*: 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>

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

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;

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
+	tcgetattr(STDIN_FILENO, oldt);
-	xset1(&tio0);
+	*t = *oldt;
-	xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
+	cfmakeraw(t);
-	// alarmed? -> exit 0
+}
-	exit(SIGALRM == signo);
+
+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?")))
+					(kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
-		, (option_mask32 & OPT_a) ? "when CTRL+D pressed" : "10s after last keypress"
+		, (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
+	// restore keyboard and console settings
-	signal_handler(SIGALRM);
+	xset1(&tio0);
+	xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
 
-	// should never be here!
 	return EXIT_SUCCESS;
 }

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 ESC "\033"
-//#define SEQ_CLEAR_TILL_END_OF_LINE   "\033[K"
+
+#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

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);

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 HIGHLIGHT   ESC"[7m"
-#define NORMAL      "\033[0m"
+#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)

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;

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 { \
+#define setTermSettings(fd, argp) \
-		if (ENABLE_FEATURE_USE_TERMIOS) tcsetattr(fd, TCSANOW, argp); \
+do { \
-	} while (0)
+	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