mirror of
https://github.com/moparisthebest/curl
synced 2024-11-13 21:15:08 -05:00
f7690db37d
POLLIN, and sets POLLERR without setting POLLIN and POLLOUT. In some libcurl code execution paths this could trigger busy wait loops with high CPU usage until a timeout condition aborted the loop. This fix for Curl_poll adresses the above in a libcurl-wide mode.
508 lines
13 KiB
C
508 lines
13 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 - 2008, 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 http://curl.haxx.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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* $Id$
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***************************************************************************/
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#include "setup.h"
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#ifdef HAVE_SYS_SELECT_H
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#include <sys/select.h>
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#endif
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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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#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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#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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#ifdef MSDOS
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#include <dos.h> /* delay() */
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#endif
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#include <curl/curl.h>
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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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/* Winsock and TPF sockets are not in range [0..FD_SETSIZE-1] */
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#if defined(USE_WINSOCK) || defined(TPF)
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#define VERIFY_SOCK(x) do { } while(0)
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#else
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#define VALID_SOCK(s) (((s) >= 0) && ((s) < FD_SETSIZE))
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#define VERIFY_SOCK(x) do { \
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if(!VALID_SOCK(x)) { \
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SET_SOCKERRNO(EINVAL); \
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return -1; \
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} \
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} while(0)
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#endif
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/* Convenience local macros */
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#define elapsed_ms (int)curlx_tvdiff(curlx_tvnow(), initial_tv)
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#ifdef CURL_ACKNOWLEDGE_EINTR
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#define error_not_EINTR (1)
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#else
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#define error_not_EINTR (error != EINTR)
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#endif
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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_ready() 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 dependant, neither factor is a citical issue
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* for the intended use of this function in the library.
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* On non-DOS and non-Winsock platforms, when compiled with
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* CURL_ACKNOWLEDGE_EINTR defined, EINTR condition is honored
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* and function might exit early without awaiting full timeout,
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* otherwise EINTR will be ignored and full timeout will elapse.
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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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static int wait_ms(int timeout_ms)
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{
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#if !defined(MSDOS) && !defined(USE_WINSOCK)
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#ifndef HAVE_POLL_FINE
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struct timeval pending_tv;
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#endif
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struct timeval initial_tv;
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int pending_ms;
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int error;
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#endif
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int r = 0;
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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(USE_WINSOCK)
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Sleep(timeout_ms);
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#else
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pending_ms = timeout_ms;
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initial_tv = curlx_tvnow();
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do {
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#if defined(HAVE_POLL_FINE)
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r = poll(NULL, 0, pending_ms);
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#else
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pending_tv.tv_sec = pending_ms / 1000;
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pending_tv.tv_usec = (pending_ms % 1000) * 1000;
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r = select(0, NULL, NULL, NULL, &pending_tv);
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#endif /* HAVE_POLL_FINE */
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if(r != -1)
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break;
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error = SOCKERRNO;
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if(error && error_not_EINTR)
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break;
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pending_ms = timeout_ms - elapsed_ms;
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if(pending_ms <= 0)
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break;
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} while(r == -1);
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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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* This is an internal function used for waiting for read or write
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* events on a pair of file descriptors. It uses poll() when a fine
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* 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
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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,
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* unles 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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* When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition
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* is honored and function might exit early without awaiting timeout,
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* otherwise EINTR will be ignored.
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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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* CURL_CSELECT_IN | CURL_CSELECT_OUT | CURL_CSELECT_ERR
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*/
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int Curl_socket_ready(curl_socket_t readfd, curl_socket_t writefd,
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int timeout_ms)
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{
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#ifdef HAVE_POLL_FINE
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struct pollfd pfd[2];
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int num;
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#else
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struct timeval pending_tv;
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struct timeval *ptimeout;
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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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struct timeval initial_tv = {0,0};
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int pending_ms = 0;
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int error;
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int r;
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int ret;
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if((readfd == CURL_SOCKET_BAD) && (writefd == CURL_SOCKET_BAD)) {
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r = wait_ms(timeout_ms);
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return r;
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}
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/* Avoid initial timestamp, avoid curlx_tvnow() 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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if(timeout_ms > 0) {
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pending_ms = timeout_ms;
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initial_tv = curlx_tvnow();
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}
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#ifdef HAVE_POLL_FINE
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num = 0;
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if(readfd != CURL_SOCKET_BAD) {
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pfd[num].fd = readfd;
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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;
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pfd[num].revents = 0;
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num++;
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}
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do {
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if(timeout_ms < 0)
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pending_ms = -1;
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else if(!timeout_ms)
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pending_ms = 0;
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r = poll(pfd, num, pending_ms);
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if(r != -1)
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break;
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error = SOCKERRNO;
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if(error && error_not_EINTR)
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break;
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if(timeout_ms > 0) {
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pending_ms = timeout_ms - elapsed_ms;
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if(pending_ms <= 0)
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break;
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}
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} while(r == -1);
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if(r < 0)
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return -1;
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if(r == 0)
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return 0;
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ret = 0;
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num = 0;
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if(readfd != CURL_SOCKET_BAD) {
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if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
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ret |= CURL_CSELECT_IN;
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if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
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ret |= 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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ret |= CURL_CSELECT_OUT;
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if(pfd[num].revents & (POLLERR|POLLHUP|POLLNVAL))
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ret |= CURL_CSELECT_ERR;
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}
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return ret;
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#else /* HAVE_POLL_FINE */
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FD_ZERO(&fds_err);
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maxfd = (curl_socket_t)-1;
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FD_ZERO(&fds_read);
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if(readfd != CURL_SOCKET_BAD) {
