473 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			473 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
| /***************************************************************************
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|  *                                  _   _ ____  _
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|  *  Project                     ___| | | |  _ \| |
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|  *                             / __| | | | |_) | |
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|  *                            | (__| |_| |  _ <| |___
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|  *                             \___|\___/|_| \_\_____|
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|  *
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|  * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
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|  *
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|  * This software is licensed as described in the file COPYING, which
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|  * you should have received as part of this distribution. The terms
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|  * are also available at https://curl.se/docs/copyright.html.
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|  *
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|  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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|  * copies of the Software, and permit persons to whom the Software is
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|  * furnished to do so, under the terms of the COPYING file.
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|  *
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|  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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|  * KIND, either express or implied.
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|  *
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|  ***************************************************************************/
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| 
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| #include "curl_setup.h"
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| 
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| #include <limits.h>
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| 
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| #ifdef HAVE_SYS_SELECT_H
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| #include <sys/select.h>
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| #elif defined(HAVE_UNISTD_H)
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| #include <unistd.h>
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| #endif
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| 
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| #if !defined(HAVE_SELECT) && !defined(HAVE_POLL_FINE)
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| #error "We can't compile without select() or poll() support."
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| #endif
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| 
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| #if defined(__BEOS__) && !defined(__HAIKU__)
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| /* BeOS has FD_SET defined in socket.h */
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| #include <socket.h>
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| #endif
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| 
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| #ifdef MSDOS
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| #include <dos.h>  /* delay() */
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| #endif
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| 
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| #ifdef __VXWORKS__
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| #include <strings.h>  /* bzero() in FD_SET */
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| #endif
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| 
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| #include <curl/curl.h>
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| 
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| #include "urldata.h"
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| #include "connect.h"
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| #include "select.h"
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| #include "timeval.h"
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| #include "warnless.h"
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| 
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| /*
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|  * Internal function used for waiting a specific amount of ms
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|  * in Curl_socket_check() and Curl_poll() when no file descriptor
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|  * is provided to wait on, just being used to delay execution.
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|  * WinSock select() and poll() timeout mechanisms need a valid
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|  * socket descriptor in a not null file descriptor set to work.
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|  * Waiting indefinitely with this function is not allowed, a
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|  * zero or negative timeout value will return immediately.
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|  * Timeout resolution, accuracy, as well as maximum supported
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|  * value is system dependent, neither factor is a critical issue
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|  * for the intended use of this function in the library.
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|  *
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|  * Return values:
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|  *   -1 = system call error, invalid timeout value, or interrupted
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|  *    0 = specified timeout has elapsed
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|  */
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| int Curl_wait_ms(timediff_t timeout_ms)
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| {
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|   int r = 0;
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| 
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|   if(!timeout_ms)
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|     return 0;
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|   if(timeout_ms < 0) {
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|     SET_SOCKERRNO(EINVAL);
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|     return -1;
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|   }
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| #if defined(MSDOS)
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|   delay(timeout_ms);
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| #elif defined(WIN32)
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|   /* prevent overflow, timeout_ms is typecast to ULONG/DWORD. */
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| #if TIMEDIFF_T_MAX >= ULONG_MAX
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|   if(timeout_ms >= ULONG_MAX)
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|     timeout_ms = ULONG_MAX-1;
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|     /* don't use ULONG_MAX, because that is equal to INFINITE */
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| #endif
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|   Sleep((ULONG)timeout_ms);
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| #else
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| #if defined(HAVE_POLL_FINE)
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|   /* prevent overflow, timeout_ms is typecast to int. */
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| #if TIMEDIFF_T_MAX > INT_MAX
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|   if(timeout_ms > INT_MAX)
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|     timeout_ms = INT_MAX;
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| #endif
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|   r = poll(NULL, 0, (int)timeout_ms);
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| #else
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|   {
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|     struct timeval pending_tv;
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|     timediff_t tv_sec = timeout_ms / 1000;
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|     timediff_t tv_usec = (timeout_ms % 1000) * 1000; /* max=999999 */
