X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/758a137739edff67a485ef9d534764cef8aab807..b4ac18ae9c7c937e7359a8bf9d44c6de5f07bd71:/windows/winhandl.c

diff --git a/windows/winhandl.c b/windows/winhandl.c
index 7a3cce35..f515ee57 100644
--- a/windows/winhandl.c
+++ b/windows/winhandl.c
@@ -16,6 +16,17 @@
  * write; so the output thread waits for an event object notifying
  * it to _attempt_ a write, and then it sets an event in return
  * when one completes.
+ * 
+ * (It's terribly annoying having to spawn a subthread for each
+ * direction of each handle. Technically it isn't necessary for
+ * serial ports, since we could use overlapped I/O within the main
+ * thread and wait directly on the event objects in the OVERLAPPED
+ * structures. However, we can't use this trick for some types of
+ * file handle at all - for some reason Windows restricts use of
+ * OVERLAPPED to files which were opened with the overlapped flag -
+ * and so we must use threads for those. This being the case, it's
+ * simplest just to use threads for everything rather than trying
+ * to keep track of multiple completely separate mechanisms.)
  */
 
 #include <assert.h>
@@ -102,6 +113,7 @@ static DWORD WINAPI handle_input_threadfunc(void *param)
     struct handle_input *ctx = (struct handle_input *) param;
     OVERLAPPED ovl, *povl;
     HANDLE oev;
+    int readlen;
 
     if (ctx->flags & HANDLE_FLAG_OVERLAPPED) {
 	povl = &ovl;
@@ -110,12 +122,17 @@ static DWORD WINAPI handle_input_threadfunc(void *param)
 	povl = NULL;
     }
 
+    if (ctx->flags & HANDLE_FLAG_UNITBUFFER)
+	readlen = 1;
+    else
+	readlen = sizeof(ctx->buffer);
+
     while (1) {
 	if (povl) {
 	    memset(povl, 0, sizeof(OVERLAPPED));
 	    povl->hEvent = oev;
 	}
-	ctx->readret = ReadFile(ctx->h, ctx->buffer, sizeof(ctx->buffer),
+	ctx->readret = ReadFile(ctx->h, ctx->buffer, readlen,
 				&ctx->len, povl);
 	if (povl && !ctx->readret && GetLastError() == ERROR_IO_PENDING) {
 	    WaitForSingleObject(povl->hEvent, INFINITE);
@@ -315,6 +332,7 @@ struct handle *handle_input_new(HANDLE handle, handle_inputfn_t gotdata,
 				void *privdata, int flags)
 {
     struct handle *h = snew(struct handle);
+    DWORD in_threadid; /* required for Win9x */
 
     h->output = FALSE;
     h->u.i.h = handle;
@@ -332,7 +350,7 @@ struct handle *handle_input_new(HANDLE handle, handle_inputfn_t gotdata,
     add234(handles_by_evtomain, h);
 
     CreateThread(NULL, 0, handle_input_threadfunc,
-		 &h->u.i, 0, NULL);
+		 &h->u.i, 0, &in_threadid);
     h->u.i.busy = TRUE;
 
     return h;
@@ -342,6 +360,7 @@ struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata,
 				 void *privdata, int flags)
 {
     struct handle *h = snew(struct handle);
+    DWORD out_threadid; /* required for Win9x */
 
     h->output = TRUE;
     h->u.o.h = handle;
@@ -361,7 +380,7 @@ struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata,
     add234(handles_by_evtomain, h);
 
     CreateThread(NULL, 0, handle_output_threadfunc,
-		 &h->u.i, 0, NULL);
+		 &h->u.i, 0, &out_threadid);
 
     return h;
 }