source: MondoRescue/branches/3.3/mindi-busybox/miscutils/conspy.c@ 3621

Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
  • Property svn:eol-style set to native
File size: 13.8 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * A text-mode VNC like program for Linux virtual terminals.
4 *
5 * pascal.bellard@ads-lu.com
6 *
7 * Based on Russell Stuart's conspy.c
8 * http://ace-host.stuart.id.au/russell/files/conspy.c
9 *
10 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 */
12
13//applet:IF_CONSPY(APPLET(conspy, BB_DIR_BIN, BB_SUID_DROP))
14
15//kbuild:lib-$(CONFIG_CONSPY) += conspy.o
16
17//config:config CONSPY
18//config: bool "conspy"
19//config: default y
20//config: select PLATFORM_LINUX
21//config: help
22//config: A text-mode VNC like program for Linux virtual terminals.
23//config: example: conspy NUM shared access to console num
24//config: or conspy -nd NUM screenshot of console num
25//config: or conspy -cs NUM poor man's GNU screen like
26
27//usage:#define conspy_trivial_usage
28//usage: "[-vcsndfFQ] [-x COL] [-y LINE] [CONSOLE_NO]"
29//usage:#define conspy_full_usage "\n\n"
30//usage: "A text-mode VNC like program for Linux virtual consoles."
31//usage: "\nTo exit, quickly press ESC 3 times."
32//usage: "\n"
33//usage: "\n -v Don't send keystrokes to the console"
34//usage: "\n -c Create missing /dev/{tty,vcsa}N"
35//usage: "\n -s Open a SHELL session"
36//usage: "\n -n Black & white"
37//usage: "\n -d Dump console to stdout"
38//usage: "\n -f Follow cursor"
39//usage: "\n -F Assume console is on a framebuffer device"
40//usage: "\n -Q Disable exit on ESC-ESC-ESC"
41//usage: "\n -x COL Starting column"
42//usage: "\n -y LINE Starting line"
43
44#include "libbb.h"
45#include "common_bufsiz.h"
46#include <sys/kd.h>
47
48#define ESC "\033"
49#define CURSOR_ON -1
50#define CURSOR_OFF 1
51
52#define DEV_TTY "/dev/tty"
53#define DEV_VCSA "/dev/vcsa"
54
55struct screen_info {
56 unsigned char lines, cols, cursor_x, cursor_y;
57};
58
59#define CHAR(x) (*(uint8_t*)(x))
60#define ATTR(x) (((uint8_t*)(x))[1])
61#define NEXT(x) ((x) += 2)
62#define DATA(x) (*(uint16_t*)(x))
63
64struct globals {
65 char* data;
66 int size;
67 int x, y;
68 int kbd_fd;
69 int ioerror_count;
70 int key_count;
71 int escape_count;
72 int nokeys;
73 int current;
74 int first_line_offset;
75 int last_attr;
76 // cached local tty parameters
77 unsigned width;
78 unsigned height;
79 unsigned col;
80 unsigned line;
81 smallint curoff; // unknown:0 cursor on:-1 cursor off:1
82 char attrbuf[sizeof("0;1;5;30;40m")];
83 // remote console
84 struct screen_info remote;
85 // saved local tty terminfo
86 struct termios term_orig;
87 char vcsa_name[sizeof(DEV_VCSA "NN")];
88};
89
90#define G (*ptr_to_globals)
91#define INIT_G() do { \
92 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
93 G.width = G.height = UINT_MAX; \
94 G.last_attr--; \
95} while (0)
96
97enum {
98 FLAG_v, // view only
99 FLAG_c, // create device if need
100 FLAG_Q, // never exit
101 FLAG_s, // session
102 FLAG_n, // no colors
103 FLAG_d, // dump screen
104 FLAG_f, // follow cursor
105 FLAG_F, // framebuffer
106};
107#define FLAG(x) (1 << FLAG_##x)
108#define BW (option_mask32 & FLAG(n))
109
110static void putcsi(const char *s)
111{
112 fputs(ESC"[", stdout);
113 fputs(s, stdout);
114}
115
116static void clrscr(void)
117{
118 // Home, clear till end of screen
119 putcsi("1;1H" ESC"[J");
120 G.col = G.line = 0;
121}
122
123static void set_cursor(int state)
124{
125 if (G.curoff != state) {
126 G.curoff = state;
127 putcsi("?25");
128 bb_putchar("h?l"[1 + state]);
129 }
130}
131
132static void gotoxy(int col, int line)
133{
134 if (G.col != col || G.line != line) {
135 G.col = col;
136 G.line = line;
137 printf(ESC"[%u;%uH", line + 1, col + 1);
138 }
139}
140
141static void cleanup(int code) NORETURN;
