*: use _exit() in sighandlers; showkey: do not use exit-thru-sighandler

While at it, make ESC sequences more readable; and removed check for
isatty(stdin) in reset. Code shrink:

   text    data     bss     dec     hex filename
 884771     936   17216  902923   dc70b busybox_old
 884723     936   17216  902875   dc6db busybox_unstripped

Signed-off-by: Marek Polacek <mmpolacek@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

8 files changed, 78 insertions, 72 deletions

diff --git a/console-tools/reset.c b/console-tools/reset.c
index 7dffdea18..1806ce742 100644
--- a/console-tools/reset.c
+++ b/console-tools/reset.c
@@ -8,11 +8,13 @@
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include "libbb.h"
-
 /* BTW, which "standard" package has this utility? It doesn't seem
  * to be ncurses, coreutils, console-tools... then what? */
 
+#include "libbb.h"
+
+#define ESC "\033"
+
 #if ENABLE_STTY
 int stty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 #endif
@@ -26,15 +28,15 @@ int reset_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 
         /* no options, no getopt */
 
-        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+        if (/*isatty(STDIN_FILENO) &&*/ isatty(STDOUT_FILENO)) {
                 /* See 'man 4 console_codes' for details:
                  * "ESC c"        -- Reset
                  * "ESC ( K"      -- Select user mapping
-                 * "ESC [ J"      -- Erase to the end of screen
                  * "ESC [ 0 m"    -- Reset all display attributes
+                 * "ESC [ J"      -- Erase to the end of screen
                  * "ESC [ ? 25 h" -- Make cursor visible
                  */
-                printf("\033c\033(K\033[J\033[0m\033[?25h");
+                printf(ESC"c" ESC"(K" ESC"[0m" ESC"[J" ESC"[?25h");
                 /* http://bugs.busybox.net/view.php?id=1414:
                  * people want it to reset echo etc: */
 #if ENABLE_STTY
diff --git a/console-tools/resize.c b/console-tools/resize.c
index 12e50a116..fdfe2a6a0 100644
--- a/console-tools/resize.c
+++ b/console-tools/resize.c
@@ -17,7 +17,7 @@ static void
 onintr(int sig UNUSED_PARAM)
 {
         tcsetattr(STDERR_FILENO, TCSANOW, old_termios_p);
-        exit(EXIT_FAILURE);
+        _exit(EXIT_FAILURE);
 }
 
 int resize_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
diff --git a/console-tools/showkey.c b/console-tools/showkey.c
index 149ea6465..b29c84d6a 100644
--- a/console-tools/showkey.c
+++ b/console-tools/showkey.c
@@ -10,27 +10,7 @@
 #include "libbb.h"
 #include <linux/kd.h>
 
-// set raw tty mode
-// also used by microcom
-// libbb candidates?
-static void xget1(struct termios *t, struct termios *oldt)
-{
-        tcgetattr(STDIN_FILENO, oldt);
-        *t = *oldt;
-        cfmakeraw(t);
-}
-
-static void xset1(struct termios *tio)
-{
-        int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, tio);
-        if (ret) {
-                bb_perror_msg("can't tcsetattr for stdin");
-        }
-}
 
-/*
- * GLOBALS
- */
 struct globals {
         int kbmode;
         struct termios tio, tio0;
@@ -44,13 +24,22 @@ struct globals {
 } while (0)
 
 
-static void signal_handler(int signo)
+// set raw tty mode
+// also used by microcom
+// libbb candidates?
+static void xget1(struct termios *t, struct termios *oldt)
 {
-        // restore keyboard and console settings
-        xset1(&tio0);
-        xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
-        // alarmed? -> exit 0
-        exit(SIGALRM == signo);
+        tcgetattr(STDIN_FILENO, oldt);
+        *t = *oldt;
+        cfmakeraw(t);
+}
+
+static void xset1(struct termios *t)
+{
+        int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
+        if (ret) {
+                bb_perror_msg("can't tcsetattr for stdin");
+        }
 }
 
 int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -62,20 +51,21 @@ int showkey_main(int argc UNUSED_PARAM, char **argv)
                 OPT_s = (1<<2), // display only the raw scan-codes
         };
 
+        INIT_G();
+
         // FIXME: aks are all mutually exclusive
         getopt32(argv, "aks");
 
-        INIT_G();
-
         // get keyboard settings
         xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
         printf("kb mode was %s\n\nPress any keys. Program terminates %s\n\n",
                 kbmode == K_RAW ? "RAW" :
                         (kbmode == K_XLATE ? "XLATE" :
                                 (kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
-                                        (kbmode == K_UNICODE ? "UNICODE" : "?UNKNOWN?")))
-                , (option_mask32 & OPT_a) ? "when CTRL+D pressed" : "10s after last keypress"
+                                        (kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
+                , (option_mask32 & OPT_a) ? "on EOF (ctrl-D)" : "10s after last keypress"
         );
+
         // prepare for raw mode
         xget1(&tio, &tio0);
         // put stdin in raw mode
@@ -83,34 +73,37 @@ int showkey_main(int argc UNUSED_PARAM, char **argv)
 
         if (option_mask32 & OPT_a) {
                 unsigned char c;
+
                 // just read stdin char by char
-                while (1 == safe_read(STDIN_FILENO, &c, 1)) {
+                while (1 == read(STDIN_FILENO, &c, 1)) {
                         printf("%3u 0%03o 0x%02x\r\n", c, c, c);
                         if (04 /*CTRL-D*/ == c)
                                 break;
                 }
         } else {
-                // we should exit on any signal
-                bb_signals(BB_FATAL_SIGS, signal_handler);
                 // set raw keyboard mode
                 xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));
 
