136 lines
3 KiB
C
136 lines
3 KiB
C
/* screendump 1.2 - dump the contents of the console
|
|
* Author: Kees J. Bot
|
|
* 16 Dec 1994
|
|
*/
|
|
#define nil 0
|
|
#include <sys/types.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <string.h>
|
|
#include <termios.h>
|
|
#include <sys/ioctl.h>
|
|
|
|
#define BIOS_CRTBASE 0x00463L /* BIOS parameters: CRT base. */
|
|
#define CRTBASE_MONO 0x03B4 /* Value of CRT base for mono mode. */
|
|
|
|
#define MONO_BASE 0xB0000L /* Screen memory in monochrome mode. */
|
|
#define COLOR_BASE 0xB8000L /* ... colour mode. */
|
|
|
|
#define DEF_COLS 80 /* Default screen geometry. */
|
|
#define DEF_ROWS 25
|
|
|
|
#define MAX_COLS 132 /* Maximum screen geometry. */
|
|
#define MAX_ROWS 60
|
|
|
|
char MEMORY[] = "/dev/mem"; /* Memory device to read screen. */
|
|
int mfd; /* Open memory device. */
|
|
|
|
void tell(const char *message)
|
|
{
|
|
write(2, message, strlen(message));
|
|
}
|
|
|
|
void fatal(const char *label)
|
|
{
|
|
const char *err= strerror(errno);
|
|
|
|
tell("screendump: ");
|
|
tell(label);
|
|
tell(": ");
|
|
tell(err);
|
|
tell("\n");
|
|
exit(1);
|
|
}
|
|
|
|
long video_base(void)
|
|
/* Is it monochrome or colour? */
|
|
{
|
|
static unsigned short bios_crtbase;
|
|
|
|
if (lseek(mfd, (off_t) BIOS_CRTBASE, SEEK_SET) == -1) fatal(MEMORY);
|
|
switch (read(mfd, &bios_crtbase, sizeof(bios_crtbase))) {
|
|
case -1:
|
|
fatal(MEMORY);
|
|
default:
|
|
tell("screendump: can't obtain BIOS parameter: short read\n");
|
|
exit(1);
|
|
case sizeof(bios_crtbase):
|
|
/* Fine */;
|
|
}
|
|
|
|
return bios_crtbase == CRTBASE_MONO ? MONO_BASE : COLOR_BASE;
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
static unsigned char screen[MAX_COLS * MAX_ROWS * 2];
|
|
unsigned char *ps;
|
|
long base;
|
|
int lfd;
|
|
int row;
|
|
int nrows, ncols;
|
|
struct winsize winsize;
|
|
|
|
/* Open the memory device. */
|
|
if ((mfd= open(MEMORY, O_RDONLY)) < 0) fatal(MEMORY);
|
|
|
|
base= video_base();
|
|
|
|
/* Read screen memory. */
|
|
if (lseek(mfd, base, SEEK_SET) == -1) fatal(MEMORY);
|
|
|
|
switch (read(mfd, screen, sizeof(screen))) {
|
|
case -1:
|
|
fatal(MEMORY);
|
|
default:
|
|
tell("screendump: can't obtain screen dump: short read\n");
|
|
exit(1);
|
|
case sizeof(screen):
|
|
/* Fine */;
|
|
}
|
|
|
|
/* Try to obtain the screen geometry from /dev/log. */
|
|
ncols= DEF_COLS;
|
|
nrows= DEF_ROWS;
|
|
if ((lfd= open("/dev/log", O_WRONLY)) != -1
|
|
&& ioctl(lfd, TIOCGWINSZ, &winsize) == 0
|
|
) {
|
|
if (40 <= winsize.ws_col && winsize.ws_col <= MAX_COLS) {
|
|
ncols= winsize.ws_col;
|
|
}
|
|
if (25 <= winsize.ws_row && winsize.ws_row <= MAX_COLS) {
|
|
nrows= winsize.ws_row;
|
|
}
|
|
}
|
|
if (lfd != -1) close(lfd);
|
|
|
|
/* Print the contents of the screen line by line. Omit trailing
|
|
* blanks. Note that screen memory consists of pairs of characters
|
|
* and attribute bytes.
|
|
*/
|
|
ps= screen;
|
|
for (row= 0; row < nrows; row++) {
|
|
char line[MAX_COLS + 1];
|
|
char *pl= line;
|
|
int column;
|
|
int blanks= 0;
|
|
|
|
for (column= 0; column < ncols; column++) {
|
|
if (*ps <= ' ') {
|
|
/* Skip trailing junk. */
|
|
blanks++;
|
|
} else {
|
|
/* Reinsert blanks and add a character. */
|
|
while (blanks > 0) { *pl++= ' '; blanks--; }
|
|
*pl++= *ps;
|
|
}
|
|
/* Skip character and attribute byte. */
|
|
ps+= 2;
|
|
}
|
|
*pl++= '\n';
|
|
if (write(1, line, pl - line) < 0) fatal("stdout");
|
|
}
|
|
exit(0);
|
|
}
|