From: Martin Ling <redacted>
Date: Mon, 20 Jan 2020 01:28:17 +0000 (+0000)
Subject: windows: Handle registry lookup failures correctly.
X-Git-Tag: libserialport-0.1.2~59
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=c79e0ac8ef8e978de0a5bc15af0b555ba59d7da0;p=libserialport.git

windows: Handle registry lookup failures correctly.

RegOpenKeyEx() and RegQueryInfoKey() return system error codes directly,
not by setting the thread-local errno equivalent that is returned by
GetLastError().

When returning SP_ERR_FAIL, our API specifies that sp_last_error_code()
may be called immediately afterwards to get the system error code. In
this case that would not work, as it would call GetLastError() and miss
the directly-returned result.

We therefore need to call SetLastError() with the error code before
returning with SP_ERR_FAIL.
---

diff --git a/windows.c b/windows.c
index ee15a11..a9d0927 100644
--- a/windows.c
+++ b/windows.c
@@ -483,19 +483,22 @@ SP_PRIV enum sp_return list_ports(struct sp_port ***list)
 	DWORD max_value_len, max_data_size, max_data_len;
 	DWORD value_len, data_size, data_len;
 	DWORD type, index = 0;
+	LSTATUS result;
 	char *name;
 	int name_len;
 	int ret = SP_OK;
 
 	DEBUG("Opening registry key");
-	if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("HARDWARE\\DEVICEMAP\\SERIALCOMM"),
-			0, KEY_QUERY_VALUE, &key) != ERROR_SUCCESS) {
+	if ((result = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("HARDWARE\\DEVICEMAP\\SERIALCOMM"),
+			0, KEY_QUERY_VALUE, &key)) != ERROR_SUCCESS) {
+		SetLastError(result);
 		SET_FAIL(ret, "RegOpenKeyEx() failed");
 		goto out_done;
 	}
 	DEBUG("Querying registry key value and data sizes");
-	if (RegQueryInfoKey(key, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
-				&max_value_len, &max_data_size, NULL, NULL) != ERROR_SUCCESS) {
+	if ((result = RegQueryInfoKey(key, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+				&max_value_len, &max_data_size, NULL, NULL)) != ERROR_SUCCESS) {
+		SetLastError(result);
 		SET_FAIL(ret, "RegQueryInfoKey() failed");
 		goto out_close;
 	}