hurd: permit to use mlock from non-root process

* sysdeps/mach/hurd/mlock.c (mlock): When __get_privileged_ports
returns an error, also try to use host port from __mach_host_self for
the __vm_wire call.
* sysdeps/mach/hurd/munlock.c (munlock): Likewise.

ChangeLog

@@ -1,3 +1,10 @@
+2015-07-09  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* sysdeps/mach/hurd/mlock.c (mlock): When __get_privileged_ports
+	returns an error, also try to use host port from __mach_host_self for
+	the __vm_wire call.
+	* sysdeps/mach/hurd/munlock.c (munlock): Likewise.
+
 2015-07-09  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
 	[BZ #18400]

sysdeps/mach/hurd/mlock.c

@@ -28,19 +28,20 @@
 int
 mlock (const void *addr, size_t len)
 {
-  mach_port_t hostpriv;
+  mach_port_t host;
   vm_address_t page;
   error_t err;
 
-  err = __get_privileged_ports (&hostpriv, NULL);
+  err = __get_privileged_ports (&host, NULL);
   if (err)
-    return __hurd_fail (EPERM);
+    host = __mach_host_self();
 
   page = trunc_page ((vm_address_t) addr);
   len = round_page ((vm_address_t) addr + len) - page;
-  err = __vm_wire (hostpriv, __mach_task_self (), page, len,
-		   VM_PROT_READ);
-  __mach_port_deallocate (__mach_task_self (), hostpriv);
+
+  err = __vm_wire (host, __mach_task_self (), page, len, VM_PROT_READ);
+  if (host != __mach_host_self())
+    __mach_port_deallocate (__mach_task_self (), host);
 
   return err ? __hurd_fail (err) : 0;
 }

sysdeps/mach/hurd/munlock.c

@@ -27,18 +27,20 @@
 int
 munlock (const void *addr, size_t len)
 {
-  mach_port_t hostpriv;
+  mach_port_t host;
   vm_address_t page;
   error_t err;
 
-  err = __get_privileged_ports (&hostpriv, NULL);
+  err = __get_privileged_ports (&host, NULL);
   if (err)
-    return __hurd_fail (EPERM);
+    host = __mach_host_self();
 
   page = trunc_page ((vm_address_t) addr);
   len = round_page ((vm_address_t) addr + len) - page;
-  err = __vm_wire (hostpriv, __mach_task_self (), page, len, VM_PROT_NONE);
-  __mach_port_deallocate (__mach_task_self (), hostpriv);
+
+  err = __vm_wire (host, __mach_task_self (), page, len, VM_PROT_NONE);
+  if (host != __mach_host_self())
+    __mach_port_deallocate (__mach_task_self (), host);
 
   return err ? __hurd_fail (err) : 0;
 }