Export getentropy and getrandom calls

getentropy per OpenBSD

  http://man.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/getentropy.2

getrandom per Linux

  http://man7.org/linux/man-pages/man2/getrandom.2.html

  Note that GRND_NONBLOCK is not handled

winsup/cygwin/common.din

@@ -604,6 +604,7 @@ getdelim = __getdelim SIGFE
 getdomainname SIGFE
 getdtablesize NOSIGFE
 getegid NOSIGFE
+getentropy SIGFE
 getenv NOSIGFE
 geteuid NOSIGFE
 getgid NOSIGFE
@@ -650,6 +651,7 @@ getpwnam SIGFE
 getpwnam_r SIGFE
 getpwuid SIGFE
 getpwuid_r SIGFE
+getrandom SIGFE
 getrlimit SIGFE
 getrusage SIGFE
 gets SIGFE

winsup/cygwin/include/cygwin/version.h

@@ -10,8 +10,8 @@ details. */
    the Cygwin shared library".  This version is used to track important
    changes to the DLL and is mainly informative in nature. */
 
-#define CYGWIN_VERSION_DLL_MAJOR 2006
+#define CYGWIN_VERSION_DLL_MAJOR 2007
-#define CYGWIN_VERSION_DLL_MINOR 1
+#define CYGWIN_VERSION_DLL_MINOR 0
 
 /* Major numbers before CYGWIN_VERSION_DLL_EPOCH are incompatible. */
 
@@ -470,12 +470,13 @@ details. */
   303: Export pthread_getname_np, pthread_setname_np.
   304: Export strerror_l, strptime_l, wcsftime_l.
   305: [f]pathconf flag _PC_CASE_INSENSITIVE added.
+  306: Export getentropy, getrandom.
 
   Note that we forgot to bump the api for ualarm, strtoll, strtoull,
   sigaltstack, sethostname. */
 
 #define CYGWIN_VERSION_API_MAJOR 0
-#define CYGWIN_VERSION_API_MINOR 305
+#define CYGWIN_VERSION_API_MINOR 306
 
 /* There is also a compatibity version number associated with the shared memory
    regions.  It is incremented when incompatible changes are made to the shared

winsup/cygwin/include/sys/random.h

@@ -0,0 +1,29 @@
+/* sys/random.h header file for Cygwin.
+
+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 _SYS_RANDOM_H
+#define _SYS_RANDOM_H
+
+#include <_ansi.h>
+#include <sys/types.h>
+
+/* getrandom flags */
+#define GRND_NONBLOCK	1
+#define GRND_RANDOM	2
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+ssize_t getrandom (void *__ptr, size_t __len, unsigned int __flags);
+int getentropy (void *__ptr, size_t __len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SYS_RANDOM_H */

winsup/cygwin/miscfuncs.cc

@@ -14,6 +14,7 @@ details. */
 #include <alloca.h>
 #include <limits.h>
 #include <sys/param.h>
+#include <sys/random.h>
 #include <wchar.h>
 #include "cygtls.h"
 #include "ntdll.h"
@@ -234,19 +235,62 @@ check_iovec (const struct iovec *iov, int iovcnt, bool forwrite)
   return -1;
 }
 
-/* Used by arc2random, fhandler_socket and fhandler_random. */
 extern "C" int
 getentropy (void *ptr, size_t len)
 {
-  if (!RtlGenRandom (ptr, len))
+  /* Per BSD man page: The maximum buffer size permitted is 256 bytes.
+     If buflen exceeds this, an error of EIO will be indicated. */
+  if (len > 256)
     {
-      debug_printf ("%E = RtlGenRandom()");
+      debug_printf ("len (%U) > 256", len);
       set_errno (EIO);
       return -1;
     }
+  __try
+    {
+      if (!RtlGenRandom (ptr, len))
+	{
+	  debug_printf ("RtlGenRandom() = FALSE");
+	  set_errno (EIO);
+	  return -1;
+	}
+    }
+  __except (EFAULT)
+    {
+      return -1;
+    }
+  __endtry
   return 0;
 }
 
+extern "C" ssize_t
+getrandom (void *ptr, size_t len, unsigned int flags)
+{
+  if (flags & ~(GRND_NONBLOCK | GRND_RANDOM))
+    {
+      debug_printf ("invalid flags: %y", flags);
+      set_errno (EINVAL);
+      return -1;
+    }
+  /* Max. bytes returned by Linux call. */
+  len = MAX (len, (flags & GRND_RANDOM) ? 512 : 33554431);
+  __try
+    {
+      if (!RtlGenRandom (ptr, len))
+	{
+	  debug_printf ("RtlGenRandom() = FALSE");
+	  set_errno (EIO);
+	  return -1;
+	}
+    }
+  __except (EFAULT)
+    {
+      return -1;
+    }
+  __endtry
+  return len;
+}
+
 /* Try hard to schedule another thread.  
    Remember not to call this in a lock condition or you'll potentially
    suffer starvation.  */

winsup/cygwin/release/2.7.0

@@ -0,0 +1,14 @@
+What's new:
+-----------
+
+- New API: getentropy, getrandom.
+
+
+What changed:
+-------------
+
+
+Bug Fixes
+---------
+
+