| /* vi: set sw=4 ts=4: */ |
| /* |
| * A text-mode VNC like program for Linux virtual terminals. |
| * |
| * pascal.bellard@ads-lu.com |
| * |
| * Based on Russell Stuart's conspy.c |
| * http://ace-host.stuart.id.au/russell/files/conspy.c |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| |
| //applet:IF_CONSPY(APPLET(conspy, BB_DIR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_CONSPY) += conspy.o |
| |
| //config:config CONSPY |
| //config: bool "conspy" |
| //config: default y |
| //config: select PLATFORM_LINUX |
| //config: help |
| //config: A text-mode VNC like program for Linux virtual terminals. |
| //config: example: conspy NUM shared access to console num |
| //config: or conspy -nd NUM screenshot of console num |
| //config: or conspy -cs NUM poor man's GNU screen like |
| |
| //usage:#define conspy_trivial_usage |
| //usage: "[-vcsndfFQ] [-x COL] [-y LINE] [CONSOLE_NO]" |
| //usage:#define conspy_full_usage "\n\n" |
| //usage: "A text-mode VNC like program for Linux virtual consoles." |
| //usage: "\nTo exit, quickly press ESC 3 times." |
| //usage: "\n" |
| //usage: "\n -v Don't send keystrokes to the console" |
| //usage: "\n -c Create missing /dev/{tty,vcsa}N" |
| //usage: "\n -s Open a SHELL session" |
| //usage: "\n -n Black & white" |
| //usage: "\n -d Dump console to stdout" |
| //usage: "\n -f Follow cursor" |
| //usage: "\n -F Assume console is on a framebuffer device" |
| //usage: "\n -Q Disable exit on ESC-ESC-ESC" |
| //usage: "\n -x COL Starting column" |
| //usage: "\n -y LINE Starting line" |
| |
| #include "libbb.h" |
| #include <sys/kd.h> |
| |
| #define ESC "\033" |
| #define CURSOR_ON -1 |
| #define CURSOR_OFF 1 |
| |
| #define DEV_TTY "/dev/tty" |
| #define DEV_VCSA "/dev/vcsa" |
| |
| struct screen_info { |
| unsigned char lines, cols, cursor_x, cursor_y; |
| }; |
| |
| #define CHAR(x) (*(uint8_t*)(x)) |
| #define ATTR(x) (((uint8_t*)(x))[1]) |
| #define NEXT(x) ((x) += 2) |
| #define DATA(x) (*(uint16_t*)(x)) |
| |
| struct globals { |
| char* data; |
| int size; |
| int x, y; |
| int kbd_fd; |
| int ioerror_count; |
| int key_count; |
| int escape_count; |
| int nokeys; |
| int current; |
| int first_line_offset; |
| int last_attr; |
| // cached local tty parameters |
| unsigned width; |
| unsigned height; |
| unsigned col; |
| unsigned line; |
| smallint curoff; // unknown:0 cursor on:-1 cursor off:1 |
| char attrbuf[sizeof("0;1;5;30;40m")]; |
| // remote console |
| struct screen_info remote; |
| // saved local tty terminfo |
| struct termios term_orig; |
| char vcsa_name[sizeof(DEV_VCSA "NN")]; |
| }; |
| |
| #define G (*ptr_to_globals) |
| #define INIT_G() do { \ |
| SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ |
| G.width = G.height = UINT_MAX; \ |
| G.last_attr--; \ |
| } while (0) |
| |
| enum { |
| FLAG_v, // view only |
| FLAG_c, // create device if need |
| FLAG_Q, // never exit |
| FLAG_s, // session |
| FLAG_n, // no colors |
| FLAG_d, // dump screen |
| FLAG_f, // follow cursor |
| FLAG_F, // framebuffer |
| }; |
