linux-user: Remove redundant default action check in queue_signal()

Both queue_signal() and process_pending_signals() did check for default
actions of signals, this is redundant and also causes fatal and stopping
signals to incorrectly cause guest system calls to be interrupted.

The code in queue_signal() is removed.

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-21-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

linux-user/signal.c

@@ -525,46 +525,10 @@ int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info)
     TaskState *ts = cpu->opaque;
     struct emulated_sigtable *k;
     struct sigqueue *q, **pq;
-    abi_ulong handler;
-    int queue;
 
     trace_user_queue_signal(env, sig);
     k = &ts->sigtab[sig - 1];
-    queue = gdb_queuesig ();
-    handler = sigact_table[sig - 1]._sa_handler;
 
-    if (sig == TARGET_SIGSEGV && sigismember(&ts->signal_mask, SIGSEGV)) {
-        /* Guest has blocked SIGSEGV but we got one anyway. Assume this
-         * is a forced SIGSEGV (ie one the kernel handles via force_sig_info
-         * because it got a real MMU fault). A blocked SIGSEGV in that
-         * situation is treated as if using the default handler. This is
-         * not correct if some other process has randomly sent us a SIGSEGV
-         * via kill(), but that is not easy to distinguish at this point,
-         * so we assume it doesn't happen.
-         */
-        handler = TARGET_SIG_DFL;
-    }
-
-    if (!queue && handler == TARGET_SIG_DFL) {
-        if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) {
-            kill(getpid(),SIGSTOP);
-            return 0;
-        } else
-        /* default handler : ignore some signal. The other are fatal */
-        if (sig != TARGET_SIGCHLD &&
-            sig != TARGET_SIGURG &&
-            sig != TARGET_SIGWINCH &&
-            sig != TARGET_SIGCONT) {
-            force_sig(sig);
-        } else {
-            return 0; /* indicate ignored */
-        }
-    } else if (!queue && handler == TARGET_SIG_IGN) {
-        /* ignore signal */
-        return 0;
-    } else if (!queue && handler == TARGET_SIG_ERR) {
-        force_sig(sig);
-    } else {
         pq = &k->first;
         if (sig < TARGET_SIGRTMIN) {
             /* if non real time signal, we queue exactly one signal */
@@ -591,7 +555,6 @@ int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info)
         /* signal that a new signal is pending */
         atomic_set(&ts->signal_pending, 1);
         return 1; /* indicates that the signal was queued */
-    }
 }
 
 #ifndef HAVE_SAFE_SYSCALL