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| #ifdef HAVE_SUSECONDS_T
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| #if TIMEDIFF_T_MAX > TIME_T_MAX
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|     /* tv_sec overflow check in case time_t is signed */
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|     if(tv_sec > TIME_T_MAX)
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|       tv_sec = TIME_T_MAX;
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| #endif
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|     pending_tv.tv_sec = (time_t)tv_sec;
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|     pending_tv.tv_usec = (suseconds_t)tv_usec;
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| #else
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| #if TIMEDIFF_T_MAX > INT_MAX
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|     /* tv_sec overflow check in case time_t is signed */
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|     if(tv_sec > INT_MAX)
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|       tv_sec = INT_MAX;
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| #endif
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|     pending_tv.tv_sec = (int)tv_sec;
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|     pending_tv.tv_usec = (int)tv_usec;
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| #endif
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|     r = select(0, NULL, NULL, NULL, &pending_tv);
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|   }
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| #endif /* HAVE_POLL_FINE */
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| #endif /* USE_WINSOCK */
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|   if(r)
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|     r = -1;
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|   return r;
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| }
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| 
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| #ifndef HAVE_POLL_FINE
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| /*
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|  * This is a wrapper around select() to aid in Windows compatibility.
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|  * A negative timeout value makes this function wait indefinitely,
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|  * unless no valid file descriptor is given, when this happens the
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|  * negative timeout is ignored and the function times out immediately.
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|  *
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|  * Return values:
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|  *   -1 = system call error or fd >= FD_SETSIZE
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|  *    0 = timeout
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|  *    N = number of signalled file descriptors
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|  */
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| static int our_select(curl_socket_t maxfd,   /* highest socket number */
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|                       fd_set *fds_read,      /* sockets ready for reading */
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|                       fd_set *fds_write,     /* sockets ready for writing */
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|                       fd_set *fds_err,       /* sockets with errors */
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|                       timediff_t timeout_ms) /* milliseconds to wait */
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| {
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|   struct timeval pending_tv;
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|   struct timeval *ptimeout;
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| 
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| #ifdef USE_WINSOCK
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|   /* WinSock select() can't handle zero events.  See the comment below. */
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|   if((!fds_read || fds_read->fd_count == 0) &&
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|      (!fds_write || fds_write->fd_count == 0) &&
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|      (!fds_err || fds_err->fd_count == 0)) {
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|     /* no sockets, just wait */
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|     return Curl_wait_ms(timeout_ms);
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|   }
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| #endif
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| 
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|   ptimeout = &pending_tv;
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|   if(timeout_ms < 0) {
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|     ptimeout = NULL;
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|   }
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|   else if(timeout_ms > 0) {
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|     timediff_t tv_sec = timeout_ms / 1000;
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|     timediff_t tv_usec = (timeout_ms % 1000) * 1000; /* max=999999 */
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| #ifdef HAVE_SUSECONDS_T
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| #if TIMEDIFF_T_MAX > TIME_T_MAX
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|     /* tv_sec overflow check in case time_t is signed */
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|     if(tv_sec > TIME_T_MAX)
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|       tv_sec = TIME_T_MAX;
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| #endif
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|     pending_tv.tv_sec = (time_t)tv_sec;
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|     pending_tv.tv_usec = (suseconds_t)tv_usec;
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| #elif defined(WIN32) /* maybe also others in the future */
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| #if TIMEDIFF_T_MAX > LONG_MAX
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|     /* tv_sec overflow check on Windows there we know it is long */
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|     if(tv_sec > LONG_MAX)
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|       tv_sec = LONG_MAX;
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| #endif
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|     pending_tv.tv_sec = (long)tv_sec;
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|     pending_tv.tv_usec = (long)tv_usec;
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| #else
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| #if TIMEDIFF_T_MAX > INT_MAX
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|     /* tv_sec overflow check in case time_t is signed */
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|     if(tv_sec > INT_MAX)
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|       tv_sec = INT_MAX;
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| #endif
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|     pending_tv.tv_sec = (int)tv_sec;
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|     pending_tv.tv_usec = (int)tv_usec;
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| #endif
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|   }
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|   else {
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|     pending_tv.tv_sec = 0;
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|     pending_tv.tv_usec = 0;
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|   }
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| 
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| #ifdef USE_WINSOCK
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|   /* WinSock select() must not be called with an fd_set that contains zero
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|     fd flags, or it will return WSAEINVAL.  But, it also can't be called
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|     with no fd_sets at all!  From the documentation:
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| 
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|     Any two of the parameters, readfds, writefds, or exceptfds, can be
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|     given as null. At least one must be non-null, and any non-null
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|     descriptor set must contain at least one handle to a socket.
