mirror of https://github.com/c-ares/c-ares.git
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Daniel Stenberg
19 years ago
parent
cb2a75dece
commit
8d63eb75a9
4 changed files with 160 additions and 26 deletions
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.\" $Id$ |
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.\" |
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.\" Copyright 1998 by Daniel Stenberg |
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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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.TH ARES_GETSOCK 3 "22 December 2005" |
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.SH NAME |
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ares_getsock \- get file descriptors to wait on |
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.SH SYNOPSIS |
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.nf |
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.B #include <ares.h> |
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.PP |
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.B int ares_getsock(ares_channel \fIchannel\fP, int *\fIsocks\fP, |
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.B int \fInumsocks\fP); |
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.fi |
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.SH DESCRIPTION |
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The |
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.B ares_getsock |
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function retrieves the set of file descriptors which the calling |
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application should wait on for reading and/or writing for the |
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processing of name service queries pending on the name service channel |
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identified by |
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.IR channel . |
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File descriptors will be set in the integer array pointed to by |
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\fIsocks\fP. |
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\fInumsocks\fP is the size of the given array in number of ints. |
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|
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This function can only return information about up to 16 sockets. If more are |
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in use (however unlikely that is), they are simply not reported back. |
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.SH RETURN VALUES |
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\fBares_getsock\fP returns a bitmask for what actions to wait for on the |
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different sockets. The ares.h header file provides these convenience macros to |
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extract the information appropriately: |
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|
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.nf |
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#define ARES_GETSOCK_MAXNUM 16 /* ares_getsock() can return info about |
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this many sockets */ |
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#define ARES_GETSOCK_READABLE(bits,num) (bits & (1<< (num))) |
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#define ARES_GETSOCK_WRITABLE(bits,num) (bits & (1 << ((num) + \ |
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ARES_GETSOCK_MAXNUM))) |
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.fi |
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.SH SEE ALSO |
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.BR ares_timeout (3), |
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.BR ares_fds (3), |
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.BR ares_process (3) |
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@ -0,0 +1,71 @@ |
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/* $Id$ */ |
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|
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/* Copyright 2005 by Daniel Stenberg.
|
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* |
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* Permission to use, copy, modify, and distribute this software and its |
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* documentation for any purpose and without fee is hereby granted, provided |
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* that the above copyright notice appear in all copies and that both that |
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* copyright 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 advertising or |
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* publicity pertaining to distribution of the software without specific, |
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* written prior permission. M.I.T. makes no representations about the |
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* suitability of 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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|
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#include "setup.h" |
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#include <sys/types.h> |
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|
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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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|
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#include "ares.h" |
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#include "ares_private.h" |
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|
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int ares_getsock(ares_channel channel, |
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int *s, |
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int numsocks) /* size of the 'socks' array */ |
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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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int sockindex=0; |
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int bitmap = 0; |
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unsigned int setbits = 0xffffffff; |
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|
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ares_socket_t *socks = (ares_socket_t *)s; |
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|
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/* No queries, no file descriptors. */ |
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if (!channel->queries) |
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return 0; |
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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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if (server->udp_socket != ARES_SOCKET_BAD) |
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{ |
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if(sockindex >= numsocks) |
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break; |
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socks[sockindex] = server->udp_socket; |
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bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex); |
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sockindex++; |
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} |
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if (server->tcp_socket != ARES_SOCKET_BAD) |
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{ |
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if(sockindex >= numsocks) |
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break; |
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socks[sockindex] = server->tcp_socket; |
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bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex); |
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sockindex++; |
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|
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if (server->qhead) { |
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/* then the tcp socket is also writable! */ |
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bitmap |= ARES_GETSOCK_WRITABLE(setbits, sockindex-1); |
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} |
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|
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} |
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} |
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return (int)nfds; |
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} |
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