Simplify and avoid signal-handling races.

* nt/inc/ms-w32.h (emacs_raise): New macro.
* src/alloc.c (die):
* src/sysdep.c (emacs_abort) [HAVE_NTGUI]:
Avoid recursive loop if there's a fatal error in the function itself.
* src/atimer.c (pending_atimers):
* src/blockinput.h: Don't include "atimer.h"; no longer needed.
(interrupt_input_pending): Remove.  All uses removed.
pending_signals now counts both atimers and ordinary interrupts.
This is less racy than having three separate pending-signal flags.
(block_input, unblock_input, totally_unblock_input, unblock_input_to)
(input_blocked_p):
Rename from their upper-case counterparts BLOCK_INPUT,
UNBLOCK_INPUT, TOTALLY_UNBLOCK_INPUT, UNBLOCK_INPUT_TO,
INPUT_BLOCKED_P, and turn into functions.  All uses changed.
This makes it easier to access volatile variables more accurately.
(BLOCK_INPUT_RESIGNAL): Remove.  All uses replaced by unblock_input ().
(input_blocked_p): Prefer this to 'interrupt_input_blocked', as
that's more reliable if the code is buggy and sets
interrupt_input_blocked to a negative value.  All uses changed.
* src/atimer.c (deliver_alarm_signal):
Remove.  No need to deliver this to the parent; any thread can
handle this signal now.  All uses replaced by underlying handler.
* src/atimer.c (turn_on_atimers):
* src/dispnew.c (handle_window_change_signal):
* src/emacs.c (handle_danger_signal):
* src/keyboard.c (kbd_buffer_get_event):
Don't reestablish signal handler; not needed with sigaction.
* src/blockinput.h (UNBLOCK_INPUT_TO, TOTALLY_UNBLOCK_INPUT)
(UNBLOCK_INPUT_TO):
Rework to avoid unnecessary accesses to volatile variables.
(UNBLOCK_INPUT_TO): Now a function.
(totally_unblock_input, unblock_input): New decls.
* src/data.c (handle_arith_signal, deliver_arith_signal): Move to sysdep.c
(init_data): Remove.  Necessary stuff now done in init_signal.
* src/emacs.c, src/xdisp.c: Include "atimer.h", since we invoke atimer functions.
* src/emacs.c (handle_fatal_signal, deliver_fatal_signal): Move to sysdep.c.
(fatal_error_code): Remove; no longer needed.
(terminate_due_to_signal): Rename from fatal_error_backtrace, since
it doesn't always backtrace.  All uses changed.  No need to reset
signal to default, since sigaction and/or die does that for us now.
Use emacs_raise (FOO), not kill (getpid (), FOO).
(main): Check more-accurately whether we're dumping.
Move fatal-error setup to sysdep.c
* src/floatfns.c: Do not include "syssignal.h"; no longer needed.
* src/gtkutil.c (xg_get_file_name, xg_get_font):
Remove no-longer-needed signal-mask manipulation.
* src/keyboard.c, src/process.c (POLL_FOR_INPUT):
Don't depend on USE_ASYNC_EVENTS, a symbol that is never defined.
* src/keyboard.c (read_avail_input): Remove.
All uses replaced by gobble_input.
(Ftop_level): Use TOTALLY_UNBLOCK_INPUT rather than open code.
(kbd_buffer_store_event_hold, gobble_input):
(record_asynch_buffer_change) [USABLE_SIGIO]:
(store_user_signal_events):
No need to mess with signal mask.
(gobble_input): If blocking input and there are terminals, simply
set pending_signals to 1 and return.  All hooks changed to not
worry about whether input is blocked.
(process_pending_signals): Clear pending_signals before processing
them, in case a signal comes in while we're processing.
By convention callers now test pending_signals before calling us.
(UNBLOCK_INPUT_TO, unblock_input, totally_unblock_input):
New functions, to support changes to blockinput.h.