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| 
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|     It is unclear why WinSock doesn't just handle this for us instead of
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|     calling this an error. Luckily, with WinSock, we can _also_ ask how
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|     many bits are set on an fd_set. So, let's just check it beforehand.
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|   */
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|   return select((int)maxfd + 1,
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|                 fds_read && fds_read->fd_count ? fds_read : NULL,
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|                 fds_write && fds_write->fd_count ? fds_write : NULL,
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|                 fds_err && fds_err->fd_count ? fds_err : NULL, ptimeout);
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| #else
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|   return select((int)maxfd + 1, fds_read, fds_write, fds_err, ptimeout);
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| #endif
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| }
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| 
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| #endif
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| 
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| /*
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|  * Wait for read or write events on a set of file descriptors. It uses poll()
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|  * when a fine poll() is available, in order to avoid limits with FD_SETSIZE,
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|  * otherwise select() is used.  An error is returned if select() is being used
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|  * and a file descriptor is too large for FD_SETSIZE.
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|  *
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|  * A negative timeout value makes this function wait indefinitely,
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|  * unless no valid file descriptor is given, when this happens the
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|  * negative timeout is ignored and the function times out immediately.
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|  *
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|  * Return values:
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|  *   -1 = system call error or fd >= FD_SETSIZE
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|  *    0 = timeout
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|  *    [bitmask] = action as described below
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|  *
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|  * CURL_CSELECT_IN - first socket is readable
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|  * CURL_CSELECT_IN2 - second socket is readable
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|  * CURL_CSELECT_OUT - write socket is writable
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|  * CURL_CSELECT_ERR - an error condition occurred
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|  */
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| int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
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|                       curl_socket_t readfd1,
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|                       curl_socket_t writefd, /* socket to write to */
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|                       timediff_t timeout_ms) /* milliseconds to wait */
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| {
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|   struct pollfd pfd[3];
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|   int num;
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|   int r;
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| 
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|   if((readfd0 == CURL_SOCKET_BAD) && (readfd1 == CURL_SOCKET_BAD) &&
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|      (writefd == CURL_SOCKET_BAD)) {
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|     /* no sockets, just wait */
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|     return Curl_wait_ms(timeout_ms);
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|   }
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| 
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|   /* Avoid initial timestamp, avoid Curl_now() call, when elapsed
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|      time in this function does not need to be measured. This happens
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|      when function is called with a zero timeout or a negative timeout
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|      value indicating a blocking call should be performed. */
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| 
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|   num = 0;
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|   if(readfd0 != CURL_SOCKET_BAD) {
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|     pfd[num].fd = readfd0;
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|     pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
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|     pfd[num].revents = 0;
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|     num++;
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|   }
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|   if(readfd1 != CURL_SOCKET_BAD) {
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|     pfd[num].fd = readfd1;
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|     pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
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|     pfd[num].revents = 0;
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|     num++;
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|   }
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|   if(writefd != CURL_SOCKET_BAD) {
