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1 
2 /* Copyright (C) 2005 - 2010, Daniel Stenberg
3  *
4  * Permission to use, copy, modify, and distribute this software and its
5  * documentation for any purpose and without fee is hereby granted, provided
6  * that the above copyright notice appear in all copies and that both that
7  * copyright notice and this permission notice appear in supporting
8  * documentation, and that the name of M.I.T. not be used in advertising or
9  * publicity pertaining to distribution of the software without specific,
10  * written prior permission.  M.I.T. makes no representations about the
11  * suitability of this software for any purpose.  It is provided "as is"
12  * without express or implied warranty.
13  */
14 
15 #include "ares_setup.h"
16 
17 #include "ares.h"
18 #include "ares_private.h"
19 
ares_getsock(ares_channel channel,ares_socket_t * socks,int numsocks)20 int ares_getsock(ares_channel channel,
21                  ares_socket_t *socks,
22                  int numsocks) /* size of the 'socks' array */
23 {
24   struct server_state *server;
25   int i;
26   int sockindex=0;
27   int bitmap = 0;
28   unsigned int setbits = 0xffffffff;
29 
30   /* Are there any active queries? */
31   int active_queries = !ares__is_list_empty(&(channel->all_queries));
32 
33   for (i = 0; i < channel->nservers; i++)
34     {
35       server = &channel->servers[i];
36       /* We only need to register interest in UDP sockets if we have
37        * outstanding queries.
38        */
39       if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
40         {
41           if(sockindex >= numsocks || sockindex >= ARES_GETSOCK_MAXNUM)
42             break;
43           socks[sockindex] = server->udp_socket;
44           bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex);
45           sockindex++;
46         }
47       /* We always register for TCP events, because we want to know
48        * when the other side closes the connection, so we don't waste
49        * time trying to use a broken connection.
50        */
51       if (server->tcp_socket != ARES_SOCKET_BAD)
52        {
53          if(sockindex >= numsocks || sockindex >= ARES_GETSOCK_MAXNUM)
54            break;
55          socks[sockindex] = server->tcp_socket;
56          bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex);
57 
58          if (server->qhead && active_queries)
59            /* then the tcp socket is also writable! */
60            bitmap |= ARES_GETSOCK_WRITABLE(setbits, sockindex);
61 
62          sockindex++;
63        }
64     }
65   return bitmap;
66 }
67