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/*
* Screen-capture program for Linux text consoles
* The "vcs" and "vcsa" drivers give read/write access to a vt's video memory,
* somewhat like direct access to segment 0xb800 under DOS. The vcs version is
* character-only, the vcsa version is character-attribute. There's one for
* each vt, and they're numbered 7,0+ and 7,128+, respectively, with
* /dev/vcs[a]0 corresponding to "/dev/tty".
*/
/*
dscrn.c (c) Bob McCracken
Usage: dscrn [ttyno] > foo
*/
#include <stdio.h>
#include <unistd.h>
#include <termios.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/major.h>
#define PSIZE 4096 /* screen page size */
#define BSIZE (PSIZE << 3) /* 8 pages per vt */
char buf [BSIZE];
void main (int argc, char **argv)
{
int c, x, y; char dev [16]; struct winsize w;
x = (argc < 2) ? 0 : atoi(argv[1]);
ioctl (0, TIOCGWINSZ, &w);
if (x >= 0 && x <= MAX_CHRDEV) /* ttyno in range? */
{
sprintf (dev, "/dev/vcs%d", x); /* only want chars, not attrs */
if ((x = open (dev, 0)) >= 0)
{
y = read (x, buf, BSIZE); close (x);
for (c = x = 0; x < y; x++)
{
if (putchar (buf[x]) == '\n') c = 0; /* (Actually, there
shouldn't be any
newlines in it.) */
else if (++c >= w.ws_col) { c = 0; putchar ('\n'); }
}
}
}
}
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