* misc/sys/cdefs.h (__warndecl, __errordecl): For GCC 4.3+ define

	with __warning__/__error__ attributes.
	(__warnattr): Define.
	* stdlib/bits/stdlib.h (__realpath_chk_warn, __ptsname_r_chk_warn,
	__mbstowcs_chk_warn, __wcstombs_chk_warn): New aliases with
	__warnattr.
	(realpath, ptsname_r, mbstowcs, wcstombs): Call __*_chk_warn instead
	of __*_chk if compile time detectable overflow is found.
	* libio/bits/stdio2.h (__fgets_chk_warn, __fread_chk_warn,
	__fgets_unlocked_chk_warn, __fread_unlocked_chk_warn): New aliases
	with __warnattr.
	(fgets, fread, fgets_unlocked, fread_unlocked): Call __*_chk_warn
	instead of __*_chk if compile time detectable overflow is found.
	(__gets_alias): Rename to...
	(__gets_warn): ... this.  Add __warnattr.
	(gets): Call __gets_warn instead of __gets_alias.
	* socket/bits/socket2.h (__recv_chk_warn, __recvfrom_chk_warn): New
	aliases with __warnattr.
	(recv, recvfrom): Call __*_chk_warn instead of __*_chk if compile
	time detectable overflow is found.
	* posix/bits/unistd.h (__read_chk_warn, __pread_chk_warn,
	__pread64_chk_warn, __readlink_chk_warn, __readlinkat_chk_warn,
	__getcwd_chk_warn, __confstr_chk_warn, __getgroups_chk_warn,
	__ttyname_r_chk_warn, __getlogin_r_chk_warn, __gethostname_chk_warn,
	__getdomainname_chk_warn): New aliases with __warnattr.
	(read, pread, pread64, readlink, readlinkat, getcwd, confstr,
	getgroups, ttyname_r, getlogin_r, gethostname, getdomainname): Call
	__*_chk_warn instead of __*_chk if compile time detectable overflow
	is found.
	(__getgroups_chk): Rename argument to __listlen from listlen.
	(__getwd_alias): Rename to...
	(__getwd_warn): ... this.  Add __warnattr.
	(getwd): Call __getwd_warn instead of __getwd_alias.
	* wcsmbs/bits/wchar2.h (__wmemcpy_chk_warn, __wmemmove_chk_warn,
	__wmempcpy_chk_warn, __wmemset_chk_warn, __wcsncpy_chk_warn,
	__wcpncpy_chk_warn, __fgetws_chk_warn, __fgetws_unlocked_chk_warn,
	__mbsrtowcs_chk_warn, __wcsrtombs_chk_warn, __mbsnrtowcs_chk_warn,
	__wcsnrtombs_chk_warn): New aliases with __warnattr.
	(wmemcpy, wmemmove, wmempcpy, wmemset, mbsrtowcs, wcsrtombs,
	mbsnrtowcs, wcsnrtombs): Call __*_chk_warn instead of __*_chk if
	compile time detectable overflow is found.
	(wcsncpy, wcpncpy): Likewise.  For constant __n fix check whether
	to use __*_chk or not.
	(fgetws, fgetws_unlocked): Divide __bos by sizeof (wchar_t), both
	in comparisons which function should be called and in __*_chk*
	arguments.  Call __*_chk_warn instead of __*_chk if compile time
	detectable overflow is found.
	(swprintf, vswprintf): Divide __bos by sizeof (wchar_t) in
	__*_chk argument.
	* debug/tst-chk1.c (do_test): Add a few more tests.

1 files changed, 64 insertions, 18 deletions

diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h
index 841a0ff..8889540 100644
--- a/libio/bits/stdio2.h
+++ b/libio/bits/stdio2.h
@@ -131,14 +131,16 @@ vfprintf (FILE *__restrict __stream,
 #endif
 
 extern char *__gets_chk (char *__str, size_t) __wur;
-extern char *__REDIRECT (__gets_alias, (char *__str), gets) __wur;
+extern char *__REDIRECT (__gets_warn, (char *__str), gets)
+     __wur __warnattr ("please use fgets or getline instead, gets can't "
+		       "specify buffer size");
 
 __extern_always_inline __wur char *
 gets (char *__str)
 {
   if (__bos (__str) != (size_t) -1)
     return __gets_chk (__str, __bos (__str));
-  return __gets_alias (__str);
+  return __gets_warn (__str);
 }
 
 extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
@@ -146,13 +148,23 @@ extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
 extern char *__REDIRECT (__fgets_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets) __wur;
+extern char *__REDIRECT (__fgets_chk_warn,
+			 (char *__restrict __s, size_t __size, int __n,
+			  FILE *__restrict __stream), __fgets_chk)
+     __wur __warnattr ("fgets called with bigger size than length "
+		       "of destination buffer");
 