+                // we should exit on any signal; signals should interrupt read
+                bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
+
                 // read and show scancodes
-                while (1) {
+                while (!bb_got_signal) {
                         char buf[18];
                         int i, n;
+
                         // setup 10s watchdog
                         alarm(10);
                         // read scancodes
                         n = read(STDIN_FILENO, buf, sizeof(buf));
                         i = 0;
                         while (i < n) {
-                                char c = buf[i];
-                                // show raw scancodes ordered? ->
                                 if (option_mask32 & OPT_s) {
+                                        // show raw scancodes
                                         printf("0x%02x ", buf[i++]);
-                                // show interpreted scancodes (default) ? ->
                                 } else {
+                                        // show interpreted scancodes (default)
+                                        char c = buf[i];
                                         int kc;
                                         if (i+2 < n
                                          && (c & 0x7f) == 0
@@ -130,9 +123,9 @@ int showkey_main(int argc UNUSED_PARAM, char **argv)
                 }
         }
 
-        // cleanup
-        signal_handler(SIGALRM);
+        // restore keyboard and console settings
+        xset1(&tio0);
+        xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
 
-        // should never be here!
         return EXIT_SUCCESS;
 }
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 066b569f6..68006ffba 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -94,8 +94,10 @@ static bool BB_ispunct(CHAR_T c) { return ((unsigned)c < 256 && ispunct(c)); }
 #endif
 
 
-#define SEQ_CLEAR_TILL_END_OF_SCREEN "\033[J"
-//#define SEQ_CLEAR_TILL_END_OF_LINE   "\033[K"
+#define ESC "\033"
+
+#define SEQ_CLEAR_TILL_END_OF_SCREEN  ESC"[J"
+//#define SEQ_CLEAR_TILL_END_OF_LINE  ESC"[K"
 
 
 enum {
@@ -446,7 +448,7 @@ static void input_backward(unsigned num)
                         } while (--num);
                         return;
                 }
-                printf("\033[%uD", num);
+                printf(ESC"[%uD", num);
                 return;
         }
 
@@ -471,7 +473,7 @@ static void input_backward(unsigned num)
                  */
                 unsigned sv_cursor;
                 /* go to 1st column; go up to first line */
-                printf("\r" "\033[%uA", cmdedit_y);
+                printf("\r" ESC"[%uA", cmdedit_y);
                 cmdedit_y = 0;
                 sv_cursor = cursor;
                 put_prompt(); /* sets cursor to 0 */
@@ -488,12 +490,12 @@ static void input_backward(unsigned num)
                 cmdedit_x = (width * cmdedit_y - num) % width;
                 cmdedit_y -= lines_up;
                 /* go to 1st column; go up */
-                printf("\r" "\033[%uA", lines_up);
+                printf("\r" ESC"[%uA", lines_up);
                 /* go to correct column.
                  * xterm, konsole, Linux VT interpret 0 as 1 below! wow.
                  * need to *make sure* we skip it if cmdedit_x == 0 */
                 if (cmdedit_x)
-                        printf("\033[%uC", cmdedit_x);
+                        printf(ESC"[%uC", cmdedit_x);
         }
 }
 
@@ -501,7 +503,7 @@ static void input_backward(unsigned num)
 static void redraw(int y, int back_cursor)
 {
         if (y > 0) /* up y lines */
-                printf("\033[%uA", y);
+                printf(ESC"[%uA", y);
         bb_putchar('\r');
         put_prompt();
         put_till_end_and_adv_cursor();
@@ -1626,7 +1628,7 @@ static void ask_terminal(void)
         pfd.events = POLLIN;
         if (safe_poll(&pfd, 1, 0) == 0) {
                 S.sent_ESC_br6n = 1;
-                fputs("\033" "[6n", stdout);
+                fputs(ESC"[6n", stdout);
                 fflush_all(); /* make terminal see it ASAP! */
         }
 }
@@ -2074,7 +2076,7 @@ int FAST_FUNC read_line_input(const char *prompt, char *command, int maxsize, li
                 case CTRL('L'):
                 vi_case(CTRL('L')|VI_CMDMODE_BIT:)
                         /* Control-l -- clear screen */
-                        printf("\033[H"); /* cursor to top,left */
+                        printf(ESC"[H"); /* cursor to top,left */
                         redraw(0, command_len - cursor);
                         break;
 #if MAX_HISTORY > 0
diff --git a/miscutils/conspy.c b/miscutils/conspy.c
index 01928b35f..040fa86f3 100644
--- a/miscutils/conspy.c
+++ b/miscutils/conspy.c
@@ -43,6 +43,9 @@
 #include "libbb.h"
 #include <sys/kd.h>
 
