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authorRoland McGrath <roland@gnu.org>1996-01-05 00:30:10 +0000
committerRoland McGrath <roland@gnu.org>1996-01-05 00:30:10 +0000
commitb93904a94f55b6e877428de7cc949b9b37a661f4 (patch)
tree777d4a781d147b5c8adfe5aa6e82be63c4c8f281 /libdiskfs/disk-pager.c
parentc0d0ff528b07581d77c149e44cfa232ada515d6d (diff)
Initial revision
Diffstat (limited to 'libdiskfs/disk-pager.c')
-rw-r--r--libdiskfs/disk-pager.c102
1 files changed, 102 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);
+}