fs3270.c

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/*
 * IBM/3270 Driver - fullscreen driver.
 *
 * Author(s):
 *   Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
 *   Rewritten for 2.5/2.6 by Martin Schwidefsky <[email protected]>
 *     Copyright IBM Corp. 2003, 2009
 */

#include <linux/bootmem.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <asm/compat.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/ebcdic.h>
#include <asm/idals.h>

#include "raw3270.h"
#include "ctrlchar.h"

static struct raw3270_fn fs3270_fn;

struct fs3270 {
    struct raw3270_view view;
    struct pid *fs_pid;     /* Pid of controlling program. */
    int read_command;       /* ccw command to use for reads. */
    int write_command;      /* ccw command to use for writes. */
    int attention;          /* Got attention. */
    int active;         /* Fullscreen view is active. */
    struct raw3270_request *init;   /* single init request. */
    wait_queue_head_t wait;     /* Init & attention wait queue. */
    struct idal_buffer *rdbuf;  /* full-screen-deactivate buffer */
    size_t rdbuf_size;      /* size of data returned by RDBUF */
};

static DEFINE_MUTEX(fs3270_mutex);

static void
fs3270_wake_up(struct raw3270_request *rq, void *data)
{
    wake_up((wait_queue_head_t *) data);
}

static inline int
fs3270_working(struct fs3270 *fp)
{
    /*
     * The fullscreen view is in working order if the view
     * has been activated AND the initial request is finished.
     */
    return fp->active && raw3270_request_final(fp->init);
}

static int
fs3270_do_io(struct raw3270_view *view, struct raw3270_request *rq)
{
    struct fs3270 *fp;
    int rc;

    fp = (struct fs3270 *) view;
    rq->callback = fs3270_wake_up;
    rq->callback_data = &fp->wait;

    do {
        if (!fs3270_working(fp)) {
            /* Fullscreen view isn't ready yet. */
            rc = wait_event_interruptible(fp->wait,
                              fs3270_working(fp));
            if (rc != 0)
                break;
        }
        rc = raw3270_start(view, rq);
        if (rc == 0) {
            /* Started successfully. Now wait for completion. */
            wait_event(fp->wait, raw3270_request_final(rq));
        }
    } while (rc == -EACCES);
    return rc;
}

/*
 * Switch to the fullscreen view.
 */
static void
fs3270_reset_callback(struct raw3270_request *rq, void *data)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) rq->view;
    raw3270_request_reset(rq);
    wake_up(&fp->wait);
}

static void
fs3270_restore_callback(struct raw3270_request *rq, void *data)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) rq->view;
    if (rq->rc != 0 || rq->rescnt != 0) {
        if (fp->fs_pid)
            kill_pid(fp->fs_pid, SIGHUP, 1);
    }
    fp->rdbuf_size = 0;
    raw3270_request_reset(rq);
    wake_up(&fp->wait);
}

static int
fs3270_activate(struct raw3270_view *view)
{
    struct fs3270 *fp;
    char *cp;
    int rc;

    fp = (struct fs3270 *) view;

    /* If an old init command is still running just return. */
    if (!raw3270_request_final(fp->init))
        return 0;

    if (fp->rdbuf_size == 0) {
        /* No saved buffer. Just clear the screen. */
        raw3270_request_set_cmd(fp->init, TC_EWRITEA);
        fp->init->callback = fs3270_reset_callback;
    } else {
        /* Restore fullscreen buffer saved by fs3270_deactivate. */
        raw3270_request_set_cmd(fp->init, TC_EWRITEA);
        raw3270_request_set_idal(fp->init, fp->rdbuf);
        fp->init->ccw.count = fp->rdbuf_size;
        cp = fp->rdbuf->data[0];
        cp[0] = TW_KR;
        cp[1] = TO_SBA;
        cp[2] = cp[6];
        cp[3] = cp[7];
        cp[4] = TO_IC;
        cp[5] = TO_SBA;
        cp[6] = 0x40;
        cp[7] = 0x40;
        fp->init->rescnt = 0;
        fp->init->callback = fs3270_restore_callback;
    }
    rc = fp->init->rc = raw3270_start_locked(view, fp->init);
    if (rc)
        fp->init->callback(fp->init, NULL);
    else
        fp->active = 1;
    return rc;
}

/*
 * Shutdown fullscreen view.
 */
static void
fs3270_save_callback(struct raw3270_request *rq, void *data)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) rq->view;

    /* Correct idal buffer element 0 address. */
    fp->rdbuf->data[0] -= 5;
    fp->rdbuf->size += 5;

    /*
     * If the rdbuf command failed or the idal buffer is
     * to small for the amount of data returned by the
     * rdbuf command, then we have no choice but to send
     * a SIGHUP to the application.
     */
    if (rq->rc != 0 || rq->rescnt == 0) {
        if (fp->fs_pid)
            kill_pid(fp->fs_pid, SIGHUP, 1);
        fp->rdbuf_size = 0;
    } else
        fp->rdbuf_size = fp->rdbuf->size - rq->rescnt;
    raw3270_request_reset(rq);
    wake_up(&fp->wait);
}

static void
fs3270_deactivate(struct raw3270_view *view)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) view;
    fp->active = 0;