| #define FLAG(x) (1 << FLAG_##x) |
| #define BW (option_mask32 & FLAG(n)) |
| |
| static void putcsi(const char *s) |
| { |
| fputs(ESC"[", stdout); |
| fputs(s, stdout); |
| } |
| |
| static void clrscr(void) |
| { |
| // Home, clear till end of screen |
| putcsi("1;1H" ESC"[J"); |
| G.col = G.line = 0; |
| } |
| |
| static void set_cursor(int state) |
| { |
| if (G.curoff != state) { |
| G.curoff = state; |
| putcsi("?25"); |
| bb_putchar("h?l"[1 + state]); |
| } |
| } |
| |
| static void gotoxy(int col, int line) |
| { |
| if (G.col != col || G.line != line) { |
| G.col = col; |
| G.line = line; |
| printf(ESC"[%u;%uH", line + 1, col + 1); |
| } |
| } |
| |
| static void cleanup(int code) NORETURN; |
| static void cleanup(int code) |
| { |
| set_cursor(CURSOR_ON); |
| tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig); |
| if (ENABLE_FEATURE_CLEAN_UP) { |
| close(G.kbd_fd); |
| } |
| // Reset attributes |
| if (!BW) |
| putcsi("0m"); |
| bb_putchar('\n'); |
| if (code > EXIT_FAILURE) |
| kill_myself_with_sig(code); |
| exit(code); |
| } |
| |
| static void screen_read_close(void) |
| { |
| unsigned i, j; |
| int vcsa_fd; |
| char *data; |
| |
| // Close & re-open vcsa in case they have swapped virtual consoles |
| vcsa_fd = xopen(G.vcsa_name, O_RDONLY); |
| xread(vcsa_fd, &G.remote, 4); |
| i = G.remote.cols * 2; |
| G.first_line_offset = G.y * i; |
| i *= G.remote.lines; |
| if (G.data == NULL) { |
| G.size = i; |
| G.data = xzalloc(2 * i); |
| } |
| if (G.size != i) { |
| cleanup(EXIT_FAILURE); |
| } |
| data = G.data + G.current; |
| xread(vcsa_fd, data, G.size); |
| close(vcsa_fd); |
| for (i = 0; i < G.remote.lines; i++) { |
| for (j = 0; j < G.remote.cols; j++, NEXT(data)) { |
| unsigned x = j - G.x; // if will catch j < G.x too |
| unsigned y = i - G.y; // if will catch i < G.y too |
| |
| if (y >= G.height || x >= G.width) |
| DATA(data) = 0; |
| else { |
| uint8_t ch = CHAR(data); |
| if (ch < ' ') |
| CHAR(data) = ch | 0x40; |
| else if (ch > 0x7e) |
| CHAR(data) = '?'; |
| } |
| } |
| } |
| } |
| |
| static void screen_char(char *data) |
| { |
| if (!BW) { |
| uint8_t attr_diff; |
| uint8_t attr = ATTR(data); |
| |
| if (option_mask32 & FLAG(F)) { |
| attr >>= 1; |
| } |
| attr_diff = G.last_attr ^ attr; |
| if (attr_diff) { |
| // Attribute layout for VGA compatible text videobuffer: |
| // blinking text |
| // |red bkgd |
| // ||green bkgd |
| // |||blue bkgd |
| // vvvv |
| // 00000000 <- lsb bit on the right |
| // bold text / text 8th bit |
| // red text |
| // green text |
| // blue text |
| // TODO: apparently framebuffer-based console uses different layout |
| // (bug? attempt to get 8th text bit in better position?) |
| // red bkgd |
| // |green bkgd |
| // ||blue bkgd |
| // vvv |
| // 00000000 <- lsb bit on the right |
| // bold text |
| // red text |
| // green text |
| // blue text |
| // text 8th bit |
| // converting RGB color bit triad to BGR: |
| static const char color[8] = "04261537"; |
| const uint8_t fg_mask = 0x07, bold_mask = 0x08; |
