moparisthebest/curl
1
0
Fork 0
mirror of https://github.com/moparisthebest/curl synced 2024-11-05 09:05:04 -05:00
Code Issues Releases Wiki Activity
e21bd22f84
curl/lib/select.c
Marc Hoersken e21bd22f84
select: fix poll-based check not detecting connect failure 
This commit changes Curl_socket_check to use POLLPRI to
check for connect failure on the write socket, because
POLLPRI maps to fds_err. This is in line with select(2).

The select-based socket check correctly checks for connect
failures by adding the write socket also to fds_err.

The poll-based implementation (which internally can itself
fallback to select again) did not previously check for
connect failure by using POLLPRI with the write socket.

See the follow up commit to this for more information.

This commit makes sure connect failures can be detected
and handled if HAVE_POLL_FINE is defined, eg. on msys2-devel.

Reviewed-by: Daniel Stenberg
Reviewed-by: Jay Satiro

Replaces #5509
Prepares #5707
2020-08-25 11:20:58 +02:00

543 lines
15 KiB
C
Raw Blame History

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, 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 https://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.
*
***************************************************************************/
#include "curl_setup.h"
#include <limits.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#elif defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if !defined(HAVE_SELECT) && !defined(HAVE_POLL_FINE)
#error "We can't compile without select() or poll() support."
#endif
#if defined(__BEOS__) && !defined(__HAIKU__)
/* BeOS has FD_SET defined in socket.h */
#include <socket.h>
#endif
#ifdef MSDOS
#include <dos.h> /* delay() */
#endif
#ifdef __VXWORKS__
#include <strings.h> /* bzero() in FD_SET */
#endif
#include <curl/curl.h>
#include "urldata.h"
#include "connect.h"
#include "select.h"
#include "timeval.h"
#include "warnless.h"
/*
* Internal function used for waiting a specific amount of ms
* in Curl_socket_check() 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.
* Timeout resolution, accuracy, as well as maximum supported
* value is system dependent, neither factor is a citical issue
* for the intended use of this function in the library.
*
* Return values:
* -1 = system call error, invalid timeout value, or interrupted
* 0 = specified timeout has elapsed
*/
int Curl_wait_ms(timediff_t timeout_ms)
{
int r = 0;
if(!timeout_ms)
return 0;
if(timeout_ms < 0) {
SET_SOCKERRNO(EINVAL);
return -1;
}
#if defined(MSDOS)
delay(timeout_ms);
#elif defined(WIN32)
/* prevent overflow, timeout_ms is typecast to ULONG/DWORD. */
#if TIMEDIFF_T_MAX >= ULONG_MAX
if(timeout_ms >= ULONG_MAX)
timeout_ms = ULONG_MAX-1;
/* don't use ULONG_MAX, because that is equal to INFINITE */
#endif
Sleep((ULONG)timeout_ms);
#else
#if defined(HAVE_POLL_FINE)
/* prevent overflow, timeout_ms is typecast to int. */
#if TIMEDIFF_T_MAX > INT_MAX
if(timeout_ms > INT_MAX)
timeout_ms = INT_MAX;
#endif
r = poll(NULL, 0, (int)timeout_ms);
#else
{
struct timeval pending_tv;
timediff_t tv_sec = timeout_ms / 1000;
timediff_t tv_usec = (timeout_ms % 1000) * 1000; /* max=999999 */
#ifdef HAVE_SUSECONDS_T
#if TIMEDIFF_T_MAX > TIME_T_MAX
/* tv_sec overflow check in case time_t is signed */
if(tv_sec > TIME_T_MAX)
tv_sec = TIME_T_MAX;
#endif
pending_tv.tv_sec = (time_t)tv_sec;
pending_tv.tv_usec = (suseconds_t)tv_usec;
#else
#if TIMEDIFF_T_MAX > INT_MAX
/* tv_sec overflow check in case time_t is signed */
if(tv_sec > INT_MAX)
tv_sec = INT_MAX;
#endif
pending_tv.tv_sec = (int)tv_sec;
pending_tv.tv_usec = (int)tv_usec;
#endif
r = select(0, NULL, NULL, NULL, &pending_tv);
}
#endif /* HAVE_POLL_FINE */
#endif /* USE_WINSOCK */
if(r)
r = -1;
return r;
}
/*
* This is a wrapper around select() to aid in Windows compatibility.