142static void cleanup(int code)
143{
144 set_cursor(CURSOR_ON);
145 tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
146 if (ENABLE_FEATURE_CLEAN_UP) {
147 close(G.kbd_fd);
148 }
149 // Reset attributes
150 if (!BW)
151 putcsi("0m");
152 bb_putchar('\n');
153 if (code > EXIT_FAILURE)
154 kill_myself_with_sig(code);
155 exit(code);
156}
157
158static void screen_read_close(void)
159{
160 unsigned i, j;
161 int vcsa_fd;
162 char *data;
163
164 // Close & re-open vcsa in case they have swapped virtual consoles
165 vcsa_fd = xopen(G.vcsa_name, O_RDONLY);
166 xread(vcsa_fd, &G.remote, 4);
167 i = G.remote.cols * 2;
168 G.first_line_offset = G.y * i;
169 i *= G.remote.lines;
170 if (G.data == NULL) {
171 G.size = i;
172 G.data = xzalloc(2 * i);
173 }
174 if (G.size != i) {
175 cleanup(EXIT_FAILURE);
176 }
177 data = G.data + G.current;
178 xread(vcsa_fd, data, G.size);
179 close(vcsa_fd);
180 for (i = 0; i < G.remote.lines; i++) {
181 for (j = 0; j < G.remote.cols; j++, NEXT(data)) {
182 unsigned x = j - G.x; // if will catch j < G.x too
183 unsigned y = i - G.y; // if will catch i < G.y too
184
185 if (y >= G.height || x >= G.width)
186 DATA(data) = 0;
187 else {
188 uint8_t ch = CHAR(data);
189 if (ch < ' ')
190 CHAR(data) = ch | 0x40;
191 else if (ch > 0x7e)
192 CHAR(data) = '?';
193 }
194 }
195 }
196}
197
198static void screen_char(char *data)
199{
200 if (!BW) {
201 uint8_t attr_diff;
202 uint8_t attr = ATTR(data);
203
204 if (option_mask32 & FLAG(F)) {
205 attr >>= 1;
206 }
207 attr_diff = G.last_attr ^ attr;
208 if (attr_diff) {
209// Attribute layout for VGA compatible text videobuffer:
210// blinking text
211// |red bkgd
212// ||green bkgd
213// |||blue bkgd
214// vvvv
215// 00000000 <- lsb bit on the right
216// bold text / text 8th bit
217// red text
218// green text
219// blue text
220// TODO: apparently framebuffer-based console uses different layout
221// (bug? attempt to get 8th text bit in better position?)
222// red bkgd
223// |green bkgd
224// ||blue bkgd
225// vvv
226// 00000000 <- lsb bit on the right
227// bold text
228// red text
229// green text
230// blue text
231// text 8th bit
232 // converting RGB color bit triad to BGR:
233 static const char color[8] = "04261537";
234 const uint8_t fg_mask = 0x07, bold_mask = 0x08;
235 const uint8_t bg_mask = 0x70, blink_mask = 0x80;
236 char *ptr;
237
238 ptr = G.attrbuf;
239
240 // (G.last_attr & ~attr) has 1 only where
241 // G.last_attr has 1 but attr has 0.
242 // Here we check whether we have transition
243 // bold->non-bold or blink->non-blink:
244 if (G.last_attr < 0 // initial value
245 || ((G.last_attr & ~attr) & (bold_mask | blink_mask)) != 0
246 ) {
247 *ptr++ = '0'; // "reset all attrs"
248 *ptr++ = ';';
249 // must set fg & bg, maybe need to set bold or blink:
250 attr_diff = attr | ~(bold_mask | blink_mask);
251 }
252 G.last_attr = attr;
253 if (attr_diff & bold_mask) {
254 *ptr++ = '1';
255 *ptr++ = ';';
256 }
257 if (attr_diff & blink_mask) {
258 *ptr++ = '5';
259 *ptr++ = ';';
260 }
261 if (attr_diff & fg_mask) {
262 *ptr++ = '3';
263 *ptr++ = color[attr & fg_mask];
264 *ptr++ = ';';
265 }
266 if (attr_diff & bg_mask) {
267 *ptr++ = '4';
268 *ptr++ = color[(attr & bg_mask) >> 4];
269 ptr++; // last attribute
270 }
271 if (ptr != G.attrbuf) {
272 ptr[-1] = 'm';
273 *ptr = '\0';
274 putcsi(G.attrbuf);
275 }
276 }
277 }
278 putchar(CHAR(data));
279 G.col++;
280}
281
282static void screen_dump(void)
283{
284 int linefeed_cnt;
285 int line, col;
286 int linecnt = G.remote.lines - G.y;
287 char *data = G.data + G.current + G.first_line_offset;
288
289 linefeed_cnt = 0;
290 for (line = 0; line < linecnt && line < G.height; line++) {
291 int space_cnt = 0;
292 for (col = 0; col < G.remote.cols; col++, NEXT(data)) {
293 unsigned tty_col = col - G.x; // if will catch col < G.x too
294
