*: 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 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;
 }