getopt32: add new syntax of 'o:+' and 'o:*' for -o NUM and -o LIST
[oweals/busybox.git] / miscutils / conspy.c
index 11105f0b8ad6ab69b18ce461a51cc55063aeb52c..e80158e39a14a10fec042483da4c8bcac11b1050 100644 (file)
@@ -7,16 +7,17 @@
  * 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.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-//applet:IF_CONSPY(APPLET(conspy, _BB_DIR_BIN, _BB_SUID_DROP))
+//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:      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 -cs NUM  poor man's GNU screen like
 
 //usage:#define conspy_trivial_usage
-//usage:       "[-vcsndf] [-x COL] [-y LINE] [CONSOLE_NO]"
+//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:     "\nOptions:"
 //usage:     "\n       -v      Don't send keystrokes to the console"
-//usage:     "\n       -c      Create missing devices in /dev"
+//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 "common_bufsiz.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)[0]))
-#define ATTR(x) ((uint8_t)((x)[1]))
-#define NEXT(x) ((x)+=2)
+#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 {
@@ -56,70 +66,146 @@ struct globals {
        int size;
        int x, y;
        int kbd_fd;
-       unsigned width;
-       unsigned height;
-       unsigned col;
-       unsigned line;
        int ioerror_count;
        int key_count;
        int escape_count;
        int nokeys;
        int current;
-       int vcsa_fd;
-       uint16_t last_attr;
-       uint8_t last_bold;
-       uint8_t last_blink;
-       uint8_t last_fg;
-       uint8_t last_bg;
-       char attrbuf[sizeof("\033[0;1;5;30;40m")];
-       smallint curoff;
+       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))); \
-       strcpy((char*)&G.last_attr, "\xff\xff\xff\xff\xff\xff" "\033["); \
+       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;
-       char *data = G.data + G.current;
-
-       xread(G.vcsa_fd, data, G.size);
-       G.last_attr = 0;
+       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 (CHAR(data) < ' ')
-                               *data = ' '; // CHAR(data) = ' ';
                        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) = '?';
+                       }
                }
        }
-       close(G.vcsa_fd);
 }
 
 static void screen_char(char *data)
 {
-       uint8_t attr = ATTR(data);
+       if (!BW) {
+               uint8_t attr_diff;
+               uint8_t attr = ATTR(data);
 
-       if (!BW && G.last_attr != attr) {
+               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
@@ -143,95 +229,62 @@ static void screen_char(char *data)
 //      green text
 //       blue text
 //        text 8th bit
-               // converting RGB color bit triad to BGR:
-               static const char color[8] = "04261537";
-               char *ptr;
-               uint8_t fg, bold, bg, blink;
-
-               G.last_attr = attr;
-
-               //attr >>= 1; // for framebuffer console
-               ptr = G.attrbuf + sizeof("\033[")-1;
-               fg    = (attr & 0x07);
-               bold  = (attr & 0x08);
-               bg    = (attr & 0x70);
-               blink = (attr & 0x80);
-               if (G.last_bold > bold || G.last_blink > blink) {
-                       G.last_bold = G.last_blink = 0;
-                       G.last_bg = 0xff;
-                       *ptr++ = '0';
-                       *ptr++ = ';';
-               }
-               if (G.last_bold != bold) {
-                       G.last_bold = bold;
-                       *ptr++ = '1';
-                       *ptr++ = ';';
-               }
-               if (G.last_blink != blink) {
-                       G.last_blink = blink;
-                       *ptr++ = '5';
-                       *ptr++ = ';';
-               }
-               if (G.last_fg != fg) {
-                       G.last_fg = fg;
-                       *ptr++ = '3';
-                       *ptr++ = color[fg];
-                       *ptr++ = ';';
-               }
-               if (G.last_bg != bg) {
-                       G.last_bg = bg;
-                       *ptr++ = '4';
-                       *ptr++ = color[bg >> 4];
-                       *ptr++ = ';';
-               }
-               if (ptr != G.attrbuf + sizeof("\033[")-1) {
-                       ptr[-1] = 'm';
-                       *ptr = '\0';
-                       fputs(G.attrbuf, stdout);
+                       // 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 clrscr(void)
-{
-       // Home, clear till end of src, cursor on
-       fputs("\033[1;1H" "\033[J" "\033[?25h", stdout);
-       G.curoff = G.col = G.line = 0;
-}
-
-static void curoff(void)
-{
-       if (!G.curoff) {
-               G.curoff = 1;
-               fputs("\033[?25l", stdout);
-       }
-}
-
-static void curon(void)
-{
-       if (G.curoff) {
-               G.curoff = 0;
-               fputs("\033[?25h", stdout);
-       }
-}
-
-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 screen_dump(void)
 {
        int linefeed_cnt;
        int line, col;
        int linecnt = G.remote.lines - G.y;
-       char *data = G.data + G.current + (2 * G.y * G.remote.cols);
+       char *data = G.data + G.current + G.first_line_offset;
 
