mdw@git.distorted.org.uk Git - adns/blob - src/poll.c

   1 /*
   2  * poll.c
   3  * - wrappers for poll(2)
   4  */
   5 /*
   6  *  This file is part of adns, which is
   7  *    Copyright (C) 1997-2000,2003,2006,2014  Ian Jackson
   8  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
   9  *    Copyright (C) 1991 Massachusetts Institute of Technology
  10  *  (See the file INSTALL for full details.)
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 3, or (at your option)
  15  *  any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software Foundation.
  24  */
  25
  26 #include <limits.h>
  27 #include <string.h>
  28
  29 #include "internal.h"
  30
  31 #ifdef HAVE_POLL
  32
  33 int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io,
  34                     int *timeout_io, const struct timeval *now) {
  35   struct timeval tv_nowbuf, tv_tobuf, *tv_to;
  36   int space, found, timeout_ms, r;
  37   struct pollfd fds_tmp[MAX_POLLFDS];
  38
  39   adns__consistency(ads,0,cc_entex);
  40
  41   if (timeout_io) {
  42     adns__must_gettimeofday(ads,&now,&tv_nowbuf);
  43     if (!now) { *nfds_io= 0; r= 0; goto xit; }
  44
  45     timeout_ms= *timeout_io;
  46     if (timeout_ms == -1) {
  47       tv_to= 0;
  48     } else {
  49       tv_tobuf.tv_sec= timeout_ms / 1000;
  50       tv_tobuf.tv_usec= (timeout_ms % 1000)*1000;
  51       tv_to= &tv_tobuf;
  52     }
  53
  54     adns__timeouts(ads, 0, &tv_to,&tv_tobuf, *now);
  55
  56     if (tv_to) {
  57       assert(tv_to == &tv_tobuf);
  58       timeout_ms= (tv_tobuf.tv_usec+999)/1000;
  59       assert(tv_tobuf.tv_sec < (INT_MAX-timeout_ms)/1000);
  60       timeout_ms += tv_tobuf.tv_sec*1000;
  61     } else {
  62       timeout_ms= -1;
  63     }
  64     *timeout_io= timeout_ms;
  65   }
  66
  67   space= *nfds_io;
  68   if (space >= MAX_POLLFDS) {
  69     found= adns__pollfds(ads,fds);
  70     *nfds_io= found;
  71   } else {
  72     found= adns__pollfds(ads,fds_tmp);
  73     *nfds_io= found;
  74     if (space < found) { r= ERANGE; goto xit; }
  75     memcpy(fds,fds_tmp,sizeof(struct pollfd)*found);
  76   }
  77   r= 0;
  78 xit:
  79   adns__returning(ads,0);
  80   return r;
  81 }
  82
  83 void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds,
  84                     const struct timeval *now) {
  85   struct timeval tv_buf;
  86
  87   adns__consistency(ads,0,cc_entex);
  88   adns__must_gettimeofday(ads,&now,&tv_buf);
  89   if (now) {
  90     adns__timeouts(ads, 1, 0,0, *now);
  91     adns__fdevents(ads, fds,nfds, 0,0,0,0, *now,0);
  92   }
  93   adns__returning(ads,0);
  94 }
  95
  96 int adns_wait_poll(adns_state ads,
  97                    adns_query *query_io,
  98                    adns_answer **answer_r,
  99                    void **context_r) {
 100   int r, nfds, to;
 101   struct pollfd fds[MAX_POLLFDS];
 102
 103   adns__consistency(ads,0,cc_entex);
 104
 105   for (;;) {
 106     r= adns__internal_check(ads,query_io,answer_r,context_r);
 107     if (r != EAGAIN) goto xit;
 108     nfds= MAX_POLLFDS; to= -1;
 109     adns_beforepoll(ads,fds,&nfds,&to,0);
 110     r= poll(fds,nfds,to);
 111     if (r == -1) {
 112       if (errno == EINTR) {
 113         if (ads->iflags & adns_if_eintr) { r= EINTR; goto xit; }
 114       } else {
 115         adns__diag(ads,-1,0,"poll failed in wait: %s",strerror(errno));
 116         adns_globalsystemfailure(ads);
 117       }
 118     } else {
 119       assert(r >= 0);
 120       adns_afterpoll(ads,fds,nfds,0);
 121     }
 122   }
 123
 124  xit:
 125   adns__returning(ads,0);
 126   return r;
 127 }
 128
 129 #endif