1 files changed, 87 insertions, 0 deletions
diff --git a/src/VBox/Runtime/generic/RTEnvDupEx-generic.cpp b/src/VBox/Runtime/generic/RTEnvDupEx-generic.cpp
new file mode 100644
index 00000000..e6bcb6d2
--- /dev/null
+++ b/src/VBox/Runtime/generic/RTEnvDupEx-generic.cpp
@@ -0,0 +1,87 @@
+/* $Id: RTEnvDupEx-generic.cpp $ */
+/** @file
+ * IPRT - Environment, RTEnvDupEx, generic.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/env.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+
+
+RTDECL(char *) RTEnvDupEx(RTENV Env, const char *pszVar)
+{
+    /*
+     * Try with a small buffer.  This helps avoid allocating a heap buffer for
+     * variables that doesn't exist.
+     */
+    char szSmall[256];
+    int rc = RTEnvGetEx(Env, pszVar, szSmall, sizeof(szSmall), NULL);
+    if (RT_SUCCESS(rc))
+        return RTStrDup(szSmall);
+    if (rc != VERR_BUFFER_OVERFLOW)
+        return NULL;
+
+    /*
+     * It's a big bugger.
+     */
+    size_t cbBuf = _1K;
+    do
+    {
+        char *pszBuf = RTStrAlloc(cbBuf);
+        AssertBreak(pszBuf);
+
+        rc = RTEnvGetEx(Env, pszVar, pszBuf, cbBuf, NULL);
+        if (RT_SUCCESS(rc))
+            return pszBuf;
+
+        RTStrFree(pszBuf);
+
+        /* If overflow double the buffer. */
+        if (rc != VERR_BUFFER_OVERFLOW)
+            break;
+        cbBuf *= 2;
+    } while (cbBuf < _64M);
+
+    return NULL;
+}
+RT_EXPORT_SYMBOL(RTEnvDupEx);
+