1 files changed, 70 insertions, 0 deletions
diff --git a/lib/vsnprintf.c b/lib/vsnprintf.c
new file mode 100644
index 0000000..acd4e2d
--- /dev/null
+++ b/lib/vsnprintf.c
@@ -0,0 +1,70 @@
+/* Formatted output to strings.
+   Copyright (C) 2004, 2006-2023 Free Software Foundation, Inc.
+   Written by Simon Josefsson and Yoann Vandoorselaere <yoann@prelude-ids.org>.
+
+   This file 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 file 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 program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification.  */
+#include <stdio.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "vasnprintf.h"
+
+/* Print formatted output to string STR.  Similar to vsprintf, but
+   additional length SIZE limit how much is written into STR.  Returns
+   string length of formatted string (which may be larger than SIZE).
+   STR may be NULL, in which case nothing will be written.  On error,
+   return a negative value.  */
+int
+vsnprintf (char *str, size_t size, const char *format, va_list args)
+{
+  char *output;
+  size_t len;
+  size_t lenbuf = size;
+
+  output = vasnprintf (str, &lenbuf, format, args);
+  len = lenbuf;
+
+  if (!output)
+    return -1;
+
+  if (output != str)
+    {
+      if (size)
+        {
+          size_t pruned_len = (len < size ? len : size - 1);
+          memcpy (str, output, pruned_len);
+          str[pruned_len] = '\0';
+        }
+
+      free (output);
+    }
+
+  if (len > INT_MAX)
+    {
+      errno = EOVERFLOW;
+      return -1;
+    }
+
+  return len;
+}