+
+#define ESC "\033"
+
 struct screen_info {
         unsigned char lines, cols, cursor_x, cursor_y;
 };
@@ -70,7 +73,7 @@ struct globals {
         unsigned col;
         unsigned line;
         smallint curoff; // unknown:0 cursor on:-1 cursor off:1
-        char attrbuf[sizeof("\033[0;1;5;30;40m")];
+        char attrbuf[sizeof(ESC"[0;1;5;30;40m")];
         // remote console
         struct screen_info remote;
         // saved local tty terminfo
@@ -101,7 +104,7 @@ enum {
 static void clrscr(void)
 {
         // Home, clear till end of screen
-        fputs("\033[1;1H" "\033[J", stdout);
+        fputs(ESC"[1;1H" ESC"[J", stdout);
         G.col = G.line = 0;
 }
 
@@ -109,7 +112,7 @@ static void set_cursor(int state)
 {
         if (G.curoff != state) {
                 G.curoff = state;
-                fputs("\033[?25", stdout);
+                fputs(ESC"[?25", stdout);
                 bb_putchar("h?l"[1 + state]);
         }
 }
@@ -119,7 +122,7 @@ 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);
+                printf(ESC"[%u;%uH", line + 1, col + 1);
         }
 }
 
@@ -132,7 +135,7 @@ static void cleanup(int code)
         }
         // Reset attributes
         if (!BW)
-                fputs("\033[0m", stdout);
+                fputs(ESC"[0m", stdout);
         bb_putchar('\n');
         if (code > 1)
                 kill_myself_with_sig(code);
diff --git a/miscutils/less.c b/miscutils/less.c
index 500059d2a..9e12c11a7 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -28,13 +28,15 @@
 #include "xregex.h"
 #endif
 
+
+#define ESC "\033"
 /* The escape codes for highlighted and normal text */
-#define HIGHLIGHT   "\033[7m"
-#define NORMAL      "\033[0m"
+#define HIGHLIGHT   ESC"[7m"
+#define NORMAL      ESC"[0m"
 /* The escape code to home and clear to the end of screen */
-#define CLEAR       "\033[H\033[J"
+#define CLEAR       ESC"[H\033[J"
 /* The escape code to clear to the end of line */
-#define CLEAR_2_EOL "\033[K"
+#define CLEAR_2_EOL ESC"[K"
 
 enum {
 /* Absolute max of lines eaten */
@@ -165,12 +167,12 @@ static void set_tty_cooked(void)
    top-left corner of the console */
 static void move_cursor(int line, int row)
 {
-        printf("\033[%u;%uH", line, row);
+        printf(ESC"[%u;%uH", line, row);
 }
 
 static void clear_line(void)
 {
-        printf("\033[%u;0H" CLEAR_2_EOL, max_displayed_line + 2);
+        printf(ESC"[%u;0H" CLEAR_2_EOL, max_displayed_line + 2);
 }
 
 static void print_hilite(const char *str)
diff --git a/miscutils/watchdog.c b/miscutils/watchdog.c
index 36902a214..630782660 100644
--- a/miscutils/watchdog.c
+++ b/miscutils/watchdog.c
@@ -24,7 +24,7 @@ static void watchdog_shutdown(int sig UNUSED_PARAM)
         write(3, &V, 1);  /* Magic, see watchdog-api.txt in kernel */
         if (ENABLE_FEATURE_CLEAN_UP)
                 close(3);
-        exit(EXIT_SUCCESS);
+        _exit(EXIT_SUCCESS);
 }
 
 int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
diff --git a/util-linux/more.c b/util-linux/more.c
index 1fd6f9ee8..788609a08 100644
--- a/util-linux/more.c
+++ b/util-linux/more.c
@@ -29,16 +29,20 @@ struct globals {
 #define new_settings     (G.new_settings    )
 #define cin_fileno       (G.cin_fileno      )
 
-#define setTermSettings(fd, argp) do { \
-                if (ENABLE_FEATURE_USE_TERMIOS) tcsetattr(fd, TCSANOW, argp); \
-        } while (0)
+#define setTermSettings(fd, argp) \
+do { \
+        if (ENABLE_FEATURE_USE_TERMIOS) \
+                tcsetattr(fd, TCSANOW, argp); \
+} while (0)
 #define getTermSettings(fd, argp) tcgetattr(fd, argp)
 
 static void gotsig(int sig UNUSED_PARAM)
 {
-        bb_putchar('\n');
+        /* bb_putchar_stderr doesn't use stdio buffering,
+         * therefore it is safe in signal handler */
+        bb_putchar_stderr('\n');
         setTermSettings(cin_fileno, &initial_settings);
-        exit(EXIT_FAILURE);
+        _exit(EXIT_FAILURE);
 }
 
 #define CONVERTED_TAB_SIZE 8