* - user-visible check/wait and event-loop-related functions
*/
/*
- * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
+ * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson
*
* 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
#include <string.h>
#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"
-/* TCP connection management */
+/* TCP connection management. */
+
+void adns__tcp_closenext(adns_state ads) {
+ int serv;
+
+ serv= ads->tcpserver;
+ close(ads->tcpsocket);
+ ads->tcpstate= server_disconnected;
+ ads->tcprecv.used= ads->tcpsend.used= 0;
+ ads->tcpserver= (serv+1)%ads->nservers;
+}
void adns__tcp_broken(adns_state ads, const char *what, const char *why) {
int serv;
assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok);
serv= ads->tcpserver;
adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why);
- close(ads->tcpsocket);
- ads->tcpstate= server_disconnected;
+ adns__tcp_closenext(ads);
for (qu= ads->timew.head; qu; qu= nqu) {
nqu= qu->next;
- if (qu->state == query_udp) continue;
+ if (qu->state == query_tosend) continue;
assert(qu->state == query_tcpwait || qu->state == query_tcpsent);
qu->state= query_tcpwait;
qu->tcpfailed |= (1<<serv);
adns__query_fail(qu,adns_s_allservfail);
}
}
-
- ads->tcprecv.used= ads->tcpsend.used= 0;
- ads->tcpserver= (serv+1)%ads->nservers;
}
static void tcp_connected(adns_state ads, struct timeval now) {
ads->tcpstate= server_ok;
for (qu= ads->timew.head; qu; qu= nqu) {
nqu= qu->next;
- if (qu->state == query_udp) continue;
+ if (qu->state == query_tosend) continue;
assert (qu->state == query_tcpwait);
adns__query_tcp(qu,now);
}
int r, fd, tries;
struct sockaddr_in addr;
struct protoent *proto;
- /* fixme: single TCP timeout, not once per server */
for (tries=0; tries<ads->nservers; tries++) {
if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return;
addr.sin_family= AF_INET;
addr.sin_port= htons(DNS_PORT);
addr.sin_addr= ads->servers[ads->tcpserver].addr;
- r= connect(fd,&addr,sizeof(addr));
+ r= connect(fd,(const struct sockaddr*)&addr,sizeof(addr));
ads->tcpsocket= fd;
ads->tcpstate= server_connecting;
if (r==0) { tcp_connected(ads,now); continue; }
}
}
-/* `Interest' functions - find out which fd's we might be interested in,
- * and when we want to be called back for a timeout.
- */
+/* 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_maxto(struct timeval **tv_io, struct timeval *tvbuf,
struct timeval maxto) {
inter_maxto(tv_io,tvbuf,maxtime);
}
-static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
- if (!maxfd || !fds) return;
- if (fd>=*maxfd) *maxfd= fd+1;
- FD_SET(fd,fds);
-}
-
-static void checktimeouts(adns_state ads, struct timeval now,
- struct timeval **tv_io, struct timeval *tvbuf) {
+void adns__timeouts(adns_state ads, int act,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now) {
adns_query qu, nqu;
-
+
for (qu= ads->timew.head; qu; qu= nqu) {
nqu= qu->next;
- if (timercmp(&now,&qu->timeout,>)) {
+ if (!timercmp(&now,&qu->timeout,>)) {
+ if (!tv_io) continue;
+ inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+ } else {
+ if (!act) continue;
LIST_UNLINK(ads->timew,qu);
- if (qu->state != query_udp) {
+ if (qu->state != query_tosend) {
adns__query_fail(qu,adns_s_timeout);
} else {
- adns__query_udp(qu,now);
+ adns__query_send(qu,now);
}
- } else {
- inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+ nqu= ads->timew.head;
}
}
}
-
-void adns_interest(adns_state ads, int *maxfd,
- fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
- struct timeval **tv_io, struct timeval *tvbuf) {
- struct timeval now;
- struct timeval tvto_lr;
- int r;
-
-/*fprintf(stderr,"adns_interest\n");*/
- r= gettimeofday(&now,0);
- if (r) {
- adns__warn(ads,-1,0,"gettimeofday failed - will sleep for a bit: %s",
- strerror(errno));
- timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
- inter_maxto(tv_io, tvbuf, tvto_lr);
- } else {
- checktimeouts(ads,now,tv_io,tvbuf);
- }
-
- inter_addfd(maxfd,readfds,ads->udpsocket);
+void adns_firsttimeout(adns_state ads,
+ struct timeval **tv_io, struct timeval *tvbuf,
+ struct timeval now) {
+ adns__timeouts(ads, 0, tv_io,tvbuf, now);
+}
+
+void adns_processtimeouts(adns_state ads, const struct timeval *now) {
+ struct timeval tv_buf;
+
+ adns__must_gettimeofday(ads,&now,&tv_buf); if (!now) return;
+ adns__timeouts(ads, 1, 0,0, *now);
+}
+
+/* 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:
- break;
+ return 1;
case server_connecting:
- inter_addfd(maxfd,writefds,ads->tcpsocket);