295 if (tty_col >= G.width)
296 continue;
297 space_cnt++;
298 if (BW && CHAR(data) == ' ')
299 continue;
300 while (linefeed_cnt != 0) {
301 //bb_putchar('\r'); - tty driver does it for us
302 bb_putchar('\n');
303 linefeed_cnt--;
304 }
305 while (--space_cnt)
306 bb_putchar(' ');
307 screen_char(data);
308 }
309 linefeed_cnt++;
310 }
311}
312
313static void curmove(void)
314{
315 unsigned cx = G.remote.cursor_x - G.x;
316 unsigned cy = G.remote.cursor_y - G.y;
317 int cursor = CURSOR_OFF;
318
319 if (cx < G.width && cy < G.height) {
320 gotoxy(cx, cy);
321 cursor = CURSOR_ON;
322 }
323 set_cursor(cursor);
324}
325
326static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
327{
328 int fd = open(name, O_RDONLY);
329 if (fd != -1)
330 close(fd);
331 else if (errno == ENOENT)
332 mknod(name, S_IFCHR | 0660, dev);
333}
334
335static NOINLINE void start_shell_in_child(const char* tty_name)
336{
337 int pid = xvfork();
338 if (pid == 0) {
339 struct termios termchild;
340 const char *shell = get_shell_name();
341
342 signal(SIGHUP, SIG_IGN);
343 // set tty as a controlling tty
344 setsid();
345 // make tty to be input, output, error
346 close(0);
347 xopen(tty_name, O_RDWR); // uses fd 0
348 xdup2(0, 1);
349 xdup2(0, 2);
350 ioctl(0, TIOCSCTTY, 1);
351 tcsetpgrp(0, getpid());
352 tcgetattr(0, &termchild);
353 termchild.c_lflag |= ECHO;
354 termchild.c_oflag |= ONLCR | XTABS;
355 termchild.c_iflag |= ICRNL;
356 termchild.c_iflag &= ~IXOFF;
357 tcsetattr_stdin_TCSANOW(&termchild);
358 execl(shell, shell, "-i", (char *) NULL);
359 bb_simple_perror_msg_and_die(shell);
360 }
361}
362
363int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
364int conspy_main(int argc UNUSED_PARAM, char **argv)
365{
366 char tty_name[sizeof(DEV_TTY "NN")];
367 struct termios termbuf;
368 unsigned opts;
369 unsigned ttynum;
370 int poll_timeout_ms;
371#if ENABLE_LONG_OPTS
372 static const char getopt_longopts[] ALIGN1 =
373 "viewonly\0" No_argument "v"
374 "createdevice\0" No_argument "c"
375 "neverquit\0" No_argument "Q"
376 "session\0" No_argument "s"
377 "nocolors\0" No_argument "n"
378 "dump\0" No_argument "d"
379 "follow\0" No_argument "f"
380 "framebuffer\0" No_argument "F"
381 ;
382
383 applet_long_options = getopt_longopts;
384#endif
385#define keybuf bb_common_bufsiz1
386 setup_common_bufsiz();
387
388 INIT_G();
389 strcpy(G.vcsa_name, DEV_VCSA);
390
391 opt_complementary = "x+:y+"; // numeric params
392 opts = getopt32(argv, "vcQsndfFx:y:", &G.x, &G.y);
393 argv += optind;
394 ttynum = 0;
395 if (argv[0]) {
396 ttynum = xatou_range(argv[0], 0, 63);
397 sprintf(G.vcsa_name + sizeof(DEV_VCSA)-1, "%u", ttynum);
398 }
399 sprintf(tty_name, "%s%u", DEV_TTY, ttynum);
400 if (opts & FLAG(c)) {
401 if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v))
402 create_cdev_if_doesnt_exist(tty_name, makedev(4, ttynum));
403 create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum));
404 }
405 if ((opts & FLAG(s)) && ttynum) {
406 start_shell_in_child(tty_name);
407 }
408
409 screen_read_close();
410 if (opts & FLAG(d)) {
411 screen_dump();
412 bb_putchar('\n');
413 return 0;
414 }
415
416 bb_signals(BB_FATAL_SIGS, cleanup);
417
418 // All characters must be passed through to us unaltered
419 G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
420 tcgetattr(G.kbd_fd, &G.term_orig);
421 termbuf = G.term_orig;
422 termbuf.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL);
423 //termbuf.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n
424 termbuf.c_lflag &= ~(ISIG|ICANON|ECHO);
425 termbuf.c_cc[VMIN] = 1;
426 termbuf.c_cc[VTIME] = 0;
427 tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
428
429 poll_timeout_ms = 250;
430 while (1) {
431 struct pollfd pfd;
432 int bytes_read;
433 int i, j;
434 char *data, *old;
435
436 // in the first loop G.width = G.height = 0: refresh
