Recommit: Update libusb 1.0.9 to libusbx 1.0.16

third_party/libusb/src/msvc/missing.c

+/*
+ * Source file for missing WinCE functionality
+ * Copyright © 2012 RealVNC Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "missing.h"
+
+#include <config.h>
+#include <libusbi.h>
+
+#include <windows.h>
+
+// The registry path to store environment variables
+#define ENVIRONMENT_REG_PATH _T("Software\\libusb\\environment")
+
+/* Workaround getenv not being available on WinCE.
+ * Instead look in HKLM\Software\libusb\environment */
+char *getenv(const char *name)
+{
+        static char value[MAX_PATH];
+        TCHAR wValue[MAX_PATH];
+        WCHAR wName[MAX_PATH];
+        DWORD dwType, dwData;
+        HKEY hkey;
+        LONG rc;
+
+        if (!name)
+                return NULL;
+
+        if (MultiByteToWideChar(CP_UTF8, 0, name, -1, wName, MAX_PATH) <= 0) {
+                usbi_dbg("Failed to convert environment variable name to wide string");
+                return NULL;
+        }
+        wName[MAX_PATH - 1] = 0; // Be sure it's NUL terminated
+
+        rc = RegOpenKeyEx(HKEY_LOCAL_MACHINE, ENVIRONMENT_REG_PATH, 0, KEY_QUERY_VALUE, &hkey);
+        if (rc != ERROR_SUCCESS) {
+                usbi_dbg("Failed to open registry key for getenv with error %d", rc);
+                return NULL;
+        }
+
+        // Attempt to read the key
+        dwData = sizeof(wValue);
+        rc = RegQueryValueEx(hkey, wName, NULL, &dwType,
+                (LPBYTE)&wValue, &dwData);
+        RegCloseKey(hkey);
+        if (rc != ERROR_SUCCESS) {
+                usbi_dbg("Failed to read registry key value for getenv with error %d", rc);
+                return NULL;
+        }
+        if (dwType != REG_SZ) {
+                usbi_dbg("Registry value was of type %d instead of REG_SZ", dwType);
+                return NULL;
+        }
+
+        // Success in reading the key, convert from WCHAR to char
+        if (WideCharToMultiByte(CP_UTF8, 0,
+                        wValue, dwData / sizeof(*wValue),
+                        value, MAX_PATH,
+                        NULL, NULL) <= 0) {
+                usbi_dbg("Failed to convert environment variable value to narrow string");
+                return NULL;
+        }
+        value[MAX_PATH - 1] = 0; // Be sure it's NUL terminated
+        return value;
+}