+ pollfds_buf[1].events= POLLOUT;
break;
case server_ok:
- inter_addfd(maxfd,readfds,ads->tcpsocket);
- inter_addfd(maxfd,exceptfds,ads->tcpsocket);
- if (ads->tcpsend.used) inter_addfd(maxfd,writefds,ads->tcpsocket);
+ pollfds_buf[1].events= ads->tcpsend.used ? POLLIN|POLLOUT|POLLPRI : POLLIN|POLLPRI;
break;
default:
abort();
}
+ pollfds_buf[1].fd= ads->tcpsocket;
+ return 2;
}
-/* Callback procedures - these do the real work of reception and timeout, etc. */
-
-static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
- return maxfd<0 || !fds ? 1 :
- fd<maxfd && FD_ISSET(fd,fds);
-}
-
-static int internal_callback(adns_state ads, int maxfd,
- const fd_set *readfds, const fd_set *writefds,
- const fd_set *exceptfds,
- struct timeval now) {
- int skip, want, dgramlen, count, udpaddrlen, r, serv;
+int adns_processreadable(adns_state ads, int fd, const struct timeval *now) {
+ int skip, want, dgramlen, r, udpaddrlen, serv;
byte udpbuf[DNS_MAXUDP];
struct sockaddr_in udpaddr;
-
- count= 0;
-
+
switch (ads->tcpstate) {
case server_disconnected:
- break;
case server_connecting:
- if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
- count++;
- assert(ads->tcprecv.used==0);
- if (!adns__vbuf_ensure(&ads->tcprecv,1)) return -1;
- if (ads->tcprecv.buf) {
- r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
- if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
- tcp_connected(ads,now);
- } else if (r>0) {
- adns__tcp_broken(ads,"connect/read","sent data before first request");
- } else if (errno!=EINTR) {
- adns__tcp_broken(ads,"connect/read",strerror(errno));
- }
- }
- }
break;
case server_ok:
- count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
- callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
- (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
- if (callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
- skip= 0;
- for (;;) {
- if (ads->tcprecv.used<skip+2) {
- want= 2;
- } else {
- dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
- if (ads->tcprecv.used<skip+2+dgramlen) {
- want= 2+dgramlen;
- } else {
- adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,now);
- skip+= 2+dgramlen; continue;
- }
- }
- ads->tcprecv.used -= skip;
- memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
- skip= 0;
- if (!adns__vbuf_ensure(&ads->tcprecv,want)) return -1;
- 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;
+ if (fd != ads->tcpsocket) break;
+ skip= 0;
+ for (;;) {
+ if (ads->tcprecv.used<skip+2) {
+ want= 2;
+ } else {
+ dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
+ if (ads->tcprecv.used<skip+2+dgramlen) {
+ want= 2+dgramlen;
} else {
- if (r<0) {
- if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
- if (errno==EINTR) continue;
- }
- adns__tcp_broken(ads,"read",r?strerror(errno):"closed");
- break;
+ adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,1,*now);
+ skip+= 2+dgramlen; continue;
}
}
- } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
- adns__tcp_broken(ads,"select","exceptional condition detected");
- } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
- r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
- if (r<0) {
- if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
- adns__tcp_broken(ads,"write",strerror(errno));
+ ads->tcprecv.used -= skip;
+ memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
+ skip= 0;
+ if (!adns__vbuf_ensure(&ads->tcprecv,want)) return ENOMEM;
+ 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) return 0;
+ if (errno==EINTR) continue;
+ if (errno_resources(errno)) return errno;
}
- } else if (r>0) {
- ads->tcpsend.used -= r;
- memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
+ adns__tcp_broken(ads,"read",r?strerror(errno):"closed");
+ return 0;
}
- }
- break;
+ } /* never reached */
default:
abort();
}
-
- if (callb_checkfd(maxfd,readfds,ads->udpsocket)) {
- count++;
+ if (fd == ads->udpsocket) {
for (;;) {
udpaddrlen= sizeof(udpaddr);
- r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,&udpaddr,&udpaddrlen);
+ r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0,
+ (struct sockaddr*)&udpaddr,&udpaddrlen);
if (r<0) {
- if (!(errno == EAGAIN || errno == EWOULDBLOCK ||
- errno == EINTR || errno == ENOMEM || errno == ENOBUFS))
- adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno));
- break;
+ if (errno == EAGAIN || errno == EWOULDBLOCK) return 0;
+ if (errno == EINTR) continue;
+ if (errno_resources(errno)) return errno;
+ adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno));
+ return 0;
}
