conspy: new applet

Signed-off-by: Pascal Bellard <pascal.bellard@ads-lu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 472 insertions, 0 deletions

diff --git a/miscutils/conspy.c b/miscutils/conspy.c
new file mode 100644
index 0000000..7ba7959
--- /dev/null
+++ b/miscutils/conspy.c
@@ -0,0 +1,472 @@
+/* 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 tarball for details.
+ *
+ * example :	conspy num		shared access to console num
+ * or		conspy -d num		screenshot of console num
+ * or		conspy -cs num		poor man's GNU screen like
+ */
+
+//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 n
+//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 -d num   screenshot of console num
+//config:	  or        conspy -cs num  poor man's GNU screen like
+
+//usage:#define conspy_trivial_usage
+//usage:     "[-vcsndf] [-x ROW] [-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:     "\nOptions:"
+//usage:     "\n	-v	Don't send keystrokes to the console"
+//usage:     "\n	-c	Create missing devices in /dev"
+//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	-x ROW	Starting row"
+//usage:     "\n	-y LINE	Starting line"
+
+#include "libbb.h"
+#include <sys/kd.h>
+
+struct screen_info {
+	unsigned char lines, rows, cursor_x, cursor_y;
+};
+
+#define CHAR(x) ((x)[0])
+#define ATTR(x) ((x)[1])
+#define NEXT(x) ((x)+=2)
+#define DATA(x) (* (short *) (x))
+
+struct globals {
+	char* data;
+	int size;
+	int x, y;
+	int kbd_fd;
+	unsigned width;
+	unsigned height;
+	char mask;
+	char last_attr;
+	struct screen_info info;
+	struct termios term_orig;
+};
+
+#define G (*ptr_to_globals)
+#define INIT_G() do { \
+	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+} while (0)
+
+static void screen_read_close(int fd, char *data)
+{
+	unsigned i, j;
+
+	xread(fd, data, G.size);
+	G.last_attr = 0;
+	for (i = 0; i < G.info.lines; i++) {
+		for (j = 0; j < G.info.rows; 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 (CHAR(data) < ' ')
+				CHAR(data) = ' ';
+			if (y >= G.height || x >= G.width)
+				DATA(data) = 0;
+		}
+	}
+	close(fd);
+}
+
+static void screen_char(char *data)
+{
+	if (((G.last_attr - ATTR(data)) & G.mask) != 0) {
+		//                            BLGCRMOW
+		static const char color[8] = "04261537";
+
+		printf("\033[%c;4%c;3%cm",
+			(ATTR(data) & 8) ? '1'  // bold
+					 : '0', // defaults
+			color[(ATTR(data) >> 4) & 7], color[ATTR(data) & 7]);
+		G.last_attr = ATTR(data);
+	}
+	bb_putchar(CHAR(data));
+}
+
+#define clrscr()  printf("\033[1;1H" "\033[0J")
+#define curoff()  printf("\033[?25l")
+
+static void curon(void)
+{
+	printf("\033[?25h");
+}
+
+static void gotoxy(int row, int line)
+{
+	printf("\033[%u;%uH", line + 1, row + 1);
+}
+
+static void screen_dump(char *data)
+{
+	int space, linefeed, line, row;
+	int linecnt = G.info.lines - G.y;
+
+	data += 2 * G.y * G.info.rows;
+	for (linefeed = line = 0; line < linecnt && line < G.height; line++) {
+		for (space = row = 0; row < G.info.rows; row++, NEXT(data)) {
+			unsigned tty_row = row - G.x; // if will catch row < G.x too
+
+			if (tty_row >= G.width)
+				continue;
+			space++;
+			if (((G.last_attr - ATTR(data)) & G.mask) && CHAR(data) == ' ')
+				continue;
+			while (linefeed != 0) {
+				bb_putchar('\r');
+				bb_putchar('\n');
