Re: [PATCH 5/5] Add arc4random() etc. from OpenBSD 5.8

[Corinna Vinschen <vinschen at redhat dot com>]

On Mar 18 17:25, Corinna Vinschen wrote:
> On Mar 18 15:48, Sebastian Huber wrote:
> > On 18/03/16 14:50, Corinna Vinschen wrote:
> > >On Mar 18 12:28, Corinna Vinschen wrote:
> > >>>On Mar 18 11:49, Sebastian Huber wrote:
> > >>>> >According to the OpenBSD man page, "A Replacement Call for Random".  It
> > >>>> >offers high quality random numbers derived from input data obtained by
> > >>>> >the OpenBSD specific getentropy() system call which is declared in
> > >>>> ><unistd.h> and must be implemented for each Newlib port externally.  The
> > >>>> >arc4random() functions are used for example in LibreSSL and OpenSSH.
> > >>>> >
> > >>>> >Cygwin provides currently its own implementation of the arc4random
> > >>>> >family.  Maybe it makes sense to use this getentropy() implementation:
> > >>>> >
> > >>>> >http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libcrypto/crypto/getentropy_win.c?rev=1.4&content-type=text/x-cvsweb-markup
> > >>>
> > >>>No, that pulls in a dependency to another DLL which we're trying to avoid.
> > >>>Using RtlGenRandom should work though.  I have to test this.
> > >All patches applied.  I immediately implemented the changes required for
> > >Cygwin.  In the first place that required to add two functions
> > >arc4random_stir and arc4random_addrandom to maintain backward
> > >compatibility since both OpenBSD functions were already exported by
> > >Cygwin.
> > 
> > My aim with the "newlib/libc/sys/*/include/machine/_arc4random.h" file was
> > to avoid #ifdef SYS_XYZ cascades in the generic files. It seems that for
> > Cygwin there is no "newlib/libc/sys/cygwin" directory. Would it be possible
> > to add this and place a
> > "newlib/libc/sys/cygwin/include/machine/_arc4random.h" in it?
> 
> That might be possible, but the arc4random.h file does not even have
> provisions for redefining _ARC4_LOCK/_ARC4_UNLOCK.  The file defines
> them unconditionally.

Patch proposal:

commit dc12772137ad6fd65f8628e4f8b0625163e46e28
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Fri Mar 18 18:01:07 2016 +0100

    Allow machine-dependent arc4 locking
    
    newlib:
    	* libc/stdlib/arc4random.h: Remove Cygwin-specific locking code.
    	Conditionalize arc4 locking.  Check for _ARC4_LOCK_INIT being
    	undefined to fall back to default implementation.
    
    cygwin:
    	* include/machine/_arc4random.h: New file.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

diff --git a/newlib/libc/stdlib/arc4random.h b/newlib/libc/stdlib/arc4random.h
index 8bb72f4..54bcbe8 100644
--- a/newlib/libc/stdlib/arc4random.h
+++ b/newlib/libc/stdlib/arc4random.h
@@ -37,30 +37,17 @@
 #include <sys/lock.h>
 #include <signal.h>
 
-__LOCK_INIT(static, _arc4random_mutex);
+#ifndef _ARC4_LOCK_INIT
 
-#ifdef __CYGWIN__
-
-extern int __isthreaded;
-
-#define _ARC4_LOCK()				\
-        do {					\
-	  if (__isthreaded)			\
-	    __lock_acquire (_arc4random_mutex);	\
-        } while (0)
-
-#define _ARC4_UNLOCK()				\
-        do {					\
-	  if (__isthreaded)			\
-	    __lock_release (_arc4random_mutex);	\
-        } while (0)
-#else
+#define _ARC4_LOCK_INIT __LOCK_INIT(static, _arc4random_mutex);
 
 #define _ARC4_LOCK() __lock_acquire(_arc4random_mutex)
 
 #define _ARC4_UNLOCK() __lock_release(_arc4random_mutex)
 
-#endif
+#endif /* _ARC4_LOCK_INIT */
+
+_ARC4_LOCK_INIT
 
 #ifdef _ARC4RANDOM_DATA
 _ARC4RANDOM_DATA
diff --git a/winsup/cygwin/include/machine/_arc4random.h b/winsup/cygwin/include/machine/_arc4random.h
new file mode 100644
index 0000000..3ce2458
--- /dev/null
+++ b/winsup/cygwin/include/machine/_arc4random.h
@@ -0,0 +1,30 @@
+/* machine/_arc4random.h
+
+   Copyright 2016 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#ifndef _MACHINE_ARC4RANDOM_H
+#define _MACHINE_ARC4RANDOM_H
+
+extern int __isthreaded;
+
+#define _ARC4_LOCK_INIT	__LOCK_INIT(static, _arc4random_mutex);
+
+#define _ARC4_LOCK()				\
+        do {					\
+	  if (__isthreaded)			\
+	    __lock_acquire (_arc4random_mutex);	\
+        } while (0)
+
+#define _ARC4_UNLOCK()				\
+        do {					\
+	  if (__isthreaded)			\
+	    __lock_release (_arc4random_mutex);	\
+        } while (0)
+
+#endif /* _MACHINE_ARC4RANDOM_H */ 


Ok?


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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