New internal function __access_noerrno

Implement an internal version of __access called __access_noerrno that
avoids setting errno.  This is useful to check accessibility of files
very early on in process startup i.e. before TLS setup.  This allows
tunables to replace MALLOC_CHECK_ safely (i.e. check existence of
/etc/suid-debug to enable/disable MALLOC_CHECK) and at the same time
initialize very early so that it can override IFUNCs.

Checked on x86_64.

	* hurd/hurd.h (__hurd_fail_noerrno): New function.
	* include/unistd.h [IS_IN (rtld) || !defined SHARED]: Declare
	__access_noerrno.
	* io/access.c (__access_noerrno): New function.
	* sysdeps/mach/hurd/access.c (hurd_fail_seterrno): New function.
	(hurd_fail_seterrno): Likewise.
	(access_common): Likewise.
	(__access_noerrno): Likewise.
	* sysdeps/nacl/access.c (__access_noerrno): Likewise.
	* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
	* sysdeps/nacl/nacl-interfaces.h (NACL_CALL_NOERRNO): New
	macro.

1 files changed, 29 insertions, 0 deletions

diff --git a/hurd/hurd.h b/hurd/hurd.h
index ec0782797d..c089d4c445 100644
--- a/hurd/hurd.h
+++ b/hurd/hurd.h
@@ -75,6 +75,35 @@ __hurd_fail (error_t err)
   errno = err;
   return -1;
 }
+
+_HURD_H_EXTERN_INLINE int
+__hurd_fail_noerrno (error_t err)
+{
+  switch (err)
+    {
+    case EMACH_SEND_INVALID_DEST:
+    case EMIG_SERVER_DIED:
+      /* The server has disappeared!  */
+      err = EIEIO;
+      break;
+
+    case KERN_NO_SPACE:
+      err = ENOMEM;
+      break;
+
+    case KERN_INVALID_ARGUMENT:
+      err = EINVAL;
+      break;
+
+    case 0:
+      return 0;
+
+    default:
+      break;
+    }
+
+  return -1;
+}
 
 /* Basic ports and info, initialized by startup.  */