    /* If an old init command is still running just return. */
    if (!raw3270_request_final(fp->init))
        return;

    /* Prepare read-buffer request. */
    raw3270_request_set_cmd(fp->init, TC_RDBUF);
    /*
     * Hackish: skip first 5 bytes of the idal buffer to make
     * room for the TW_KR/TO_SBA/<address>/<address>/TO_IC sequence
     * in the activation command.
     */
    fp->rdbuf->data[0] += 5;
    fp->rdbuf->size -= 5;
    raw3270_request_set_idal(fp->init, fp->rdbuf);
    fp->init->rescnt = 0;
    fp->init->callback = fs3270_save_callback;

    /* Start I/O to read in the 3270 buffer. */
    fp->init->rc = raw3270_start_locked(view, fp->init);
    if (fp->init->rc)
        fp->init->callback(fp->init, NULL);
}

static int
fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
{
    /* Handle ATTN. Set indication and wake waiters for attention. */
    if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION) {
        fp->attention = 1;
        wake_up(&fp->wait);
    }

    if (rq) {
        if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
            rq->rc = -EIO;
        else
            /* Normal end. Copy residual count. */
            rq->rescnt = irb->scsw.cmd.count;
    }
    return RAW3270_IO_DONE;
}

/*
 * Process reads from fullscreen 3270.
 */
static ssize_t
fs3270_read(struct file *filp, char __user *data, size_t count, loff_t *off)
{
    struct fs3270 *fp;
    struct raw3270_request *rq;
    struct idal_buffer *ib;
    ssize_t rc;
    
    if (count == 0 || count > 65535)
        return -EINVAL;
    fp = filp->private_data;
    if (!fp)
        return -ENODEV;
    ib = idal_buffer_alloc(count, 0);
    if (IS_ERR(ib))
        return -ENOMEM;
    rq = raw3270_request_alloc(0);
    if (!IS_ERR(rq)) {
        if (fp->read_command == 0 && fp->write_command != 0)
            fp->read_command = 6;
        raw3270_request_set_cmd(rq, fp->read_command ? : 2);
        raw3270_request_set_idal(rq, ib);
        rc = wait_event_interruptible(fp->wait, fp->attention);
        fp->attention = 0;
        if (rc == 0) {
            rc = fs3270_do_io(&fp->view, rq);
            if (rc == 0) {
                count -= rq->rescnt;
                if (idal_buffer_to_user(ib, data, count) != 0)
                    rc = -EFAULT;
                else
                    rc = count;

            }
        }
        raw3270_request_free(rq);
    } else
        rc = PTR_ERR(rq);
    idal_buffer_free(ib);
    return rc;
}

/*
 * Process writes to fullscreen 3270.
 */
static ssize_t
fs3270_write(struct file *filp, const char __user *data, size_t count, loff_t *off)
{
    struct fs3270 *fp;
    struct raw3270_request *rq;
    struct idal_buffer *ib;
    int write_command;
    ssize_t rc;

    fp = filp->private_data;
    if (!fp)
        return -ENODEV;
    ib = idal_buffer_alloc(count, 0);
    if (IS_ERR(ib))
        return -ENOMEM;
    rq = raw3270_request_alloc(0);
    if (!IS_ERR(rq)) {
        if (idal_buffer_from_user(ib, data, count) == 0) {
            write_command = fp->write_command ? : 1;
            if (write_command == 5)
                write_command = 13;
            raw3270_request_set_cmd(rq, write_command);
            raw3270_request_set_idal(rq, ib);
            rc = fs3270_do_io(&fp->view, rq);
            if (rc == 0)
                rc = count - rq->rescnt;
        } else
            rc = -EFAULT;
        raw3270_request_free(rq);
    } else
        rc = PTR_ERR(rq);
    idal_buffer_free(ib);
    return rc;
}

/*
 * process ioctl commands for the tube driver
 */
static long
fs3270_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    char __user *argp;
    struct fs3270 *fp;
    struct raw3270_iocb iocb;
    int rc;

    fp = filp->private_data;
    if (!fp)
        return -ENODEV;
    if (is_compat_task())
        argp = compat_ptr(arg);
    else
        argp = (char __user *)arg;
    rc = 0;
    mutex_lock(&fs3270_mutex);
    switch (cmd) {
    case TUBICMD:
        fp->read_command = arg;
        break;
    case TUBOCMD:
        fp->write_command = arg;
        break;
    case TUBGETI:
        rc = put_user(fp->read_command, argp);
        break;
    case TUBGETO:
        rc = put_user(fp->write_command, argp);
        break;
    case TUBGETMOD:
        iocb.model = fp->view.model;
        iocb.line_cnt = fp->view.rows;
        iocb.col_cnt = fp->view.cols;
        iocb.pf_cnt = 24;
        iocb.re_cnt = 20;
        iocb.map = 0;
        if (copy_to_user(argp, &iocb, sizeof(struct raw3270_iocb)))
            rc = -EFAULT;
        break;
    }
    mutex_unlock(&fs3270_mutex);
    return rc;
}

