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/*
* linux/drivers/char/vc_screen.c
*
* Provide access to virtual console memory.
* /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
* /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
* [minor: N]
*
* /dev/vcsaN: idem, but including attributes, and prefixed with
* the 4 bytes lines,columns,x,y (as screendump used to give)
* [minor: N+128]
*
* This replaces screendump and part of selection, so that the system
* administrator can control access using file system permissions.
*
* aeb@cwi.nl - efter Friedas begravelse - 950211
*/
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/fs.h>
#include <asm/segment.h>
#include "vt_kern.h"
#include "selection.h"
#define HEADER_SIZE 4
static inline int
vcs_size(struct inode *inode)
{
int size = video_num_lines * video_num_columns;
if (MINOR(inode->i_rdev) & 128)
size = 2*size + HEADER_SIZE;
return size;
}
static int
vcs_lseek(struct inode *inode, struct file *file, off_t offset, int orig)
{
int size = vcs_size(inode);
switch (orig) {
case 0:
file->f_pos = offset;
break;
case 1:
file->f_pos += offset;
break;
case 2:
file->f_pos = size + offset;
break;
default:
return -EINVAL;
}
if (file->f_pos < 0 || file->f_pos > size)
return -EINVAL;
return file->f_pos;
}
static int
vcs_read(struct inode *inode, struct file *file, char *buf, int count)
{
unsigned long p = file->f_pos;
unsigned int cons = MINOR(inode->i_rdev);
int viewed, attr, size, read;
char *buf0;
unsigned short *org;
attr = (cons & 128);
cons = (cons & 127);
if (cons == 0) {
cons = fg_console;
viewed = 1;
} else {
cons--;
viewed = 0;
}
if (!vc_cons_allocated(cons))
return -ENXIO;
size = vcs_size(inode);
if (count < 0 || p > size)
return -EINVAL;
if (count > size - p)
count = size - p;
buf0 = buf;
if (!attr) {
org = screen_pos(cons, p, viewed);
while (count-- > 0)
put_fs_byte(scr_readw(org++) & 0xff, buf++);
} else {
if (p < HEADER_SIZE) {
char header[HEADER_SIZE];
header[0] = (char) video_num_lines;
header[1] = (char) video_num_columns;
getconsxy(cons, header+2);
while (p < HEADER_SIZE && count-- > 0)
put_fs_byte(header[p++], buf++);
}
p -= HEADER_SIZE;
org = screen_pos(cons, p/2, viewed);
if ((p & 1) && count-- > 0)
put_fs_byte(scr_readw(org++) >> 8, buf++);
while (count > 1) {
put_fs_word(scr_readw(org++), buf);
buf += 2;
count -= 2;
}
if (count > 0)
put_fs_byte(scr_readw(org) & 0xff, buf++);
}
read = buf - buf0;
file->f_pos += read;
return read;
}
static int
vcs_write(struct inode *inode, struct file *file, char *buf, int count)
{
unsigned long p = file->f_pos;
unsigned int cons = MINOR(inode->i_rdev);
int viewed, attr, size, written;
char *buf0;
unsigned short *org;
attr = (cons & 128);
cons = (cons & 127);
if (cons == 0) {
cons = fg_console;
viewed = 1;
} else {
cons--;
viewed = 0;
}
if (!vc_cons_allocated(cons))
return -ENXIO;
size = vcs_size(inode);
if (count < 0 || p > size)
return -EINVAL;
if (count > size - p)
count = size - p;
buf0 = buf;
if (!attr) {
org = screen_pos(cons, p, viewed);
while (count-- > 0) {
scr_writew((scr_readw(org) & 0xff00) |
get_fs_byte(buf++), org);
org++;
}
} else {
if (p < HEADER_SIZE) {
char header[HEADER_SIZE];
getconsxy(cons, header+2);
while (p < HEADER_SIZE && count-- > 0)
header[p++] = get_fs_byte(buf++);
if (!viewed)
putconsxy(cons, header+2);
}
p -= HEADER_SIZE;
org = screen_pos(cons, p/2, viewed);
if ((p & 1) && count-- > 0) {
scr_writew((get_fs_byte(buf++) << 8) |
(scr_readw(org) & 0xff), org);
org++;
}
while (count > 1) {
scr_writew(get_fs_word(buf), org++);
buf += 2;
count -= 2;
}
if (count > 0)
scr_writew((scr_readw(org) & 0xff00) |
get_fs_byte(buf++), org);
}
written = buf - buf0;
file->f_pos += written;
return written;
}
static int
vcs_open(struct inode *inode, struct file *filp)
{
unsigned int cons = (MINOR(inode->i_rdev) & 127);
if(cons && !vc_cons_allocated(cons-1))
return -ENXIO;
return 0;
}
static struct file_operations vcs_fops = {
vcs_lseek, /* lseek */
vcs_read, /* read */
vcs_write, /* write */
NULL, /* readdir */
NULL, /* select */
NULL, /* ioctl */
NULL, /* mmap */
vcs_open, /* open */
NULL, /* release */
NULL /* fsync */
};
long vcs_init(long kmem_start)
{
if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
printk("unable to get major %d for vcs device", VCS_MAJOR);
return kmem_start;
}
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