* A negative timeout value makes this function wait indefinitely,
* unless no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* N = number of signalled file descriptors
*/
int Curl_select(curl_socket_t maxfd, /* highest socket number */
fd_set *fds_read, /* sockets ready for reading */
fd_set *fds_write, /* sockets ready for writing */
fd_set *fds_err, /* sockets with errors */
timediff_t timeout_ms) /* milliseconds to wait */
{
struct timeval pending_tv;
struct timeval *ptimeout;
int r;
#ifdef USE_WINSOCK
/* WinSock select() can't handle zero events. See the comment below. */
if((!fds_read || fds_read->fd_count == 0) &&
(!fds_write || fds_write->fd_count == 0) &&
(!fds_err || fds_err->fd_count == 0)) {
r = Curl_wait_ms(timeout_ms);
return r;
}
#endif
ptimeout = &pending_tv;
if(timeout_ms < 0) {
ptimeout = NULL;
}
else if(timeout_ms > 0) {
timediff_t tv_sec = timeout_ms / 1000;
timediff_t tv_usec = (timeout_ms % 1000) * 1000; /* max=999999 */
#ifdef HAVE_SUSECONDS_T
#if TIMEDIFF_T_MAX > TIME_T_MAX
/* tv_sec overflow check in case time_t is signed */
if(tv_sec > TIME_T_MAX)
tv_sec = TIME_T_MAX;
#endif
pending_tv.tv_sec = (time_t)tv_sec;
pending_tv.tv_usec = (suseconds_t)tv_usec;
#elif defined(WIN32) /* maybe also others in the future */
#if TIMEDIFF_T_MAX > LONG_MAX
/* tv_sec overflow check on Windows there we know it is long */
if(tv_sec > LONG_MAX)
tv_sec = LONG_MAX;
#endif
pending_tv.tv_sec = (long)tv_sec;
pending_tv.tv_usec = (long)tv_usec;
#else
#if TIMEDIFF_T_MAX > INT_MAX
/* tv_sec overflow check in case time_t is signed */
if(tv_sec > INT_MAX)
tv_sec = INT_MAX;
#endif
pending_tv.tv_sec = (int)tv_sec;
pending_tv.tv_usec = (int)tv_usec;
#endif
}
else {
pending_tv.tv_sec = 0;
pending_tv.tv_usec = 0;
}
#ifdef USE_WINSOCK
/* WinSock select() must not be called with an fd_set that contains zero
fd flags, or it will return WSAEINVAL. But, it also can't be called
with no fd_sets at all! From the documentation:
Any two of the parameters, readfds, writefds, or exceptfds, can be
given as null. At least one must be non-null, and any non-null
descriptor set must contain at least one handle to a socket.
It is unclear why WinSock doesn't just handle this for us instead of
calling this an error.
*/
r = select((int)maxfd + 1,
fds_read && fds_read->fd_count ? fds_read : NULL,
fds_write && fds_write->fd_count ? fds_write : NULL,
fds_err && fds_err->fd_count ? fds_err : NULL, ptimeout);
#else
r = select((int)maxfd + 1, fds_read, fds_write, fds_err, ptimeout);
#endif
return r;
}
/*
* Wait for read or write events on a set of file descriptors. It uses poll()
* when a fine poll() is available, in order to avoid limits with FD_SETSIZE,
* otherwise select() is used. An error is returned if select() is being used
* and a file descriptor is too large for FD_SETSIZE.
*
* A negative timeout value makes this function wait indefinitely,
* unless no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* [bitmask] = action as described below
*
* CURL_CSELECT_IN - first socket is readable
* CURL_CSELECT_IN2 - second socket is readable
* CURL_CSELECT_OUT - write socket is writable
* CURL_CSELECT_ERR - an error condition occurred
*/
int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
curl_socket_t readfd1,
curl_socket_t writefd, /* socket to write to */
timediff_t timeout_ms) /* milliseconds to wait */
{
#ifdef HAVE_POLL_FINE
struct pollfd pfd[3];
int num;
#else
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
int r;
int ret;
if((readfd0 == CURL_SOCKET_BAD) && (readfd1 == CURL_SOCKET_BAD) &&
(writefd == CURL_SOCKET_BAD)) {
/* no sockets, just wait */
r = Curl_wait_ms(timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid Curl_now() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
#ifdef HAVE_POLL_FINE
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd0;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd1;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
