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/*
* An implementation of a loadable kernel mode driver providing
* multiple kernel/user space bidirectional communications links.
*
* Author: Alan Cox <alan@redhat.com>
*
* 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 of the License, or (at your option) any later version.
*
* Adapted to become the Linux 2.0 Coda pseudo device
* Peter Braam <braam@maths.ox.ac.uk>
* Michael Callahan <mjc@emmy.smith.edu>
*
* Changes for Linux 2.1
* Copyright (c) 1997 Carnegie-Mellon University
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/lp.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <asm/poll.h>
#include <asm/uaccess.h>
#include <linux/coda.h>
#include <linux/coda_linux.h>
#include <linux/coda_fs_i.h>
#include <linux/coda_psdev.h>
#include <linux/coda_proc.h>
#define upc_free(r) kfree(r)
/*
* Coda stuff
*/
extern struct file_system_type coda_fs_type;
/* statistics */
int coda_hard; /* allows signals during upcalls */
unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
struct venus_comm coda_comms[MAX_CODADEVS];
kmem_cache_t *cii_cache, *cred_cache, *upc_cache;
/*
* Device operations
*/
static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
{
struct venus_comm *vcp = (struct venus_comm *) file->private_data;
unsigned int mask = POLLOUT | POLLWRNORM;
poll_wait(file, &vcp->vc_waitq, wait);
if (!list_empty(&vcp->vc_pending))
mask |= POLLIN | POLLRDNORM;
return mask;
}
static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
unsigned int cmd, unsigned long arg)
{
unsigned int data;
switch(cmd) {
case CIOC_KERNEL_VERSION:
data = CODA_KERNEL_VERSION;
return put_user(data, (int *) arg);
default:
return -ENOTTY;
}
return 0;
}
/*
* Receive a message written by Venus to the psdev
*/
static ssize_t coda_psdev_write(struct file *file, const char *buf,
size_t nbytes, loff_t *off)
{
struct venus_comm *vcp = (struct venus_comm *) file->private_data;
struct upc_req *req = NULL;
struct upc_req *tmp;
struct list_head *lh;
struct coda_in_hdr hdr;
ssize_t retval = 0, count = 0;
int error;
/* Peek at the opcode, uniquefier */
if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
return -EFAULT;
CDEBUG(D_PSDEV, "(process,opc,uniq)=(%d,%ld,%ld), nbytes %ld\n",
current->pid, hdr.opcode, hdr.unique, (long)nbytes);
if (DOWNCALL(hdr.opcode)) {
struct super_block *sb = NULL;
union outputArgs *dcbuf;
int size = sizeof(*dcbuf);
sb = vcp->vc_sb;
if ( !sb ) {
CDEBUG(D_PSDEV, "coda_psdev_write: downcall, no SB!\n");
count = nbytes;
goto out;
}
CDEBUG(D_PSDEV, "handling downcall\n");
if ( nbytes < sizeof(struct coda_out_hdr) ) {
printk("coda_downcall opc %ld uniq %ld, not enough!\n",
hdr.opcode, hdr.unique);
count = nbytes;
goto out;
}
if ( nbytes > size ) {
printk("Coda: downcall opc %ld, uniq %ld, too much!",
hdr.opcode, hdr.unique);
nbytes = size;
}
CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
if (copy_from_user(dcbuf, buf, nbytes)) {
CODA_FREE(dcbuf, nbytes);
retval = -EFAULT;
goto out;
}
/* what downcall errors does Venus handle ? */
lock_kernel();
error = coda_downcall(hdr.opcode, dcbuf, sb);
unlock_kernel();
CODA_FREE(dcbuf, nbytes);
if (error) {
printk("psdev_write: coda_downcall error: %d\n", error);
retval = error;
goto out;
}
count = nbytes;
goto out;
}
/* Look for the message on the processing queue. */
lock_kernel();
list_for_each(lh, &vcp->vc_processing) {
tmp = list_entry(lh, struct upc_req , uc_chain);
if (tmp->uc_unique == hdr.unique) {
req = tmp;
list_del(&req->uc_chain);
break;
}
}
unlock_kernel();
if (!req) {
printk("psdev_write: msg (%ld, %ld) not found\n",
hdr.opcode, hdr.unique);
retval = -ESRCH;
goto out;
}
CDEBUG(D_PSDEV,"Eureka: uniq %ld on queue!\n", hdr.unique);
/* move data into response buffer. */
if (req->uc_outSize < nbytes) {
printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %ld, uniq: %ld.\n",
req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
nbytes = req->uc_outSize; /* don't have more space! */
}
if (copy_from_user(req->uc_data, buf, nbytes)) {
req->uc_flags |= REQ_ABORT;
wake_up(&req->uc_sleep);
retval = -EFAULT;
goto out;
}
/* adjust outsize. is this useful ?? */
req->uc_outSize = nbytes;
req->uc_flags |= REQ_WRITE;
count = nbytes;
/* Convert filedescriptor into a file handle */
if (req->uc_opcode == CODA_OPEN_BY_FD) {
struct coda_open_by_fd_out *outp =
(struct coda_open_by_fd_out *)req->uc_data;
outp->fh = fget(outp->fd);
}
CDEBUG(D_PSDEV,
"Found! Count %ld for (opc,uniq)=(%ld,%ld), upc_req at %p\n",
(long)count, hdr.opcode, hdr.unique, &req);
wake_up(&req->uc_sleep);
out:
return(count ? count : retval);
}
/*
* Read a message from the kernel to Venus
*/
