1 files changed, 547 insertions, 0 deletions

diff --git a/miscutils/conspy.c b/miscutils/conspy.c
new file mode 100644
index 000000000..509a0f271
--- /dev/null
+++ b/miscutils/conspy.c
@@ -0,0 +1,547 @@
+/* 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.
+ */
+
+//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 -nd NUM  screenshot of console num
+//config:         or        conspy -cs NUM  poor man's GNU screen like
+
+//usage:#define conspy_trivial_usage
+//usage:        "[-vcsndf] [-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:     "\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 COL  Starting column"
+//usage:     "\n        -y LINE Starting line"
+
+#include "libbb.h"
+#include <sys/kd.h>
+
+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("\033[0;1;5;30;40m")];
+        // remote console
+        struct screen_info remote;
+        // saved local tty terminfo
+        struct termios term_orig;
+        char vcsa_name[sizeof("/dev/vcsaNN")];
+};
+
+#define G (*ptr_to_globals)
+#define INIT_G() do { \
+        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+        G.attrbuf[0] = '\033'; \
+        G.attrbuf[1] = '['; \
+        G.width = G.height = UINT_MAX; \
+        G.last_attr--; \
+} while (0)
+
+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)
+#define BW (option_mask32 & FLAG(n))
+
+static void clrscr(void)
+{
+        // Home, clear till end of screen
+        fputs("\033[1;1H" "\033[J", stdout);
+        G.col = G.line = 0;
+}
+
+static void set_cursor(int state)
+{
+        if (G.curoff != state) {
+                G.curoff = state;
+                fputs("\033[?25", stdout);
+                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("\033[%u;%uH", line + 1, col + 1);
+        }
+}
+
+static void cleanup(int code)
+{
+        set_cursor(-1); // cursor on
+        tcsetattr(G.kbd_fd, TCSANOW, &G.term_orig);
+        if (ENABLE_FEATURE_CLEAN_UP) {
+                close(G.kbd_fd);
+        }
+        // Reset attributes
+        if (!BW)
+                fputs("\033[0m", stdout);
+        bb_putchar('\n');
+        if (code > 1)
+                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);
+        }
+        else if (G.size != i) {
+                cleanup(1);
+        }
+        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 (CHAR(data) < ' ')
+                                CHAR(data) = ' ';
+                        if (y >= G.height || x >= G.width)
+                                DATA(data) = 0;
+                }
+        }
+}
+
+static void screen_char(char *data)
+{
+        if (!BW) {
+                uint8_t attr = ATTR(data);
+                //uint8_t attr = ATTR(data) >> 1; // for framebuffer console
+                uint8_t 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 + 2; // skip "ESC ["
+
+                        // (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++ = ';';
+                        }
+                        if (ptr != G.attrbuf + 2) {
+                                ptr[-1] = 'm';
+                                *ptr = '\0';
+                                fputs(G.attrbuf, stdout);
+                        }
+                }
+        }
+        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 = 1;
+
+        if (cx < G.width && cy < G.height) {
+                gotoxy(cx, cy);
+                cursor = -1;
+        }
+        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;
+                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);
+        }
+}
+
+int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int conspy_main(int argc UNUSED_PARAM, char **argv)
+{
+        char tty_name[sizeof("/dev/ttyNN")];
+#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"
+                "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(G.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(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)
+                                cleanup(1);
+                        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)
+                                cleanup(1);
+
+                        // Do exit processing
+                        for (i = 0; i < bytes_read; i++) {
+                                if (k[i] != '\033')
+                                        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) */
+}