We avoid the problem by using poll(2).
On systems without poll(2) (older bsd-ish systems, and win32), we emulate
poll(2) using select(2) and check for valid descriptors before attempting
to access them via the descriptor sets.
If an out-of-range descriptor is detected, an E_WARNING is raised suggesting
that PHP should be recompiled with a larger FD_SETSIZE (and also with a
suggested value).
Most uses of select(2) in the source are to poll a single descriptor, so
a couple of handy wrapper functions have been added to make this easier.
A configure option --enable-fd-setsize has been added to both the unix and
win32 builds; on unix we default to 16384 and on windows we default to 256.
Windows FD_SETSIZE imposes a limit on the maximum number of descriptors that
can be select()ed at once, whereas the unix FD_SETSIZE limit is based on the
highest numbered descriptor; 256 should be plenty for PHP scripts under windows
(the default OS setting is 64).
The win32 specific parts are untested; will do that now.
. stream_socket_client() - similar to fsockopen(), but more powerful.
. stream_socket_server() - Creates a server socket.
. stream_socket_accept() - Accept a client connection.
. stream_socket_get_name() - Get local or remote name of socket.
Tidy up some leaks and debug printfs.
Move more streams functions into streamsfuncs.c and streamsfuncs.h.
Main Changes:
- Implement a socket transport layer for use by all code that needs to open
some kind of "special" socket for network or IPC.
- Extensions can register (and override) transports.
- Implement ftruncate() on streams via the ioctl-alike option interface.
- Implement mmap() on streams via the ioctl-alike option interface.
- Implement generic crypto API via the ioctl-alike option interface.
(currently only supports OpenSSL, but could support other SSL toolkits,
and other crypto transport protocols).
Impact:
- tcp sockets can be overloaded by the openssl capable sockets at runtime,
removing the link-time requirement for ssl:// and https:// sockets and
streams.
- checking stream types using PHP_STREAM_IS_SOCKET is deprecated, since
there are now a range of possible socket-type streams.
Working towards:
- socket servers using the new transport layer
- mmap support under win32
- Cleaner code.
# I will be updating the win32 build to add the new files shortly
# after this commit.
windows sockets. The winsock implementation will only work with sockets;
our implementation works with sockets and file descriptors.
By association, stream_select() will now operate correctly with files, pipes and sockets.
This change required linking against the winsock2 library. In terms of
compatibility, only older versions of windows 95 do not have winsock2
installed by default. It is available as a redistributable file, and is most likely installed by any OS patches (eg: Internet Explorer) applied by the user.
Also, add a win32 compatible pipe test when opening a stream from a pipe. This test will only work on NT, win2k and XP platforms. Without this test, interleaved fread() and select() calls would cause the read buffer to be clobbered. I will be working on a fix for this issue for win9x.
Analysis:
On systems with HAVE_GETADDRINFO and IPV6 support, php_hostconnect would
attempt to connect to each possible address that matched the requested IP.
If the remote host:port combination are dropping packets this would cause the
first connection to timeout (after waiting for the full timeout duration).
PHP would then attempt the second address and wait the full duration again.
Solution:
If the first connection attempt times out, abort the connection loop.
I've moved EOF detection into the streams layer; a stream reader
implementation should set stream->eof when it detects EOF.
Fixed test for user streams - it still fails but that is due to an output
buffering bug.
with regard to sockets. The behaviour should be aligned with PHP 4.2 now.
This has been verified to some degree.
If the underlying stream operations block when no new data is readable,
we need to take extra precautions.
If there is buffered data available, we check for a EOL. If it exists,
we pass the data immediately back to the caller. This saves a call
to the read implementation and will not block where blocking
is not necessary at all.
If the stream buffer contains more data than the caller requested,
we can also avoid that costly step and simply return that data.
