stdio: Clean up, add all of LSB stdio plus more

* Add all (non-wchar) stdio functions from LSB, plus those found in use
  in other applications. Document those functions from LSB as such.
* Use a consistent structure and paramater names for all functions.
* flag == 0 means FORTIFY_SOURCE=1, so the implemented checks should be
  unconditional.
* Add all possible checks without parsing the format string.
* Move functions from wchar.h to their own appropriately-named file.

Signed-off-by: Samuel Holland <samuel@sholland.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/libgcompat/wchar.c b/libgcompat/wchar.c
new file mode 100644
index 0000000..1ddaa1f
--- /dev/null
+++ b/libgcompat/wchar.c
@@ -0,0 +1,40 @@
+#include <assert.h> /* assert */
+#include <stdarg.h> /* va_list, va_start, va_end */
+#include <stddef.h> /* size_t */
+#include <wchar.h>  /* wchar_t, *wprintf */
+
+int __vswprintf_chk(wchar_t *s, size_t n, int flag, size_t slen,
+                    const wchar_t *format, va_list ap);
+
+/**
+ * Convert formatted wide-character output, with stack checking
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---swprintf-chk-1.html
+ */
+int __swprintf_chk(wchar_t *s, size_t n, int flag, size_t slen,
+                   const wchar_t *format, ...)
+{
+	int ret;
+	va_list ap;
+
+	va_start(ap, format);
+	ret = __vswprintf_chk(s, n, flag, slen, format, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+/**
+ * Convert formatted wide-character output, with stack checking
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---vswprintf-chk-1.html
+ */
+int __vswprintf_chk(wchar_t *s, size_t n, int flag, size_t slen,
+                    const wchar_t *format, va_list ap)
+{
+	assert(s != NULL || n == 0);
+	assert(slen >= n);
+	assert(format != NULL);
+
+	return vswprintf(s, n, format, ap);
+}