* sysdeps/unix/sysv/linux/kernel-features.h: Define

	__ASSUME_PROC_SELF_FD_SYMLINK.
	* sysdeps/unix/sysv/linux/ttyname.c: Cleanups.  Avoid compatibility
	code is possible.  Move compatibility code in .text.compat section.
	* sysdeps/unix/sysv/linux/ttyname_r.c: Likewise.

3 files changed, 45 insertions, 22 deletions

diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 37d25b1a5c..139e3d5a72 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -85,6 +85,12 @@
 # define __ASSUME_SENDFILE		1
 #endif
 
+/* Only very old kernels had no real symlinks for terminal descriptors
+   in /proc/self/fd.  */
+#if __LINUX_KERNEL_VERSION >= 131584
+# define __ASSUME_PROC_SELF_FD_SYMLINK	1
+#endif
+
 /* On x86 another `getrlimit' syscall was added in 2.3.25.  */
 #if __LINUX_KERNEL_VERSION >= 131865 && defined __i386__
 # define __ASSUME_NEW_GETRLIMIT_SYSCALL	1
diff --git a/sysdeps/unix/sysv/linux/ttyname.c b/sysdeps/unix/sysv/linux/ttyname.c
index 68d24f195e..aed0fd8e0a 100644
--- a/sysdeps/unix/sysv/linux/ttyname.c
+++ b/sysdeps/unix/sysv/linux/ttyname.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991,92,93,1996-2001,2002 Free Software Foundation, Inc.
+/* Copyright (C) 1991,92,93,1996-2002,2006 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
@@ -27,6 +27,7 @@
 #include <stdlib.h>
 
 #include <stdio-common/_itoa.h>
+#include <kernel-features.h>
 
 #if 0
 /* Is this used anywhere?  It is not exported.  */
@@ -41,7 +42,7 @@ static char *getttyname (const char *dev, dev_t mydev,
 libc_freeres_ptr (static char *getttyname_name);
 
 static char *
-internal_function
+internal_function attribute_compat_text_section
 getttyname (const char *dev, dev_t mydev, ino64_t myino, int save, int *dostat)
 {
   static size_t namelen;
@@ -117,10 +118,12 @@ ttyname (int fd)
   int dostat = 0;
   char *name;
   int save = errno;
-  int len;
 
-  if (!__isatty (fd))
-    return NULL;
+  if (__builtin_expect (!__isatty (fd), 0))
+    {
+      __set_errno (ENOTTY);
+      return NULL;
+    }
 
   /* We try using the /proc filesystem.  */
   *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
@@ -136,10 +139,19 @@ ttyname (int fd)
 	}
     }
 
-  len = __readlink (procname, ttyname_buf, buflen);
-  if (len != -1
-      /* This is for Linux 2.0.  */
-      && ttyname_buf[0] != '[')
+  ssize_t len = __readlink (procname, ttyname_buf, buflen);
+  if (__builtin_expect (len == -1 && errno == ENOENT, 0))
+    {
+      __set_errno (EBADF);
+      return NULL;
+    }
+
+  if (__builtin_expect (len != -1
+#ifndef __ASSUME_PROC_SELF_FD_SYMLINK
+			/* This is for Linux 2.0.  */
+			&& ttyname_buf[0] != '['
+#endif
+			, 1))
     {
       if ((size_t) len >= buflen)
 	return NULL;
diff --git a/sysdeps/unix/sysv/linux/ttyname_r.c b/sysdeps/unix/sysv/linux/ttyname_r.c
index eee4d862b2..bd415f167b 100644
--- a/sysdeps/unix/sysv/linux/ttyname_r.c
+++ b/sysdeps/unix/sysv/linux/ttyname_r.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991,92,93,1995-2001, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 1991,92,93,1995-2001,2003,2006 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
@@ -27,13 +27,14 @@
 #include <stdlib.h>
 
 #include <stdio-common/_itoa.h>
+#include <kernel-features.h>
 
 static int getttyname_r (char *buf, size_t buflen,
 			 dev_t mydev, ino64_t myino, int save,
 			 int *dostat) internal_function;
 
 static int
-internal_function
+internal_function attribute_compat_text_section
 getttyname_r (char *buf, size_t buflen, dev_t mydev, ino64_t myino,
 	      int save, int *dostat)
 {
@@ -99,7 +100,6 @@ __ttyname_r (int fd, char *buf, size_t buflen)
   struct stat64 st, st1;
   int dostat = 0;
   int save = errno;
-  int ret;
 
   /* Test for the absolute minimal size.  This makes life easier inside
      the loop.  */
@@ -115,29 +115,34 @@ __ttyname_r (int fd, char *buf, size_t buflen)
       return ERANGE;
     }
 
+  if (__builtin_expect (!__isatty (fd), 0))
+    {
+      __set_errno (ENOTTY);
+      return ENOTTY;
+    }
+
   /* We try using the /proc filesystem.  */
   *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
 
-  ret = __readlink (procname, buf, buflen - 1);
-  if (ret == -1 && errno == ENOENT)
+  ssize_t ret = __readlink (procname, buf, buflen - 1);
+  if (__builtin_expect (ret == -1 && errno == ENOENT, 0))
     {
       __set_errno (EBADF);
       return EBADF;
     }
 
-  if (!__isatty (fd))
-    {
-      __set_errno (ENOTTY);
-      return ENOTTY;
-    }
-
-  if (ret == -1 && errno == ENAMETOOLONG)
+  if (__builtin_expect (ret == -1 && errno == ENAMETOOLONG, 0))
     {
       __set_errno (ERANGE);
       return ERANGE;
     }
 
-  if (ret != -1 && buf[0] != '[')
+  if (__builtin_expect (ret != -1
+#ifndef __ASSUME_PROC_SELF_FD_SYMLINK
+			/* This is for Linux 2.0.  */
+			&& buf[0] != '['
+#endif
+			, 1))
     {
       buf[ret] = '\0';
       return 0;