luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2025-02-03 17:56:17 +01:00
Code Issues Packages Projects Releases Wiki Activity

gsocket: Fix g_socket_get_available_bytes() on Windows and OS X

Browse Source 
On Windows and OS X, FIONREAD on a UDP socket gets the total number of
bytes available, not the number of bytes available in the next packet,
which is the more useful number (and how the function always behaved
on Linux).

On OS X, fix this by using SO_NREAD. On Windows, fix this by doing a
MSG_PEEK recv() into a giant buffer, since there is apparently no
other way to get the information.

https://bugzilla.gnome.org/show_bug.cgi?id=686786
This commit is contained in:
Dan Winship 2013-08-24 13:55:06 -04:00
parent 8d62c2495a
commit 9fd0927e58
1 changed files with 26 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
gio/gsocket.c
View File

@ -2457,24 +2457,44 @@ g_socket_check_connect_result (GSocket *socket,
*
* Get the amount of data pending in the OS input buffer.
*
* If @socket is a UDP or SCTP socket, this will return the size of
* just the next packet, even if additional packets are buffered after
* that one.
*
* Note that on Windows, this function is rather inefficient in the
* UDP case, and so if you know any plausible upper bound on the size
* of the incoming packet, it is better to just do a
* g_socket_receive() with a buffer of that size, rather than calling
* g_socket_get_available_bytes() first and then doing a receive of
* exactly the right size.
*
* Returns: the number of bytes that can be read from the socket
* without blocking or -1 on error.
* without blocking or truncating, or -1 on error.
*
* Since: 2.32
*/
gssize
g_socket_get_available_bytes (GSocket *socket)
{
gulong avail = 0;
#ifdef G_OS_WIN32
const gint bufsize = 64 * 1024;
static guchar *buf = NULL;
#endif
gint avail;
g_return_val_if_fail (G_IS_SOCKET (socket), -1);
#ifndef G_OS_WIN32
#if defined (SO_NREAD)
if (!g_socket_get_option (socket, SOL_SOCKET, SO_NREAD, &avail, NULL))
return -1;
#elif !defined (G_OS_WIN32)
if (ioctl (socket->priv->fd, FIONREAD, &avail) < 0)
return -1;
avail = -1;
#else
if (ioctlsocket (socket->priv->fd, FIONREAD, &avail) == SOCKET_ERROR)
return -1;
if (G_UNLIKELY (g_once_init_enter (&buf)))
g_once_init_leave (&buf, g_malloc (bufsize));
avail = recv (socket->priv->fd, buf, bufsize, MSG_PEEK);
#endif
return avail;