curl/lib/select.c

/***************************************************************************
 *                                  _   _ ____  _
 *  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

/*
 * 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)
{
#if defined(HAVE_POLL_FINE) || defined(CURL_HAVE_WSAPOLL)
  struct pollfd pfd[2];
  int num;
  int r;
  int ret;

  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 {
#ifdef CURL_HAVE_WSAPOLL
    r = WSAPoll(pfd, num, timeout_ms);
#else
    r = poll(pfd, num, timeout_ms);
#endif
  } 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
  struct timeval timeout;
  fd_set fds_read;
  fd_set fds_write;
  fd_set fds_err;
  curl_socket_t maxfd;
  int r;
  int ret;

  timeout.tv_sec = timeout_ms / 1000;
  timeout.tv_usec = (timeout_ms % 1000) * 1000;

  if((readfd == CURL_SOCKET_BAD) && (writefd == CURL_SOCKET_BAD)) {
    /* According to POSIX we should pass in NULL pointers if we don't want to
       wait for anything in particular but just use the timeout function.
       Windows however returns immediately if done so. I copied the MSDOS
       delay() use from src/main.c that already had this work-around. */
#ifdef WIN32
    Sleep(timeout_ms);
#elif defined(__MSDOS__)
    delay(timeout_ms);
#else
    select(0, NULL, NULL, NULL, &timeout);
#endif
    return 0;
  }

  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
}

/*
 * 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)
{
  int r;
#ifdef HAVE_POLL_FINE
  do {
#ifdef CURL_HAVE_WSAPOLL
    r = WSAPoll(ufds, nfds, timeout_ms);
#else
    r = poll(ufds, nfds, timeout_ms);
#endif
  } while((r == -1) && (SOCKERRNO == EINTR));
#else  /* 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;
  unsigned int i;

  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;
#if !defined(USE_WINSOCK) && !defined(TPF)
    /* Winsock and TPF sockets are not in range [0..FD_SETSIZE-1] */
    if (ufds[i].fd >= FD_SETSIZE) {
      SET_SOCKERRNO(EINVAL);
      return -1;
    }
#endif
    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 */