        linefeed_cnt = 0;
        for (line = 0; line < linecnt && line < G.height; line++) {
@@ -261,41 +314,13 @@ 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) {
-               curoff();
-       } else {
-               curon();
+       if (cx < G.width && cy < G.height) {
                gotoxy(cx, cy);
+               cursor = CURSOR_ON;
        }
-       fflush_all();
-}
-
-static void cleanup(int code)
-{
-       curon();
-       fflush_all();
-       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); // does not return
-       exit(code);
-}
-
-static void get_initial_data(const char* vcsa_name)
-{
-       G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
-       xread(G.vcsa_fd, &G.remote, 4);
-       G.size = G.remote.cols * G.remote.lines * 2;
-       G.width = G.height = UINT_MAX;
-       G.data = xzalloc(2 * G.size);
-       screen_read_close();
+       set_cursor(cursor);
 }
 
 static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
@@ -309,16 +334,11 @@ static void create_cdev_if_doesnt_exist(const char* name, dev_t dev)
 
 static NOINLINE void start_shell_in_child(const char* tty_name)
 {
-       int pid = vfork();
-       if (pid < 0) {
-               bb_perror_msg_and_die("vfork");
-       }
+       int pid = xvfork();
        if (pid == 0) {
                struct termios termchild;
-               char *shell = getenv("SHELL");
+               const char *shell = get_shell_name();
 
-               if (!shell)
-                       shell = (char *) DEFAULT_SHELL;
                signal(SIGHUP, SIG_IGN);
                // set tty as a controlling tty
                setsid();
@@ -343,9 +363,7 @@ static NOINLINE void start_shell_in_child(const char* tty_name)
 int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int conspy_main(int argc UNUSED_PARAM, char **argv)
 {
-       char vcsa_name[sizeof("/dev/vcsaNN")];
-       char tty_name[sizeof("/dev/ttyNN")];
-#define keybuf bb_common_bufsiz1
+       char tty_name[sizeof(DEV_TTY "NN")];
        struct termios termbuf;
        unsigned opts;
        unsigned ttynum;
@@ -354,36 +372,41 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
        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
+#define keybuf bb_common_bufsiz1
+       setup_common_bufsiz();
+
        INIT_G();
-       strcpy(vcsa_name, "/dev/vcsa");
+       strcpy(G.vcsa_name, DEV_VCSA);
 
-       opt_complementary = "x+:y+"; // numeric params
-       opts = getopt32(argv, "vcsndfx:y:", &G.x, &G.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(vcsa_name + sizeof("/dev/vcsa")-1, "%u", ttynum);
+               sprintf(G.vcsa_name + sizeof(DEV_VCSA)-1, "%u", ttynum);
        }
-       sprintf(tty_name, "%s%u", "/dev/tty", 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(vcsa_name, makedev(7, 128 + ttynum));
+               create_cdev_if_doesnt_exist(G.vcsa_name, makedev(7, 128 + ttynum));
        }
        if ((opts & FLAG(s)) && ttynum) {
                start_shell_in_child(tty_name);
        }
 
