X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/4a0b6d6164ce80aa9c7b160080e2995eec2fa2ce..681beafc906c71e3d8fa523fc9e6b0fd9be3ed7a:/windows/winser.c

diff --git a/windows/winser.c b/windows/winser.c
index cd31b5af..ab88406d 100644
--- a/windows/winser.c
+++ b/windows/winser.c
@@ -221,8 +221,39 @@ static const char *serial_init(void *frontend_handle, void **backend_handle,
 	logevent(serial->frontend, msg);
     }
 
-    serport = CreateFile(cfg->serline, GENERIC_READ | GENERIC_WRITE, 0, NULL,
-			 OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
+    {
+	/*
+	 * Munge the string supplied by the user into a Windows filename.
+	 *
+	 * Windows supports opening a few "legacy" devices (including
+	 * COM1-9) by specifying their names verbatim as a filename to
+	 * open. (Thus, no files can ever have these names. See
+	 * <http://msdn2.microsoft.com/en-us/library/aa365247.aspx>
+	 * ("Naming a File") for the complete list of reserved names.)
+	 *
+	 * However, this doesn't let you get at devices COM10 and above.
+	 * For that, you need to specify a filename like "\\.\COM10".
+	 * This is also necessary for special serial and serial-like
+	 * devices such as \\.\WCEUSBSH001. It also works for the "legacy"
+	 * names, so you can do \\.\COM1 (verified as far back as Win95).
+	 * See <http://msdn2.microsoft.com/en-us/library/aa363858.aspx>
+	 * (CreateFile() docs).
+	 *
+	 * So, we believe that prepending "\\.\" should always be the
+	 * Right Thing. However, just in case someone finds something to
+	 * talk to that doesn't exist under there, if the serial line
+	 * contains a backslash, we use it verbatim. (This also lets
+	 * existing configurations using \\.\ continue working.)
+	 */
+	char *serfilename =
+	    dupprintf("%s%s",
+		      strchr(cfg->serline, '\\') ? "" : "\\\\.\\",
+		      cfg->serline);
+	serport = CreateFile(serfilename, GENERIC_READ | GENERIC_WRITE, 0, NULL,
+			     OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
+	sfree(serfilename);
+    }
+
     if (serport == INVALID_HANDLE_VALUE)
 	return "Unable to open serial port";
 
@@ -423,5 +454,7 @@ Backend serial_backend = {
     serial_provide_logctx,
     serial_unthrottle,
     serial_cfg_info,
-    1
+    "serial",
+    PROT_SERIAL,
+    0
 };