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) 1997-2000,2003,2006,2014-2016  Ian Jackson
   8  *    Copyright (C) 2014  Mark Wooding
   9  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  10  *    Copyright (C) 1991 Massachusetts Institute of Technology
  11  *  (See the file INSTALL for full details.)
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; either version 3, or (at your option)
  16  *  any later version.
  17  *
  18  *  This program is distributed in the hope that it will be useful,
  19  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *  GNU General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License
  24  *  along with this program; if not, write to the Free Software Foundation.
  25  */
  26
  27 #include <limits.h>
  28 #include <string.h>
  29
  30 #include "internal.h"
  31
  32 #ifdef HAVE_POLL
  33
  34 int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io,
  35                     int *timeout_io, const struct timeval *now) {
  36   struct timeval tv_nowbuf, tv_tobuf, *tv_to;
  37   int space, found, timeout_ms, r;
  38   struct pollfd fds_tmp[MAX_POLLFDS];
  39
  40   adns__consistency(ads,0,cc_entex);
  41
  42   if (timeout_io) {
  43     adns__must_gettimeofday(ads,&now,&tv_nowbuf);
  44     if (!now) { *nfds_io= 0; r= 0; goto xit; }
  45
  46     timeout_ms= *timeout_io;
  47     if (timeout_ms == -1) {
  48       tv_to= 0;
  49     } else {
  50       tv_tobuf.tv_sec= timeout_ms / 1000;
  51       tv_tobuf.tv_usec= (timeout_ms % 1000)*1000;
  52       tv_to= &tv_tobuf;
  53     }
  54
  55     adns__timeouts(ads, 0, &tv_to,&tv_tobuf, *now);
  56
  57     if (tv_to) {
  58       assert(tv_to == &tv_tobuf);
  59       timeout_ms= (tv_tobuf.tv_usec+999)/1000;
  60       assert(tv_tobuf.tv_sec < (INT_MAX-timeout_ms)/1000);
  61       timeout_ms += tv_tobuf.tv_sec*1000;
  62     } else {
  63       timeout_ms= -1;
  64     }
  65     *timeout_io= timeout_ms;
  66   }
  67
  68   space= *nfds_io;
  69   if (space >= MAX_POLLFDS) {
  70     found= adns__pollfds(ads,fds);
  71     *nfds_io= found;
  72   } else {
  73     found= adns__pollfds(ads,fds_tmp);
  74     *nfds_io= found;
  75     if (space < found) { r= ERANGE; goto xit; }
  76     memcpy(fds,fds_tmp,sizeof(struct pollfd)*found);
  77   }
  78   r= 0;
  79 xit:
  80   adns__returning(ads,0);
  81   return r;
  82 }
  83
  84 void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds,
  85                     const struct timeval *now) {
  86   struct timeval tv_buf;
  87
  88   adns__consistency(ads,0,cc_entex);
  89   adns__must_gettimeofday(ads,&now,&tv_buf);
  90   if (now) {
  91     adns__timeouts(ads, 1, 0,0, *now);
  92     adns__fdevents(ads, fds,nfds, 0,0,0,0, *now,0);
  93   }
  94   adns__returning(ads,0);
  95 }
  96
  97 int adns_wait_poll(adns_state ads,
  98                    adns_query *query_io,
  99                    adns_answer **answer_r,
 100                    void **context_r) {
 101   int r, nfds, to;
 102   struct pollfd fds[MAX_POLLFDS];
 103
 104   adns__consistency(ads,0,cc_entex);
 105
 106   for (;;) {
 107     r= adns__internal_check(ads,query_io,answer_r,context_r);
 108     if (r != EAGAIN) goto xit;
 109     nfds= MAX_POLLFDS; to= -1;
 110     adns_beforepoll(ads,fds,&nfds,&to,0);
 111     r= poll(fds,nfds,to);
 112     if (r == -1) {
 113       if (errno == EINTR) {
 114         if (ads->iflags & adns_if_eintr) { r= EINTR; goto xit; }
 115       } else {
 116         adns__diag(ads,-1,0,"poll failed in wait: %s",strerror(errno));
 117         adns_globalsystemfailure(ads);
 118       }
 119     } else {
 120       assert(r >= 0);
 121       adns_afterpoll(ads,fds,nfds,0);
 122     }
 123   }
 124
 125  xit:
 126   adns__returning(ads,0);
 127   return r;
 128 }
 129
 130 #endif