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|     pfd[num].fd = writefd;
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|     pfd[num].events = POLLWRNORM|POLLOUT|POLLPRI;
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|     pfd[num].revents = 0;
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|     num++;
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|   }
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| 
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|   r = Curl_poll(pfd, num, timeout_ms);
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|   if(r <= 0)
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|     return r;
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| 
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|   r = 0;
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|   num = 0;
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|   if(readfd0 != CURL_SOCKET_BAD) {
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|     if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
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|       r |= CURL_CSELECT_IN;
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|     if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
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|       r |= CURL_CSELECT_ERR;
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|     num++;
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|   }
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|   if(readfd1 != CURL_SOCKET_BAD) {
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|     if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
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|       r |= CURL_CSELECT_IN2;
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|     if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
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|       r |= CURL_CSELECT_ERR;
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|     num++;
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|   }
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|   if(writefd != CURL_SOCKET_BAD) {
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|     if(pfd[num].revents & (POLLWRNORM|POLLOUT))
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|       r |= CURL_CSELECT_OUT;
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|     if(pfd[num].revents & (POLLERR|POLLHUP|POLLPRI|POLLNVAL))
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|       r |= CURL_CSELECT_ERR;
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|   }
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| 
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|   return r;
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| }
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| 
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| /*
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|  * This is a wrapper around poll().  If poll() does not exist, then
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|  * select() is used instead.  An error is returned if select() is
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|  * being used and a file descriptor is too large for FD_SETSIZE.
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|  * A negative timeout value makes this function wait indefinitely,
 | |
|  * unless no valid file descriptor is given, when this happens the
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|  * negative timeout is ignored and the function times out immediately.
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|  *
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|  * Return values:
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|  *   -1 = system call error or fd >= FD_SETSIZE
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|  *    0 = timeout
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|  *    N = number of structures with non zero revent fields
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|  */
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| int Curl_poll(struct pollfd ufds[], unsigned int nfds, timediff_t timeout_ms)
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| {
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| #ifdef HAVE_POLL_FINE
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|   int pending_ms;
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| #else
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|   fd_set fds_read;
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|   fd_set fds_write;
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|   fd_set fds_err;
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|   curl_socket_t maxfd;
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| #endif
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|   bool fds_none = TRUE;
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|   unsigned int i;
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|   int r;
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| 
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|   if(ufds) {
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|     for(i = 0; i < nfds; i++) {
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|       if(ufds[i].fd != CURL_SOCKET_BAD) {
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|         fds_none = FALSE;
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|         break;
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|       }
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|     }
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|   }
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|   if(fds_none) {
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|     /* no sockets, just wait */
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|     return Curl_wait_ms(timeout_ms);
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|   }
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| 
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|   /* Avoid initial timestamp, avoid Curl_now() call, when elapsed
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|      time in this function does not need to be measured. This happens
