1 /* vi: set sw=4 ts=4: */
3 * A text-mode VNC like program for Linux virtual terminals.
5 * pascal.bellard@ads-lu.com
7 * Based on Russell Stuart's conspy.c
8 * http://ace-host.stuart.id.au/russell/files/conspy.c
10 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 //applet:IF_CONSPY(APPLET(conspy, BB_DIR_BIN, BB_SUID_DROP))
15 //kbuild:lib-$(CONFIG_CONSPY) += conspy.o
17 //config:config CONSPY
18 //config: bool "conspy"
20 //config: depends on PLATFORM_LINUX
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
27 //usage:#define conspy_trivial_usage
28 //usage: "[-vcsndf] [-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."
34 //usage: "\n -v Don't send keystrokes to the console"
35 //usage: "\n -c Create missing devices in /dev"
36 //usage: "\n -s Open a SHELL session"
37 //usage: "\n -n Black & white"
38 //usage: "\n -d Dump console to stdout"
39 //usage: "\n -f Follow cursor"
40 //usage: "\n -x COL Starting column"
41 //usage: "\n -y LINE Starting line"
50 unsigned char lines, cols, cursor_x, cursor_y;
53 #define CHAR(x) (*(uint8_t*)(x))
54 #define ATTR(x) (((uint8_t*)(x))[1])
55 #define NEXT(x) ((x) += 2)
56 #define DATA(x) (*(uint16_t*)(x))
68 int first_line_offset;
70 // cached local tty parameters
75 smallint curoff; // unknown:0 cursor on:-1 cursor off:1
76 char attrbuf[sizeof(ESC"[0;1;5;30;40m")];
78 struct screen_info remote;
79 // saved local tty terminfo
80 struct termios term_orig;
81 char vcsa_name[sizeof("/dev/vcsaNN")];
84 #define G (*ptr_to_globals)
85 #define INIT_G() do { \
86 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
87 G.attrbuf[0] = '\033'; \
89 G.width = G.height = UINT_MAX; \
95 FLAG_c, // create device if need
98 FLAG_d, // dump screen
99 FLAG_f, // follow cursor
101 #define FLAG(x) (1 << FLAG_##x)
102 #define BW (option_mask32 & FLAG(n))
104 static void clrscr(void)
106 // Home, clear till end of screen
107 fputs(ESC"[1;1H" ESC"[J", stdout);
111 static void set_cursor(int state)
113 if (G.curoff != state) {
115 fputs(ESC"[?25", stdout);
116 bb_putchar("h?l"[1 + state]);
120 static void gotoxy(int col, int line)
122 if (G.col != col || G.line != line) {
125 printf(ESC"[%u;%uH", line + 1, col + 1);
129 static void cleanup(int code)
131 set_cursor(-1); // cursor on
132 tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
133 if (ENABLE_FEATURE_CLEAN_UP) {
138 fputs(ESC"[0m", stdout);
141 kill_myself_with_sig(code);
145 static void screen_read_close(void)
151 // Close & re-open vcsa in case they have swapped virtual consoles
152 vcsa_fd = xopen(G.vcsa_name, O_RDONLY);
153 xread(vcsa_fd, &G.remote, 4);
154 i = G.remote.cols * 2;
155 G.first_line_offset = G.y * i;
157 if (G.data == NULL) {
159 G.data = xzalloc(2 * i);
161 else if (G.size != i) {
164 data = G.data + G.current;
165 xread(vcsa_fd, data, G.size);
167 for (i = 0; i < G.remote.lines; i++) {
168 for (j = 0; j < G.remote.cols; j++, NEXT(data)) {
169 unsigned x = j - G.x; // if will catch j < G.x too
170 unsigned y = i - G.y; // if will catch i < G.y too
172 if (CHAR(data) < ' ')
174 if (y >= G.height || x >= G.width)
180 static void screen_char(char *data)
183 uint8_t attr = ATTR(data);
184 //uint8_t attr = ATTR(data) >> 1; // for framebuffer console
185 uint8_t attr_diff = G.last_attr ^ attr;
188 // Attribute layout for VGA compatible text videobuffer:
194 // 00000000 <- lsb bit on the right
195 // bold text / text 8th bit
199 // TODO: apparently framebuffer-based console uses different layout
200 // (bug? attempt to get 8th text bit in better position?)
