| 1 | /* |
| 2 | * event.c |
| 3 | * - event loop core |
| 4 | * - TCP connection management |
| 5 | * - user-visible check/wait and event-loop-related functions |
| 6 | */ |
| 7 | /* |
| 8 | * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2, or (at your option) |
| 13 | * any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, write to the Free Software Foundation, |
| 22 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 23 | */ |
| 24 | |
| 25 | #include <string.h> |
| 26 | #include <errno.h> |
| 27 | #include <stdlib.h> |
| 28 | #include <unistd.h> |
| 29 | |
| 30 | #include <sys/types.h> |
| 31 | #include <sys/time.h> |
| 32 | #include <netdb.h> |
| 33 | #include <sys/socket.h> |
| 34 | #include <netinet/in.h> |
| 35 | #include <arpa/inet.h> |
| 36 | |
| 37 | #include "internal.h" |
| 38 | |
| 39 | /* TCP connection management. */ |
| 40 | |
| 41 | void adns__tcp_closenext(adns_state ads) { |
| 42 | int serv; |
| 43 | |
| 44 | serv= ads->tcpserver; |
| 45 | close(ads->tcpsocket); |
| 46 | ads->tcpstate= server_disconnected; |
| 47 | ads->tcprecv.used= ads->tcpsend.used= 0; |
| 48 | ads->tcpserver= (serv+1)%ads->nservers; |
| 49 | } |
| 50 | |
| 51 | void adns__tcp_broken(adns_state ads, const char *what, const char *why) { |
| 52 | int serv; |
| 53 | adns_query qu, nqu; |
| 54 | |
| 55 | assert(ads->tcpstate == server_connecting || ads->tcpstate == server_ok); |
| 56 | serv= ads->tcpserver; |
| 57 | adns__warn(ads,serv,0,"TCP connection lost: %s: %s",what,why); |
| 58 | adns__tcp_closenext(ads); |
| 59 | |
| 60 | for (qu= ads->timew.head; qu; qu= nqu) { |
| 61 | nqu= qu->next; |
| 62 | if (qu->state == query_udp) continue; |
| 63 | assert(qu->state == query_tcpwait || qu->state == query_tcpsent); |
| 64 | qu->state= query_tcpwait; |
| 65 | qu->tcpfailed |= (1<<serv); |
| 66 | if (qu->tcpfailed == (1<<ads->nservers)-1) { |
| 67 | LIST_UNLINK(ads->timew,qu); |
| 68 | adns__query_fail(qu,adns_s_allservfail); |
| 69 | } |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | static void tcp_connected(adns_state ads, struct timeval now) { |
| 74 | adns_query qu, nqu; |
| 75 | |
| 76 | adns__debug(ads,ads->tcpserver,0,"TCP connected"); |
| 77 | ads->tcpstate= server_ok; |
| 78 | for (qu= ads->timew.head; qu; qu= nqu) { |
| 79 | nqu= qu->next; |
| 80 | if (qu->state == query_udp) continue; |
| 81 | assert (qu->state == query_tcpwait); |
| 82 | adns__query_tcp(qu,now); |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | void adns__tcp_tryconnect(adns_state ads, struct timeval now) { |
| 87 | int r, fd, tries; |
| 88 | struct sockaddr_in addr; |
| 89 | struct protoent *proto; |
| 90 | |
| 91 | for (tries=0; tries<ads->nservers; tries++) { |
| 92 | if (ads->tcpstate == server_connecting || ads->tcpstate == server_ok) return; |
| 93 | assert(ads->tcpstate == server_disconnected); |
| 94 | assert(!ads->tcpsend.used); |
| 95 | assert(!ads->tcprecv.used); |
| 96 | |
| 97 | proto= getprotobyname("tcp"); |
| 98 | if (!proto) { adns__diag(ads,-1,0,"unable to find protocol no. for TCP !"); return; } |
| 99 | fd= socket(AF_INET,SOCK_STREAM,proto->p_proto); |
| 100 | if (fd<0) { |
| 101 | adns__diag(ads,-1,0,"cannot create TCP socket: %s",strerror(errno)); |
| 102 | return; |
| 103 | } |
| 104 | r= adns__setnonblock(ads,fd); |