| const uint8_t bg_mask = 0x70, blink_mask = 0x80; |
| char *ptr; |
| |
| ptr = G.attrbuf; |
| |
| // (G.last_attr & ~attr) has 1 only where |
| // G.last_attr has 1 but attr has 0. |
| // Here we check whether we have transition |
| // bold->non-bold or blink->non-blink: |
| if (G.last_attr < 0 // initial value |
| || ((G.last_attr & ~attr) & (bold_mask | blink_mask)) != 0 |
| ) { |
| *ptr++ = '0'; // "reset all attrs" |
| *ptr++ = ';'; |
| // must set fg & bg, maybe need to set bold or blink: |
| attr_diff = attr | ~(bold_mask | blink_mask); |
| } |
| G.last_attr = attr; |
| if (attr_diff & bold_mask) { |
| *ptr++ = '1'; |
| *ptr++ = ';'; |
| } |
| if (attr_diff & blink_mask) { |
| *ptr++ = '5'; |
| *ptr++ = ';'; |
| } |
| if (attr_diff & fg_mask) { |
| *ptr++ = '3'; |
| *ptr++ = color[attr & fg_mask]; |
| *ptr++ = ';'; |
| } |
| if (attr_diff & bg_mask) { |
| *ptr++ = '4'; |
| *ptr++ = color[(attr & bg_mask) >> 4]; |
| ptr++; // last attribute |
| } |
| if (ptr != G.attrbuf) { |
| ptr[-1] = 'm'; |
| *ptr = '\0'; |
| putcsi(G.attrbuf); |
| } |
| } |
| } |
| putchar(CHAR(data)); |
| G.col++; |
| } |
| |
| static void screen_dump(void) |
| { |
| int linefeed_cnt; |
| int line, col; |
| int linecnt = G.remote.lines - G.y; |
| char *data = G.data + G.current + G.first_line_offset; |
| |
| linefeed_cnt = 0; |
| for (line = 0; line < linecnt && line < G.height; line++) { |
| int space_cnt = 0; |
| for (col = 0; col < G.remote.cols; col++, NEXT(data)) { |
| unsigned tty_col = col - G.x; // if will catch col < G.x too |
| |
| if (tty_col >= G.width) |
| continue; |
| space_cnt++; |
| if (BW && CHAR(data) == ' ') |
| continue; |
| while (linefeed_cnt != 0) { |
| //bb_putchar('\r'); - tty driver does it for us |
| bb_putchar('\n'); |
| linefeed_cnt--; |
| } |
| while (--space_cnt) |
| bb_putchar(' '); |
| screen_char(data); |
| } |
| linefeed_cnt++; |
| } |
| } |
| |
| static void curmove(void) |
| { |
| unsigned cx = G.remote.cursor_x - G.x; |
| unsigned cy = G.remote.cursor_y - G.y; |
| int cursor = CURSOR_OFF; |
| |
| if (cx < G.width && cy < G.height) { |
| gotoxy(cx, cy); |
| cursor = CURSOR_ON; |
| } |
| set_cursor(cursor); |
| } |
| |
| static void create_cdev_if_doesnt_exist(const char* name, dev_t dev) |
| { |
| int fd = open(name, O_RDONLY); |
| if (fd != -1) |
| close(fd); |
| else if (errno == ENOENT) |
| mknod(name, S_IFCHR | 0660, dev); |
| } |
| |
| static NOINLINE void start_shell_in_child(const char* tty_name) |
| { |
| int pid = xvfork(); |
| if (pid == 0) { |
| struct termios termchild; |
| const char *shell = get_shell_name(); |
| |
| signal(SIGHUP, SIG_IGN); |
| // set tty as a controlling tty |
| setsid(); |
| // make tty to be input, output, error |
| close(0); |
| xopen(tty_name, O_RDWR); // uses fd 0 |
| xdup2(0, 1); |
| xdup2(0, 2); |
| ioctl(0, TIOCSCTTY, 1); |
| tcsetpgrp(0, getpid()); |
| tcgetattr(0, &termchild); |
| termchild.c_lflag |= ECHO; |
| termchild.c_oflag |= ONLCR | XTABS; |
| termchild.c_iflag |= ICRNL; |
| termchild.c_iflag &= ~IXOFF; |
| tcsetattr_stdin_TCSANOW(&termchild); |
