*: 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>

1 files changed, 33 insertions, 40 deletions

diff --git a/console-tools/showkey.c b/console-tools/showkey.c
index 149ea64..b29c84d 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;
 }