| 105 | if (r) { |
| 106 | adns__diag(ads,-1,0,"cannot make TCP socket nonblocking: %s",strerror(r)); |
| 107 | close(fd); |
| 108 | return; |
| 109 | } |
| 110 | memset(&addr,0,sizeof(addr)); |
| 111 | addr.sin_family= AF_INET; |
| 112 | addr.sin_port= htons(DNS_PORT); |
| 113 | addr.sin_addr= ads->servers[ads->tcpserver].addr; |
| 114 | r= connect(fd,(const struct sockaddr*)&addr,sizeof(addr)); |
| 115 | ads->tcpsocket= fd; |
| 116 | ads->tcpstate= server_connecting; |
| 117 | if (r==0) { tcp_connected(ads,now); continue; } |
| 118 | if (errno == EWOULDBLOCK || errno == EINPROGRESS) return; |
| 119 | adns__tcp_broken(ads,"connect",strerror(errno)); |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | /* Timeout handling functions. */ |
| 124 | |
| 125 | void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io, |
| 126 | struct timeval *tv_buf) { |
| 127 | const struct timeval *now; |
| 128 | int r; |
| 129 | |
| 130 | now= *now_io; |
| 131 | if (now) return; |
| 132 | r= gettimeofday(tv_buf,0); if (!r) { *now_io= tv_buf; return; } |
| 133 | adns__diag(ads,-1,0,"gettimeofday failed: %s",strerror(errno)); |
| 134 | adns_globalsystemfailure(ads); |
| 135 | return; |
| 136 | } |
| 137 | |
| 138 | static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf, |
| 139 | struct timeval maxto) { |
| 140 | struct timeval *rbuf; |
| 141 | |
| 142 | if (!tv_io) return; |
| 143 | rbuf= *tv_io; |
| 144 | if (!rbuf) { |
| 145 | *tvbuf= maxto; *tv_io= tvbuf; |
| 146 | } else { |
| 147 | if (timercmp(rbuf,&maxto,>)) *rbuf= maxto; |
| 148 | } |
| 149 | /*fprintf(stderr,"inter_maxto maxto=%ld.%06ld result=%ld.%06ld\n", |
| 150 | maxto.tv_sec,maxto.tv_usec,(**tv_io).tv_sec,(**tv_io).tv_usec);*/ |
| 151 | } |
| 152 | |
| 153 | static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf, |
| 154 | struct timeval now, struct timeval maxtime) { |
| 155 | ldiv_t dr; |
| 156 | |
| 157 | /*fprintf(stderr,"inter_maxtoabs now=%ld.%06ld maxtime=%ld.%06ld\n", |
| 158 | now.tv_sec,now.tv_usec,maxtime.tv_sec,maxtime.tv_usec);*/ |
| 159 | if (!tv_io) return; |
| 160 | maxtime.tv_sec -= (now.tv_sec+2); |
| 161 | maxtime.tv_usec -= (now.tv_usec-2000000); |
| 162 | dr= ldiv(maxtime.tv_usec,1000000); |
| 163 | maxtime.tv_sec += dr.quot; |
| 164 | maxtime.tv_usec -= dr.quot*1000000; |
| 165 | if (maxtime.tv_sec<0) timerclear(&maxtime); |
| 166 | inter_maxto(tv_io,tvbuf,maxtime); |
| 167 | } |
| 168 | |
| 169 | void adns__timeouts(adns_state ads, int act, |
| 170 | struct timeval **tv_io, struct timeval *tvbuf, |
| 171 | struct timeval now) { |
| 172 | adns_query qu, nqu; |
| 173 | |
| 174 | for (qu= ads->timew.head; qu; qu= nqu) { |
| 175 | nqu= qu->next; |
| 176 | if (timercmp(&now,&qu->timeout,<=)) { |
| 177 | if (!tv_io) continue; |
| 178 | inter_maxtoabs(tv_io,tvbuf,now,qu->timeout); |
| 179 | } else { |
| 180 | if (!act) continue; |
| 181 | LIST_UNLINK(ads->timew,qu); |
| 182 | if (qu->state != query_udp) { |
| 183 | adns__query_fail(qu,adns_s_timeout); |
| 184 | } else { |
| 185 | adns__query_udp(qu,now); |
| 186 | } |
| 187 | nqu= ads->timew.head; |
| 188 | } |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | void adns_firsttimeout(adns_state ads, |
| 193 | struct timeval **tv_io, struct timeval *tvbuf, |
| 194 | struct timeval now) { |
