* posix/bits/unistd.h: Avoid calling __*_chk variants if we can

	determine the call will never trigger a failure.

	* sysdeps/i386/i686/memset_chk.S: Remove alias and warning.
	* sysdeps/x86_64/memset_chk.S: Likewise.

2005-02-24  Roland McGrath  <roland@redhat.com>

	* debug/Versions (libc: GLIBC_2.4): Remove
	__memset_zero_constant_len_parameter.
	* sysdeps/generic/memset_chk.c: Remove alias and warning.
	* misc/sys/cdefs.h (__warndecl): New macro.
	* debug/warning-nop.c: New file.
	* string/bits/string3.h (memset): Call __warn_memset_zero_len with no
	arguments, instead of calling __memset_zero_constant_len_parameter.
	Use __warndecl for __warn_memset_zero_len.
	* debug/Makefile (routines): Add $(static-only-routines).
	(static-only-routines): New variable.

5 files changed, 50 insertions, 17 deletions

diff --git a/debug/Makefile b/debug/Makefile
index a3f20fd..c904913 100644
--- a/debug/Makefile
+++ b/debug/Makefile
@@ -24,14 +24,16 @@ subdir	:= debug
 headers	:= execinfo.h
 distribute = sigcontextinfo.h register-dump.h frame.h
 
-routines := backtrace backtracesyms backtracesymsfd noophooks \
+routines  = backtrace backtracesyms backtracesymsfd noophooks \
 	    memcpy_chk memmove_chk mempcpy_chk memset_chk stpcpy_chk \
 	    strcat_chk strcpy_chk strncat_chk strncpy_chk \
 	    sprintf_chk vsprintf_chk snprintf_chk vsnprintf_chk \
 	    printf_chk fprintf_chk vprintf_chk vfprintf_chk \
 	    gets_chk chk_fail readonly-area fgets_chk fgets_u_chk \
 	    read_chk pread_chk pread64_chk recv_chk recvfrom_chk \
-	    readlink_chk getwd_chk getcwd_chk
+	    readlink_chk getwd_chk getcwd_chk \
+	    $(static-only-routines)
+static-only-routines := warning-nop
 
 CFLAGS-backtrace.c = -fno-omit-frame-pointer
 CFLAGS-sprintf_chk.c = -D_IO_MTSAFE_IO
diff --git a/debug/Versions b/debug/Versions
index a4229d7..fd97834 100644
--- a/debug/Versions
+++ b/debug/Versions
@@ -22,7 +22,6 @@ libc {
     __fgets_chk; __fgets_unlocked_chk;
     __read_chk; __pread_chk; __pread64_chk;
     __readlink_chk; __getcwd_chk; __getwd_chk;
-    __memset_zero_constant_len_parameter;
     __recv_chk; __recvfrom_chk;
   }
 }
diff --git a/debug/pread_chk.c b/debug/pread_chk.c
index 6dfa2ab..483b5d0 100644
--- a/debug/pread_chk.c
+++ b/debug/pread_chk.c
@@ -23,11 +23,8 @@
 ssize_t
 __pread_chk (int fd, void *buf, size_t nbytes, off_t offset, size_t buflen)
 {
-  /* In case NBYTES is greater than BUFLEN, we read BUFLEN+1 bytes.
-     This might overflow the buffer but the damage is reduced to just
-     one byte.  And the program will terminate right away.  */
-  ssize_t n = __pread (fd, buf, offset, MIN (nbytes, buflen + 1));
-  if (n > 0 && (size_t) n > buflen)
+  if (nbytes > buflen)
     __chk_fail ();
-  return n;
+
+  return __pread (fd, buf, offset, MIN (nbytes, buflen + 1));
 }
diff --git a/debug/read_chk.c b/debug/read_chk.c
index 88404ed..f738c48 100644
--- a/debug/read_chk.c
+++ b/debug/read_chk.c
@@ -27,15 +27,12 @@
 ssize_t
 __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
 {
-  /* In case NBYTES is greater than BUFLEN, we read BUFLEN+1 bytes.
-     This might overflow the buffer but the damage is reduced to just
-     one byte.  And the program will terminate right away.  */
+  if (nbytes > buflen)
+    __chk_fail ();
+
 #ifdef HAVE_INLINED_SYSCALLS
-  ssize_t n = INLINE_SYSCALL (read, 3, fd, buf, MIN (nbytes, buflen + 1));
+  return = INLINE_SYSCALL (read, 3, fd, buf, nbytes);
 #else
-  ssize_t n = __read (fd, buf, MIN (nbytes, buflen + 1));
+  return = __read (fd, buf, nbytes);
 #endif
-  if (n > 0 && (size_t) n > buflen)
-    __chk_fail ();
-  return n;
 }
diff --git a/debug/warning-nop.c b/debug/warning-nop.c
new file mode 100644
index 0000000..84de3a9
--- /dev/null
+++ b/debug/warning-nop.c
@@ -0,0 +1,38 @@
+/* Dummy nop functions to elicit link-time warnings.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sys/cdefs.h>
+
+void __nop (void)
+{
+}
+
+/* Don't insert any other #include's before this #undef!  */
+
+#undef __warndecl
+#define __warndecl(name, msg) \
+  strong_alias (__nop, name) link_warning (name, msg)
+
+#undef	__USE_FORTIFY_LEVEL
+#define __USE_FORTIFY_LEVEL 99
+
+/* Following here we need an #include for each public header file
+   that uses __warndecl.  */
+
+#include <string.h>