bb_askpass: handle Ctrl-C, restore termoios on Ctrl-C.

sulogin: remove alarm handling, as it is redundant there.
code shrink. After all differences cancel out:

   text    data     bss     dec     hex filename
 777543    1000    9532  788075   c066b busybox_old
 777543    1000    9532  788075   c066b busybox_unstripped

2 files changed, 50 insertions, 47 deletions

diff --git a/libbb/bb_askpass.c b/libbb/bb_askpass.c
index 435314ea0..fd12f92dc 100644
--- a/libbb/bb_askpass.c
+++ b/libbb/bb_askpass.c
@@ -17,7 +17,7 @@ static void askpass_timeout(int ATTRIBUTE_UNUSED ignore)
 {
 }
 
-char *bb_askpass(int timeout, const char * prompt)
+char *bb_askpass(int timeout, const char *prompt)
 {
         /* Was static char[BIGNUM] */
         enum { sizeof_passwd = 128 };
@@ -25,35 +25,36 @@ char *bb_askpass(int timeout, const char * prompt)
 
         char *ret;
         int i;
-        struct sigaction sa;
-        struct termios old, new;
+        struct sigaction sa, oldsa;
+        struct termios tio, oldtio;
 
         if (!passwd)
                 passwd = xmalloc(sizeof_passwd);
         memset(passwd, 0, sizeof_passwd);
 
-        tcgetattr(STDIN_FILENO, &old);
+        tcgetattr(STDIN_FILENO, &oldtio);
         tcflush(STDIN_FILENO, TCIFLUSH);
+        tio = oldtio;
+        tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
+        tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
+        tcsetattr(STDIN_FILENO, TCSANOW, &tio);
 
-        fputs(prompt, stdout);
-        fflush(stdout);
-
-        tcgetattr(STDIN_FILENO, &new);
-        new.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
-        new.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
-        tcsetattr(STDIN_FILENO, TCSANOW, &new);
-
+        memset(&sa, 0, sizeof(sa));
+        /* sa.sa_flags = 0; - no SA_RESTART! */
+        /* SIGINT and SIGALRM will interrupt read below */
+        sa.sa_handler = askpass_timeout;
+        sigaction(SIGINT, &sa, &oldsa);
         if (timeout) {
-                sa.sa_flags = 0;
-                sa.sa_handler = askpass_timeout;
                 sigaction(SIGALRM, &sa, NULL);
                 alarm(timeout);
         }
 
+        fputs(prompt, stdout);
+        fflush(stdout);
         ret = NULL;
-        /* On timeout, read will hopefully be interrupted by SIGALRM,
+        /* On timeout or Ctrl-C, read will hopefully be interrupted,
          * and we return NULL */
-        if (read(STDIN_FILENO, passwd, sizeof_passwd-1) > 0) {
+        if (read(STDIN_FILENO, passwd, sizeof_passwd - 1) > 0) {
                 ret = passwd;
                 i = 0;
                 /* Last byte is guaranteed to be 0
@@ -67,8 +68,9 @@ char *bb_askpass(int timeout, const char * prompt)
         if (timeout) {
                 alarm(0);
         }
+        sigaction(SIGINT, &oldsa, NULL);
 
-        tcsetattr(STDIN_FILENO, TCSANOW, &old);
+        tcsetattr(STDIN_FILENO, TCSANOW, &oldtio);
         bb_putchar('\n');
         fflush(stdout);
         return ret;
diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index 7f100a162..f633fbbf1 100644
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -9,29 +9,26 @@
 
 #include "libbb.h"
 
-static const char *const forbid[] = {
-        "ENV",
-        "BASH_ENV",
-        "HOME",
-        "IFS",
-        "PATH",
-        "SHELL",
-        "LD_LIBRARY_PATH",
-        "LD_PRELOAD",
-        "LD_TRACE_LOADED_OBJECTS",
-        "LD_BIND_NOW",
-        "LD_AOUT_LIBRARY_PATH",
-        "LD_AOUT_PRELOAD",
-        "LD_NOWARN",
-        "LD_KEEPDIR",
-        (char *) 0
-};
-
-
-static void catchalarm(int ATTRIBUTE_UNUSED junk)
-{
-        exit(EXIT_FAILURE);
-}
+static const char forbid[] ALIGN1 =
+        "ENV" "\0"
+        "BASH_ENV" "\0"
+        "HOME" "\0"
+        "IFS" "\0"
+        "PATH" "\0"
+        "SHELL" "\0"
+        "LD_LIBRARY_PATH" "\0"
+        "LD_PRELOAD" "\0"
+        "LD_TRACE_LOADED_OBJECTS" "\0"
+        "LD_BIND_NOW" "\0"
+        "LD_AOUT_LIBRARY_PATH" "\0"
+        "LD_AOUT_PRELOAD" "\0"
+        "LD_NOWARN" "\0"
+        "LD_KEEPDIR" "\0";
+
+//static void catchalarm(int ATTRIBUTE_UNUSED junk)
+//{
+//      exit(EXIT_FAILURE);
+//}
 
 
 int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -40,7 +37,7 @@ int sulogin_main(int argc, char **argv)
         char *cp;
         int timeout = 0;
         char *timeout_arg;
-        const char *const *p;
+        const char *p;
         struct passwd *pwd;
         const char *shell;
 #if ENABLE_FEATURE_SHADOWPASSWDS
@@ -71,10 +68,14 @@ int sulogin_main(int argc, char **argv)
         }
 
         /* Clear out anything dangerous from the environment */
-        for (p = forbid; *p; p++)
-                unsetenv(*p);
+        p = forbid;
+        do {
+                unsetenv(p);
+                p += strlen(p) + 1;
+        } while (*p);
 
-        signal(SIGALRM, catchalarm);
+// bb_askpass() already handles this
+//      signal(SIGALRM, catchalarm);
 
         pwd = getpwuid(0);
         if (!pwd) {
@@ -105,7 +106,7 @@ int sulogin_main(int argc, char **argv)
                 bb_error_msg("login incorrect");
         }
         memset(cp, 0, strlen(cp));
-        signal(SIGALRM, SIG_DFL);
+//      signal(SIGALRM, SIG_DFL);
 
         bb_info_msg("System Maintenance Mode");
 
@@ -122,6 +123,6 @@ int sulogin_main(int argc, char **argv)
         /* Exec login shell with no additional parameters. Never returns. */
         run_shell(shell, 1, NULL, NULL);
 
-auth_error:
-        bb_error_msg_and_die("no password entry for 'root'");
+ auth_error:
+        bb_error_msg_and_die("no password entry for root");
 }