| 195 | adns__timeouts(ads, 0, tv_io,tvbuf, now); |
| 196 | } |
| 197 | |
| 198 | void adns_processtimeouts(adns_state ads, const struct timeval *now) { |
| 199 | struct timeval tv_buf; |
| 200 | |
| 201 | adns__must_gettimeofday(ads,&now,&tv_buf); if (!now) return; |
| 202 | adns__timeouts(ads, 1, 0,0, *now); |
| 203 | } |
| 204 | |
| 205 | /* fd handling functions. These are the top-level of the real work of |
| 206 | * reception and often transmission. |
| 207 | */ |
| 208 | |
| 209 | int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]) { |
| 210 | /* Returns the number of entries filled in. Always zeroes revents. */ |
| 211 | |
| 212 | assert(MAX_POLLFDS==2); |
| 213 | |
| 214 | pollfds_buf[0].fd= ads->udpsocket; |
| 215 | pollfds_buf[0].events= POLLIN; |
| 216 | pollfds_buf[0].revents= 0; |
| 217 | |
| 218 | switch (ads->tcpstate) { |
| 219 | case server_disconnected: |
| 220 | return 1; |
| 221 | case server_connecting: |
| 222 | pollfds_buf[1].events= POLLOUT; |
| 223 | break; |
| 224 | case server_ok: |
| 225 | pollfds_buf[1].events= ads->tcpsend.used ? POLLIN|POLLOUT|POLLPRI : POLLIN|POLLPRI; |
| 226 | break; |
| 227 | default: |
| 228 | abort(); |
| 229 | } |
| 230 | pollfds_buf[1].fd= ads->tcpsocket; |
| 231 | return 2; |
| 232 | } |
| 233 | |
| 234 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now) { |
| 235 | int skip, want, dgramlen, r, udpaddrlen, serv; |
| 236 | byte udpbuf[DNS_MAXUDP]; |
| 237 | struct sockaddr_in udpaddr; |
| 238 | |
| 239 | switch (ads->tcpstate) { |
| 240 | case server_disconnected: |
| 241 | case server_connecting: |
| 242 | break; |
| 243 | case server_ok: |
| 244 | if (fd != ads->tcpsocket) break; |
| 245 | skip= 0; |
| 246 | for (;;) { |
| 247 | if (ads->tcprecv.used<skip+2) { |
| 248 | want= 2; |
| 249 | } else { |
| 250 | dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1]; |
| 251 | if (ads->tcprecv.used<skip+2+dgramlen) { |
| 252 | want= 2+dgramlen; |
| 253 | } else { |
| 254 | adns__procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,ads->tcpserver,*now); |
| 255 | skip+= 2+dgramlen; continue; |
| 256 | } |
| 257 | } |
| 258 | ads->tcprecv.used -= skip; |
| 259 | memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used); |
| 260 | skip= 0; |
| 261 | if (!adns__vbuf_ensure(&ads->tcprecv,want)) return ENOMEM; |
| 262 | assert(ads->tcprecv.used <= ads->tcprecv.avail); |
| 263 | if (ads->tcprecv.used == ads->tcprecv.avail) continue; |
| 264 | r= read(ads->tcpsocket, |
| 265 | ads->tcprecv.buf+ads->tcprecv.used, |
| 266 | ads->tcprecv.avail-ads->tcprecv.used); |
| 267 | if (r>0) { |
| 268 | ads->tcprecv.used+= r; |
| 269 | } else { |
| 270 | if (r) { |
| 271 | if (errno==EAGAIN || errno==EWOULDBLOCK) return 0; |
| 272 | if (errno==EINTR) continue; |
| 273 | if (errno_resources(errno)) return errno; |
| 274 | } |
| 275 | adns__tcp_broken(ads,"read",r?strerror(errno):"closed"); |
| 276 | return 0; |
| 277 | } |
| 278 | } /* never reached */ |
| 279 | default: |
| 280 | abort(); |
| 281 | } |
| 282 | if (fd == ads->udpsocket) { |
| 283 | for (;;) { |
| 284 | udpaddrlen= sizeof(udpaddr); |
| 285 | r= recvfrom(ads->udpsocket,udpbuf,sizeof(udpbuf),0, |
| 286 | (struct sockaddr*)&udpaddr,&udpaddrlen); |
| 287 | if (r<0) { |
| 288 | if (errno == EAGAIN || errno == EWOULDBLOCK) return 0; |
