Initial revision

2 files changed, 164 insertions, 0 deletions

diff --git a/libdiskfs/disk-pager.c b/libdiskfs/disk-pager.c
new file mode 100644
index 00000000..5446c7bf
--- /dev/null
+++ b/libdiskfs/disk-pager.c
@@ -0,0 +1,102 @@
+/* Map the disk image and handle faults accessing it.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   Written by Roland McGrath.
+
+   This program 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.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include "priv.h"
+#include "diskfs-pager.h"
+#include <hurd/sigpreempt.h>
+#include <error.h>
+
+struct pager *disk_pager;
+void *disk_image;
+extern struct port_bucket *pager_bucket;
+
+static void fault_handler (int sig, long int sigcode, struct sigcontext *scp);
+static struct hurd_signal_preempter preempter =
+  { preempter: NULL, handler: (sighandler_t) &fault_handler, };
+
+
+/* A top-level function for the paging thread that just services paging
+   requests.  */
+static void
+service_paging_requests (any_t foo __attribute__ ((unused)))
+{
+  for (;;)
+    ports_manage_port_operations_multithread (pager_bucket, pager_demuxer,
+					      1000 * 60 * 2, 1000 * 60 * 10,
+					      1, MACH_PORT_NULL);
+}
+
+void
+disk_pager_setup (struct user_pager_info *upi, int may_cache)
+{
+  error_t err;
+  mach_port_t disk_pager_port;
+
+  if (! pager_bucket)
+    pager_bucket = ports_create_bucket ();
+
+  /* Make a thread to service paging requests.  */
+  cthread_detach (cthread_fork ((cthread_fn_t) service_paging_requests,
+				(any_t) 0));
+
+  /* Create the pager.  */
+  disk_pager = pager_create (upi, pager_bucket,
+			     may_cache, MEMORY_OBJECT_COPY_NONE);
+  assert (disk_pager);
+
+  /* Get a port to the disk pager.  */
+  disk_pager_port = pager_get_port (disk_pager);
+  mach_port_insert_right (mach_task_self (), disk_pager_port, disk_pager_port,
+			  MACH_MSG_TYPE_MAKE_SEND);
+
+  /* Now map the disk image.  */
+  err = vm_map (mach_task_self (), (vm_address_t *)&disk_image,
+		diskfs_device_size << diskfs_log2_device_block_size,
+		0, 1, disk_pager_port, 0, 0,
+		VM_PROT_READ | (diskfs_readonly ? 0 : VM_PROT_WRITE),
+		VM_PROT_READ | VM_PROT_WRITE,
+		VM_INHERIT_NONE);
+  if (err)
+    error (2, err, "cannot vm_map whole disk");
+
+  /* Set up the signal preempter to catch faults on the disk image.  */
+  preempter.first = (vm_address_t) disk_image;
+  preempter.last = ((vm_address_t) disk_image +
+		    (diskfs_device_size << diskfs_log2_device_block_size));
+  hurd_preempt_signals (&preempter);
+
+  /* We have the mapping; we no longer need the send right.  */
+  mach_port_deallocate (mach_task_self (), disk_pager_port);
+}
+
+static void
+fault_handler (int sig, long int sigcode, struct sigcontext *scp)
+{
+  jmp_buf *env = cthread_data (cthread_self ());
+  error_t err;
+
+  assert (env && "unexpected fault on disk image");
+
+  /* Fetch the error code from the pager.  */
+  assert (scp->sc_error == EKERN_MEMORY_ERROR);
+  err = pager_get_error (disk_pager, sigcode);
+  assert (err);
+
+  /* Make `diskfault_catch' return the error code.  */
+  longjmp (*env, err);
+}
diff --git a/libdiskfs/diskfs-pager.h b/libdiskfs/diskfs-pager.h
new file mode 100644
index 00000000..7b2463b3
--- /dev/null
+++ b/libdiskfs/diskfs-pager.h
@@ -0,0 +1,62 @@
+/* Map the disk image and handle faults accessing it.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   Written by Roland McGrath.
+
+   This program 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.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#ifndef _HURD_DISKFS_PAGER_H
+#define _HURD_DISKFS_PAGER_H 1
+#include <hurd/pager.h>
+#include <hurd/ports.h>
+#include <setjmp.h>
+#include <cthreads.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdlib.h>
+
+
+/* Set up the three variables below and prepare a signal preempter
+   so that the `diskfs_catch_exception' macro below works.
+   INFO and MAY_CACHE are passed to `pager_create'.  */
+extern void disk_pager_setup (struct user_pager_info *info, int may_cache);
+
+extern struct port_bucket *pager_bucket; /* Ports bucket used by pagers.  */
+extern struct pager *disk_pager; /* Pager backing to the disk.  */
+extern void *disk_image;	/* Region mapping entire disk from it.  */
+
+/* Return zero now.  Return a second time with a nonzero error_t
+   if this thread faults accessing `disk_image' before calling
+   `diskfs_end_catch_exception' (below).  */
+#define diskfs_catch_exception()					      \
+({									      \
+    jmp_buf *env = alloca (sizeof (jmp_buf));				      \
+    error_t err;							      \
+    assert (cthread_data (cthread_self ()) == 0);			      \
+    err = setjmp (*env);						      \
+    if (err == 0)							      \
+      cthread_set_data (cthread_self (), env);				      \
+    err;								      \
+})
+
+/* No longer handle faults on `disk_image' in this thread.
+   Any unexpected fault hereafter will crash the program.  */
+#define diskfs_end_catch_exception()					      \
+({									      \
+    assert (cthread_data () != 0);					      \
+    cthread_set_data (cthread_self (), 0);				      \
+})
+
+
+#endif	/* hurd/diskfs-pager.h */