pfd[num].fd = writefd;
pfd[num].events = POLLWRNORM|POLLOUT|POLLPRI;
pfd[num].revents = 0;
num++;
}
r = Curl_poll(pfd, num, timeout_ms);
if(r <= 0)
return r;
ret = 0;
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN2;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLWRNORM|POLLOUT))
ret |= CURL_CSELECT_OUT;
if(pfd[num].revents & (POLLERR|POLLHUP|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
}
return ret;
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
FD_ZERO(&fds_read);
if(readfd0 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd0);
FD_SET(readfd0, &fds_read);
FD_SET(readfd0, &fds_err);
maxfd = readfd0;
}
if(readfd1 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd1);
FD_SET(readfd1, &fds_read);
FD_SET(readfd1, &fds_err);
if(readfd1 > maxfd)
maxfd = readfd1;
}
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;
}
/* We know that we have at least one bit set in at least two fd_sets in
this case, but we may have no bits set in either fds_read or fd_write,
so check for that and handle it. Luckily, with WinSock, we can _also_
ask how many bits are set on an fd_set.
Note also that WinSock ignores the first argument, so we don't worry
about the fact that maxfd is computed incorrectly with WinSock (since
curl_socket_t is unsigned in such cases and thus -1 is the largest
value).
*/
r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms);
if(r < 0)
return -1;
if(r == 0)
return 0;
ret = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd0, &fds_read))
ret |= CURL_CSELECT_IN;
if(FD_ISSET(readfd0, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd1, &fds_read))
ret |= CURL_CSELECT_IN2;
if(FD_ISSET(readfd1, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(writefd != CURL_SOCKET_BAD) {
if(FD_ISSET(writefd, &fds_write))
ret |= CURL_CSELECT_OUT;
if(FD_ISSET(writefd, &fds_err))
ret |= CURL_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 is too large for FD_SETSIZE.
* A negative timeout value makes this function wait indefinitely,
* unless no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* N = number of structures with non zero revent fields
*/
int Curl_poll(struct pollfd ufds[], unsigned int nfds, timediff_t timeout_ms)
{
#ifdef HAVE_POLL_FINE
int pending_ms;
#else
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) {
/* no sockets, just wait */
r = Curl_wait_ms(timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid Curl_now() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
#ifdef HAVE_POLL_FINE
/* prevent overflow, timeout_ms is typecast to int. */
#if TIMEDIFF_T_MAX > INT_MAX
if(timeout_ms > INT_MAX)
timeout_ms = INT_MAX;
#endif
if(timeout_ms > 0)
pending_ms = (int)timeout_ms;
else if(timeout_ms < 0)
pending_ms = -1;
else
pending_ms = 0;
r = poll(ufds, nfds, pending_ms);
if(r < 0)
return -1;
if(r == 0)
return 0;
for(i = 0; i < nfds; i++) {
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
if(ufds[i].revents & POLLHUP)
ufds[i].revents |= POLLIN;
if(ufds[i].revents & POLLERR)
ufds[i].revents |= (POLLIN|POLLOUT);
}
#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++) {
ufds[i].revents = 0;
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
VERIFY_SOCK(ufds[i].fd);
if(ufds[i].events & (POLLIN|POLLOUT|POLLPRI|
POLLRDNORM|POLLWRNORM|POLLRDBAND)) {
if(ufds[i].fd > maxfd)
maxfd = ufds[i].fd;
if(ufds[i].events & (POLLRDNORM|POLLIN))
FD_SET(ufds[i].fd, &fds_read);
if(ufds[i].events & (POLLWRNORM|POLLOUT))
FD_SET(ufds[i].fd, &fds_write);
if(ufds[i].events & (POLLRDBAND|POLLPRI))
FD_SET(ufds[i].fd, &fds_err);
}
}
r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms);
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 |= POLLPRI;
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 */
Reference in New Issue View Git Blame Copy Permalink