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VERIFY_SOCK(readfd);
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FD_SET(readfd, &fds_read);
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FD_SET(readfd, &fds_err);
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maxfd = readfd;
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}
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FD_ZERO(&fds_write);
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if(writefd != CURL_SOCKET_BAD) {
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VERIFY_SOCK(writefd);
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FD_SET(writefd, &fds_write);
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FD_SET(writefd, &fds_err);
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if(writefd > maxfd)
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maxfd = writefd;
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}
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ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
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do {
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if(timeout_ms > 0) {
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pending_tv.tv_sec = pending_ms / 1000;
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pending_tv.tv_usec = (pending_ms % 1000) * 1000;
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}
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else if(!timeout_ms) {
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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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r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
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if(r != -1)
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break;
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error = SOCKERRNO;
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if(error && error_not_EINTR)
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break;
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if(timeout_ms > 0) {
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pending_ms = timeout_ms - elapsed_ms;
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if(pending_ms <= 0)
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break;
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}
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} while(r == -1);
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if(r < 0)
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return -1;
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if(r == 0)
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return 0;
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ret = 0;
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if(readfd != CURL_SOCKET_BAD) {
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if(FD_ISSET(readfd, &fds_read))
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ret |= CURL_CSELECT_IN;
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if(FD_ISSET(readfd, &fds_err))
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ret |= CURL_CSELECT_ERR;
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}
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if(writefd != CURL_SOCKET_BAD) {
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if(FD_ISSET(writefd, &fds_write))
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ret |= CURL_CSELECT_OUT;
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if(FD_ISSET(writefd, &fds_err))
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ret |= CURL_CSELECT_ERR;
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}
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return ret;
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#endif /* HAVE_POLL_FINE */
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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,
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* unles 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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* When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition
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* is honored and function might exit early without awaiting timeout,
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* otherwise EINTR will be ignored.
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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, int timeout_ms)
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{
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#ifndef HAVE_POLL_FINE
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struct timeval pending_tv;
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struct timeval *ptimeout;
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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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struct timeval initial_tv = {0,0};
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bool fds_none = TRUE;
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unsigned int i;
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int pending_ms = 0;
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int error;
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int r;
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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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r = wait_ms(timeout_ms);
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return r;
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}
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/* Avoid initial timestamp, avoid curlx_tvnow() 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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if(timeout_ms > 0) {
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pending_ms = timeout_ms;
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initial_tv = curlx_tvnow();
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}
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#ifdef HAVE_POLL_FINE
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do {
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if(timeout_ms < 0)
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pending_ms = -1;
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else if(!timeout_ms)
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pending_ms = 0;
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r = poll(ufds, nfds, pending_ms);
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if(r != -1)
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break;
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error = SOCKERRNO;
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if(error && error_not_EINTR)
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break;
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if(timeout_ms > 0) {
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pending_ms = timeout_ms - elapsed_ms;
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if(pending_ms <= 0)
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break;
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}
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} while(r == -1);
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if(r < 0)
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return -1;
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if(r == 0)
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return 0;
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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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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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for (i = 0; i < nfds; i++) {
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ufds[i].revents = 0;
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if(ufds[i].fd == CURL_SOCKET_BAD)
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continue;
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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);
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if(ufds[i].events & (POLLWRNORM|POLLOUT))
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FD_SET(ufds[i].fd, &fds_write);
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if(ufds[i].events & (POLLRDBAND|POLLPRI))
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FD_SET(ufds[i].fd, &fds_err);
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}
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}
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ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
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do {
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if(timeout_ms > 0) {
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pending_tv.tv_sec = pending_ms / 1000;
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pending_tv.tv_usec = (pending_ms % 1000) * 1000;
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}
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else if(!timeout_ms) {
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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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r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
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if(r != -1)
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break;
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error = SOCKERRNO;
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if(error && error_not_EINTR)
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break;
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if(timeout_ms > 0) {
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pending_ms = timeout_ms - elapsed_ms;
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if(pending_ms <= 0)
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break;
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}
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} while(r == -1);
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if(r < 0)
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return -1;
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if(r == 0)
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return 0;
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r = 0;
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for (i = 0; i < nfds; i++) {
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ufds[i].revents = 0;
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if(ufds[i].fd == CURL_SOCKET_BAD)
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continue;
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if(FD_ISSET(ufds[i].fd, &fds_read))
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ufds[i].revents |= POLLIN;
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if(FD_ISSET(ufds[i].fd, &fds_write))
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ufds[i].revents |= POLLOUT;
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if(FD_ISSET(ufds[i].fd, &fds_err))
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ufds[i].revents |= POLLPRI;
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if(ufds[i].revents != 0)
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r++;
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}
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#endif /* HAVE_POLL_FINE */
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return r;
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}
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#ifdef TPF
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/*
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* This is a replacement for select() on the TPF platform.
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* It is used whenever libcurl calls select().
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* The call below to tpf_process_signals() is required because
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* TPF's select calls are not signal interruptible.
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*
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* Return values are the same as select's.
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*/
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int tpf_select_libcurl(int maxfds, fd_set* reads, fd_set* writes,
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fd_set* excepts, struct timeval* tv)
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{
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int rc;
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rc = tpf_select_bsd(maxfds, reads, writes, excepts, tv);
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tpf_process_signals();
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return(rc);
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}
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#endif /* TPF */
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