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/*
* An implementation of a loadable kernel mode driver providing
* multiple kernel/user space bidirectional communications links.
*
* Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* 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/time.h>
#include <linux/sched.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/vmalloc.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/poll.h>
#include <asm/uaccess.h>
#include <linux/coda.h>
#include <linux/coda_psdev.h>
#include "coda_linux.h"
#include "coda_int.h"
/* 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];
static struct class *coda_psdev_class;
/*
* 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);
mutex_lock(&vcp->vc_mutex);
if (!list_empty(&vcp->vc_pending))
mask |= POLLIN | POLLRDNORM;
mutex_unlock(&vcp->vc_mutex);
return mask;
}
static long coda_psdev_ioctl(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 __user *) 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 __user *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;
if (DOWNCALL(hdr.opcode)) {
union outputArgs *dcbuf;
int size = sizeof(*dcbuf);
if ( nbytes < sizeof(struct coda_out_hdr) ) {
printk("coda_downcall opc %d uniq %d, not enough!\n",
hdr.opcode, hdr.unique);
count = nbytes;
goto out;
}
if ( nbytes > size ) {
printk("Coda: downcall opc %d, uniq %d, 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 ? */
error = coda_downcall(vcp, hdr.opcode, dcbuf);
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. */
mutex_lock(&vcp->vc_mutex);
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;
}
}
mutex_unlock(&vcp->vc_mutex);
if (!req) {
printk("psdev_write: msg (%d, %d) not found\n",
hdr.opcode, hdr.unique);
retval = -ESRCH;
goto out;
}
/* move data into response buffer. */
if (req->uc_outSize < nbytes) {
printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\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 |= CODA_REQ_ABORT;
wake_up(&req->uc_sleep);
retval = -EFAULT;
goto out;
}
/* adjust outsize. is this useful ?? */
req->uc_outSize = nbytes;
req->uc_flags |= CODA_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;
if (!outp->oh.result)
outp->fh = fget(outp->fd);
}
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 __user * 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;
mutex_lock(&vcp->vc_mutex);
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;
}
mutex_unlock(&vcp->vc_mutex);
schedule();
mutex_lock(&vcp->vc_mutex);
}
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 & CODA_REQ_ASYNC)) {
req->uc_flags |= CODA_REQ_READ;
list_add_tail(&(req->uc_chain), &vcp->vc_processing);
goto out;
}
CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
kfree(req);
out:
mutex_unlock(&vcp->vc_mutex);
return (
|