconnected: /* fall through */
+ if (!ads->tcpw.head) return;
+ if (!act) { inter_immed(tv_io,tvbuf); return; }
+ adns__tcp_tryconnect(ads,now);
+ break;
+ case server_ok:
+ if (ads->tcpw.head) return;
+ if (!ads->tcptimeout.tv_sec) {
+ assert(!ads->tcptimeout.tv_usec);
+ ads->tcptimeout= now;
+ timevaladd(&ads->tcptimeout,TCPIDLEMS);
+ }
+ case server_connecting: /* fall through */
+ if (!act || !timercmp(&now,&ads->tcptimeout,>)) {
+ inter_maxtoabs(tv_io,tvbuf,now,ads->tcptimeout);
+ return;
+ } {
+ /* TCP timeout has happened */
+ switch (ads->tcpstate) {
+ case server_connecting: /* failed to connect */
+ adns__tcp_broken(ads,"unable to make connection","timed out");
+ break;
+ case server_ok: /* idle timeout */
+ tcp_close(ads);
+ ads->tcpstate= server_disconnected;
+ return;
+ default:
+ abort();
+ }
+ }
+ break;
+ default:
+ abort();
+ }
+ }
+ return;
+ }
+
+ void adns__timeouts(adns_state ads, int act,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now) {
+ timeouts_queue(ads,act,tv_io,tvbuf,now, &ads->udpw);
+ timeouts_queue(ads,act,tv_io,tvbuf,now, &ads->tcpw);
+ tcp_events(ads,act,tv_io,tvbuf,now);
+ }
+
+ void adns_firsttimeout(adns_state ads,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now) {
+ adns__consistency(ads,0,cc_entex);
+ adns__timeouts(ads, 0, tv_io,tvbuf, now);
+ adns__consistency(ads,0,cc_entex);
+ }
+
+ void adns_processtimeouts(adns_state ads, const struct timeval *now) {
+ struct timeval tv_buf;
+
+ adns__consistency(ads,0,cc_entex);
+ adns__must_gettimeofday(ads,&now,&tv_buf);
+ if (now) adns__timeouts(ads, 1, 0,0, *now);
+ adns__consistency(ads,0,cc_entex);
+ }
+
+ /* fd handling functions. These are the top-level of the real work of
+ * reception and often transmission.
+ */
+
+ int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]) {
+ /* Returns the number of entries filled in. Always zeroes revents. */
+
+ assert(MAX_POLLFDS==2);
+
+ pollfds_buf[0].fd= ads->udpsocket;
+ pollfds_buf[0].events= POLLIN;
+ pollfds_buf[0].revents= 0;
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ case server_broken:
+ return 1;
+ case server_connecting:
+ pollfds_buf[1].events= POLLOUT;
+ break;
+ case server_ok:
+ pollfds_buf[1].events= ads->tcpsend.used ? POLLIN|POLLOUT|POLLPRI : POLLIN|POLLPRI;
+ break;
+ default:
+ abort();
+ }
+ pollfds_buf[1].fd= ads->tcpsocket;
+ return 2;
+ }
+
+ int adns_processreadable(adns_state ads, int fd, const struct timeval *now) {
+ int want, dgramlen, r, udpaddrlen, serv, old_skip;
+ byte udpbuf[DNS_MAXUDP];
+ struct sockaddr_in udpaddr;
+
+ adns__consistency(ads,0,cc_entex);
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ case server_broken:
+ case server_connecting:
+ break;
+ case server_ok:
+ if (fd != ads->tcpsocket) break;
+ assert(!ads->tcprecv_skip);
+ do {
+ if (ads->tcprecv.used >= ads->tcprecv_skip+2) {
+ dgramlen= ((ads->tcprecv.buf[ads->tcprecv_skip]<<8) |
+ ads->tcprecv.buf[ads->tcprecv_skip+1]);
+ if (ads->tcprecv.used >= ads->tcprecv_skip+2+dgramlen) {
+ old_skip= ads->tcprecv_skip;
+ ads->tcprecv_skip += 2+dgramlen;
+ adns__procdgram(ads, ads->tcprecv.buf+old_skip+2,
+ dgramlen, ads->tcpserver, 1,*now);
+ continue;
+ } else {
+ want= 2+dgramlen;
+ }
+ } else {
+ want= 2;
+ }
+ ads->tcprecv.used -= ads->tcprecv_skip;
+ memmove(ads->tcprecv.buf,ads->tcprecv.buf+ads->tcprecv_skip,ads->tcprecv.used);
