Fix F_GETOWN on some Linux archs.

The syscall conventions on some Linux archs prevented F_GETOWN from working
correctly in some situations.  This can be rectified when using the new
F_GETOWN_EX command.

ChangeLog

@@ -1,5 +1,12 @@
 2009-10-29  Ulrich Drepper  <drepper@redhat.com>
 
+	[BZ #10840]
+	* sysdeps/unix/sysv/linux/kernel-features.h: Define
+	__ASSUME_F_GETOWN_EX.
+	* sysdeps/unix/sysv/linux/fcntl.c: Implement F_GETOWN using F_GETOWN_EX
+	if possible.
+	* sysdeps/unix/sysv/linux/i386/fcntl.c: Likewise.
+
 	* sysdeps/unix/sysv/linux/sh/bits/fcntl.h: Define F_OWNER_*
 	and f_owner_ex.
 	* sysdeps/unix/sysv/linux/powerpc/bits/fcntl.h: Likewise.

sysdeps/unix/sysv/linux/fcntl.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2002, 2003, 2004, 2009 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
@@ -23,6 +23,40 @@
 #include <stdarg.h>
 
 #include <sys/syscall.h>
+#include <kernel-features.h>
+
+
+#ifdef __ASSUME_F_GETOWN_EX
+# define miss_F_GETOWN_EX 0
+#else
+static int miss_F_GETOWN_EX;
+#endif
+
+
+static int
+do_fcntl (int fd, int cmd, void *arg)
+{
+  if (cmd != F_GETOWN || miss_F_GETOWN_EX)
+    return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
+
+  INTERNAL_SYSCALL_DECL (err);
+  struct f_owner_ex fex;
+  int res = INTERNAL_SYSCALL (fcntl, err, 3, fd, F_GETOWN_EX, &fex);
+  if (!INTERNAL_SYSCALL_ERROR_P (res, err))
+    return fex.type == F_OWNER_GID ? -fex.pid : fex.pid;
+
+#ifndef __ASSUME_F_GETOWN_EX
+  if (INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
+    {
+      res = INLINE_SYSCALL (fcntl, 3, fd, F_GETOWN, arg);
+      miss_F_GETOWN_EX = 1;
+      return res;
+    }
+#endif
+
+  __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
+  return -1;
+}
 
 
 #ifndef NO_CANCELLATION
@@ -36,7 +70,7 @@ __fcntl_nocancel (int fd, int cmd, ...)
   arg = va_arg (ap, void *);
   va_end (ap);
 
-  return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
+  return do_fcntl (fd, cmd, arg);
 }
 #endif
 
@@ -52,11 +86,11 @@ __libc_fcntl (int fd, int cmd, ...)
   va_end (ap);
 
   if (SINGLE_THREAD_P || cmd != F_SETLKW)
-    return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
+    return do_fcntl (fd, cmd, arg);
 
   int oldtype = LIBC_CANCEL_ASYNC ();
 
-  int result = INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
+  int result = do_fcntl (fd, cmd, arg);
 
   LIBC_CANCEL_RESET (oldtype);
 

sysdeps/unix/sysv/linux/i386/fcntl.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2000,2002,2003,2004,2006 Free Software Foundation, Inc.
+/* Copyright (C) 2000,2002,2003,2004,2006,2009 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
@@ -30,6 +30,13 @@
 int __have_no_fcntl64;
 #endif
 
+#ifdef __ASSUME_F_GETOWN_EX
+# define miss_F_GETOWN_EX 0
+#else
+static int miss_F_GETOWN_EX;
+#endif
+
+
 #if defined NO_CANCELLATION && __ASSUME_FCNTL64 == 0
 # define __fcntl_nocancel  __libc_fcntl
 #endif
@@ -119,6 +126,26 @@ __fcntl_nocancel (int fd, int cmd, ...)
 	assert (F_SETLK - F_SETLKW == F_SETLK64 - F_SETLKW64);
 	return INLINE_SYSCALL (fcntl, 3, fd, cmd + F_SETLK - F_SETLK64, &fl);
       }
+    case F_GETOWN:
+      if (! miss_F_GETOWN_EX)
+	{
+	  INTERNAL_SYSCALL_DECL (err);
+	  struct f_owner_ex fex;
+	  int res = INTERNAL_SYSCALL (fcntl, err, 3, fd, F_GETOWN_EX, &fex);
+	  if (!INTERNAL_SYSCALL_ERROR_P (res, err))
+	    return fex.type == F_OWNER_GID ? -fex.pid : fex.pid;
+
+#ifndef __ASSUME_F_GETOWN_EX
+	  if (INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
+	    miss_F_GETOWN_EX = 1;
+	  else
+#endif
+	    {
+	      __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
+	      return -1;
+	    }
+	}
+      /* FALLTHROUGH */
     default:
       return INLINE_SYSCALL (fcntl, 3, fd, cmd, arg);
     }

sysdeps/unix/sysv/linux/kernel-features.h

@@ -542,3 +542,8 @@
 # define __ASSUME_PREADV	1
 # define __ASSUME_PWRITEV	1
 #endif
+
+/* Support for F_GETOWN_EX was introduced in 2.6.32.  */
+#if __LINUX_KERNEL_VERSION >= 0x020620
+# define __ASSUME_F_GETOWN_EX	1
+#endif