mirror of
https://github.com/sheumann/hush.git
synced 2024-08-20 19:29:02 +00:00
This change retains "or later" state! No licensing _changes_ here, only form is adjusted (article, space between "GPL" and "v2" and so on). Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
549 lines
13 KiB
C
549 lines
13 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* A text-mode VNC like program for Linux virtual terminals.
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*
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* pascal.bellard@ads-lu.com
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*
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* Based on Russell Stuart's conspy.c
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* http://ace-host.stuart.id.au/russell/files/conspy.c
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//applet:IF_CONSPY(APPLET(conspy, _BB_DIR_BIN, _BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_CONSPY) += conspy.o
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//config:config CONSPY
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//config: bool "conspy"
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//config: default n
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//config: depends on PLATFORM_LINUX
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//config: help
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//config: A text-mode VNC like program for Linux virtual terminals.
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//config: example: conspy NUM shared access to console num
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//config: or conspy -nd NUM screenshot of console num
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//config: or conspy -cs NUM poor man's GNU screen like
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//usage:#define conspy_trivial_usage
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//usage: "[-vcsndf] [-x COL] [-y LINE] [CONSOLE_NO]"
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//usage:#define conspy_full_usage "\n\n"
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//usage: "A text-mode VNC like program for Linux virtual consoles."
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//usage: "\nTo exit, quickly press ESC 3 times."
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//usage: "\n"
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//usage: "\nOptions:"
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//usage: "\n -v Don't send keystrokes to the console"
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//usage: "\n -c Create missing devices in /dev"
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//usage: "\n -s Open a SHELL session"
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//usage: "\n -n Black & white"
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//usage: "\n -d Dump console to stdout"
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//usage: "\n -f Follow cursor"
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//usage: "\n -x COL Starting column"
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//usage: "\n -y LINE Starting line"
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#include "libbb.h"
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#include <sys/kd.h>
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struct screen_info {
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unsigned char lines, cols, cursor_x, cursor_y;
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};
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#define CHAR(x) (*(uint8_t*)(x))
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#define ATTR(x) (((uint8_t*)(x))[1])
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#define NEXT(x) ((x) += 2)
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#define DATA(x) (*(uint16_t*)(x))
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struct globals {
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char* data;
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int size;
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int x, y;
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int kbd_fd;
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int ioerror_count;
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int key_count;
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int escape_count;
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int nokeys;
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int current;
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int first_line_offset;
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int last_attr;
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// cached local tty parameters
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unsigned width;
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unsigned height;
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unsigned col;
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unsigned line;
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smallint curoff; // unknown:0 cursor on:-1 cursor off:1
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char attrbuf[sizeof("\033[0;1;5;30;40m")];
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// remote console
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struct screen_info remote;
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// saved local tty terminfo
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struct termios term_orig;
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char vcsa_name[sizeof("/dev/vcsaNN")];
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};
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#define G (*ptr_to_globals)
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#define INIT_G() do { \
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SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
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G.attrbuf[0] = '\033'; \
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G.attrbuf[1] = '['; \
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G.width = G.height = UINT_MAX; \
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G.last_attr--; \
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} while (0)
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enum {
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FLAG_v, // view only
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FLAG_c, // create device if need
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FLAG_s, // session
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FLAG_n, // no colors
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FLAG_d, // dump screen
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FLAG_f, // follow cursor
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};
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#define FLAG(x) (1 << FLAG_##x)
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#define BW (option_mask32 & FLAG(n))
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static void clrscr(void)
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{
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// Home, clear till end of screen
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fputs("\033[1;1H" "\033[J", stdout);
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G.col = G.line = 0;
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}
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static void set_cursor(int state)
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{
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if (G.curoff != state) {
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G.curoff = state;
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fputs("\033[?25", stdout);
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bb_putchar("h?l"[1 + state]);
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}
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}
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static void gotoxy(int col, int line)
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{
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if (G.col != col || G.line != line) {
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G.col = col;
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G.line = line;
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printf("\033[%u;%uH", line + 1, col + 1);
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}
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}
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static void cleanup(int code)
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{
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set_cursor(-1); // cursor on
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tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