+				linefeed--;
+			}
+			while (--space)
+				bb_putchar(' ');
+			screen_char(data);
+		}
+		linefeed++;
+	}
+}
+
+static void curmove(void)
+{
+	unsigned cx = G.info.cursor_x - G.x;
+	unsigned cy = G.info.cursor_y - G.y;
+
+	if (cx >= G.width || cy >= G.height) {
+		curoff();
+	} else {
+		curon();
+		gotoxy(cx, cy);
+	}
+	fflush_all();
+}
+
+static void cleanup(int code)
+{
+	curon();
+	fflush_all();
+	tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		free(ptr_to_globals);
+		close(G.kbd_fd);
+	}
+	// Reset attributes
+	if (G.mask != 0)
+		printf("\033[0m");
+	bb_putchar('\n');
+	if (code > 1)
+		kill_myself_with_sig(code); // does not return
+	exit(code);
+}
+
+static void get_initial_data(const char* vcsa_name)
+{
+	int size;
+	int fd = xopen(vcsa_name, O_RDONLY);
+	xread(fd, &G.info, 4);
+	G.size = size = G.info.rows * G.info.lines * 2;
+	G.width = G.height = UINT_MAX;
+	G.data = xzalloc(2 * size);
+	screen_read_close(fd, G.data);
+}
+
+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 = vfork();
+	if (pid < 0) {
+		bb_perror_msg_and_die("vfork");
+	}
+	if (pid == 0) {
+		struct termios termchild;
+		char *shell = getenv("SHELL");
+
+		if (!shell)
+			shell = (char *) DEFAULT_SHELL;
+		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);
+	}
+}
+
+enum {
+	FLAG_v,  // view only
+	FLAG_c,  // create device if need
+	FLAG_s,  // session
+	FLAG_n,  // no colors
+	FLAG_d,  // dump screen
+	FLAG_f,  // follow cursor
+};
+#define FLAG(x) (1 << FLAG_##x)
+
+int conspy_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int conspy_main(int argc UNUSED_PARAM, char **argv)
+{
+	char *buffer[2];
+	char vcsa_name[sizeof("/dev/vcsa") + 2];
+	char tty_name[sizeof("/dev/tty") + 2];
+#define keybuf bb_common_bufsiz1
+	struct termios termbuf;
+	unsigned opts;
+	unsigned ttynum;
+	int poll_timeout_ms;
+	int current;
+	int ioerror_count;
+	int key_count;
+	int escape_count;
+	int nokeys;
+#if ENABLE_LONG_OPTS
+	static const char getopt_longopts[] ALIGN1 =
+		"viewonly\0"     No_argument "v"
+		"createdevice\0" No_argument "c"
+		"session\0"      No_argument "s"
+		"nocolors\0"     No_argument "n"
+		"dump\0"         No_argument "d"
+		"follow\0"       No_argument "f"
+		;
+
+	applet_long_options = getopt_longopts;
+#endif
+	INIT_G();
+	strcpy(vcsa_name, "/dev/vcsa");
+
+	opt_complementary = "x+:y+"; // numeric params
+	opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.y);
+	argv += optind;
+	ttynum = 0;
+	if (argv[0]) {
+		ttynum = xatou_range(argv[0], 0, 63);
+		sprintf(vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
+	}
+	sprintf(tty_name, "%s%u", "/dev/tty", ttynum);
+	if (!(opts & FLAG(n)))
+		G.mask = 0xff;
+	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(vcsa_name, makedev(7, 128 + ttynum));
+	}
+	if ((opts & FLAG(s)) && ttynum) {
+		start_shell_in_child(tty_name);
+	}
+
+	get_initial_data(vcsa_name);
+	G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
+	if (opts & FLAG(d)) {
+		screen_dump(G.data);
+		bb_putchar('\n');
+		if (ENABLE_FEATURE_CLEAN_UP) {
+			free(ptr_to_globals);
+			close(G.kbd_fd);
+		}
+		return 0;
+	}
+
+	bb_signals(BB_FATAL_SIGS, cleanup);
+	// All characters must be passed through to us unaltered
+	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);