(handle_input_available_signal): Now extern.
(reinvoke_input_signal): Remove.  All uses replaced by
handle_async_input.
(quit_count): Now volatile, since a signal handler uses it.
(handle_interrupt): Now takes bool IN_SIGNAL_HANDLER as arg.  All
callers changed.  Block SIGINT only if not already blocked.
Clear sigmask reliably, even if Fsignal returns, which it can.
Omit unnecessary accesses to volatile var.
(quit_throw_to_read_char): No need to restore sigmask.
* src/keyboard.c (gobble_input, handle_user_signal):
* src/process.c (wait_reading_process_output):
Call signal-handling code rather than killing ourselves.
* src/lisp.h: Include <float.h>, for...
(IEEE_FLOATING_POINT): New macro, moved here to avoid duplication.
(pending_signals): Now volatile.
(syms_of_data): Now const if IEEE floating point.
(handle_input_available_signal) [USABLE_SIGIO]:
(terminate_due_to_signal, record_child_status_change): New decls.
* src/process.c (create_process): Avoid disaster if memory is exhausted
while we're processing a vfork, by tightening the critical section
around the vfork.
(send_process_frame, process_sent_to, handle_pipe_signal)
(deliver_pipe_signal): Remove.  No longer needed, as Emacs now
ignores SIGPIPE.
(send_process): No need for setjmp/longjmp any more, since the
SIGPIPE stuff is now gone.  Instead, report an error if errno
is EPIPE.
(record_child_status_change): Now extern.  PID and W are now args.
Return void, not bool.  All callers changed.
* src/sysdep.c (wait_debugging) [(BSD_SYSTEM || HPUX) && !defined (__GNU__)]:
Remove.  All uses removed.  This bug should be fixed now in a
different way.
(wait_for_termination_1): Use waitpid rather than sigsuspend,
and record the child status change directly.  This avoids the
need to futz with the signal mask.
(process_fatal_action): Move here from emacs.c.
(emacs_sigaction_flags): New function, containing
much of what used to be in emacs_sigaction_init.
(emacs_sigaction_init): Use it.  Block nonfatal system signals that are
caught by emacs, to make races less likely.
(deliver_process_signal): Rename from handle_on_main_thread.
All uses changed.
(BACKTRACE_LIMIT_MAX): Now at top level.
(thread_backtrace_buffer, threadback_backtrace_pointers):
New static vars.
(deliver_thread_signal, deliver_fatal_thread_signal):
New functions, for more-accurate delivery of thread-specific signals.
(handle_fatal_signal, deliver_fatal_signal): Move here from emacs.c.
(deliver_arith_signal): Handle in this thread, not
in the main thread, since it's triggered by this thread.
(maybe_fatal_sig): New function.
(init_signals): New arg DUMPING so that we can be more accurate
about whether we're dumping.  Caller changed.
Treat thread-specific signals differently from process-general signals.
Block all signals while handling fatal error; that's safer.
xsignal from SIGFPE only on non-IEEE hosts, treating it as fatal
on IEEE hosts.
When batch, ignore SIGHUP, SIGINT, SIGTERM if they were already ignored.
Ignore SIGPIPE unless batch.
(emacs_backtrace): Output backtrace for the appropriate thread,
which is not necessarily the main thread.
* src/syssignal.h: Include <stdbool.h>.
(emacs_raise): New macro.
* src/xterm.c (x_connection_signal): Remove; no longer needed
now that we use sigaction.
(x_connection_closed): No need to mess with sigmask now.
(x_initialize): No need to reset SIGPIPE handler here, since
init_signals does this for us now.