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if (ENABLE_FEATURE_CLEAN_UP) {
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close(G.kbd_fd);
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}
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// Reset attributes
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if (!BW)
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fputs("\033[0m", stdout);
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bb_putchar('\n');
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if (code > 1)
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kill_myself_with_sig(code);
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exit(code);
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}
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static void screen_read_close(void)
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{
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unsigned i, j;
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int vcsa_fd;
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char *data;
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// Close & re-open vcsa in case they have swapped virtual consoles
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vcsa_fd = xopen(G.vcsa_name, O_RDONLY);
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xread(vcsa_fd, &G.remote, 4);
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i = G.remote.cols * 2;
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G.first_line_offset = G.y * i;
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i *= G.remote.lines;
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if (G.data == NULL) {
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G.size = i;
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G.data = xzalloc(2 * i);
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}
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else if (G.size != i) {
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cleanup(1);
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}
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data = G.data + G.current;
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xread(vcsa_fd, data, G.size);
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close(vcsa_fd);
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for (i = 0; i < G.remote.lines; i++) {
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for (j = 0; j < G.remote.cols; j++, NEXT(data)) {
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unsigned x = j - G.x; // if will catch j < G.x too
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unsigned y = i - G.y; // if will catch i < G.y too
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if (CHAR(data) < ' ')
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CHAR(data) = ' ';
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if (y >= G.height || x >= G.width)
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DATA(data) = 0;
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}
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}
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}
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static void screen_char(char *data)
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{
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if (!BW) {
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uint8_t attr = ATTR(data);
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//uint8_t attr = ATTR(data) >> 1; // for framebuffer console
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uint8_t attr_diff = G.last_attr ^ attr;
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if (attr_diff) {
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// Attribute layout for VGA compatible text videobuffer:
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// blinking text
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// |red bkgd
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// ||green bkgd
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// |||blue bkgd
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// vvvv
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// 00000000 <- lsb bit on the right
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// bold text / text 8th bit
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// red text
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// green text
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// blue text
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// TODO: apparently framebuffer-based console uses different layout
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// (bug? attempt to get 8th text bit in better position?)
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// red bkgd
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// |green bkgd
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// ||blue bkgd
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// vvv
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// 00000000 <- lsb bit on the right
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// bold text
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// red text
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// green text
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// blue text
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// text 8th bit
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// converting RGB color bit triad to BGR:
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static const char color[8] = "04261537";
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const uint8_t fg_mask = 0x07, bold_mask = 0x08;
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const uint8_t bg_mask = 0x70, blink_mask = 0x80;
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char *ptr;
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ptr = G.attrbuf + 2; // skip "ESC ["
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// (G.last_attr & ~attr) has 1 only where
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// G.last_attr has 1 but attr has 0.
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// Here we check whether we have transition
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// bold->non-bold or blink->non-blink:
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if (G.last_attr < 0 // initial value
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|| ((G.last_attr & ~attr) & (bold_mask | blink_mask)) != 0
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) {
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*ptr++ = '0'; // "reset all attrs"
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*ptr++ = ';';
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// must set fg & bg, maybe need to set bold or blink:
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attr_diff = attr | ~(bold_mask | blink_mask);
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}
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G.last_attr = attr;
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if (attr_diff & bold_mask) {
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*ptr++ = '1';
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*ptr++ = ';';
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}
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if (attr_diff & blink_mask) {
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*ptr++ = '5';
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*ptr++ = ';';
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}
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if (attr_diff & fg_mask) {
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*ptr++ = '3';
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*ptr++ = color[attr & fg_mask];
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*ptr++ = ';';
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}
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if (attr_diff & bg_mask) {
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*ptr++ = '4';
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*ptr++ = color[(attr & bg_mask) >> 4];
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*ptr++ = ';';
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}
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if (ptr != G.attrbuf + 2) {
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ptr[-1] = 'm';
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*ptr = '\0';
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fputs(G.attrbuf, stdout);
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}
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}
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}
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putchar(CHAR(data));
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G.col++;