+ ads->tcprecv_skip= 0;
+ if (!adns__vbuf_ensure(&ads->tcprecv,want)) { r= ENOMEM; goto xit; }
+ assert(ads->tcprecv.used <= ads->tcprecv.avail);
+ if (ads->tcprecv.used == ads->tcprecv.avail) continue;
+ r= read(ads->tcpsocket,
+ ads->tcprecv.buf+ads->tcprecv.used,
+ ads->tcprecv.avail-ads->tcprecv.used);
+ if (r>0) {
+ ads->tcprecv.used+= r;
+ } else {
+ if (r) {
+ if (errno==EAGAIN || errno==EWOULDBLOCK) { r= 0; goto xit; }
+ if (errno==EINTR) continue;
+ if (errno_resources(errno)) { r= errno; goto xit; }
+ }
+ adns__tcp_broken(ads,"read",r?strerror(errno):"closed");
+ }
+ } while (ads->tcpstate == server_ok);
+ r= 0; goto xit;
+ default:
+ abort();
+ }
+ if (fd == ads->udpsocket) {
+ for (;;) {
+ udpaddrlen= sizeof(udpaddr);
+ r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,
+ (struct sockaddr*)&udpaddr,&udpaddrlen);
+ if (r<0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK) { r= 0; goto xit; }
+ if (errno == EINTR) continue;
+ if (errno_resources(errno)) { r= errno; goto xit; }
+ adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno));
+ r= 0; goto xit;
+ }
+ if (udpaddrlen != sizeof(udpaddr)) {
+ adns__diag(ads,-1,0,"datagram received with wrong address length %d"
+ " (expected %d)", udpaddrlen,sizeof(udpaddr));
+ continue;
+ }
+ if (udpaddr.sin_family != AF_INET) {
+ adns__diag(ads,-1,0,"datagram received with wrong protocol family"
+ " %u (expected %u)",udpaddr.sin_family,AF_INET);
+ continue;
+ }
+ if (ntohs(udpaddr.sin_port) != DNS_PORT) {
+ adns__diag(ads,-1,0,"datagram received from wrong port %u (expected %u)",
+ ntohs(udpaddr.sin_port),DNS_PORT);
+ continue;
+ }
+ for (serv= 0;
+ serv < ads->nservers &&
+ ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr;
+ serv++);
+ if (serv >= ads->nservers) {
+ adns__warn(ads,-1,0,"datagram received from unknown nameserver %s",
+ inet_ntoa(udpaddr.sin_addr));
+ continue;
+ }
+ adns__procdgram(ads,udpbuf,r,serv,0,*now);
+ }
+ }
+ r= 0;
+ xit:
+ adns__consistency(ads,0,cc_entex);
+ return r;
+ }
+
+ int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) {
+ int r;
+
+ adns__consistency(ads,0,cc_entex);
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ case server_broken:
+ break;
+ case server_connecting:
+ if (fd != ads->tcpsocket) break;
+ assert(ads->tcprecv.used==0);
+ assert(ads->tcprecv_skip==0);
+ for (;;) {
+ if (!adns__vbuf_ensure(&ads->tcprecv,1)) { r= ENOMEM; goto xit; }
+ r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
+ if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
+ tcp_connected(ads,*now);
+ r= 0; goto xit;
+ }
+ if (r>0) {
+ adns__tcp_broken(ads,"connect/read","sent data before first request");
+ r= 0; goto xit;
+ }
+ if (errno==EINTR) continue;
+ if (errno_resources(errno)) { r= errno; goto xit; }
+ adns__tcp_broken(ads,"connect/read",strerror(errno));
+ r= 0; goto xit;
+ } /* not reached */
+ case server_ok:
+ if (fd != ads->tcpsocket) break;
+ while (ads->tcpsend.used) {
+ adns__sigpipe_protect(ads);
+ r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
+ adns__sigpipe_unprotect(ads);
+ if (r<0) {
+ if (errno==EINTR) continue;
+ if (errno==EAGAIN || errno==EWOULDBLOCK) { r= 0; goto xit; }
+ if (errno_resources(errno)) { r= errno; goto xit; }
+ adns__tcp_broken(ads,"write",strerror(errno));
+ r= 0; goto xit;