437 i = G.width;
438 j = G.height;
439 get_terminal_width_height(G.kbd_fd, &G.width, &G.height);
440 if (option_mask32 & FLAG(f)) {
441 int nx = G.remote.cursor_x - G.width + 1;
442 int ny = G.remote.cursor_y - G.height + 1;
443
444 if (G.remote.cursor_x < G.x) {
445 G.x = G.remote.cursor_x;
446 i = 0; // force refresh
447 }
448 if (nx > G.x) {
449 G.x = nx;
450 i = 0; // force refresh
451 }
452 if (G.remote.cursor_y < G.y) {
453 G.y = G.remote.cursor_y;
454 i = 0; // force refresh
455 }
456 if (ny > G.y) {
457 G.y = ny;
458 i = 0; // force refresh
459 }
460 }
461
462 // Scan console data and redraw our tty where needed
463 old = G.data + G.current;
464 G.current = G.size - G.current;
465 data = G.data + G.current;
466 screen_read_close();
467 if (i != G.width || j != G.height) {
468 clrscr();
469 screen_dump();
470 } else {
471 // For each remote line
472 old += G.first_line_offset;
473 data += G.first_line_offset;
474 for (i = G.y; i < G.remote.lines; i++) {
475 char *first = NULL; // first char which needs updating
476 char *last = last; // last char which needs updating
477 unsigned iy = i - G.y;
478
479 if (iy >= G.height)
480 break;
481 for (j = 0; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
482 unsigned jx = j - G.x; // if will catch j >= G.x too
483
484 if (jx < G.width && DATA(data) != DATA(old)) {
485 last = data;
486 if (!first) {
487 first = data;
488 gotoxy(jx, iy);
489 }
490 }
491 }
492 if (first) {
493 // Rewrite updated data on the local screen
494 for (; first <= last; NEXT(first))
495 screen_char(first);
496 }
497 }
498 }
499 curmove();
500
501 // Wait for local user keypresses
502 fflush_all();
503 pfd.fd = G.kbd_fd;
504 pfd.events = POLLIN;
505 bytes_read = 0;
506 switch (poll(&pfd, 1, poll_timeout_ms)) {
507 char *k;
508 case -1:
509 if (errno != EINTR)
510 goto abort;
511 break;
512 case 0:
513 if (++G.nokeys >= 4)
514 G.nokeys = G.escape_count = 0;
515 break;
516 default:
517 // Read the keys pressed
518 k = keybuf + G.key_count;
519 bytes_read = read(G.kbd_fd, k, COMMON_BUFSIZE - G.key_count);
520 if (bytes_read < 0)
521 goto abort;
522
523 // Do exit processing
524 if (!(option_mask32 & FLAG(Q))) {
525 for (i = 0; i < bytes_read; i++) {
526 if (k[i] != '\033')
527 G.escape_count = -1;
528 if (++G.escape_count >= 3)
529 cleanup(EXIT_SUCCESS);
530 }
531 }
532 }
533 poll_timeout_ms = 250;
534 if (option_mask32 & FLAG(v)) continue;
535
536 // Insert all keys pressed into the virtual console's input
537 // buffer. Don't do this if the virtual console is in scan
538 // code mode - giving ASCII characters to a program expecting
539 // scan codes will confuse it.
540 G.key_count += bytes_read;
541 if (G.escape_count == 0) {
542 int handle, result;
543 long kbd_mode;
544
545 handle = xopen(tty_name, O_WRONLY);
546 result = ioctl(handle, KDGKBMODE, &kbd_mode);
547 if (result >= 0) {
548 char *p = keybuf;
549
550 G.ioerror_count = 0;
551 if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE) {
552 G.key_count = 0; // scan code mode
553 }
554 for (; G.key_count != 0; p++, G.key_count--) {
555 result = ioctl(handle, TIOCSTI, p);
556 if (result < 0) {
557 memmove(keybuf, p, G.key_count);
558 break;
559 }
560 // If there is an application on console which reacts
561 // to keypresses, we need to make our first sleep
562 // shorter to quickly redraw whatever it printed there.
563 poll_timeout_ms = 20;
564 }
565 }
566 // We sometimes get spurious IO errors on the TTY
567 // as programs close and re-open it
568 else if (errno != EIO || ++G.ioerror_count > 4) {
569 if (ENABLE_FEATURE_CLEAN_UP)
570 close(handle);
571 goto abort;
572 }
573 // Close & re-open tty in case they have
574 // swapped virtual consoles
575 close(handle);
576 }
577 } /* while (1) */
578 abort:
579 cleanup(EXIT_FAILURE);
580}
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