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}
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static void screen_dump(void)
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{
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int linefeed_cnt;
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int line, col;
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int linecnt = G.remote.lines - G.y;
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char *data = G.data + G.current + G.first_line_offset;
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linefeed_cnt = 0;
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for (line = 0; line < linecnt && line < G.height; line++) {
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int space_cnt = 0;
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for (col = 0; col < G.remote.cols; col++, NEXT(data)) {
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unsigned tty_col = col - G.x; // if will catch col < G.x too
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if (tty_col >= G.width)
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continue;
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space_cnt++;
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if (BW && CHAR(data) == ' ')
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continue;
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while (linefeed_cnt != 0) {
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//bb_putchar('\r'); - tty driver does it for us
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bb_putchar('\n');
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linefeed_cnt--;
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}
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while (--space_cnt)
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bb_putchar(' ');
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screen_char(data);
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}
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linefeed_cnt++;
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}
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}
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static void curmove(void)
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{
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unsigned cx = G.remote.cursor_x - G.x;
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unsigned cy = G.remote.cursor_y - G.y;
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int cursor = 1;
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if (cx < G.width && cy < G.height) {
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gotoxy(cx, cy);
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cursor = -1;
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}
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set_cursor(cursor);
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}
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static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
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{
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int fd = open(name, O_RDONLY);
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if (fd != -1)
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close(fd);
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else if (errno == ENOENT)
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mknod(name, S_IFCHR | 0660, dev);
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}
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static NOINLINE void start_shell_in_child(const char* tty_name)
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{
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int pid = xvfork();
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if (pid == 0) {
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struct termios termchild;
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char *shell = getenv("SHELL");
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if (!shell)
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shell = (char *) DEFAULT_SHELL;
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signal(SIGHUP, SIG_IGN);
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// set tty as a controlling tty
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setsid();
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// make tty to be input, output, error
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close(0);
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xopen(tty_name, O_RDWR); // uses fd 0
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xdup2(0, 1);
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xdup2(0, 2);
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ioctl(0, TIOCSCTTY, 1);
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tcsetpgrp(0, getpid());
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tcgetattr(0, &termchild);
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termchild.c_lflag |= ECHO;
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termchild.c_oflag |= ONLCR | XTABS;
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termchild.c_iflag |= ICRNL;
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termchild.c_iflag &= ~IXOFF;
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tcsetattr_stdin_TCSANOW(&termchild);
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execl(shell, shell, "-i", (char *) NULL);
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bb_simple_perror_msg_and_die(shell);
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}
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}
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int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int conspy_main(int argc UNUSED_PARAM, char **argv)
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{
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char tty_name[sizeof("/dev/ttyNN")];
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#define keybuf bb_common_bufsiz1
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struct termios termbuf;
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unsigned opts;
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unsigned ttynum;
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int poll_timeout_ms;
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#if ENABLE_LONG_OPTS
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static const char getopt_longopts[] ALIGN1 =
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"viewonly\0" No_argument "v"
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"createdevice\0" No_argument "c"
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"session\0" No_argument "s"
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"nocolors\0" No_argument "n"
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"dump\0" No_argument "d"
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"follow\0" No_argument "f"
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;
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applet_long_options = getopt_longopts;
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#endif
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INIT_G();
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strcpy(G.vcsa_name, "/dev/vcsa");
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opt_complementary = "x+:y+"; // numeric params
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opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.y);
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argv += optind;
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ttynum = 0;
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if (argv[0]) {
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ttynum = xatou_range(argv[0], 0, 63);
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sprintf(G.vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
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}
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sprintf(tty_name, "%s%u", "/dev/tty", ttynum);
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if (opts & FLAG(c)) {
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if ((opts & (FLAG(s)|FLAG(v))) != FLAG(v))
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create_cdev_if_doesnt_exist(tty_name, makedev(4, ttynum));
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create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum));
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}
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if ((opts & FLAG(s)) && ttynum) {
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start_shell_in_child(tty_name);
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}
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screen_read_close();
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if (opts & FLAG(d)) {
