hush: unblock TERM, INT, HUP in child shells too.

diff --git a/shell/hush.c b/shell/hush.c
index 8dda988..13a06a4 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1022,6 +1022,15 @@ static void free_strings(char **strings)
  * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
  * and to restore tty pgrp on signal-induced exit.
  */
+enum {
+       SPECIAL_INTERACTIVE_SIGS = 0
+#if ENABLE_HUSH_JOB
+               | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
+#endif
+               | (1 << SIGTERM)
+//TODO         | (1 << SIGHUP)
+               | (1 << SIGINT)
+};
 
 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
 //{
@@ -1059,6 +1068,8 @@ static int check_and_run_traps(int sig)
 //                     G.count_SIGCHLD++;
 //                     break;
                case SIGINT:
+//TODO: add putchar('\n') also when we detect that child was killed (sleep 5 + ^C)
+                       /* Builtin was ^C'ed, make it look prettier: */
                        bb_putchar('\n');
                        G.flag_SIGINT = 1;
                        break;
@@ -2284,37 +2295,46 @@ void re_execute_shell(char ***to_free, const char *s, char *argv0, char **argv);
 
 static void reset_traps_to_defaults(void)
 {
-       enum {
-               JOBSIGS = (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
-       };
-       unsigned sig;
-
-       if (!G.traps && !(G.non_DFL_mask & JOBSIGS))
-               return;
-
-       /* This function is always called in a child shell.
+       /* This function is always called in a child shell
+        * after fork (not vfork, NOMMU doesn't use this function).
         * Child shells are not interactive.
         * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling.
         * Testcase: (while :; do :; done) + ^Z should background.
+        * Same goes for SIGTERM, SIGHUP, SIGINT.
         */
-       G.non_DFL_mask &= ~JOBSIGS;
-       sigdelset(&G.blocked_set, SIGTTIN);
-       sigdelset(&G.blocked_set, SIGTTOU);
-       sigdelset(&G.blocked_set, SIGTSTP);
+       unsigned sig;
+       unsigned mask;
 
-       if (G.traps) for (sig = 0; sig < NSIG; sig++) {
-               if (!G.traps[sig]) {
+       if (!G.traps && !(G.non_DFL_mask & SPECIAL_INTERACTIVE_SIGS))
+               return;
+
+       /* Stupid. It can be done with *single* &= op, but we can't use
+        * the fact that G.blocked_set is implemented as a bitmask... */
+       mask = (SPECIAL_INTERACTIVE_SIGS >> 1);
+       sig = 1;
+       while (1) {
+               if (mask & 1)
+                       sigdelset(&G.blocked_set, sig);
+               mask >>= 1;
+               if (!mask)
+                       break;
+               sig++;
+       }
+
+       G.non_DFL_mask &= ~SPECIAL_INTERACTIVE_SIGS;
+       mask = G.non_DFL_mask;
+       if (G.traps) for (sig = 0; sig < NSIG; sig++, mask >>= 1) {
+               if (!G.traps[sig])
                        continue;
-               }
                free(G.traps[sig]);
                G.traps[sig] = NULL;
                /* There is no signal for 0 (EXIT) */
                if (sig == 0)
                        continue;
-               /* there was a trap handler, we are removing it
-                * (if sig has non-DFL handling,
-                * we don't need to do anything) */
-               if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
+               /* There was a trap handler, we are removing it.
+                * But if sig still has non-DFL handling,
+                * we should not unblock it. */
+               if (mask & 1)
                        continue;
                sigdelset(&G.blocked_set, sig);
        }
@@ -5740,17 +5760,8 @@ static void block_signals(int second_time)
        unsigned mask;
 
        mask = (1 << SIGQUIT);
-       if (G_interactive_fd) {
-               mask = 0
-                       | (1 << SIGQUIT)
-                       | (1 << SIGTERM)
-//TODO                 | (1 << SIGHUP)
-#if ENABLE_HUSH_JOB
-                       | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
-#endif
-                       | (1 << SIGINT)
-               ;
-       }
+       if (G_interactive_fd)
+               mask = (1 << SIGQUIT) | SPECIAL_INTERACTIVE_SIGS;
        G.non_DFL_mask = mask;
 
        if (!second_time)