/*
 * Allocate fs3270 structure.
 */
static struct fs3270 *
fs3270_alloc_view(void)
{
    struct fs3270 *fp;

    fp = kzalloc(sizeof(struct fs3270),GFP_KERNEL);
    if (!fp)
        return ERR_PTR(-ENOMEM);
    fp->init = raw3270_request_alloc(0);
    if (IS_ERR(fp->init)) {
        kfree(fp);
        return ERR_PTR(-ENOMEM);
    }
    return fp;
}

/*
 * Free fs3270 structure.
 */
static void
fs3270_free_view(struct raw3270_view *view)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) view;
    if (fp->rdbuf)
        idal_buffer_free(fp->rdbuf);
    raw3270_request_free(((struct fs3270 *) view)->init);
    kfree(view);
}

/*
 * Unlink fs3270 data structure from filp.
 */
static void
fs3270_release(struct raw3270_view *view)
{
    struct fs3270 *fp;

    fp = (struct fs3270 *) view;
    if (fp->fs_pid)
        kill_pid(fp->fs_pid, SIGHUP, 1);
}

/* View to a 3270 device. Can be console, tty or fullscreen. */
static struct raw3270_fn fs3270_fn = {
    .activate = fs3270_activate,
    .deactivate = fs3270_deactivate,
    .intv = (void *) fs3270_irq,
    .release = fs3270_release,
    .free = fs3270_free_view
};

/*
 * This routine is called whenever a 3270 fullscreen device is opened.
 */
static int
fs3270_open(struct inode *inode, struct file *filp)
{
    struct fs3270 *fp;
    struct idal_buffer *ib;
    int minor, rc = 0;

    if (imajor(filp->f_path.dentry->d_inode) != IBM_FS3270_MAJOR)
        return -ENODEV;
    minor = iminor(filp->f_path.dentry->d_inode);
    /* Check for minor 0 multiplexer. */
    if (minor == 0) {
        struct tty_struct *tty = get_current_tty();
        if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
            tty_kref_put(tty);
            return -ENODEV;
        }
        minor = tty->index + RAW3270_FIRSTMINOR;
        tty_kref_put(tty);
    }
    mutex_lock(&fs3270_mutex);
    /* Check if some other program is already using fullscreen mode. */
    fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);
    if (!IS_ERR(fp)) {
        raw3270_put_view(&fp->view);
        rc = -EBUSY;
        goto out;
    }
    /* Allocate fullscreen view structure. */
    fp = fs3270_alloc_view();
    if (IS_ERR(fp)) {
        rc = PTR_ERR(fp);
        goto out;
    }

    init_waitqueue_head(&fp->wait);
    fp->fs_pid = get_pid(task_pid(current));
    rc = raw3270_add_view(&fp->view, &fs3270_fn, minor);
    if (rc) {
        fs3270_free_view(&fp->view);
        goto out;
    }

    /* Allocate idal-buffer. */
    ib = idal_buffer_alloc(2*fp->view.rows*fp->view.cols + 5, 0);
    if (IS_ERR(ib)) {
        raw3270_put_view(&fp->view);
        raw3270_del_view(&fp->view);
        rc = PTR_ERR(ib);
        goto out;
    }
    fp->rdbuf = ib;

    rc = raw3270_activate_view(&fp->view);
    if (rc) {
        raw3270_put_view(&fp->view);
        raw3270_del_view(&fp->view);
        goto out;
    }
    nonseekable_open(inode, filp);
    filp->private_data = fp;
out:
    mutex_unlock(&fs3270_mutex);
    return rc;
}

/*
 * This routine is called when the 3270 tty is closed. We wait
 * for the remaining request to be completed. Then we clean up.
 */
static int
fs3270_close(struct inode *inode, struct file *filp)
{
    struct fs3270 *fp;

    fp = filp->private_data;
    filp->private_data = NULL;
    if (fp) {
        put_pid(fp->fs_pid);
        fp->fs_pid = NULL;
        raw3270_reset(&fp->view);
        raw3270_put_view(&fp->view);
        raw3270_del_view(&fp->view);
    }
    return 0;
}

static const struct file_operations fs3270_fops = {
    .owner       = THIS_MODULE,     /* owner */
    .read        = fs3270_read,     /* read */
    .write       = fs3270_write,    /* write */
    .unlocked_ioctl  = fs3270_ioctl,    /* ioctl */
    .compat_ioctl    = fs3270_ioctl,    /* ioctl */
    .open        = fs3270_open,     /* open */
    .release     = fs3270_close,    /* release */
    .llseek     = no_llseek,
};

/*
 * 3270 fullscreen driver initialization.
 */
static int __init
fs3270_init(void)
{
    int rc;

    rc = register_chrdev(IBM_FS3270_MAJOR, "fs3270", &fs3270_fops);
    if (rc)
        return rc;
    return 0;
}

static void __exit
fs3270_exit(void)
{
    unregister_chrdev(IBM_FS3270_MAJOR, "fs3270");
}

MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(IBM_FS3270_MAJOR);

module_init(fs3270_init);
module_exit(fs3270_exit);