libports: add `ports_lookup_payload' and `ports_payload_get_name'

These two functions map payloads to objects and port names. The former
can be used like `ports_lookup_port' to look up objects, the latter to
map payloads to port names if the server function expects a
`mach_port_t'.

* libports/ports.h: Add function ports_payload_get_name.
* libports/lookup-payload.c: New file.
* libports/ports.h (ports_lookup_payload): Add declaration.
* libports/Makefile (SRCS): Add lookup-payload.c.

3 files changed, 76 insertions, 1 deletions

diff --git a/libports/Makefile b/libports/Makefile
index 30da1c11..f49cb9fd 100644
--- a/libports/Makefile
+++ b/libports/Makefile
@@ -36,7 +36,7 @@ SRCS = create-bucket.c create-class.c \
  interrupt-operation.c interrupt-on-notify.c interrupt-notified-rpcs.c \
  dead-name.c create-port.c import-port.c default-uninhibitable-rpcs.c \
  claim-right.c transfer-right.c create-port-noinstall.c create-internal.c \
- interrupted.c
+ interrupted.c extern-inline.c
 
 installhdrs = ports.h
 
diff --git a/libports/extern-inline.c b/libports/extern-inline.c
new file mode 100644
index 00000000..fbc9e539
--- /dev/null
+++ b/libports/extern-inline.c
@@ -0,0 +1,22 @@
+/* Run time callable functions for extern inlines.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+
+   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#define PORTS_DEFINE_EI
+#include "ports.h"
diff --git a/libports/ports.h b/libports/ports.h
index 652edb88..a625b479 100644
--- a/libports/ports.h
+++ b/libports/ports.h
@@ -29,6 +29,12 @@
 #include <pthread.h>
 #include <refcount.h>
 
+#ifdef PORTS_DEFINE_EI
+#define PORTS_EI
+#else
+#define PORTS_EI __extern_inline
+#endif
+
 /* These are global values for common flags used in the various structures.
    Not all of these are meaningful in all flag fields.  */
 #define PORTS_INHIBITED		0x0100 /* block RPC's */
@@ -234,6 +240,53 @@ mach_port_t ports_get_send_right (void *port);
 void *ports_lookup_port (struct port_bucket *bucket,
 			 mach_port_t port, struct port_class *class);
 
+/* Like ports_lookup_port, but uses PAYLOAD to look up the object.  If
+   this function is used, PAYLOAD must be a pointer to the port
+   structure.  */
+extern void *ports_lookup_payload (struct port_bucket *bucket,
+				   unsigned long payload,
+				   struct port_class *class);
+
+/* This returns the ports name.  This function can be used as
+   intranpayload function turning payloads back into port names.  If
+   this function is used, PAYLOAD must be a pointer to the port
+   structure.  */
+extern mach_port_t ports_payload_get_name (unsigned int payload);
+
+#if defined(__USE_EXTERN_INLINES) || defined(PORTS_DEFINE_EI)
+
+PORTS_EI void *
+ports_lookup_payload (struct port_bucket *bucket,
+		      unsigned long payload,
+		      struct port_class *class)
+{
+  struct port_info *pi = (struct port_info *) payload;
+
+  if (pi && bucket && pi->bucket != bucket)
+    pi = NULL;
+
+  if (pi && class && pi->class != class)
+    pi = NULL;
+
+  if (pi)
+    refcounts_unsafe_ref (&pi->refcounts, NULL);
+
+  return pi;
+}
+
+PORTS_EI mach_port_t
+ports_payload_get_name (unsigned int payload)
+{
+  struct port_info *pi = (struct port_info *) payload;
+
+  if (pi)
+    return pi->port_right;
+
+  return MACH_PORT_NULL;
+}
+
+#endif /* Use extern inlines.  */
+
 /* Allocate another reference to PORT. */
 void ports_port_ref (void *port);