1 files changed, 80 insertions, 0 deletions
diff --git a/lib/string/strtcpy.h b/lib/string/strtcpy.h
new file mode 100644
index 0000000..4ff6e11
--- /dev/null
+++ b/lib/string/strtcpy.h
@@ -0,0 +1,80 @@
+/*
+ * SPDX-FileCopyrightText: 2023, Alejandro Colomar <alx@kernel.org>
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+
+#ifndef SHADOW_INCLUDE_LIB_STRTCPY_H_
+#define SHADOW_INCLUDE_LIB_STRTCPY_H_
+
+
+#include <config.h>
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "attr.h"
+#include "defines.h"
+#include "sizeof.h"
+
+
+/*
+ * SYNOPSIS
+ *	[[gnu::null_terminated_string_arg(2)]]
+ *	int STRTCPY(char dst[restrict], const char *restrict src);
+ *
+ * ARGUMENTS
+ *	dst	Destination buffer where to copy a string.
+ *	src	Source string to be copied into dst.
+ *
+ * DESCRIPTION
+ *	This macro copies the string pointed to by src, into a string
+ *	at the buffer pointed to by dst.  If the destination buffer,
+ *	isn't large enough to hold the copy, the resulting string is
+ *	truncated.  The size of the buffer is calculated internally via
+ *	NITEMS().
+ *
+ * RETURN VALUE
+ *	-1	If this call truncated the resulting string.
+ *
+ *	strlen(dst)
+ *		On success.
+ *
+ * ERRORS
+ *	This function doesn't set errno.
+ */
+
+
+#define STRTCPY(dst, src)  strtcpy(dst, src, NITEMS(dst))
+
+
+ATTR_STRING(2)
+inline ssize_t strtcpy(char *restrict dst, const char *restrict src,
+    size_t dsize);
+
+
+inline ssize_t
+strtcpy(char *restrict dst, const char *restrict src, size_t dsize)
+{
+	bool    trunc;
+	size_t  dlen, slen;
+
+	if (dsize == 0)
+		return -1;
+
+	slen = strnlen(src, dsize);
+	trunc = (slen == dsize);
+	dlen = slen - trunc;
+
+	stpcpy(mempcpy(dst, src, dlen), "");
+
+	if (trunc)
+		return -1;
+
+	return slen;
+}
+
+
+#endif  // include guard