source: trunk/minix/commands/ibm/screendump.c@ 10

Last change on this file since 10 was 9, checked in by Mattia Monga, 13 years ago

Minix 3.1.2a

File size: 3.0 KB
Line 
1/* screendump 1.2 - dump the contents of the console
2 * Author: Kees J. Bot
3 * 16 Dec 1994
4 */
5#define nil 0
6#include <sys/types.h>
7#include <stdlib.h>
8#include <unistd.h>
9#include <errno.h>
10#include <fcntl.h>
11#include <string.h>
12#include <termios.h>
13#include <sys/ioctl.h>
14
15#define BIOS_CRTBASE 0x00463L /* BIOS parameters: CRT base. */
16#define CRTBASE_MONO 0x03B4 /* Value of CRT base for mono mode. */
17
18#define MONO_BASE 0xB0000L /* Screen memory in monochrome mode. */
19#define COLOR_BASE 0xB8000L /* ... colour mode. */
20
21#define DEF_COLS 80 /* Default screen geometry. */
22#define DEF_ROWS 25
23
24#define MAX_COLS 132 /* Maximum screen geometry. */
25#define MAX_ROWS 60
26
27char MEMORY[] = "/dev/mem"; /* Memory device to read screen. */
28int mfd; /* Open memory device. */
29
30void tell(const char *message)
31{
32 write(2, message, strlen(message));
33}
34
35void fatal(const char *label)
36{
37 const char *err= strerror(errno);
38
39 tell("screendump: ");
40 tell(label);
41 tell(": ");
42 tell(err);
43 tell("\n");
44 exit(1);
45}
46
47long video_base(void)
48/* Is it monochrome or colour? */
49{
50 static unsigned short bios_crtbase;
51
52 if (lseek(mfd, (off_t) BIOS_CRTBASE, SEEK_SET) == -1) fatal(MEMORY);
53 switch (read(mfd, &bios_crtbase, sizeof(bios_crtbase))) {
54 case -1:
55 fatal(MEMORY);
56 default:
57 tell("screendump: can't obtain BIOS parameter: short read\n");
58 exit(1);
59 case sizeof(bios_crtbase):
60 /* Fine */;
61 }
62
63 return bios_crtbase == CRTBASE_MONO ? MONO_BASE : COLOR_BASE;
64}
65
66void main(void)
67{
68 static unsigned char screen[MAX_COLS * MAX_ROWS * 2];
69 unsigned char *ps;
70 long base;
71 int lfd;
72 int row;
73 int nrows, ncols;
74 struct winsize winsize;
75
76 /* Open the memory device. */
77 if ((mfd= open(MEMORY, O_RDONLY)) < 0) fatal(MEMORY);
78
79 base= video_base();
80
81 /* Read screen memory. */
82 if (lseek(mfd, base, SEEK_SET) == -1) fatal(MEMORY);
83
84 switch (read(mfd, screen, sizeof(screen))) {
85 case -1:
86 fatal(MEMORY);
87 default:
88 tell("screendump: can't obtain screen dump: short read\n");
89 exit(1);
90 case sizeof(screen):
91 /* Fine */;
92 }
93
94 /* Try to obtain the screen geometry from /dev/log. */
95 ncols= DEF_COLS;
96 nrows= DEF_ROWS;
97 if ((lfd= open("/dev/log", O_WRONLY)) != -1
98 && ioctl(lfd, TIOCGWINSZ, &winsize) == 0
99 ) {
100 if (40 <= winsize.ws_col && winsize.ws_col <= MAX_COLS) {
101 ncols= winsize.ws_col;
102 }
103 if (25 <= winsize.ws_row && winsize.ws_row <= MAX_COLS) {
104 nrows= winsize.ws_row;
105 }
106 }
107 if (lfd != -1) close(lfd);
108
109 /* Print the contents of the screen line by line. Omit trailing
110 * blanks. Note that screen memory consists of pairs of characters
111 * and attribute bytes.
112 */
113 ps= screen;
114 for (row= 0; row < nrows; row++) {
115 char line[MAX_COLS + 1];
116 char *pl= line;
117 int column;
118 int blanks= 0;
119
120 for (column= 0; column < ncols; column++) {
121 if (*ps <= ' ') {
122 /* Skip trailing junk. */
123 blanks++;
124 } else {
125 /* Reinsert blanks and add a character. */
126 while (blanks > 0) { *pl++= ' '; blanks--; }
127 *pl++= *ps;
128 }
129 /* Skip character and attribute byte. */
130 ps+= 2;
131 }
132 *pl++= '\n';
133 if (write(1, line, pl - line) < 0) fatal("stdout");
134 }
135 exit(0);
136}
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