[PATCH] s390: 3270 fullscreen view

      Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix fullscreen view of the 3270 device driver.

Signed-off-by: Richard Hitt <rbh00@utsglobal.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 195 insertions, 39 deletions

diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 60afcdcf91c2..735a7fcdeff5 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -33,8 +33,11 @@ struct fs3270 {
         int read_command;               /* ccw command to use for reads. */
         int write_command;              /* ccw command to use for writes. */
         int attention;                  /* Got attention. */
-        struct raw3270_request *clear;  /* single clear request. */
-        wait_queue_head_t attn_wait;    /* Attention wait queue. */
+        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 void
@@ -43,58 +46,172 @@ 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)
 {
-        wait_queue_head_t wq;
+        struct fs3270 *fp;
         int rc;
 
-        init_waitqueue_head(&wq);
+        fp = (struct fs3270 *) view;
         rq->callback = fs3270_wake_up;
-        rq->callback_data = &wq;
-        rc = raw3270_start(view, rq);
-        if (rc)
-                return rc;
-        /* Started sucessfully. Now wait for completion. */
-        wait_event(wq, raw3270_request_final(rq));
-        return rq->rc;
+        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 sucessfully. 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_proc(fp->fs_pid, SIGHUP, 1);
+        }
+        fp->rdbuf_size = 0;
+        raw3270_request_reset(rq);
+        wake_up(&fp->wait);
 }
 
-/*
- * Switch to the fullscreen view.
- */
 static int
 fs3270_activate(struct raw3270_view *view)
 {
         struct fs3270 *fp;
+        char *cp;
+        int rc;
 
         fp = (struct fs3270 *) view;
-        raw3270_request_set_cmd(fp->clear, TC_EWRITEA);
-        fp->clear->callback = fs3270_reset_callback;
-        return raw3270_start(view, fp->clear);
+
+        /* 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_proc(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)
 {
-        // FIXME: is this a good idea? The user program using fullscreen 3270
-        // will die just because a console message appeared. On the other
-        // hand the fullscreen device is unoperational now.
         struct fs3270 *fp;
 
         fp = (struct fs3270 *) view;
-        if (fp->fs_pid != 0)
-                kill_proc(fp->fs_pid, SIGHUP, 1);
-        fp->fs_pid = 0;
+        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
@@ -103,7 +220,7 @@ fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
         /* Handle ATTN. Set indication and wake waiters for attention. */
         if (irb->scsw.dstat & DEV_STAT_ATTENTION) {
                 fp->attention = 1;
-                wake_up(&fp->attn_wait);
+                wake_up(&fp->wait);
         }
 
         if (rq) {
@@ -125,7 +242,7 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
         struct fs3270 *fp;
         struct raw3270_request *rq;
         struct idal_buffer *ib;
-        int rc;
+        ssize_t rc;
         
         if (count == 0 || count > 65535)
                 return -EINVAL;
@@ -133,7 +250,7 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
         if (!fp)
                 return -ENODEV;
         ib = idal_buffer_alloc(count, 0);
-        if (!ib)
+        if (IS_ERR(ib))
                 return -ENOMEM;
         rq = raw3270_request_alloc(0);
         if (!IS_ERR(rq)) {
@@ -141,10 +258,19 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
                         fp->read_command = 6;
                 raw3270_request_set_cmd(rq, fp->read_command ? : 2);
                 raw3270_request_set_idal(rq, ib);
-                wait_event(fp->attn_wait, fp->attention);
-                rc = fs3270_do_io(&fp->view, rq);
-                if (rc == 0 && idal_buffer_to_user(ib, data, count))
-                        rc = -EFAULT;
+                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);
@@ -162,13 +288,13 @@ fs3270_write(struct file *filp, const char *data, size_t count, loff_t *off)
         struct raw3270_request *rq;
         struct idal_buffer *ib;
         int write_command;
-        int rc;
+        ssize_t rc;
 
         fp = filp->private_data;
         if (!fp)
                 return -ENODEV;
         ib = idal_buffer_alloc(count, 0);
-        if (!ib)
+        if (IS_ERR(ib))
                 return -ENOMEM;
         rq = raw3270_request_alloc(0);
         if (!IS_ERR(rq)) {
@@ -179,6 +305,8 @@ fs3270_write(struct file *filp, const char *data, size_t count, loff_t *off)
                         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);
@@ -232,7 +360,7 @@ fs3270_ioctl(struct inode *inode, struct file *filp,
 }
 