-       get_initial_data(vcsa_name);
+       screen_read_close();
        if (opts & FLAG(d)) {
                screen_dump();
                bb_putchar('\n');
@@ -402,6 +425,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
        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;
@@ -409,35 +433,29 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                int i, j;
                char *data, *old;
 
-               // Close & re-open vcsa in case they have
-               // swapped virtual consoles
-               G.vcsa_fd = xopen(vcsa_name, O_RDONLY);
-               xread(G.vcsa_fd, &G.remote, 4);
-               if (G.size != (G.remote.cols * G.remote.lines * 2)) {
-                       cleanup(1);
-               }
+               // 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))) {
+               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
+                               i = 0; // force refresh
                        }
                        if (nx > G.x) {
                                G.x = nx;
-                               i = 0;  // force refresh
+                               i = 0; // force refresh
                        }
                        if (G.remote.cursor_y < G.y) {
                                G.y = G.remote.cursor_y;
-                               i = 0;  // force refresh
+                               i = 0; // force refresh
                        }
                        if (ny > G.y) {
                                G.y = ny;
-                               i = 0;  // force refresh
+                               i = 0; // force refresh
                        }
                }
 
@@ -451,8 +469,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                        screen_dump();
                } else {
                        // For each remote line
-                       old += G.y * G.remote.cols * 2;
-                       data += G.y * G.remote.cols * 2;
+                       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
@@ -460,10 +478,8 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
 
                                if (iy >= G.height)
                                        break;
-                               old += G.x * 2;
-                               data += G.x * 2;
-                               for (j = G.x; j < G.remote.cols; j++, NEXT(old), NEXT(data)) {
-                                       unsigned jx = j - G.x;
+                               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;
@@ -483,6 +499,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                curmove();
 
                // Wait for local user keypresses
+               fflush_all();
                pfd.fd = G.kbd_fd;
                pfd.events = POLLIN;
                bytes_read = 0;
@@ -490,7 +507,7 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                        char *k;
                case -1:
                        if (errno != EINTR)
-                               cleanup(1);
+                               goto abort;
                        break;
                case 0:
                        if (++G.nokeys >= 4)
@@ -499,56 +516,65 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
                default:
                        // Read the keys pressed
                        k = keybuf + G.key_count;
-                       bytes_read = read(G.kbd_fd, k, sizeof(keybuf) - G.key_count);
+                       bytes_read = read(G.kbd_fd, k, COMMON_BUFSIZE - G.key_count);
                        if (bytes_read < 0)
-                               cleanup(1);
+                               goto abort;
 
                        // 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);
+                       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.
-               if (!(option_mask32 & FLAG(v)) && G.escape_count == 0) {
+               G.key_count += bytes_read;
+               if (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 == -1)
-                               /* nothing */;
-                       else if (kbd_mode != K_XLATE && kbd_mode != K_UNICODE)
-                               G.key_count = 0; // scan code mode
-                       else {
-                               for (i = 0; i < G.key_count && result != -1; i++)
-                                       result = ioctl(handle, TIOCSTI, keybuf + i);
-                               G.key_count -= i;
-                               if (G.key_count)
-                                       memmove(keybuf, keybuf + i, G.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;
+                       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);
-
-                       // We sometimes get spurious IO errors on the TTY
-                       // as programs close and re-open it
-                       if (result != -1)
-                               G.ioerror_count = 0;
-                       else if (errno != EIO || ++G.ioerror_count > 4)
-                               cleanup(1);
                }
-       }
+       } /* while (1) */
+  abort:
+       cleanup(EXIT_FAILURE);
 }