lib/string/strdup/: XSTRNDUP(), STRNDUPA(): Add macros

Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/string/strdup/strndupa.c

@@ -0,0 +1,7 @@
+// SPDX-FileCopyrightText: 2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#include <config.h>
+
+#include "string/strdup/strndupa.h"

lib/string/strdup/strndupa.h

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#ifndef SHADOW_INCLUDE_LIB_STRING_STRDUP_STRNDUPA_H_
+#define SHADOW_INCLUDE_LIB_STRING_STRDUP_STRNDUPA_H_
+
+
+#include <config.h>
+
+#include <alloca.h>
+#include <string.h>
+
+#include "sizeof.h"
+#include "string/strcpy/strncat.h"
+
+
+// Similar to strndupa(3), but ensure that 's' is an array.
+#define STRNDUPA(s)                                                           \
+(                                                                             \
+	STRNCAT(strcpy(alloca(strnlen(s, NITEMS(s)) + 1), ""), s)             \
+)
+
+
+#endif  // include guard

lib/string/strdup/xstrndup.c

@@ -0,0 +1,7 @@
+// SPDX-FileCopyrightText: 2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#include <config.h>
+
+#include "string/strdup/xstrndup.h"

lib/string/strdup/xstrndup.h

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#ifndef SHADOW_INCLUDE_LIB_STRING_STRDUP_XSTRNDUP_H_
+#define SHADOW_INCLUDE_LIB_STRING_STRDUP_XSTRNDUP_H_
+
+
+#include <config.h>
+
+#include <string.h>
+
+#include "alloc.h"
+#include "sizeof.h"
+#include "string/strcpy/strncat.h"
+
+
+// Similar to strndup(3), but ensure that 's' is an array, and exit on ENOMEM.
+#define XSTRNDUP(s)                                                           \
+(                                                                             \
+	STRNCAT(strcpy(XMALLOC(strnlen(s, NITEMS(s)) + 1, char), ""), s)      \
+)
+
+
+#endif  // include guard