From 9f8c543dc81f0c4239acae6713f5414eb7dc681d Mon Sep 17 00:00:00 2001
From: sin
Date: Fri, 13 Mar 2015 11:00:46 +0000
Subject: Rework fortify implementation to use extern inline

Overriding functions with macros is legal in C but a lot of software
is not prepared for it.  Use the extern inline method to achieve the
same result.
---
 include/stdio.h | 65 +++++++++++++++++++++++++++++----------------------------
 1 file changed, 33 insertions(+), 32 deletions(-)

(limited to 'include/stdio.h')

diff --git a/include/stdio.h b/include/stdio.h
index a33514d..98e51ac 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -6,21 +6,30 @@
 #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0
 
 #ifndef __cplusplus
+#undef fgets
+#undef fread
+#undef fwrite
+#undef vsnprintf
+#undef vsnprintf
+#undef snprintf
+#undef sprintf
 
-static inline __attribute__ ((always_inline))
-char *
-__fortify_fgets(char *s, int n, FILE *fp)
+extern char *__fgets_orig(char *, int, FILE *)
+	__asm__(__USER_LABEL_PREFIX__ "fgets");
+extern __inline __attribute__((__always_inline__,__gnu_inline__))
+char *fgets(char *s, int n, FILE *fp)
 {
 	size_t bos = __builtin_object_size(s, 0);
 
 	if ((size_t)n > bos)
 		__builtin_trap();
-	return fgets(s, n, fp);
+	return __fgets_orig(s, n, fp);
 }
 
-static inline __attribute__ ((always_inline))
-size_t
-__fortify_fread(void *dst, size_t n, size_t nmemb, FILE *fp)
+extern size_t __fread_orig(void *, size_t, size_t, FILE *)
+	__asm__(__USER_LABEL_PREFIX__ "fread");
+extern __inline __attribute__((__always_inline__,__gnu_inline__))
+size_t fread(void *dst, size_t n, size_t nmemb, FILE *fp)
 {
 	size_t bos = __builtin_object_size(dst, 0);
 
@@ -28,12 +37,13 @@ __fortify_fread(void *dst, size_t n, size_t nmemb, FILE *fp)
 		__builtin_trap();
 	if (n * nmemb > bos)
 		__builtin_trap();
-	return fread(dst, n, nmemb, fp);
+	return __fread_orig(dst, n, nmemb, fp);
 }
 
-static inline __attribute__ ((always_inline))
-size_t
-__fortify_fwrite(const void *dst, size_t n, size_t nmemb, FILE *fp)
+extern size_t __fwrite_orig(const void *, size_t, size_t, FILE *)
+	__asm__(__USER_LABEL_PREFIX__ "fwrite");
+extern __inline __attribute__((__always_inline__,__gnu_inline__))
+size_t fwrite(const void *dst, size_t n, size_t nmemb, FILE *fp)
 {
 	size_t bos = __builtin_object_size(dst, 0);
 
@@ -41,48 +51,39 @@ __fortify_fwrite(const void *dst, size_t n, size_t nmemb, FILE *fp)
 		__builtin_trap();
 	if (n * nmemb > bos)
 		__builtin_trap();
-	return fwrite(dst, n, nmemb, fp);
+	return __fwrite_orig(dst, n, nmemb, fp);
 }
 
-static inline __attribute__ ((always_inline))
-int
-__fortify_vsprintf(char *s, const char *fmt, __builtin_va_list ap)
+extern int __vsprintf_orig(char *, const char *, __builtin_va_list)
+	__asm__(__USER_LABEL_PREFIX__ "vsprintf");
+extern __inline __attribute__((__always_inline__,__gnu_inline__))
+int vsprintf(char *s, const char *fmt, __builtin_va_list ap)
 {
 	size_t bos = __builtin_object_size(s, 0);
 	int r;
 
 	if (bos != (size_t)-1) {
-		r = vsnprintf(s, bos, fmt, ap);
+		r = __vsnprintf_orig(s, bos, fmt, ap);
 		if (r != -1 && (size_t)r >= bos)
 			__builtin_trap();
 	} else {
-		r = vsprintf(s, fmt, ap);
+		r = __vsprintf_orig(s, fmt, ap);
 	}
 	return r;
 }
 
-static inline __attribute__ ((always_inline))
-int
-__fortify_vsnprintf(char *s, size_t n, const char *fmt, __builtin_va_list ap)
+extern int __vsnprintf_orig(char *, size_t, const char *, __builtin_va_list)
+	__asm__(__USER_LABEL_PREFIX__ "vsnprintf");
+extern __inline __attribute__((__always_inline__,__gnu_inline__))
+int vsnprintf(char *s, size_t n, const char *fmt, __builtin_va_list ap)
 {
 	size_t bos = __builtin_object_size(s, 0);
 
 	if (n > bos)
 		__builtin_trap();
-	return vsnprintf(s, n, fmt, ap);
+	return __vsnprintf_orig(s, n, fmt, ap);
 }
 
-#undef fgets
-#define fgets(s, n, fp) __fortify_fgets(s, n, fp)
-#undef fread
-#define fread(dst, n, nmemb, fp) __fortify_fread(dst, n, nmemb, fp)
-#undef fwrite
-#define fwrite(dst, n, nmemb, fp) __fortify_fwrite(dst, n, nmemb, fp)
-#undef vsprintf
-#define vsprintf(s, fmt, ap) __fortify_vsprintf(s, fmt, ap)
-#undef vsnprintf
-#define vsnprintf(s, n, fmt, ap) __fortify_vsnprintf(s, n, fmt, ap)
-
 #undef snprintf
 #define snprintf(s, n, fmt, ...) ({ \
 	size_t _n = n; \
-- 
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