| 289 | if (errno == EINTR) continue; |
| 290 | if (errno_resources(errno)) return errno; |
| 291 | adns__warn(ads,-1,0,"datagram receive error: %s",strerror(errno)); |
| 292 | return 0; |
| 293 | } |
| 294 | if (udpaddrlen != sizeof(udpaddr)) { |
| 295 | adns__diag(ads,-1,0,"datagram received with wrong address length %d" |
| 296 | " (expected %d)", udpaddrlen,sizeof(udpaddr)); |
| 297 | continue; |
| 298 | } |
| 299 | if (udpaddr.sin_family != AF_INET) { |
| 300 | adns__diag(ads,-1,0,"datagram received with wrong protocol family" |
| 301 | " %u (expected %u)",udpaddr.sin_family,AF_INET); |
| 302 | continue; |
| 303 | } |
| 304 | if (ntohs(udpaddr.sin_port) != DNS_PORT) { |
| 305 | adns__diag(ads,-1,0,"datagram received from wrong port %u (expected %u)", |
| 306 | ntohs(udpaddr.sin_port),DNS_PORT); |
| 307 | continue; |
| 308 | } |
| 309 | for (serv= 0; |
| 310 | serv < ads->nservers && |
| 311 | ads->servers[serv].addr.s_addr != udpaddr.sin_addr.s_addr; |
| 312 | serv++); |
| 313 | if (serv >= ads->nservers) { |
| 314 | adns__warn(ads,-1,0,"datagram received from unknown nameserver %s", |
| 315 | inet_ntoa(udpaddr.sin_addr)); |
| 316 | continue; |
| 317 | } |
| 318 | adns__procdgram(ads,udpbuf,r,serv,*now); |
| 319 | } |
| 320 | } |
| 321 | return 0; |
| 322 | } |
| 323 | |
| 324 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) { |
| 325 | int r; |
| 326 | |
| 327 | switch (ads->tcpstate) { |
| 328 | case server_disconnected: |
| 329 | break; |
| 330 | case server_connecting: |
| 331 | if (fd != ads->tcpsocket) break; |
| 332 | assert(ads->tcprecv.used==0); |
| 333 | for (;;) { |
| 334 | if (!adns__vbuf_ensure(&ads->tcprecv,1)) return ENOMEM; |
| 335 | r= read(ads->tcpsocket,&ads->tcprecv.buf,1); |
| 336 | if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) { |
| 337 | tcp_connected(ads,*now); |
| 338 | return 0; |
| 339 | } |
| 340 | if (r>0) { |
| 341 | adns__tcp_broken(ads,"connect/read","sent data before first request"); |
| 342 | return 0; |
| 343 | } |
| 344 | if (errno==EINTR) continue; |
| 345 | if (errno_resources(errno)) return errno; |
| 346 | adns__tcp_broken(ads,"connect/read",strerror(errno)); |
| 347 | return 0; |
| 348 | } /* not reached */ |
| 349 | case server_ok: |
| 350 | if (!(ads->tcpsend.used && fd == ads->tcpsocket)) break; |
| 351 | for (;;) { |
| 352 | adns__sigpipe_protect(ads); |
| 353 | r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used); |
| 354 | adns__sigpipe_unprotect(ads); |
| 355 | if (r<0) { |
| 356 | if (errno==EINTR) continue; |
| 357 | if (errno==EAGAIN || errno==EWOULDBLOCK) return 0; |
| 358 | if (errno_resources(errno)) return errno; |
| 359 | adns__tcp_broken(ads,"write",strerror(errno)); |
| 360 | return 0; |
| 361 | } else if (r>0) { |
| 362 | ads->tcpsend.used -= r; |
| 363 | memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used); |
| 364 | } |
| 365 | } /* not reached */ |
| 366 | default: |
| 367 | abort(); |
| 368 | } |
| 369 | return 0; |
| 370 | } |
| 371 | |
| 372 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now) { |
| 373 | switch (ads->tcpstate) { |
| 374 | case server_disconnected: |
| 375 | break; |
| 376 | case server_connecting: |
| 377 | case server_ok: |
| 378 | if (fd != ads->tcpsocket) break; |
