[funini.com] -> [kei@sodan] -> Kernel Reading

root/fs/coda/psdev.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. coda_psdev_poll
  2. coda_psdev_ioctl
  3. coda_psdev_write
  4. coda_psdev_read
  5. coda_psdev_open
  6. coda_psdev_release
  7. init_coda_psdev
  8. init_coda
  9. exit_coda

/*
 *              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/time.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/smp_lock.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_linux.h>
#include <linux/coda_fs_i.h>
#include <linux/coda_psdev.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);
        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 __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)) {
                struct super_block *sb = NULL;
                union outputArgs *dcbuf;
                int size = sizeof(*dcbuf);

                sb = vcp->vc_sb;
                if ( !sb ) {
                        count = nbytes;
                        goto out;
                }

                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 ? */
                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 (%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 |= 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;
                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;

        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_tail(&(req->uc_chain), &vcp->vc_processing);
                goto out;
        }

        CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
        kfree(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, err;

        idx = iminor(inode);
        if (idx < 0 || idx >= MAX_CODADEVS)
                return -ENODEV;

        lock_kernel();

        err = -EBUSY;
        vcp = &coda_comms[idx];
        if (!vcp->vc_inuse) {
                vcp->vc_inuse++;

                INIT_LIST_HEAD(&vcp->vc_pending);
                INIT_LIST_HEAD(&vcp->vc_processing);
                init_waitqueue_head(&vcp->vc_waitq);
                vcp->vc_sb = NULL;
                vcp->vc_seq = 0;

                file->private_data = vcp;
                err = 0;
        }

        unlock_kernel();
        return err;
}


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, *tmp;

        if (!vcp || !vcp->vc_inuse ) {
                printk("psdev_release: Not open.\n");
                return -1;
        }

        lock_kernel();

        /* Wakeup clients so they can return. */
        list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
                list_del(&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));
                        kfree(req);
                        continue;
                }
                req->uc_flags |= REQ_ABORT;
                wake_up(&req->uc_sleep);
        }

        list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
                list_del(&req->uc_chain);

                req->uc_flags |= REQ_ABORT;
                wake_up(&req->uc_sleep);
        }

        file->private_data = NULL;
        vcp->vc_inuse--;
        unlock_kernel();
        return 0;
}


static const 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 int init_coda_psdev(void)
{
        int i, err = 0;
        if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
              printk(KERN_ERR "coda_psdev: unable to get major %d\n", 
                     CODA_PSDEV_MAJOR);
              return -EIO;
        }
        coda_psdev_class = class_create(THIS_MODULE, "coda");
        if (IS_ERR(coda_psdev_class)) {
                err = PTR_ERR(coda_psdev_class);
                goto out_chrdev;
        }               
        for (i = 0; i < MAX_CODADEVS; i++)
                device_create_drvdata(coda_psdev_class, NULL,
                                      MKDEV(CODA_PSDEV_MAJOR, i),
                                      NULL, "cfs%d", i);
        coda_sysctl_init();
        goto out;

out_chrdev:
        unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
out:
        return err;
}

MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
MODULE_LICENSE("GPL");
MODULE_VERSION("6.6");

static int __init init_coda(void)
{
        int status;
        int i;

        status = coda_init_inodecache();
        if (status)
                goto out2;
        status = init_coda_psdev();
        if ( status ) {
                printk("Problem (%d) in init_coda_psdev\n", status);
                goto out1;
        }
        
        status = register_filesystem(&coda_fs_type);
        if (status) {
                printk("coda: failed to register filesystem!\n");
                goto out;
        }
        return 0;
out:
        for (i = 0; i < MAX_CODADEVS; i++)
                device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
        class_destroy(coda_psdev_class);
        unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
        coda_sysctl_clean();
out1:
        coda_destroy_inodecache();
out2:
        return status;
}

static void __exit exit_coda(void)
{
        int err, i;

        err = unregister_filesystem(&coda_fs_type);
        if ( err != 0 ) {
                printk("coda: failed to unregister filesystem\n");
        }
        for (i = 0; i < MAX_CODADEVS; i++)
                device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
        class_destroy(coda_psdev_class);
        unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
        coda_sysctl_clean();
        coda_destroy_inodecache();
}

module_init(init_coda);
module_exit(exit_coda);


/* [<][>][^][v][top][bottom][index][help] */

[funini.com] -> [kei@sodan] -> Kernel Reading