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/* 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 =
{
signals: sigmask (SIGSEGV) | sigmask (SIGBUS),
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_check_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");
/* Clear the record, since the faulting thread will not. */
cthread_set_data (cthread_self (), 0);
/* 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);
}
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