| 379 | adns__tcp_broken(ads,"poll/select","exceptional condition detected"); |
| 380 | return 0; |
| 381 | default: |
| 382 | abort(); |
| 383 | } |
| 384 | return 0; |
| 385 | } |
| 386 | |
| 387 | static void fd_event(adns_state ads, int fd, |
| 388 | int revent, int pollflag, |
| 389 | int maxfd, const fd_set *fds, |
| 390 | int (*func)(adns_state, int fd, const struct timeval *now), |
| 391 | struct timeval now, int *r_r) { |
| 392 | int r; |
| 393 | |
| 394 | if (!(revent & pollflag)) return; |
| 395 | if (fds && !(fd<maxfd && FD_ISSET(fd,fds))) return; |
| 396 | r= func(ads,fd,&now); |
| 397 | if (r) { |
| 398 | if (r_r) { |
| 399 | *r_r= r; |
| 400 | } else { |
| 401 | adns__diag(ads,-1,0,"process fd failed after select: %s",strerror(errno)); |
| 402 | adns_globalsystemfailure(ads); |
| 403 | } |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | void adns__fdevents(adns_state ads, |
| 408 | const struct pollfd *pollfds, int npollfds, |
| 409 | int maxfd, const fd_set *readfds, |
| 410 | const fd_set *writefds, const fd_set *exceptfds, |
| 411 | struct timeval now, int *r_r) { |
| 412 | int i, fd, revents; |
| 413 | |
| 414 | for (i=0; i<npollfds; i++) { |
| 415 | fd= pollfds[i].fd; |
| 416 | if (fd >= maxfd) maxfd= fd+1; |
| 417 | revents= pollfds[i].revents; |
| 418 | fd_event(ads,fd, revents,POLLIN, maxfd,readfds, adns_processreadable,now,r_r); |
| 419 | fd_event(ads,fd, revents,POLLOUT, maxfd,writefds, adns_processwriteable,now,r_r); |
| 420 | fd_event(ads,fd, revents,POLLPRI, maxfd,exceptfds, adns_processexceptional,now,r_r); |
| 421 | } |
| 422 | } |
| 423 | |
| 424 | /* Wrappers for select(2). */ |
| 425 | |
| 426 | void adns_beforeselect(adns_state ads, int *maxfd_io, fd_set *readfds_io, |
| 427 | fd_set *writefds_io, fd_set *exceptfds_io, |
| 428 | struct timeval **tv_mod, struct timeval *tv_tobuf, |
| 429 | const struct timeval *now) { |
| 430 | struct timeval tv_nowbuf; |
| 431 | struct pollfd pollfds[MAX_POLLFDS]; |
| 432 | int i, fd, maxfd, npollfds; |
| 433 | |
| 434 | if (tv_mod && (!*tv_mod || (*tv_mod)->tv_sec || (*tv_mod)->tv_usec)) { |
| 435 | /* The caller is planning to sleep. */ |
| 436 | adns__must_gettimeofday(ads,&now,&tv_nowbuf); |
| 437 | if (!now) return; |
| 438 | adns__timeouts(ads, 1, tv_mod,tv_tobuf, *now); |
| 439 | } |
| 440 | |
| 441 | npollfds= adns__pollfds(ads,pollfds); |
| 442 | maxfd= *maxfd_io; |
| 443 | for (i=0; i<npollfds; i++) { |
| 444 | fd= pollfds[i].fd; |
| 445 | if (fd >= maxfd) maxfd= fd+1; |
| 446 | if (pollfds[i].events & POLLIN) FD_SET(fd,readfds_io); |
| 447 | if (pollfds[i].events & POLLOUT) FD_SET(fd,writefds_io); |
| 448 | if (pollfds[i].events & POLLPRI) FD_SET(fd,exceptfds_io); |
| 449 | } |
| 450 | *maxfd_io= maxfd; |
| 451 | } |
| 452 | |
| 453 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
| 454 | const fd_set *writefds, const fd_set *exceptfds, |
| 455 | const struct timeval *now) { |
| 456 | struct timeval tv_buf; |
| 457 | struct pollfd pollfds[MAX_POLLFDS]; |
| 458 | int npollfds, i; |
| 459 | |
| 460 | adns__must_gettimeofday(ads,&now,&tv_buf); |
| 461 | if (!now) return; |
| 462 | adns_processtimeouts(ads,now); |
| 463 | |
| 464 | npollfds= adns__pollfds(ads,pollfds); |
| 465 | for (i=0; i<npollfds; i++) pollfds[i].revents= POLLIN|POLLOUT|POLLPRI; |
