60 lines
1.9 KiB
C
60 lines
1.9 KiB
C
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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 "ares_setup.h"
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#include "ares.h"
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#include "ares_nowarn.h"
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#include "ares_private.h"
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int ares_fds(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
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{
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struct server_state *server;
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ares_socket_t nfds;
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int i;
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/* Are there any active queries? */
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int active_queries = !ares__is_list_empty(&(channel->all_queries));
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nfds = 0;
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for (i = 0; i < channel->nservers; i++)
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{
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server = &channel->servers[i];
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/* We only need to register interest in UDP sockets if we have
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* outstanding queries.
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*/
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if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
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{
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FD_SET(server->udp_socket, read_fds);
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if (server->udp_socket >= nfds)
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nfds = server->udp_socket + 1;
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}
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/* We always register for TCP events, because we want to know
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* when the other side closes the connection, so we don't waste
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* time trying to use a broken connection.
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*/
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if (server->tcp_socket != ARES_SOCKET_BAD)
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{
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FD_SET(server->tcp_socket, read_fds);
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if (server->qhead)
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FD_SET(server->tcp_socket, write_fds);
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if (server->tcp_socket >= nfds)
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nfds = server->tcp_socket + 1;
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}
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}
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return (int)nfds;
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}
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