| execl(shell, shell, "-i", (char *) NULL); |
| bb_simple_perror_msg_and_die(shell); |
| } |
| } |
| |
| int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int conspy_main(int argc UNUSED_PARAM, char **argv) |
| { |
| char tty_name[sizeof(DEV_TTY "NN")]; |
| #define keybuf bb_common_bufsiz1 |
| struct termios termbuf; |
| unsigned opts; |
| unsigned ttynum; |
| int poll_timeout_ms; |
| #if ENABLE_LONG_OPTS |
| static const char getopt_longopts[] ALIGN1 = |
| "viewonly\0" No_argument "v" |
| "createdevice\0" No_argument "c" |
| "neverquit\0" No_argument "Q" |
| "session\0" No_argument "s" |
| "nocolors\0" No_argument "n" |
| "dump\0" No_argument "d" |
| "follow\0" No_argument "f" |
| "framebuffer\0" No_argument "F" |
| ; |
| |
| applet_long_options = getopt_longopts; |
| #endif |
| INIT_G(); |
| strcpy(G.vcsa_name, DEV_VCSA); |
| |
| opt_complementary = "x+:y+"; // numeric params |
| opts = getopt32(argv, "vcQsndfFx:y:", &G.x, &G.y); |
| argv += optind; |
| ttynum = 0; |
| if (argv[0]) { |
| ttynum = xatou_range(argv[0], 0, 63); |
| sprintf(G.vcsa_name + sizeof(DEV_VCSA)-1, "%u", ttynum); |
| } |
| sprintf(tty_name, "%s%u", DEV_TTY, ttynum); |
| if (opts & FLAG(c)) { |
| if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v)) |
| create_cdev_if_doesnt_exist(tty_name, makedev(4, ttynum)); |
| create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum)); |
| } |
| if ((opts & FLAG(s)) && ttynum) { |
| start_shell_in_child(tty_name); |
| } |
| |
| screen_read_close(); |
| if (opts & FLAG(d)) { |
| screen_dump(); |
| bb_putchar('\n'); |
| return 0; |
| } |
| |
| bb_signals(BB_FATAL_SIGS, cleanup); |
| |
| // All characters must be passed through to us unaltered |
| G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY); |
| tcgetattr(G.kbd_fd, &G.term_orig); |
| termbuf = G.term_orig; |
| termbuf.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL); |
| //termbuf.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n |
| termbuf.c_lflag &= ~(ISIG|ICANON|ECHO); |
| termbuf.c_cc[VMIN] = 1; |
| termbuf.c_cc[VTIME] = 0; |
| tcsetattr(G.kbd_fd, TCSANOW, &termbuf); |
| |
| poll_timeout_ms = 250; |
| while (1) { |
| struct pollfd pfd; |
| int bytes_read; |
| int i, j; |
| char *data, *old; |
| |
| // in the first loop G.width = G.height = 0: refresh |
| i = G.width; |
| j = G.height; |
| get_terminal_width_height(G.kbd_fd, &G.width, &G.height); |
| if (option_mask32 & FLAG(f)) { |
| int nx = G.remote.cursor_x - G.width + 1; |
| int ny = G.remote.cursor_y - G.height + 1; |
| |
| if (G.remote.cursor_x < G.x) { |
| G.x = G.remote.cursor_x; |
| i = 0; // force refresh |
| } |
| if (nx > G.x) { |
| G.x = nx; |
| i = 0; // force refresh |
| } |
| if (G.remote.cursor_y < G.y) { |
| G.y = G.remote.cursor_y; |
| i = 0; // force refresh |
| } |
| if (ny > G.y) { |
| G.y = ny; |
| i = 0; // force refresh |
| } |
| } |
| |
| // Scan console data and redraw our tty where needed |
| old = G.data + G.current; |
| G.current = G.size - G.current; |
| data = G.data + G.current; |