| 466 | adns__fdevents(ads, |
| 467 | pollfds,npollfds, |
| 468 | maxfd,readfds,writefds,exceptfds, |
| 469 | *now, 0); |
| 470 | } |
| 471 | |
| 472 | /* General helpful functions. */ |
| 473 | |
| 474 | void adns_globalsystemfailure(adns_state ads) { |
| 475 | while (ads->timew.head) { |
| 476 | adns__query_fail(ads->timew.head, adns_s_systemfail); |
| 477 | } |
| 478 | |
| 479 | switch (ads->tcpstate) { |
| 480 | case server_connecting: |
| 481 | case server_ok: |
| 482 | adns__tcp_closenext(ads); |
| 483 | break; |
| 484 | case server_disconnected: |
| 485 | break; |
| 486 | default: |
| 487 | abort(); |
| 488 | } |
| 489 | } |
| 490 | |
| 491 | int adns_processany(adns_state ads) { |
| 492 | int r; |
| 493 | struct timeval now; |
| 494 | struct pollfd pollfds[MAX_POLLFDS]; |
| 495 | int npollfds; |
| 496 | |
| 497 | r= gettimeofday(&now,0); |
| 498 | if (!r) adns_processtimeouts(ads,&now); |
| 499 | |
| 500 | npollfds= adns__pollfds(ads,pollfds); |
| 501 | adns__fdevents(ads, |
| 502 | pollfds,npollfds, |
| 503 | 0,0,0,0, |
| 504 | now,&r); |
| 505 | return r; |
| 506 | } |
| 507 | |
| 508 | void adns__autosys(adns_state ads, struct timeval now) { |
| 509 | if (ads->iflags & adns_if_noautosys) return; |
| 510 | adns_processany(ads); |
| 511 | } |
| 512 | |
| 513 | static int internal_check(adns_state ads, |
| 514 | adns_query *query_io, |
| 515 | adns_answer **answer, |
| 516 | void **context_r) { |
| 517 | adns_query qu; |
| 518 | |
| 519 | qu= *query_io; |
| 520 | if (!qu) { |
| 521 | if (!ads->output.head) return EWOULDBLOCK; |
| 522 | qu= ads->output.head; |
| 523 | } else { |
| 524 | if (qu->id>=0) return EWOULDBLOCK; |
| 525 | } |
| 526 | LIST_UNLINK(ads->output,qu); |
| 527 | *answer= qu->answer; |
| 528 | if (context_r) *context_r= qu->ctx.ext; |
| 529 | *query_io= qu; |
| 530 | free(qu); |
| 531 | return 0; |
| 532 | } |
| 533 | |
| 534 | int adns_wait(adns_state ads, |
| 535 | adns_query *query_io, |
| 536 | adns_answer **answer_r, |
| 537 | void **context_r) { |
| 538 | int r, maxfd, rsel; |
| 539 | fd_set readfds, writefds, exceptfds; |
| 540 | struct timeval tvbuf, *tvp; |
| 541 | |
| 542 | for (;;) { |
| 543 | r= internal_check(ads,query_io,answer_r,context_r); |
| 544 | if (r != EWOULDBLOCK) return r; |
| 545 | maxfd= 0; tvp= 0; |
| 546 | FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); |
| 547 | adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf,0); |
| 548 | rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp); |
| 549 | if (rsel==-1) { |
| 550 | if (errno == EINTR) { |
| 551 | if (ads->iflags & adns_if_eintr) return EINTR; |
| 552 | } else { |
| 553 | adns__diag(ads,-1,0,"select failed in wait: %s",strerror(errno)); |
| 554 | adns_globalsystemfailure(ads); |
| 555 | } |
| 556 | } else { |
| 557 | assert(rsel >= 0); |
| 558 | adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,0); |
| 559 | } |
| 560 | } |
| 561 | } |
| 562 | |
| 563 | int adns_check(adns_state ads, |
| 564 | adns_query *query_io, |
| 565 | adns_answer **answer_r, |
| 566 | void **context_r) { |
| 567 | struct timeval now; |
| 568 | int r; |
| 569 | |
| 570 | r= gettimeofday(&now,0); |
| 571 | if (!r) adns__autosys(ads,now); |
| 572 | |
| 573 | return internal_check(ads,query_io,answer_r,context_r); |
| 574 | } |