if (udpaddrlen != sizeof(udpaddr)) {
adns__diag(ads,-1,0,"datagram received with wrong address length %d"
inet_ntoa(udpaddr.sin_addr));
continue;
}
- adns__procdgram(ads,udpbuf,r,serv,now);
+ adns__procdgram(ads,udpbuf,r,serv,0,*now);
}
}
- return count;
+ return 0;
}
-int adns_callback(adns_state ads, int maxfd,
- const fd_set *readfds, const fd_set *writefds,
- const fd_set *exceptfds) {
- struct timeval now;
+int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) {
+ int r;
+
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ break;
+ case server_connecting:
+ if (fd != ads->tcpsocket) break;
+ assert(ads->tcprecv.used==0);
+ for (;;) {
+ if (!adns__vbuf_ensure(&ads->tcprecv,1)) return ENOMEM;
+ r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
+ if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
+ tcp_connected(ads,*now);
+ return 0;
+ }
+ if (r>0) {
+ adns__tcp_broken(ads,"connect/read","sent data before first request");
+ return 0;
+ }
+ if (errno==EINTR) continue;
+ if (errno_resources(errno)) return errno;
+ adns__tcp_broken(ads,"connect/read",strerror(errno));
+ return 0;
+ } /* not reached */
+ case server_ok:
+ if (!(ads->tcpsend.used && fd == ads->tcpsocket)) break;
+ for (;;) {
+ 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) return 0;
+ if (errno_resources(errno)) return errno;
+ adns__tcp_broken(ads,"write",strerror(errno));
+ return 0;
+ } else if (r>0) {
+ ads->tcpsend.used -= r;
+ memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
+ }
+ } /* not reached */
+ default:
+ abort();
+ }
+ return 0;
+}
+
+int adns_processexceptional(adns_state ads, int fd, const struct timeval *now) {
+ switch (ads->tcpstate) {
+ case server_disconnected:
+ break;
+ case server_connecting:
+ case server_ok:
+ if (fd != ads->tcpsocket) break;
+ adns__tcp_broken(ads,"poll/select","exceptional condition detected");
+ return 0;
+ default:
+ abort();
+ }
+ 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;
+
+ 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) return;
+ adns__timeouts(ads, 1, tv_mod,tv_tobuf, *now);
+ }
- r= gettimeofday(&now,0); if (r) return -1;
- checktimeouts(ads,now,0,0);
- return internal_callback(ads,maxfd,readfds,writefds,exceptfds,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;
+}
+
+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__must_gettimeofday(ads,&now,&tv_buf);
+ if (!now) return;
+ 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);
+}
+
+/* General helpful functions. */
+
+void adns_globalsystemfailure(adns_state ads) {
+ while (ads->timew.head) {
+ adns__query_fail(ads->timew.head, adns_s_systemfail);
+ }
+
+ switch (ads->tcpstate) {
+ case server_connecting:
+ case server_ok:
+ adns__tcp_closenext(ads);
+ break;
+ case server_disconnected:
+ break;
+ default:
+ abort();
+ }
}
-/* User-visible functions and their implementation. */
+int adns_processany(adns_state ads) {
+ int r;
+ struct timeval now;
+ struct pollfd pollfds[MAX_POLLFDS];
+ int npollfds;
+
+ r= gettimeofday(&now,0);
+ if (!r) adns_processtimeouts(ads,&now);
+
+ npollfds= adns__pollfds(ads,pollfds);
+ adns__fdevents(ads,
+ pollfds,npollfds,
+ 0,0,0,0,
+ now,&r);
+ return r;
+}
void adns__autosys(adns_state ads, struct timeval now) {
if (ads->iflags & adns_if_noautosys) return;
- adns_callback(ads,-1,0,0,0);
+ adns_processany(ads);
}
static int internal_check(adns_state ads,
LIST_UNLINK(ads->output,qu);
*answer= qu->answer;
if (context_r) *context_r= qu->ctx.ext;
+ *query_io= qu;
free(qu);
return 0;
}
adns_query *query_io,
adns_answer **answer_r,
void **context_r) {
- int r, maxfd, rsel, rcb;
+ int r, maxfd, rsel;
fd_set readfds, writefds, exceptfds;
struct timeval tvbuf, *tvp;
if (r != EWOULDBLOCK) return r;
maxfd= 0; tvp= 0;
FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
- adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
+ adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf,0);
rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
if (rsel==-1) {
- if (errno == EINTR && !(ads->iflags & adns_if_eintr)) continue;
- return errno;
+ if (errno == EINTR) {
+ if (ads->iflags & adns_if_eintr) return EINTR;
+ } 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);
}
- rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
- assert(rcb==rsel);
}
}
struct timeval now;
int r;
- r= gettimeofday(&now,0); if (r) return errno;
- adns__autosys(ads,now);
+ r= gettimeofday(&now,0);
+ if (!r) adns__autosys(ads,now);
+
return internal_check(ads,query_io,answer_r,context_r);
}
~mdw / adns / blobdiff