205 // 00000000 <- lsb bit on the right
211 // converting RGB color bit triad to BGR:
212 static const char color[8] = "04261537";
213 const uint8_t fg_mask = 0x07, bold_mask = 0x08;
214 const uint8_t bg_mask = 0x70, blink_mask = 0x80;
217 ptr = G.attrbuf + 2; // skip "ESC ["
219 // (G.last_attr & ~attr) has 1 only where
220 // G.last_attr has 1 but attr has 0.
221 // Here we check whether we have transition
222 // bold->non-bold or blink->non-blink:
223 if (G.last_attr < 0 // initial value
224 || ((G.last_attr & ~attr) & (bold_mask | blink_mask)) != 0
226 *ptr++ = '0'; // "reset all attrs"
228 // must set fg & bg, maybe need to set bold or blink:
229 attr_diff = attr | ~(bold_mask | blink_mask);
232 if (attr_diff & bold_mask) {
236 if (attr_diff & blink_mask) {
240 if (attr_diff & fg_mask) {
242 *ptr++ = color[attr & fg_mask];
245 if (attr_diff & bg_mask) {
247 *ptr++ = color[(attr & bg_mask) >> 4];
250 if (ptr != G.attrbuf + 2) {
253 fputs(G.attrbuf, stdout);
261 static void screen_dump(void)
265 int linecnt = G.remote.lines - G.y;
266 char *data = G.data + G.current + G.first_line_offset;
269 for (line = 0; line < linecnt && line < G.height; line++) {
271 for (col = 0; col < G.remote.cols; col++, NEXT(data)) {
272 unsigned tty_col = col - G.x; // if will catch col < G.x too
274 if (tty_col >= G.width)
277 if (BW && CHAR(data) == ' ')
279 while (linefeed_cnt != 0) {
280 //bb_putchar('\r'); - tty driver does it for us
292 static void curmove(void)
294 unsigned cx = G.remote.cursor_x - G.x;
295 unsigned cy = G.remote.cursor_y - G.y;
298 if (cx < G.width && cy < G.height) {
305 static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
307 int fd = open(name, O_RDONLY);
310 else if (errno == ENOENT)
311 mknod(name, S_IFCHR | 0660, dev);
314 static NOINLINE void start_shell_in_child(const char* tty_name)
318 struct termios termchild;
319 char *shell = getenv("SHELL");
322 shell = (char *) DEFAULT_SHELL;
323 signal(SIGHUP, SIG_IGN);
324 // set tty as a controlling tty
326 // make tty to be input, output, error
328 xopen(tty_name, O_RDWR); // uses fd 0
331 ioctl(0, TIOCSCTTY, 1);
332 tcsetpgrp(0, getpid());
333 tcgetattr(0, &termchild);
334 termchild.c_lflag |= ECHO;
335 termchild.c_oflag |= ONLCR | XTABS;
336 termchild.c_iflag |= ICRNL;
337 termchild.c_iflag &= ~IXOFF;
338 tcsetattr_stdin_TCSANOW(&termchild);
339 execl(shell, shell, "-i", (char *) NULL);
340 bb_simple_perror_msg_and_die(shell);
344 int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
345 int conspy_main(int argc UNUSED_PARAM, char **argv)
347 char tty_name[sizeof("/dev/ttyNN")];
348 #define keybuf bb_common_bufsiz1
349 struct termios termbuf;
354 static const char getopt_longopts[] ALIGN1 =
355 "viewonly\0" No_argument "v"
356 "createdevice\0" No_argument "c"
357 "session\0" No_argument "s"
358 "nocolors\0" No_argument "n"
359 "dump\0" No_argument "d"
360 "follow\0" No_argument "f"
363 applet_long_options = getopt_longopts;
366 strcpy(G.vcsa_name, "/dev/vcsa");
368 opt_complementary = "x+:y+"; // numeric params
369 opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.y);
373 ttynum = xatou_range(argv[0], 0, 63);
374 sprintf(G.vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
376 sprintf(tty_name, "%s%u", "/dev/tty", ttynum);
377 if (opts & FLAG(c)) {
378 if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v))
379 create_cdev_if_doesnt_exist(tty_name, makedev(4, ttynum));