 /*
- * Allocate tty3270 structure.
+ * Allocate fs3270 structure.
  */
 static struct fs3270 *
 fs3270_alloc_view(void)
@@ -243,8 +371,8 @@ fs3270_alloc_view(void)
         if (!fp)
                 return ERR_PTR(-ENOMEM);
         memset(fp, 0, sizeof(struct fs3270));
-        fp->clear = raw3270_request_alloc(0);
-        if (!IS_ERR(fp->clear)) {
+        fp->init = raw3270_request_alloc(0);
+        if (IS_ERR(fp->init)) {
                 kfree(fp);
                 return ERR_PTR(-ENOMEM);
         }
@@ -252,12 +380,17 @@ fs3270_alloc_view(void)
 }
 
 /*
- * Free tty3270 structure.
+ * Free fs3270 structure.
  */
 static void
 fs3270_free_view(struct raw3270_view *view)
 {
-        raw3270_request_free(((struct fs3270 *) view)->clear);
+        struct fs3270 *fp;
+
+        fp = (struct fs3270 *) view;
+        if (fp->rdbuf)
+                idal_buffer_free(fp->rdbuf);
+        raw3270_request_free(((struct fs3270 *) view)->init);
         kfree(view);
 }
 
@@ -285,11 +418,20 @@ static int
 fs3270_open(struct inode *inode, struct file *filp)
 {
         struct fs3270 *fp;
+        struct idal_buffer *ib;
         int minor, rc;
 
         if (imajor(filp->f_dentry->d_inode) != IBM_FS3270_MAJOR)
                 return -ENODEV;
         minor = iminor(filp->f_dentry->d_inode);
+        /* Check for minor 0 multiplexer. */
+        if (minor == 0) {
+                if (!current->signal->tty)
+                        return -ENODEV;
+                if (current->signal->tty->driver->major != IBM_TTY3270_MAJOR)
+                        return -ENODEV;
+                minor = current->signal->tty->index + RAW3270_FIRSTMINOR;
+        }
         /* Check if some other program is already using fullscreen mode. */
         fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);
         if (!IS_ERR(fp)) {
@@ -301,7 +443,7 @@ fs3270_open(struct inode *inode, struct file *filp)
         if (IS_ERR(fp))
                 return PTR_ERR(fp);
 
-        init_waitqueue_head(&fp->attn_wait);
+        init_waitqueue_head(&fp->wait);
         fp->fs_pid = current->pid;
         rc = raw3270_add_view(&fp->view, &fs3270_fn, minor);
         if (rc) {
@@ -309,8 +451,18 @@ fs3270_open(struct inode *inode, struct file *filp)
                 return rc;
         }
 
+        /* 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);
+                return PTR_ERR(fp);
+        }
+        fp->rdbuf = ib;
+
         rc = raw3270_activate_view(&fp->view);
         if (rc) {
+                raw3270_put_view(&fp->view);
                 raw3270_del_view(&fp->view);
                 return rc;
         }
@@ -329,8 +481,12 @@ fs3270_close(struct inode *inode, struct file *filp)
 
         fp = filp->private_data;
         filp->private_data = 0;
-        if (fp)
+        if (fp) {
+                fp->fs_pid = 0;
+                raw3270_reset(&fp->view);
+                raw3270_put_view(&fp->view);
                 raw3270_del_view(&fp->view);
+        }
         return 0;
 }