#include <stdio.h>
#include <assert.h>
+#include <limits.h>
#define DEFINE_PLUG_METHOD_MACROS
#include "tree234.h"
HANDLE send_H, recv_H;
struct handle *send_h, *recv_h;
+ /*
+ * Freezing one of these sockets is a slightly fiddly business,
+ * because the reads from the handle are happening in a separate
+ * thread as blocking system calls and so once one is in progress
+ * it can't sensibly be interrupted. Hence, after the user tries
+ * to freeze one of these sockets, it's unavoidable that we may
+ * receive one more load of data before we manage to get
+ * winhandl.c to stop reading.
+ */
+ enum {
+ UNFROZEN, /* reading as normal */
+ FREEZING, /* have been set to frozen but winhandl is still reading */
+ FROZEN, /* really frozen - winhandl has been throttled */
+ THAWING /* we're gradually releasing our remaining data */
+ } frozen;
+ /* We buffer data here if we receive it from winhandl while frozen. */
+ bufchain inputdata;
+
char *error;
Plug plug;
-
- void *privptr;
};
static int handle_gotdata(struct handle *h, void *data, int len)
} else if (len == 0) {
return plug_closing(ps->plug, NULL, 0, 0);
} else {
- return plug_receive(ps->plug, 0, data, len);
+ assert(ps->frozen != FREEZING && ps->frozen != THAWING);
+ if (ps->frozen == FREEZING) {
+ /*
+ * If we've received data while this socket is supposed to
+ * be frozen (because the read winhandl.c started before
+ * sk_set_frozen was called has now returned) then buffer
+ * the data for when we unfreeze.
+ */
+ bufchain_add(&ps->inputdata, data, len);
+
+ /*
+ * And return a very large backlog, to prevent further
+ * data arriving from winhandl until we unfreeze.
+ */
+ return INT_MAX;
+ } else {
+ return plug_receive(ps->plug, 0, data, len);
+ }
}
}
CloseHandle(ps->send_H);
if (ps->recv_H != ps->send_H)
CloseHandle(ps->recv_H);
+ bufchain_clear(&ps->inputdata);
sfree(ps);
}
/* do nothing */
}
-static void sk_handle_set_private_ptr(Socket s, void *ptr)
+static void handle_socket_unfreeze(void *psv)
{
- Handle_Socket ps = (Handle_Socket) s;
- ps->privptr = ptr;
-}
+ Handle_Socket ps = (Handle_Socket) psv;
+ void *data;
+ int len, new_backlog;
-static void *sk_handle_get_private_ptr(Socket s)
-{
- Handle_Socket ps = (Handle_Socket) s;
- return ps->privptr;
+ /*
+ * If we've been put into a state other than THAWING since the
+ * last callback, then we're done.
+ */
+ if (ps->frozen != THAWING)
+ return;
+
+ /*
+ * Get some of the data we've buffered.
+ */
+ bufchain_prefix(&ps->inputdata, &data, &len);
+ assert(len > 0);
+
+ /*
+ * Hand it off to the plug.
+ */
+ new_backlog = plug_receive(ps->plug, 0, data, len);
+
+ if (bufchain_size(&ps->inputdata) > 0) {
+ /*
+ * If there's still data in our buffer, stay in THAWING state,
+ * and reschedule ourself.
+ */
+ queue_toplevel_callback(handle_socket_unfreeze, ps);
+ } else {
+ /*
+ * Otherwise, we've successfully thawed!
+ */
+ ps->frozen = UNFROZEN;
+ handle_unthrottle(ps->recv_h, new_backlog);
+ }
}
static void sk_handle_set_frozen(Socket s, int is_frozen)
{
Handle_Socket ps = (Handle_Socket) s;
- /*
- * FIXME
- */
+ if (is_frozen) {
+ switch (ps->frozen) {
+ case FREEZING:
+ case FROZEN:
+ return; /* nothing to do */
+
+ case THAWING:
+ /*
+ * We were in the middle of emptying our bufchain, and got
+ * frozen again. In that case, winhandl.c is already
+ * throttled, so just return to FROZEN state. The toplevel
+ * callback will notice and disable itself.
+ */
+ ps->frozen = FROZEN;
+ break;
+
+ case UNFROZEN:
+ /*
+ * The normal case. Go to FREEZING, and expect one more
+ * load of data from winhandl if we're unlucky.
+ */
+ ps->frozen = FREEZING;
+ break;
+ }
+ } else {
+ switch (ps->frozen) {
+ case UNFROZEN:
+ case THAWING:
+ return; /* nothing to do */
+
+ case FREEZING:
+ /*
+ * If winhandl didn't send us any data throughout the time
+ * we were frozen, then we'll still be in this state and
+ * can just unfreeze in the trivial way.
+ */
+ assert(bufchain_size(&ps->inputdata) == 0);
+ ps->frozen = UNFROZEN;
+ break;
+
+ case FROZEN:
+ /*
+ * If we have buffered data, go to THAWING and start
+ * releasing it in top-level callbacks.
+ */
+ ps->frozen = THAWING;
+ queue_toplevel_callback(handle_socket_unfreeze, ps);
+ }
+ }
}
static const char *sk_handle_socket_error(Socket s)
return ps->error;
}
+static char *sk_handle_peer_info(Socket s)
+{
+ Handle_Socket ps = (Handle_Socket) s;
+ ULONG pid;
+ static HMODULE kernel32_module;
+ DECL_WINDOWS_FUNCTION(static, BOOL, GetNamedPipeClientProcessId,
+ (HANDLE, PULONG));
+
+ if (!kernel32_module) {
+ kernel32_module = load_system32_dll("kernel32.dll");
+ GET_WINDOWS_FUNCTION(kernel32_module, GetNamedPipeClientProcessId);
+ }
+
+ /*
+ * Of course, not all handles managed by this module will be
+ * server ends of named pipes, but if they are, then it's useful
+ * to log what we can find out about the client end.
+ */
+ if (p_GetNamedPipeClientProcessId &&
+ p_GetNamedPipeClientProcessId(ps->send_H, &pid))
+ return dupprintf("process id %lu", (unsigned long)pid);
+
+ return NULL;
+}
+
Socket make_handle_socket(HANDLE send_H, HANDLE recv_H, Plug plug,
int overlapped)
{
sk_handle_write_oob,
sk_handle_write_eof,
sk_handle_flush,
- sk_handle_set_private_ptr,
- sk_handle_get_private_ptr,
sk_handle_set_frozen,
- sk_handle_socket_error
+ sk_handle_socket_error,
+ sk_handle_peer_info,
};
Handle_Socket ret;
ret->fn = &socket_fn_table;
ret->plug = plug;
ret->error = NULL;
+ ret->frozen = UNFROZEN;
+ bufchain_init(&ret->inputdata);
ret->recv_H = recv_H;
ret->recv_h = handle_input_new(ret->recv_H, handle_gotdata, ret, flags);