79 строки
2.4 KiB
C
79 строки
2.4 KiB
C
/* $Id$ */
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#include <time.h>
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#include "ares.h"
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#include "ares_private.h"
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/* WARNING: Beware that this is linear in the number of outstanding
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* requests! You are probably far better off just calling ares_process()
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* once per second, rather than calling ares_timeout() to figure out
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* when to next call ares_process().
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*/
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struct timeval *ares_timeout(ares_channel channel, struct timeval *maxtv,
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struct timeval *tvbuf)
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{
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struct query *query;
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struct list_node* list_head;
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struct list_node* list_node;
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time_t now;
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time_t offset, min_offset; /* these use time_t since some 32 bit systems
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still use 64 bit time_t! (like VS2005) */
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/* No queries, no timeout (and no fetch of the current time). */
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if (ares__is_list_empty(&(channel->all_queries)))
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return maxtv;
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/* Find the minimum timeout for the current set of queries. */
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time(&now);
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min_offset = -1;
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list_head = &(channel->all_queries);
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for (list_node = list_head->next; list_node != list_head;
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list_node = list_node->next)
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{
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query = list_node->data;
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if (query->timeout == 0)
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continue;
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offset = query->timeout - now;
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if (offset < 0)
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offset = 0;
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if (min_offset == -1 || offset < min_offset)
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min_offset = offset;
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}
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/* If we found a minimum timeout and it's sooner than the one
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* specified in maxtv (if any), return it. Otherwise go with
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* maxtv.
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*/
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if (min_offset != -1 && (!maxtv || min_offset <= maxtv->tv_sec))
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{
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tvbuf->tv_sec = (long)min_offset;
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tvbuf->tv_usec = 0;
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return tvbuf;
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}
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else
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return maxtv;
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}
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