+	termbuf.c_lflag &= ~(ISIG|ICANON|ECHO);
+	termbuf.c_cc[VMIN] = 1;
+	termbuf.c_cc[VTIME] = 0;
+	tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
+	buffer[0] = G.data;
+	buffer[1] = G.data + G.size;
+	poll_timeout_ms = 250;
+	ioerror_count = key_count = escape_count = nokeys = current = 0;
+	while (1) {
+		struct pollfd pfd;
+		int vcsa_handle;
+		int bytes_read;
+		int i, j;
+		int next = 1 - current;
+		char *data = buffer[next];
+		char *old  = buffer[current];
+
+		// Close & re-open vcsa in case they have
+		// swapped virtual consoles
+		vcsa_handle = xopen(vcsa_name, O_RDONLY);
+		xread(vcsa_handle, &G.info, 4);
+		if (G.size != (G.info.rows * G.info.lines * 2)) {
+			cleanup(1);
+		}
+		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.info.cursor_x - G.width + 1;
+			int ny = G.info.cursor_y - G.height + 1;
+
+			if (G.info.cursor_x < G.x) {
+				G.x = G.info.cursor_x;
+				i = 0;	// force refresh
+			}
+			if (nx > G.x) {
+				G.x = nx;
+				i = 0;	// force refresh
+			}
+			if (G.info.cursor_y < G.y) {
+				G.y = G.info.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
+		screen_read_close(vcsa_handle, data);
+		if (i != G.width || j != G.height) {
+			clrscr();
+			screen_dump(data);
+		}
+		else for (i = 0; i < G.info.lines; i++) {
+			char *last = last;
+			char *first = NULL;
+			int iy = i - G.y;
+
+			if (iy >= (int) G.height)
+				break;
+			for (j = 0; j < G.info.rows; j++) {
+				last = data;
+				if (DATA(data) != DATA(old) && iy >= 0) {
+					unsigned jx = j - G.x;
+
+					last = NULL;
+					if (first == NULL && jx < G.width) {
+						first = data;
+						gotoxy(jx, iy);
+					}
+				}
+				NEXT(old);
+				NEXT(data);
+			}
+			if (first == NULL)
+				continue;
+			if (last == NULL)
+				last = data;
+
+			// Write the data to the screen
+			for (; first < last; NEXT(first))
+				screen_char(first);
+		}
+		current = next;
+		curmove();
+
+		// Wait for local user keypresses
+		pfd.fd = G.kbd_fd;
+		pfd.events = POLLIN;
+		bytes_read = 0;
+		switch (poll(&pfd, 1, poll_timeout_ms)) {
+		case -1:
+			if (errno != EINTR)
+				cleanup(1);
+			break;
+		case 0:
+			if (++nokeys >= 4)
+				nokeys = escape_count = 0;
+			break;
+		default:
+			// Read the keys pressed
+			bytes_read = read(G.kbd_fd, keybuf + key_count,
+					sizeof(keybuf) - key_count);
+			if (bytes_read < 0)
+				cleanup(1);
+
+			// Do exit processing
+			for (i = 0; i < bytes_read; i++) {
+				if (keybuf[key_count + i] != '\033')
+					escape_count = 0;
+				else if (++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)) && escape_count == 0) {
+			int handle, result;
+			long kbd_mode;
+
+			key_count += bytes_read;
+			handle = xopen(tty_name, O_WRONLY);
+			result = ioctl(handle, KDGKBMODE, &kbd_mode);
+			if (result == -1)
+				/* nothing */;
+			else if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE)
+				key_count = 0; // scan code mode
+			else {
+				for (i = 0; i < key_count && result != -1; i++)
+					result = ioctl(handle, TIOCSTI, keybuf + i);
+				key_count -= i;
+				if (key_count)
+					memmove(keybuf, keybuf + i, key_count);
+				// 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 != -1)
+				ioerror_count = 0;
+			else if (errno != EIO || ++ioerror_count > 4)
+				cleanup(1);
+		}
+	}
+}