[PATCH hurd] Use c_string for default_pager_filename_t to define a new default_pager_paging_storage RPC.

[Flavio Cruz]

This brings us a bit closer to having all types' msgt_size representable
with a single byte. We will be able to avoid mach_msg_type_long_t
entirely for x86_64 since mach_msg_type_t can represent long types using
a separate field.
---
 hurd/default_pager.defs | 30 ++++++++++++++++++++++--------
 mach-defpager/setup.c   | 10 ++++++++++
 sutils/swapon.c         |  9 +++++++--
 trans/proxy-defpager.c  | 11 +++++++++++
 4 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/hurd/default_pager.defs b/hurd/default_pager.defs
index 6b834584..3ca34fc4 100644
--- a/hurd/default_pager.defs
+++ b/hurd/default_pager.defs
@@ -69,14 +69,10 @@ skip;                               /* 
default_pager_paging_file */
 
 skip;                          /* default_pager_register_fileserver */
 
-/* Add or remove an area of paging storage, which is a subset of the
-   Mach device for which device_open returned DEVICE_PORT.  The area
-   consists of the concatenation of contiguous regions described by
-   RUNS.  Each even-numbered element of RUNS gives the starting record
-   number of a region whose length is given by the next odd-numbered
-   element.  NAME is used in any diagnostics the default pager prints
-   about device errors when paging.  When removing a paging area, NAME
-   and RUNS must match exactly.  */
+/* Deprecated RPC to add or remove an area of paging storage.
+ * Was superseded in favor of default_pager_paging_storage_new which
+ * uses the correct type for default_pager_filename_t using c_string.
+ */
 routine default_pager_paging_storage(
                default_pager           : mach_port_t;
                device_port             : mach_port_t;
@@ -101,3 +97,21 @@ routine default_pager_storage_info(
                        array[] of vm_size_t, dealloc;
        out     name                    : data_t);
 
+type new_default_pager_filename_t = c_string[256]
+       ctype: default_pager_filename_t;
+
+/* Add or remove an area of paging storage, which is a subset of the
+   Mach device for which device_open returned DEVICE_PORT.  The area
+   consists of the concatenation of contiguous regions described by
+   RUNS.  Each even-numbered element of RUNS gives the starting record
+   number of a region whose length is given by the next odd-numbered
+   element.  NAME is used in any diagnostics the default pager prints
+   about device errors when paging.  When removing a paging area, NAME
+   and RUNS must match exactly.  */
+routine default_pager_paging_storage_new(
+               default_pager           : mach_port_t;
+               device_port             : mach_port_t;
+               runs                    : recnum_array_t =
+                      array[] of recnum_t;
+               name                    : new_default_pager_filename_t;
+               add                     : boolean_t);
diff --git a/mach-defpager/setup.c b/mach-defpager/setup.c
index 8cd1fed2..087ede71 100644
--- a/mach-defpager/setup.c
+++ b/mach-defpager/setup.c
@@ -100,6 +100,16 @@ S_default_pager_paging_storage (mach_port_t pager,
   return 0;
 }
 
+kern_return_t
+S_default_pager_paging_storage_new (mach_port_t pager,
+                               mach_port_t device,
+                               const recnum_t *runs, mach_msg_type_number_t 
nrun,
+                               const_default_pager_filename_t name,
+                               boolean_t add)
+{
+  return S_default_pager_paging_storage (pager,
+      device, runs, nrun, name, add);
+}
 
 /* Called to read a page from backing store.  */
 int
diff --git a/sutils/swapon.c b/sutils/swapon.c
index 2ee3cd7f..c965d8e2 100644
--- a/sutils/swapon.c
+++ b/sutils/swapon.c
@@ -409,8 +409,13 @@ swaponoff (const char *file, int add, int skipnotexisting)
       runs[j++] = store->runs[i].start;
       runs[j++] = store->runs[i].length;
     }
-  err = default_pager_paging_storage (def_pager, store->port,
-                                     runs, j, file, add);
+  err = default_pager_paging_storage_new (def_pager, store->port,
+                                         runs, j, file, add);
+  if (err == MIG_BAD_ID || err == EOPNOTSUPP)
+    {
+      err = default_pager_paging_storage (def_pager, store->port,
+                                         runs, j, file, add);
+    }
 
   store_free (store);
 
diff --git a/trans/proxy-defpager.c b/trans/proxy-defpager.c
index 878beffe..5d952546 100644
--- a/trans/proxy-defpager.c
+++ b/trans/proxy-defpager.c
@@ -112,6 +112,17 @@ S_default_pager_paging_storage (mach_port_t default_pager,
     ?: mach_port_deallocate (mach_task_self (), device);
 }
 
+kern_return_t
+S_default_pager_paging_storage_new (mach_port_t default_pager,
+                               mach_port_t device,
+                               const recnum_t *runs, mach_msg_type_number_t 
nruns,
+                               const_default_pager_filename_t name,
+                               boolean_t add)
+{
+  return S_default_pager_paging_storage (default_pager,
+      device, runs, nruns, name, add);
+}
+
 kern_return_t
 S_default_pager_object_set_size (mach_port_t memory_object,
                                 mach_port_seqno_t seqno,
-- 
2.39.2