380 create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum));
382 if ((opts & FLAG(s)) && ttynum) {
383 start_shell_in_child(tty_name);
387 if (opts & FLAG(d)) {
393 bb_signals(BB_FATAL_SIGS, cleanup);
395 // All characters must be passed through to us unaltered
396 G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
397 tcgetattr(G.kbd_fd, &G.term_orig);
398 termbuf = G.term_orig;
399 termbuf.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL);
400 //termbuf.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n
401 termbuf.c_lflag &= ~(ISIG|ICANON|ECHO);
402 termbuf.c_cc[VMIN] = 1;
403 termbuf.c_cc[VTIME] = 0;
404 tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
406 poll_timeout_ms = 250;
413 // in the first loop G.width = G.height = 0: refresh
416 get_terminal_width_height(G.kbd_fd, &G.width, &G.height);
417 if (option_mask32 & FLAG(f)) {
418 int nx = G.remote.cursor_x - G.width + 1;
419 int ny = G.remote.cursor_y - G.height + 1;
421 if (G.remote.cursor_x < G.x) {
422 G.x = G.remote.cursor_x;
423 i = 0; // force refresh
427 i = 0; // force refresh
429 if (G.remote.cursor_y < G.y) {
430 G.y = G.remote.cursor_y;
431 i = 0; // force refresh
435 i = 0; // force refresh
439 // Scan console data and redraw our tty where needed
440 old = G.data + G.current;
441 G.current = G.size - G.current;
442 data = G.data + G.current;
444 if (i != G.width || j != G.height) {
448 // For each remote line
449 old += G.first_line_offset;
450 data += G.first_line_offset;
451 for (i = G.y; i < G.remote.lines; i++) {
452 char *first = NULL; // first char which needs updating
453 char *last = last; // last char which needs updating
454 unsigned iy = i - G.y;
458 for (j = 0; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
459 unsigned jx = j - G.x; // if will catch j >= G.x too
461 if (jx < G.width && DATA(data) != DATA(old)) {
470 // Rewrite updated data on the local screen
471 for (; first <= last; NEXT(first))
478 // Wait for local user keypresses
483 switch (poll(&pfd, 1, poll_timeout_ms)) {
491 G.nokeys = G.escape_count = 0;
494 // Read the keys pressed
495 k = keybuf + G.key_count;
496 bytes_read = read(G.kbd_fd, k, sizeof(keybuf) - G.key_count);
500 // Do exit processing
501 for (i = 0; i < bytes_read; i++) {
504 else if (++G.escape_count >= 3)
508 poll_timeout_ms = 250;
510 // Insert all keys pressed into the virtual console's input
511 // buffer. Don't do this if the virtual console is in scan
512 // code mode - giving ASCII characters to a program expecting
513 // scan codes will confuse it.
514 if (!(option_mask32 & FLAG(v)) && G.escape_count == 0) {
518 G.key_count += bytes_read;
519 handle = xopen(tty_name, O_WRONLY);
520 result = ioctl(handle, KDGKBMODE, &kbd_mode);
524 if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE) {
525 G.key_count = 0; // scan code mode
527 for (; G.key_count != 0; p++, G.key_count--) {
528 result = ioctl(handle, TIOCSTI, p);
530 memmove(keybuf, p, G.key_count);
533 // If there is an application on console which reacts
534 // to keypresses, we need to make our first sleep
535 // shorter to quickly redraw whatever it printed there.
536 poll_timeout_ms = 20;
539 // Close & re-open tty in case they have
540 // swapped virtual consoles
543 // We sometimes get spurious IO errors on the TTY
544 // as programs close and re-open it
547 else if (errno != EIO || ++G.ioerror_count > 4)