3 files changed, 157 insertions, 2 deletions

diff --git a/stdio.c b/stdio.c
index f26b69b..bef7ef8 100644
--- a/stdio.c
+++ b/stdio.c
@@ -1,3 +1,116 @@
+#include <assert.h>
+#include <stdarg.h>
 #include <stdio.h>
+#include <wchar.h>
+
+size_t __fread_chk(void *ptr, size_t size, size_t nmemb, FILE *stream)
+{
+	assert(ptr != NULL);
+	assert(stream != NULL);
+	return fread(ptr, size, nmemb, stream);
+}
+
+int __printf_chk(int flag, const char *format, ...)
+{
+	va_list argp;
+	int result;
+
+	if(flag > 0)
+	{
+		assert(format != NULL);
+	}
+
+	va_start(argp, format);
+	result = vprintf(format, argp);
+	va_end(argp);
+
+	return result;
+}
+
+int __fprintf_chk(FILE *stream, int flag, const char *format, ...)
+{
+	va_list argp;
+	int result;
+
+	if(flag > 0)
+	{
+		assert(stream != NULL);
+		assert(format != NULL);
+	}
+
+	va_start(argp, format);
+	result = vfprintf(stream, format, argp);
+	va_end(argp);
+
+	return result;
+}
+
+int __snprintf_chk(char *str, size_t size, int flag, size_t strlen, const char *format, ...)
+{
+	va_list argp;
+	int result;
+
+	if(flag > 0)
+	{
+		assert(str != NULL);
+		assert(format != NULL);
+	}
+	// must always be done per LFS
+	assert(size <= strlen);
+
+	va_start(argp, format);
+	result = vsnprintf(str, size, format, argp);
+	va_end(argp);
+
+	return result;
+}
+
+int __swprintf_chk(wchar_t *wcs, size_t maxlen, int flag, size_t wcslen, const wchar_t *format, ...)
+{
+	va_list argp;
+	int result;
+
+	if(flag > 0)
+	{
+		assert(wcs != NULL);
+		assert(format != NULL);
+	}
+	// must always be done per LFS
+	assert(maxlen <= wcslen);
+
+	va_start(argp, format);
+	result = vswprintf(wcs, maxlen, format, argp);
+	va_end(argp);
+
+	return result;
+}
+
+int __vasprintf_chk(char **strp, const char *fmt, va_list ap)
+{
+	assert(strp != NULL);
+	assert(fmt != NULL);
+	return vasprintf(strp, fmt, ap);
+}
+
+int __vfprintf_chk(FILE *stream, int flag, const char *format, va_list ap)
+{
+	if(flag > 0)
+	{
+		assert(stream != NULL);
+		assert(format != NULL);
+	}
+	return vfprintf(stream, format, ap);
+}
+
+int __vsnprintf_chk(char *str, size_t size, int flag, size_t strlen, const char *format, va_list ap)
+{
+	if(flag > 0)
+	{
+		assert(str != NULL);
+		assert(format != NULL);
+	}
+	// must always be done per LFS
+	assert(size <= strlen);
+	return vsnprintf(str, size, format, ap);
+}
 
-asm(".equ __IO_2_1_stdout_, _stdout");
diff --git a/stdlib.c b/stdlib.c
index b81eb91..30c904e 100644
--- a/stdlib.c
+++ b/stdlib.c
@@ -1,6 +1,12 @@
 #include <assert.h>	// assert
 #include <stdlib.h>	// strtod
 
+char *__realpath_chk(const char *path, char *resolved_path)
+{
+	assert(path != NULL);
+	return realpath(path, resolved_path);
+}
+
 double __strtod_internal(const char *__nptr, char **__endptr, int __group)
 {
 	assert(__group == 0);
diff --git a/string.c b/string.c
index 5bbb1b3..e50716a 100644
--- a/string.c
+++ b/string.c
@@ -1,4 +1,40 @@
-#include <string.h>	/* strndup */
+#include <assert.h>	/* assert */
+#include <string.h>	/* memcpy, strcpy, strncat, strndup */
+
+/* "Checked" memcpy */
+void *__memcpy_chk(void *dest, const void *src, size_t len, size_t destlen)
+{
+	assert(dest != NULL);
+	assert(src != NULL);
+	assert(len <= destlen);
+	if(src < dest)
+	{
+		assert(!(src + len >= dest));
+	} else {
+		assert(!(dest + len >= src));
+	}
+	return memcpy(dest, src, len);
+}
+
+/* "Checked" strncat */
+char *__strncat_chk(char *dest, const char *src, size_t n, size_t destlen)
+{
+	assert(dest != NULL);
+	assert(src != NULL);
+	assert(n <= destlen);
+
+	return strncat(dest, src, n);
+}
+
+/* "Checked" strcpy */
+char *__strcpy_chk(char *dest, const char *src, size_t destlen)
+{
+	assert(dest != NULL);
+	assert(src != NULL);
+	assert(strlen(src) < destlen);
+
+	return strcpy(dest, src);
+}
 
 /* Literally a useless __ alias. */
 char *__strndup(const char *str, size_t count)