static ssize_t coda_psdev_read(struct file * file, char * buf,
size_t nbytes, loff_t *off)
{
DECLARE_WAITQUEUE(wait, current);
struct venus_comm *vcp = (struct venus_comm *) file->private_data;
struct upc_req *req;
ssize_t retval = 0, count = 0;
if (nbytes == 0)
return 0;
lock_kernel();
add_wait_queue(&vcp->vc_waitq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (list_empty(&vcp->vc_pending)) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
break;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&vcp->vc_waitq, &wait);
if (retval)
goto out;
req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
list_del(&req->uc_chain);
/* Move the input args into userspace */
count = req->uc_inSize;
if (nbytes < req->uc_inSize) {
printk ("psdev_read: Venus read %ld bytes of %d in message\n",
(long)nbytes, req->uc_inSize);
count = nbytes;
}
if (copy_to_user(buf, req->uc_data, count))
retval = -EFAULT;
/* If request was not a signal, enqueue and don't free */
if (!(req->uc_flags & REQ_ASYNC)) {
req->uc_flags |= REQ_READ;
list_add(&(req->uc_chain), vcp->vc_processing.prev);
goto out;
}
CDEBUG(D_PSDEV, "vcread: signal msg (%d, %d)\n",
req->uc_opcode, req->uc_unique);
CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
upc_free(req);
out:
unlock_kernel();
return (count ? count : retval);
}
static int coda_psdev_open(struct inode * inode, struct file * file)
{
struct venus_comm *vcp;
int idx;
lock_kernel();
idx = MINOR(inode->i_rdev);
if(idx >= MAX_CODADEVS) {
unlock_kernel();
return -ENODEV;
}
vcp = &coda_comms[idx];
if(vcp->vc_inuse) {
unlock_kernel();
return -EBUSY;
}
if (!vcp->vc_inuse++) {
INIT_LIST_HEAD(&vcp->vc_pending);
INIT_LIST_HEAD(&vcp->vc_processing);
init_waitqueue_head(&vcp->vc_waitq);
vcp->vc_sb = 0;
vcp->vc_seq = 0;
}
file->private_data = vcp;
CDEBUG(D_PSDEV, "device %i - inuse: %d\n", idx, vcp->vc_inuse);
unlock_kernel();
return 0;
}
static int coda_psdev_release(struct inode * inode, struct file * file)
{
struct venus_comm *vcp = (struct venus_comm *) file->private_data;
struct upc_req *req;
struct list_head *lh, *next;
lock_kernel();
if ( !vcp->vc_inuse ) {
unlock_kernel();
printk("psdev_release: Not open.\n");
return -1;
}
CDEBUG(D_PSDEV, "psdev_release: inuse %d\n", vcp->vc_inuse);
if (--vcp->vc_inuse) {
unlock_kernel();
return 0;
}
/* Wakeup clients so they can return. */
CDEBUG(D_PSDEV, "wake up pending clients\n");
lh = vcp->vc_pending.next;
next = lh;
while ( (lh = next) != &vcp->vc_pending) {
next = lh->next;
req = list_entry(lh, struct upc_req, uc_chain);
/* Async requests need to be freed here */
if (req->uc_flags & REQ_ASYNC) {
CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
upc_free(req);
continue;
}
req->uc_flags |= REQ_ABORT;
wake_up(&req->uc_sleep);
}
lh = &vcp->vc_processing;
CDEBUG(D_PSDEV, "wake up processing clients\n");
while ( (lh = lh->next) != &vcp->vc_processing) {
req = list_entry(lh, struct upc_req, uc_chain);
req->uc_flags |= REQ_ABORT;
wake_up(&req->uc_sleep);
}
CDEBUG(D_PSDEV, "Done.\n");
unlock_kernel();
return 0;
}
static struct file_operations coda_psdev_fops = {
owner: THIS_MODULE,
read: coda_psdev_read,
write: coda_psdev_write,
poll: coda_psdev_poll,
ioctl: coda_psdev_ioctl,
open: coda_psdev_open,
release: coda_psdev_release,
};
static devfs_handle_t devfs_handle;
static int init_coda_psdev(void)
{
if(devfs_register_chrdev(CODA_PSDEV_MAJOR,"coda_psdev",
&coda_psdev_fops)) {
printk(KERN_ERR "coda_psdev: unable to get major %d\n",
CODA_PSDEV_MAJOR);
return -EIO;
}
devfs_handle = devfs_mk_dir (NULL, "coda", NULL);
devfs_register_series (devfs_handle, "%u", MAX_CODADEVS, DEVFS_FL_NONE,
CODA_PSDEV_MAJOR, 0,
S_IFCHR | S_IRUSR | S_IWUSR,
&coda_psdev_fops, NULL);
coda_sysctl_init();
return 0;
}
MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
MODULE_LICENSE("GPL");
static int __init init_coda(void)
{
int status;
printk(KERN_INFO "Coda Kernel/Venus communications, v5.3.18, coda@cs.cmu.edu\n");
status = init_coda_psdev();
if ( status ) {
printk("Problem (%d) in init_coda_psdev\n", status);
return status;
}
status = register_filesystem(&coda_fs_type);
if (status) {
printk("coda: failed to register filesystem!\n");
devfs_unregister(devfs_handle);
devfs_unregister_chrdev(CODA_PSDEV_MAJOR,"coda_psdev");
coda_sysctl_clean();
}
return status;
}
static void __exit exit_coda(void)
{
int err;
err = unregister_filesystem(&coda_fs_type);
if ( err != 0 ) {
printk("coda: failed to unregister filesystem\n");
}
devfs_unregister(devfs_handle);
devfs_unregister_chrdev(CODA_PSDEV_MAJOR, "coda_psdev");
coda_sysctl_clean();
}
module_init(init_coda);
module_exit(exit_coda);
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