+ } else if (r>0) {
+ ads->tcpsend.used -= r;
+ memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
+ }
+ }
+ r= 0;
+ goto xit;
+ default:
+ abort();
+ }
+ r= 0;
+ xit:
+ adns__consistency(ads,0,cc_entex);
+ return r;
+ }
+
+ int adns_processexceptional(adns_state ads, int fd, const struct timeval *now) {
+ adns__consistency(ads,0,cc_entex);
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ case server_broken:
+ break;
+ case server_connecting:
+ case server_ok:
+ if (fd != ads->tcpsocket) break;
+ adns__tcp_broken(ads,"poll/select","exceptional condition detected");
+ break;
+ default:
+ abort();
+ }
+ adns__consistency(ads,0,cc_entex);
+ return 0;
+ }
+
+ static void fd_event(adns_state ads, int fd,
+ int revent, int pollflag,
+ int maxfd, const fd_set *fds,
+ int (*func)(adns_state, int fd, const struct timeval *now),
+ struct timeval now, int *r_r) {
+ int r;
+
+ if (!(revent & pollflag)) return;
+ if (fds && !(fd<maxfd && FD_ISSET(fd,fds))) return;
+ r= func(ads,fd,&now);
+ if (r) {
+ if (r_r) {
+ *r_r= r;
+ } else {
+ adns__diag(ads,-1,0,"process fd failed after select: %s",strerror(errno));
+ adns_globalsystemfailure(ads);
+ }
+ }
+ }
+
+ void adns__fdevents(adns_state ads,
+ const struct pollfd *pollfds, int npollfds,
+ int maxfd, const fd_set *readfds,
+ const fd_set *writefds, const fd_set *exceptfds,
+ struct timeval now, int *r_r) {
+ int i, fd, revents;
+
+ for (i=0; i<npollfds; i++) {
+ fd= pollfds[i].fd;
+ if (fd >= maxfd) maxfd= fd+1;
+ revents= pollfds[i].revents;
+ fd_event(ads,fd, revents,POLLIN, maxfd,readfds, adns_processreadable,now,r_r);
+ fd_event(ads,fd, revents,POLLOUT, maxfd,writefds, adns_processwriteable,now,r_r);
+ fd_event(ads,fd, revents,POLLPRI, maxfd,exceptfds, adns_processexceptional,now,r_r);
+ }
+ }
+
+ /* Wrappers for select(2). */
+
+ void adns_beforeselect(adns_state ads, int *maxfd_io, fd_set *readfds_io,
+ fd_set *writefds_io, fd_set *exceptfds_io,
+ struct timeval **tv_mod, struct timeval *tv_tobuf,
+ const struct timeval *now) {
+ struct timeval tv_nowbuf;
+ struct pollfd pollfds[MAX_POLLFDS];
+ int i, fd, maxfd, npollfds;
+
+ adns__consistency(ads,0,cc_entex);
+
+ if (tv_mod && (!*tv_mod || (*tv_mod)->tv_sec || (*tv_mod)->tv_usec)) {
+ /* The caller is planning to sleep. */
+ adns__must_gettimeofday(ads,&now,&tv_nowbuf);
+ if (!now) { inter_immed(tv_mod,tv_tobuf); goto xit; }
+ adns__timeouts(ads, 0, tv_mod,tv_tobuf, *now);
+ }
+
+ npollfds= adns__pollfds(ads,pollfds);
+ maxfd= *maxfd_io;
+ for (i=0; i<npollfds; i++) {
+ fd= pollfds[i].fd;
+ if (fd >= maxfd) maxfd= fd+1;
+ if (pollfds[i].events & POLLIN) FD_SET(fd,readfds_io);
+ if (pollfds[i].events & POLLOUT) FD_SET(fd,writefds_io);
+ if (pollfds[i].events & POLLPRI) FD_SET(fd,exceptfds_io);
+ }
+ *maxfd_io= maxfd;
+
+ xit:
+ adns__consistency(ads,0,cc_entex);
+ }
+
+ void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds,
+ const fd_set *writefds, const fd_set *exceptfds,
+ const struct timeval *now) {
+ struct timeval tv_buf;
+ struct pollfd pollfds[MAX_POLLFDS];
+ int npollfds, i;
+
+ adns__consistency(ads,0,cc_entex);
+ adns__must_gettimeofday(ads,&now,&tv_buf);
+ if (!now) goto xit;
+ adns_processtimeouts(ads,now);
+
+ npollfds= adns__pollfds(ads,pollfds);
+ for (i=0; i<npollfds; i++) pollfds[i].revents= POLLIN|POLLOUT|POLLPRI;