 __extern_always_inline __wur char *
 fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
 {
-  if (__bos (__s) != (size_t) -1
-      && (!__builtin_constant_p (__n) || (size_t) __n > __bos (__s)))
-    return __fgets_chk (__s, __bos (__s), __n, __stream);
+  if (__bos (__s) != (size_t) -1)
+    {
+      if (!__builtin_constant_p (__n) || __n <= 0)
+	return __fgets_chk (__s, __bos (__s), __n, __stream);
+
+      if ((size_t) __n > __bos (__s))
+	return __fgets_chk_warn (__s, __bos (__s), __n, __stream);
+    }
   return __fgets_alias (__s, __n, __stream);
 }
 
@@ -163,17 +175,28 @@ extern size_t __REDIRECT (__fread_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
 			  fread) __wur;
+extern size_t __REDIRECT (__fread_chk_warn,
+			  (void *__restrict __ptr, size_t __ptrlen,
+			   size_t __size, size_t __n,
+			   FILE *__restrict __stream),
+			  __fread_chk)
+     __wur __warnattr ("fread called with bigger size * nmemb than length "
+		       "of destination buffer");
 
 __extern_always_inline __wur size_t
 fread (void *__restrict __ptr, size_t __size, size_t __n,
        FILE *__restrict __stream)
 {
-  if (__bos0 (__ptr) != (size_t) -1
-      && (!__builtin_constant_p (__size)
+  if (__bos0 (__ptr) != (size_t) -1)
+    {
+      if (!__builtin_constant_p (__size)
 	  || !__builtin_constant_p (__n)
-	  || (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2))
-	  || __size * __n > __bos0 (__ptr)))
-    return __fread_chk (__ptr, __bos0 (__ptr), __size, __n, __stream);
+	  || (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2)))
+	return __fread_chk (__ptr, __bos0 (__ptr), __size, __n, __stream);
+
+      if (__size * __n > __bos0 (__ptr))
+	return __fread_chk_warn (__ptr, __bos0 (__ptr), __size, __n, __stream);
+    }
   return __fread_alias (__ptr, __size, __n, __stream);
 }
 
@@ -183,13 +206,23 @@ extern char *__fgets_unlocked_chk (char *__restrict __s, size_t __size,
 extern char *__REDIRECT (__fgets_unlocked_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets_unlocked) __wur;
+extern char *__REDIRECT (__fgets_unlocked_chk_warn,
+			 (char *__restrict __s, size_t __size, int __n,
+			  FILE *__restrict __stream), __fgets_unlocked_chk)
+     __wur __warnattr ("fgets_unlocked called with bigger size than length "
+		       "of destination buffer");
 
 __extern_always_inline __wur char *
 fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
 {
-  if (__bos (__s) != (size_t) -1
-      && (!__builtin_constant_p (__n) || (size_t) __n > __bos (__s)))
-    return __fgets_unlocked_chk (__s, __bos (__s), __n, __stream);
+  if (__bos (__s) != (size_t) -1)
+    {
+      if (!__builtin_constant_p (__n) || __n <= 0)
+	return __fgets_unlocked_chk (__s, __bos (__s), __n, __stream);
+
+      if ((size_t) __n > __bos (__s))
+	return __fgets_unlocked_chk_warn (__s, __bos (__s), __n, __stream);
+    }
   return __fgets_unlocked_alias (__s, __n, __stream);
 }
 #endif
@@ -203,17 +236,30 @@ extern size_t __REDIRECT (__fread_unlocked_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
 			  fread_unlocked) __wur;
+extern size_t __REDIRECT (__fread_unlocked_chk_warn,
+			  (void *__restrict __ptr, size_t __ptrlen,
+			   size_t __size, size_t __n,
+			   FILE *__restrict __stream),
+			  __fread_unlocked_chk)
+     __wur __warnattr ("fread_unlocked called with bigger size * nmemb than "
+		       "length of destination buffer");
 
 __extern_always_inline __wur size_t
 fread_unlocked (void *__restrict __ptr, size_t __size, size_t __n,
 		FILE *__restrict __stream)
 {
-  if (__bos0 (__ptr) != (size_t) -1
-      && (!__builtin_constant_p (__size)
+  if (__bos0 (__ptr) != (size_t) -1)
+    {
+      if (!__builtin_constant_p (__size)
 	  || !__builtin_constant_p (__n)
-	  || (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2))
-	  || __size * __n > __bos0 (__ptr)))
-    return __fread_unlocked_chk (__ptr, __bos0 (__ptr), __size, __n, __stream);
+	  || (__size | __n) >= (((size_t) 1) << (8 * sizeof (size_t) / 2)))
+	return __fread_unlocked_chk (__ptr, __bos0 (__ptr), __size, __n,
+				     __stream);
+
+      if (__size * __n > __bos0 (__ptr))
+	return __fread_unlocked_chk_warn (__ptr, __bos0 (__ptr), __size, __n,
+					  __stream);
+    }
 
 # ifdef __USE_EXTERN_INLINES
   if (__builtin_constant_p (__size)