| screen_read_close(); |
| if (i != G.width || j != G.height) { |
| clrscr(); |
| screen_dump(); |
| } else { |
| // For each remote line |
| old += G.first_line_offset; |
| data += G.first_line_offset; |
| for (i = G.y; i < G.remote.lines; i++) { |
| char *first = NULL; // first char which needs updating |
| char *last = last; // last char which needs updating |
| unsigned iy = i - G.y; |
| |
| if (iy >= G.height) |
| break; |
| for (j = 0; j < G.remote.cols; j++, NEXT(old), NEXT(data)) { |
| unsigned jx = j - G.x; // if will catch j >= G.x too |
| |
| if (jx < G.width && DATA(data) != DATA(old)) { |
| last = data; |
| if (!first) { |
| first = data; |
| gotoxy(jx, iy); |
| } |
| } |
| } |
| if (first) { |
| // Rewrite updated data on the local screen |
| for (; first <= last; NEXT(first)) |
| screen_char(first); |
| } |
| } |
| } |
| curmove(); |
| |
| // Wait for local user keypresses |
| fflush_all(); |
| pfd.fd = G.kbd_fd; |
| pfd.events = POLLIN; |
| bytes_read = 0; |
| switch (poll(&pfd, 1, poll_timeout_ms)) { |
| char *k; |
| case -1: |
| if (errno != EINTR) |
| goto abort; |
| break; |
| case 0: |
| if (++G.nokeys >= 4) |
| G.nokeys = G.escape_count = 0; |
| break; |
| default: |
| // Read the keys pressed |
| k = keybuf + G.key_count; |
| bytes_read = read(G.kbd_fd, k, sizeof(keybuf) - G.key_count); |
| if (bytes_read < 0) |
| goto abort; |
| |
| // Do exit processing |
| if (!(option_mask32 & FLAG(Q))) { |
| for (i = 0; i < bytes_read; i++) { |
| if (k[i] != '\033') |
| G.escape_count = -1; |
| if (++G.escape_count >= 3) |
| cleanup(EXIT_SUCCESS); |
| } |
| } |
| } |
| poll_timeout_ms = 250; |
| if (option_mask32 & FLAG(v)) continue; |
| |
| // Insert all keys pressed into the virtual console's input |
| // buffer. Don't do this if the virtual console is in scan |
| // code mode - giving ASCII characters to a program expecting |
| // scan codes will confuse it. |
| G.key_count += bytes_read; |
| if (G.escape_count == 0) { |
| int handle, result; |
| long kbd_mode; |
| |
| handle = xopen(tty_name, O_WRONLY); |
| result = ioctl(handle, KDGKBMODE, &kbd_mode); |
| if (result >= 0) { |
| char *p = keybuf; |
| |
| G.ioerror_count = 0; |
| if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE) { |
| G.key_count = 0; // scan code mode |
| } |
| for (; G.key_count != 0; p++, G.key_count--) { |
| result = ioctl(handle, TIOCSTI, p); |
| if (result < 0) { |
| memmove(keybuf, p, G.key_count); |
| break; |
| } |
| // If there is an application on console which reacts |
| // to keypresses, we need to make our first sleep |
| // shorter to quickly redraw whatever it printed there. |
| poll_timeout_ms = 20; |
| } |
| } |
| // We sometimes get spurious IO errors on the TTY |
| // as programs close and re-open it |
| else if (errno != EIO || ++G.ioerror_count > 4) { |
| if (ENABLE_FEATURE_CLEAN_UP) |
| close(handle); |
| goto abort; |
| } |
| // Close & re-open tty in case they have |
| // swapped virtual consoles |
| close(handle); |
| } |
| } /* while (1) */ |
| abort: |
| cleanup(EXIT_FAILURE); |
| } |