[RFC] Get selection to buffer addition

[salvador <salvador@inti.gov.ar>]

Hi all:

I'm sending this mail again with the patch in plain text and not
gzip+uuencoded, sorry for any inconvenience.

What I'm looking for:
  I'm looking for comments and approval for a small addition to the console
driver (drivers/char/console.c).

Small description:
  The included patches adds a couple of new services to the TIOCLINUX ioctl
call, they are:

13 (get selection into a buffer): It copies the contents of the selection
buffer (maintained in kernel space) into a user space provided buffer. Is
something like "paste to a buffer"  instead of just paste to the current
console.

14 (get selection length): Returns the length of the selection buffer (0 if
none selected).
-----------

The included file contains diffs that apply
without offsets into 2.4.7 kernel, they are valid for 2.2.18 too (with
offset).
I also include a simple test program that calls the new services. The test
program is really simple and assumes you can open /dev/tty1 (you are
there or you are root ;-)

Additional question: Why the switch uses numbers? Shouldn't these values be
defined as something like TIOCLINUX_GET_SELECTION in a header?

What's the purpose? Just allow pasting in text editors using menues or
without the mouse middle button and avoiding to missinterpret the pasted
text as keystrokes.

SET

Patch (about 77 lines):
-------------------------------------------
--- linux-2.4.7.orig/drivers/char/console.c     Tue Jun 12 15:17:17 2001
+++ linux-2.4.7/drivers/char/console.c  Thu Jul 26 17:33:46 2001
@@ -14,6 +14,8 @@
  *
  * Copy and paste function by Andrew Haylett,
  *   some enhancements by Alessandro Rubini.
+ *   get selection into a buffer and length by
+ *       Salvador E. Tropea <salvador@inti.gov.ar>
  *
  * Code to check for different video-cards mostly by Galen Hunt,
  * <g-hunt@ee.utah.edu>
@@ -2204,6 +2206,10 @@
                        return 0;
                case 12:        /* get fg_console */
                        return fg_console;
+               case 13:        /* get selection into a buffer */
+                       return get_selection_buffer(arg);
+               case 14:        /* get selection length */
+                       return put_user(get_selection_length(), (unsigned int
*)((char *)arg + 1));
        }
        return -EINVAL;
 }
--- linux-2.4.7.orig/drivers/char/selection.c   Fri Feb  9 16:30:22 2001
+++ linux-2.4.7/drivers/char/selection.c        Thu Jul 26 17:53:46 2001
@@ -288,6 +288,41 @@
        return 0;
 }

+/* Copy the contents of the selection buffer into a
+ * user space buffer.
+ * Invoked by ioctl().
+ */
+int get_selection_buffer(const unsigned long arg)
+{
+       char *dest;
+       unsigned int length;
+
+       if (get_user(length, (unsigned int *)(arg + sizeof(char))))
+               return -EFAULT;
+
+       dest = (char *)(arg + sizeof(char) + sizeof(unsigned int));
+
+       if (length > sel_buffer_lth)
+               length = sel_buffer_lth;
+
+       if (sel_buffer) {
+               if (copy_to_user(dest, sel_buffer, length))
+                       return -EFAULT;
+       } else {
+               length = 0;
+       }
+       __put_user(length, (unsigned long *)(arg + sizeof(char)));
+       return 0;
+}
+
+/* Get the selection buffer length.
+ * Invoked by ioctl().
+ */
+unsigned int get_selection_length(void)
+{
+       return sel_buffer ? sel_buffer_lth : 0;
+}
+
 /* Insert the contents of the selection buffer into the
  * queue of the tty associated with the current console.
  * Invoked by ioctl().
--- linux-2.4.7.orig/include/linux/selection.h  Fri Jul 20 16:53:56 2001
+++ linux-2.4.7/include/linux/selection.h       Thu Jul 26 17:40:07 2001
@@ -17,6 +17,8 @@
 extern int sel_loadlut(const unsigned long arg);
 extern int mouse_reporting(void);
 extern void mouse_report(struct tty_struct * tty, int butt, int mrx, int
mry);
+extern int get_selection_buffer(const unsigned long arg);
+extern unsigned int get_selection_length(void);

 #define video_num_columns      (vc_cons[currcons].d->vc_cols)
 #define video_num_lines                (vc_cons[currcons].d->vc_rows)
-------------------------------------------
End of patch.

Test program:
-------------------------------------------
#include <stdio.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
 int i,res,fd,largo;
 char buffer[sizeof(unsigned int)+2],*s;
 unsigned int *lg=(unsigned int *)(buffer+1);

 fd=open("/dev/tty1",O_RDWR);

 printf("Finding the length of the selection:\n");
 buffer[0]=14;
 res=ioctl(fd,TIOCLINUX,&buffer);
 printf("The iotcl returns %d\n",res);
 printf("Length: %u\n",*lg);
 largo=*lg;
 if (*lg==0) return 0;

 printf("Asking for the selection:\n");
 s=(char *)malloc(largo+sizeof(unsigned int)+2);
 s[0]=13;
 lg=(unsigned int *)(s+1);
 *lg=largo;
 res=ioctl(fd,TIOCLINUX,s);
 printf("The iotcl returns %d\n",res);
 largo=*lg;
 printf("Length returned: %d\n",largo);
 s+=1+sizeof(unsigned int);
 s[largo]=0;

 for (i=0; s[i]; i++)
     if (s[i]==13) s[i]=10;
 printf("Selection: '%s' (%d)\n",s,s[0]);
 return 0;
}

--
Salvador Eduardo Tropea (SET). (Electronics Engineer)
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