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|      when function is called with a zero timeout or a negative timeout
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|      value indicating a blocking call should be performed. */
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| 
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| #ifdef HAVE_POLL_FINE
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| 
 | |
|   /* prevent overflow, timeout_ms is typecast to int. */
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| #if TIMEDIFF_T_MAX > INT_MAX
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|   if(timeout_ms > INT_MAX)
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|     timeout_ms = INT_MAX;
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| #endif
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|   if(timeout_ms > 0)
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|     pending_ms = (int)timeout_ms;
 | |
|   else if(timeout_ms < 0)
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|     pending_ms = -1;
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|   else
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|     pending_ms = 0;
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|   r = poll(ufds, nfds, pending_ms);
 | |
|   if(r <= 0)
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|     return r;
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| 
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|   for(i = 0; i < nfds; i++) {
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|     if(ufds[i].fd == CURL_SOCKET_BAD)
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|       continue;
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|     if(ufds[i].revents & POLLHUP)
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|       ufds[i].revents |= POLLIN;
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|     if(ufds[i].revents & POLLERR)
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|       ufds[i].revents |= POLLIN|POLLOUT;
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|   }
 | |
| 
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| #else  /* HAVE_POLL_FINE */
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| 
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|   FD_ZERO(&fds_read);
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|   FD_ZERO(&fds_write);
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|   FD_ZERO(&fds_err);
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|   maxfd = (curl_socket_t)-1;
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| 
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|   for(i = 0; i < nfds; i++) {
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|     ufds[i].revents = 0;
 | |
|     if(ufds[i].fd == CURL_SOCKET_BAD)
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|       continue;
 | |
|     VERIFY_SOCK(ufds[i].fd);
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|     if(ufds[i].events & (POLLIN|POLLOUT|POLLPRI|
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|                          POLLRDNORM|POLLWRNORM|POLLRDBAND)) {
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|       if(ufds[i].fd > maxfd)
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|         maxfd = ufds[i].fd;
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|       if(ufds[i].events & (POLLRDNORM|POLLIN))
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|         FD_SET(ufds[i].fd, &fds_read);
 | |
|       if(ufds[i].events & (POLLWRNORM|POLLOUT))
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|         FD_SET(ufds[i].fd, &fds_write);
 | |
|       if(ufds[i].events & (POLLRDBAND|POLLPRI))
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|         FD_SET(ufds[i].fd, &fds_err);
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   /*
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|      Note also that WinSock ignores the first argument, so we don't worry
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|      about the fact that maxfd is computed incorrectly with WinSock (since
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|      curl_socket_t is unsigned in such cases and thus -1 is the largest
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|      value).
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|   */
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|   r = our_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms);
 | |
|   if(r <= 0)
 | |
|     return r;
 | |
| 
 | |
|   r = 0;
 | |
|   for(i = 0; i < nfds; i++) {
 | |
|     ufds[i].revents = 0;
 | |
|     if(ufds[i].fd == CURL_SOCKET_BAD)
 | |
|       continue;
 | |
|     if(FD_ISSET(ufds[i].fd, &fds_read)) {
 | |
|       if(ufds[i].events & POLLRDNORM)
 | |
|         ufds[i].revents |= POLLRDNORM;
 | |
|       if(ufds[i].events & POLLIN)
 | |
|         ufds[i].revents |= POLLIN;
 | |
|     }
 | |
|     if(FD_ISSET(ufds[i].fd, &fds_write)) {
 | |
|       if(ufds[i].events & POLLWRNORM)
 | |
|         ufds[i].revents |= POLLWRNORM;
 | |
|       if(ufds[i].events & POLLOUT)
 | |
|         ufds[i].revents |= POLLOUT;
 | |
|     }
 | |
|     if(FD_ISSET(ufds[i].fd, &fds_err)) {
 | |
|       if(ufds[i].events & POLLRDBAND)
 | |
|         ufds[i].revents |= POLLRDBAND;
 | |
|       if(ufds[i].events & POLLPRI)
 | |
|         ufds[i].revents |= POLLPRI;
 | |
|     }
 | |
|     if(ufds[i].revents)
 | |
|       r++;
 | |
|   }
 | |
| 
 | |
| #endif  /* HAVE_POLL_FINE */
 | |
| 
 | |
|   return r;
 | |
| }
 | |
| 
 | |
| #ifdef TPF
 | |
| /*
 | |
|  * This is a replacement for select() on the TPF platform.
 | |
|  * It is used whenever libcurl calls select().
 | |
|  * The call below to tpf_process_signals() is required because
 | |
|  * TPF's select calls are not signal interruptible.
 | |
|  *
 | |
|  * Return values are the same as select's.
 | |
|  */
 | |
| int tpf_select_libcurl(int maxfds, fd_set *reads, fd_set *writes,
 | |
|                        fd_set *excepts, struct timeval *tv)
 | |
| {
 | |
|    int rc;
 | |
| 
 | |
|    rc = tpf_select_bsd(maxfds, reads, writes, excepts, tv);
 | |
|    tpf_process_signals();
 | |
|    return rc;
 | |
| }
 | |
| #endif /* TPF */
 |