+ adns__fdevents(ads,
+ pollfds,npollfds,
+ maxfd,readfds,writefds,exceptfds,
+ *now, 0);
+ xit:
+ adns__consistency(ads,0,cc_entex);
+ }
+
+ /* General helpful functions. */
+
+ void adns_globalsystemfailure(adns_state ads) {
+ adns__consistency(ads,0,cc_entex);
+
+ while (ads->udpw.head) adns__query_fail(ads->udpw.head, adns_s_systemfail);
+ while (ads->tcpw.head) adns__query_fail(ads->tcpw.head, adns_s_systemfail);
+
+ switch (ads->tcpstate) {
+ case server_connecting:
+ case server_ok:
+ adns__tcp_broken(ads,0,0);
+ break;
+ case server_disconnected:
+ case server_broken:
+ break;
+ default:
+ abort();
+ }
+ adns__consistency(ads,0,cc_entex);
+ }
+
+ int adns_processany(adns_state ads) {
+ int r, i;
+ struct timeval now;
+ struct pollfd pollfds[MAX_POLLFDS];
+ int npollfds;
+
+ adns__consistency(ads,0,cc_entex);
+
+ r= gettimeofday(&now,0);
+ if (!r) adns_processtimeouts(ads,&now);
+
+ /* We just use adns__fdevents to loop over the fd's trying them.
+ * This seems more sensible than calling select, since we're most
+ * likely just to want to do a read on one or two fds anyway.
+ */
+ npollfds= adns__pollfds(ads,pollfds);
+ for (i=0; i<npollfds; i++) pollfds[i].revents= pollfds[i].events & ~POLLPRI;
+ adns__fdevents(ads,
+ pollfds,npollfds,
+ 0,0,0,0,
+ now,&r);
+
+ adns__consistency(ads,0,cc_entex);
+ return 0;
+ }
+
+ void adns__autosys(adns_state ads, struct timeval now) {
+ if (ads->iflags & adns_if_noautosys) return;
+ adns_processany(ads);
+ }
+
+ int adns__internal_check(adns_state ads,
+ adns_query *query_io,
+ adns_answer **answer,
+ void **context_r) {
+ adns_query qu;
+
+ qu= *query_io;
+ if (!qu) {
+ if (ads->output.head) {
+ qu= ads->output.head;
+ } else if (ads->udpw.head || ads->tcpw.head) {
+ return EAGAIN;
+ } else {
+ return ESRCH;
+ }
+ } else {
+ if (qu->id>=0) return EAGAIN;
+ }
+ LIST_UNLINK(ads->output,qu);
+ *answer= qu->answer;
+ if (context_r) *context_r= qu->ctx.ext;
+ *query_io= qu;
+ free(qu);
+ return 0;
+ }
+
+ int adns_wait(adns_state ads,
+ adns_query *query_io,
+ adns_answer **answer_r,
+ void **context_r) {
+ int r, maxfd, rsel;
+ fd_set readfds, writefds, exceptfds;
+ struct timeval tvbuf, *tvp;
+
+ adns__consistency(ads,*query_io,cc_entex);
+ for (;;) {
+ r= adns__internal_check(ads,query_io,answer_r,context_r);
+ if (r != EAGAIN) break;
+ maxfd= 0; tvp= 0;
+ FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
+ adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf,0);
+ assert(tvp);
+ rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
+ if (rsel==-1) {
+ if (errno == EINTR) {
+ if (ads->iflags & adns_if_eintr) { r= EINTR; break; }
+ } else {
+ adns__diag(ads,-1,0,"select failed in wait: %s",strerror(errno));
+ adns_globalsystemfailure(ads);
+ }
+ } else {
+ assert(rsel >= 0);
+ adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,0);
+ }
+ }
+ adns__consistency(ads,0,cc_entex);
+ return r;
+ }
+
+ int adns_check(adns_state ads,
+ adns_query *query_io,
+ adns_answer **answer_r,
+ void **context_r) {
+ struct timeval now;
+ int r;
+
+ adns__consistency(ads,*query_io,cc_entex);
+ r= gettimeofday(&now,0);
+ if (!r) adns__autosys(ads,now);
+
+ r= adns__internal_check(ads,query_io,answer_r,context_r);
+ adns__consistency(ads,0,cc_entex);
+ return r;
+ }
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