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screen_dump();
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bb_putchar('\n');
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return 0;
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}
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bb_signals(BB_FATAL_SIGS, cleanup);
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// All characters must be passed through to us unaltered
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G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
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tcgetattr(G.kbd_fd, &G.term_orig);
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termbuf = G.term_orig;
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termbuf.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL);
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//termbuf.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n
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termbuf.c_lflag &= ~(ISIG|ICANON|ECHO);
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termbuf.c_cc[VMIN] = 1;
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termbuf.c_cc[VTIME] = 0;
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tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
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poll_timeout_ms = 250;
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while (1) {
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struct pollfd pfd;
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int bytes_read;
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int i, j;
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char *data, *old;
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// in the first loop G.width = G.height = 0: refresh
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i = G.width;
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j = G.height;
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get_terminal_width_height(G.kbd_fd, &G.width, &G.height);
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if (option_mask32 & FLAG(f)) {
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int nx = G.remote.cursor_x - G.width + 1;
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int ny = G.remote.cursor_y - G.height + 1;
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if (G.remote.cursor_x < G.x) {
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G.x = G.remote.cursor_x;
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i = 0; // force refresh
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}
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if (nx > G.x) {
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G.x = nx;
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i = 0; // force refresh
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}
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if (G.remote.cursor_y < G.y) {
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G.y = G.remote.cursor_y;
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i = 0; // force refresh
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}
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if (ny > G.y) {
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G.y = ny;
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i = 0; // force refresh
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}
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}
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// Scan console data and redraw our tty where needed
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old = G.data + G.current;
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G.current = G.size - G.current;
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data = G.data + G.current;
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screen_read_close();
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if (i != G.width || j != G.height) {
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clrscr();
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screen_dump();
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} else {
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// For each remote line
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old += G.first_line_offset;
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data += G.first_line_offset;
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for (i = G.y; i < G.remote.lines; i++) {
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char *first = NULL; // first char which needs updating
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char *last = last; // last char which needs updating
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unsigned iy = i - G.y;
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if (iy >= G.height)
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break;
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for (j = 0; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
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unsigned jx = j - G.x; // if will catch j >= G.x too
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if (jx < G.width && DATA(data) != DATA(old)) {
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last = data;
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if (!first) {
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first = data;
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gotoxy(jx, iy);
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}
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}
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}
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if (first) {
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// Rewrite updated data on the local screen
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for (; first <= last; NEXT(first))
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screen_char(first);
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}
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}
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}
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curmove();
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// Wait for local user keypresses
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fflush_all();
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pfd.fd = G.kbd_fd;
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pfd.events = POLLIN;
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bytes_read = 0;
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switch (poll(&pfd, 1, poll_timeout_ms)) {
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char *k;
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case -1:
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if (errno != EINTR)
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cleanup(1);
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break;
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case 0:
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if (++G.nokeys >= 4)
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G.nokeys = G.escape_count = 0;
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break;
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default:
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// Read the keys pressed
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k = keybuf + G.key_count;
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bytes_read = read(G.kbd_fd, k, sizeof(keybuf) - G.key_count);
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if (bytes_read < 0)
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cleanup(1);
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// Do exit processing
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for (i = 0; i < bytes_read; i++) {
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if (k[i] != '\033')
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G.escape_count = 0;
|
|
else if (++G.escape_count >= 3)
|
|
cleanup(0);
|
|
}
|
|
}
|
|
poll_timeout_ms = 250;
|
|
|
|
// 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.
|
|
if (!(option_mask32 & FLAG(v)) && G.escape_count == 0) {
|
|
int handle, result;
|
|
long kbd_mode;
|
|
|
|
G.key_count += bytes_read;
|
|
handle = xopen(tty_name, O_WRONLY);
|
|
result = ioctl(handle, KDGKBMODE, &kbd_mode);
|
|
if (result >= 0) {
|
|
char *p = keybuf;
|
|
|
|
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;
|
|
}
|
|
}
|
|
// Close & re-open tty in case they have
|
|
// swapped virtual consoles
|
|
close(handle);
|
|
|
|
// We sometimes get spurious IO errors on the TTY
|
|
// as programs close and re-open it
|
|
if (result >= 0)
|
|
G.ioerror_count = 0;
|
|
else if (errno != EIO || ++G.ioerror_count > 4)
|
|
cleanup(1);
|
|
}
|
|
} /* while (1) */
|
|
}
|