lib/string/strcpy/: strtcat(), STRTCAT(): Add APIs

Signed-off-by: Alejandro Colomar <[email protected]>

Author: alejandro-colomar

lib/Makefile.am

@@ -223,6 +223,8 @@ libshadow_la_SOURCES = \
 	string/strcpy/strncat.h \
 	string/strcpy/strncpy.c \
 	string/strcpy/strncpy.h \
+	string/strcpy/strtcat.c \
+	string/strcpy/strtcat.h \
 	string/strcpy/strtcpy.c \
 	string/strcpy/strtcpy.h \
 	string/strdup/strndupa.c \

lib/string/strcpy/strtcat.c

@@ -0,0 +1,13 @@
+// SPDX-FileCopyrightText: 2025, Alejandro Colomar <[email protected]>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#include "config.h"
+
+#include "string/strcpy/strtcat.h"
+
+#include <sys/types.h>
+
+
+extern inline ssize_t strtcat(char *restrict dst, const char *restrict src,
+    ssize_t dsize);

lib/string/strcpy/strtcat.h

@@ -0,0 +1,44 @@
+// SPDX-FileCopyrightText: 2025, Alejandro Colomar <[email protected]>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#ifndef SHADOW_INCLUDE_LIB_STRING_STRCPY_STRTCAT_H_
+#define SHADOW_INCLUDE_LIB_STRING_STRCPY_STRTCAT_H_
+
+
+#include "config.h"
+
+#include <string.h>
+#include <sys/types.h>
+
+#include "attr.h"
+#include "sizeof.h"
+#include "string/strcpy/strtcpy.h"
+
+
+#define STRTCAT(dst, src)  strtcat(dst, src, countof(dst))
+
+
+ATTR_STRING(2)
+inline ssize_t strtcat(char *restrict dst, const char *restrict src,
+    ssize_t dsize);
+
+
+// string truncate catenate
+// Returns new length, or -1 on truncation.
+inline ssize_t
+strtcat(char *restrict dst, const char *restrict src, ssize_t dsize)
+{
+	ssize_t  oldlen, n;
+
+	oldlen = strlen(dst);
+
+	n = strtcpy(dst + oldlen, src, dsize - oldlen);
+	if (n == -1)
+		return -1;
+
+	return oldlen + n;
+}
+
+
+#endif  // include guard