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curl/lib/select.c

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
***************************************************************************/
#include "setup.h"
#include <errno.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifndef HAVE_SELECT
#error "We can't compile without select() support!"
#endif
#ifdef __BEOS__
/* BeOS has FD_SET defined in socket.h */
#include <socket.h>
#endif
#ifdef __MSDOS__
#include <dos.h> /* delay() */
#endif
#include <curl/curl.h>
#include "urldata.h"
#include "connect.h"
#include "select.h"
/* Winsock and TPF sockets are not in range [0..FD_SETSIZE-1] */
#if defined(USE_WINSOCK) || defined(TPF)
#define VERIFY_SOCK(x) do { } while (0)
#else
#define VALID_SOCK(s) (((s) >= 0) && ((s) < FD_SETSIZE))
#define VERIFY_SOCK(x) do { \
if(!VALID_SOCK(x)) { \
SET_SOCKERRNO(EINVAL); \
return -1; \
} \
} while(0)
#endif
/*
* Internal function used for waiting a specific amount of ms
* in Curl_select() and Curl_poll() when no file descriptor is
* provided to wait on, just being used to delay execution.
* WinSock select() and poll() timeout mechanisms need a valid
* socket descriptor in a not null file descriptor set to work.
* Waiting indefinitely with this function is not allowed, a
* zero or negative timeout value will return immediately.
*/
static void wait_ms(int timeout_ms)
{
#if !defined(__MSDOS__) && \
!defined(USE_WINSOCK) && \
!defined(HAVE_POLL_FINE)
struct timeval timeout;
#endif
if (timeout_ms <= 0)
return;
#if defined(__MSDOS__)
delay(timeout_ms);
#elif defined(USE_WINSOCK)
Sleep(timeout_ms);
#elif defined(HAVE_POLL_FINE)
poll(NULL, 0, timeout_ms);
#else
timeout.tv_sec = timeout_ms / 1000;
timeout.tv_usec = (timeout_ms % 1000) * 1000;
select(0, NULL, NULL, NULL, &timeout);
#endif
}
/*
* This is an internal function used for waiting for read or write
* events on single file descriptors. It attempts to replace select()
* in order to avoid limits with FD_SETSIZE.
*
* Return values:
* -1 = system call error
* 0 = timeout
* CSELECT_IN | CSELECT_OUT | CSELECT_ERR
*/
int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
{
#ifdef HAVE_POLL_FINE
struct pollfd pfd[2];
int num;
#else
struct timeval timeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
int r;
int ret;
if((readfd == CURL_SOCKET_BAD) && (writefd == CURL_SOCKET_BAD)) {
wait_ms(timeout_ms);
return 0;
}
#ifdef HAVE_POLL_FINE
num = 0;
if (readfd != CURL_SOCKET_BAD) {
pfd[num].fd = readfd;
pfd[num].events = POLLIN;
num++;
}
if (writefd != CURL_SOCKET_BAD) {
pfd[num].fd = writefd;
pfd[num].events = POLLOUT;
num++;
}
do {
r = poll(pfd, num, timeout_ms);
} while((r == -1) && (SOCKERRNO == EINTR));
if (r < 0)
return -1;
if (r == 0)
return 0;
ret = 0;
num = 0;
if (readfd != CURL_SOCKET_BAD) {
if (pfd[num].revents & (POLLIN|POLLHUP))
ret |= CSELECT_IN;
if (pfd[num].revents & POLLERR) {
#ifdef __CYGWIN__
/* Cygwin 1.5.21 needs this hack to pass test 160 */
if (ERRNO == EINPROGRESS)
ret |= CSELECT_IN;
else
#endif
ret |= CSELECT_ERR;
}
num++;
}
if (writefd != CURL_SOCKET_BAD) {
if (pfd[num].revents & POLLOUT)
ret |= CSELECT_OUT;
if (pfd[num].revents & (POLLERR|POLLHUP))
ret |= CSELECT_ERR;
}
return ret;
#else /* HAVE_POLL_FINE */
timeout.tv_sec = timeout_ms / 1000;
timeout.tv_usec = (timeout_ms % 1000) * 1000;
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
FD_ZERO(&fds_read);
if (readfd != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd);
FD_SET(readfd, &fds_read);
FD_SET(readfd, &fds_err);
maxfd = readfd;
}
FD_ZERO(&fds_write);
if (writefd != CURL_SOCKET_BAD) {
VERIFY_SOCK(writefd);
FD_SET(writefd, &fds_write);
FD_SET(writefd, &fds_err);
if (writefd > maxfd)
maxfd = writefd;
}
do {
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout);
} while((r == -1) && (SOCKERRNO == EINTR));
if (r < 0)
return -1;
if (r == 0)
return 0;
ret = 0;
if (readfd != CURL_SOCKET_BAD) {
if (FD_ISSET(readfd, &fds_read))
ret |= CSELECT_IN;
if (FD_ISSET(readfd, &fds_err))
ret |= CSELECT_ERR;
}
if (writefd != CURL_SOCKET_BAD) {
if (FD_ISSET(writefd, &fds_write))
ret |= CSELECT_OUT;
if (FD_ISSET(writefd, &fds_err))
ret |= CSELECT_ERR;
}
return ret;
#endif /* HAVE_POLL_FINE */
}
/*
* This is a wrapper around poll(). If poll() does not exist, then
* select() is used instead. An error is returned if select() is
* being used and a file descriptor too large for FD_SETSIZE.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* 1 = number of structures with non zero revent fields
*/
int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
{
#ifndef HAVE_POLL_FINE
struct timeval timeout;
struct timeval *ptimeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
bool fds_none = TRUE;
unsigned int i;
int r;
if (ufds) {
for (i = 0; i < nfds; i++) {
if (ufds[i].fd != CURL_SOCKET_BAD) {
fds_none = FALSE;
break;
}
}
}
if (fds_none) {
wait_ms(timeout_ms);
return 0;
}
#ifdef HAVE_POLL_FINE
do {
r = poll(ufds, nfds, timeout_ms);
} while((r == -1) && (SOCKERRNO == EINTR));
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
for (i = 0; i < nfds; i++) {
if (ufds[i].fd == CURL_SOCKET_BAD)
continue;
VERIFY_SOCK(ufds[i].fd);
if (ufds[i].fd > maxfd)
maxfd = ufds[i].fd;
if (ufds[i].events & POLLIN)
FD_SET(ufds[i].fd, &fds_read);
if (ufds[i].events & POLLOUT)
FD_SET(ufds[i].fd, &fds_write);
if (ufds[i].events & POLLERR)
FD_SET(ufds[i].fd, &fds_err);
}
if (timeout_ms < 0) {
ptimeout = NULL; /* wait forever */
} else {
timeout.tv_sec = timeout_ms / 1000;
timeout.tv_usec = (timeout_ms % 1000) * 1000;
ptimeout = &timeout;
}
do {
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
} while((r == -1) && (SOCKERRNO == EINTR));
if (r < 0)
return -1;
if (r == 0)
return 0;
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))
ufds[i].revents |= POLLIN;
if (FD_ISSET(ufds[i].fd, &fds_write))
ufds[i].revents |= POLLOUT;
if (FD_ISSET(ufds[i].fd, &fds_err))
ufds[i].revents |= POLLERR;
if (ufds[i].revents != 0)
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 */
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