Fixes: debbugs:12471

1 files changed, 17 insertions, 17 deletions

diff --git a/src/window.c b/src/window.c
index 6798be8231c..86f86deedb2 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2819,7 +2819,7 @@ window-start value is reasonable when this function is called.  */)
         }
     }
 
-  BLOCK_INPUT;
+  block_input ();
   if (!FRAME_INITIAL_P (f))
     {
         Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);
@@ -2961,7 +2961,7 @@ window-start value is reasonable when this function is called.  */)
     }
 
   adjust_glyphs (f);
-  UNBLOCK_INPUT;
+  unblock_input ();
 
   run_window_configuration_change_hook (f);
 
@@ -3696,14 +3696,14 @@ be applied on the Elisp level.  */)
                (horflag ? r->total_cols : r->total_lines)))
     return Qnil;
 
-  BLOCK_INPUT;
+  block_input ();
   window_resize_apply (r, horflag);
 
   windows_or_buffers_changed++;
   FRAME_WINDOW_SIZES_CHANGED (f) = 1;
 
   adjust_glyphs (f);
-  UNBLOCK_INPUT;
+  unblock_input ();
 
   run_window_configuration_change_hook (f);
 
@@ -3973,13 +3973,13 @@ set correctly.  See the code of `split-window' for how this is done.  */)
   wset_new_total (n, total_size);
   wset_new_normal (n, normal_size);
 
-  BLOCK_INPUT;
+  block_input ();
   window_resize_apply (p, horflag);
   adjust_glyphs (f);
   /* Set buffer of NEW to buffer of reference window.  Don't run
      any hooks.  */
   set_window_buffer (new, r->buffer, 0, 1);
-  UNBLOCK_INPUT;
+  unblock_input ();
 
   /* Maybe we should run the scroll functions in Elisp (which already
      runs the configuration change hook).  */
@@ -4060,7 +4060,7 @@ Signal an error when WINDOW is the only window on its frame.  */)
     {
 
       /* Block input.  */
-      BLOCK_INPUT;
+      block_input ();
       window_resize_apply (p, horflag);
 
       /* If this window is referred to by the dpyinfo's mouse
@@ -4132,7 +4132,7 @@ Signal an error when WINDOW is the only window on its frame.  */)
           else
             fset_selected_window (f, new_selected_window);
 
-          UNBLOCK_INPUT;
+          unblock_input ();
 
           /* Now look whether `get-mru-window' gets us something.  */
           mru_window = call1 (Qget_mru_window, frame);
@@ -4147,7 +4147,7 @@ Signal an error when WINDOW is the only window on its frame.  */)
             fset_selected_window (f, new_selected_window);
         }
       else
-        UNBLOCK_INPUT;
+        unblock_input ();
 
       /* Must be run by the caller:
          run_window_configuration_change_hook (f);  */
@@ -4197,7 +4197,7 @@ grow_mini_window (struct window *w, int delta)
                  root, make_number (- delta));
   if (INTEGERP (value) && window_resize_check (r, 0))
     {
-      BLOCK_INPUT;
+      block_input ();
       window_resize_apply (r, 0);
 
       /* Grow the mini-window.  */
@@ -4209,7 +4209,7 @@ grow_mini_window (struct window *w, int delta)
       w->last_overlay_modified = 0;
 
       adjust_glyphs (f);
-      UNBLOCK_INPUT;
+      unblock_input ();
     }
 }
 
@@ -4234,7 +4234,7 @@ shrink_mini_window (struct window *w)
                      root, make_number (size - 1));
       if (INTEGERP (value) && window_resize_check (r, 0))
         {
-          BLOCK_INPUT;
+          block_input ();
           window_resize_apply (r, 0);
 
           /* Shrink the mini-window.  */
@@ -4246,7 +4246,7 @@ shrink_mini_window (struct window *w)
           w->last_overlay_modified = 0;
 
           adjust_glyphs (f);
-          UNBLOCK_INPUT;
+          unblock_input ();
         }
       /* If the above failed for whatever strange reason we must make a
          one window frame here.  The same routine will be needed when
@@ -4278,7 +4278,7 @@ DEFUN ("resize-mini-window-internal", Fresize_mini_window_internal, Sresize_mini
       && XINT (w->new_total) > 0
       && height == XINT (r->new_total) + XINT (w->new_total))
     {
-      BLOCK_INPUT;
+      block_input ();
       window_resize_apply (r, 0);
 
       wset_total_lines (w, w->new_total);
@@ -4288,7 +4288,7 @@ DEFUN ("resize-mini-window-internal", Fresize_mini_window_internal, Sresize_mini
       windows_or_buffers_changed++;
       FRAME_WINDOW_SIZES_CHANGED (f) = 1;
       adjust_glyphs (f);
-      UNBLOCK_INPUT;
+      unblock_input ();
 
       run_window_configuration_change_hook (f);
       return Qt;
@@ -5624,7 +5624,7 @@ the return value is nil.  Otherwise the value is t.  */)
 
       /* The mouse highlighting code could get screwed up
          if it runs during this.  */
-      BLOCK_INPUT;
+      block_input ();
 
       if (data->frame_lines != previous_frame_lines
           || data->frame_cols != previous_frame_cols)
@@ -5875,7 +5875,7 @@ the return value is nil.  Otherwise the value is t.  */)
         }
 
       adjust_glyphs (f);
-      UNBLOCK_INPUT;
+      unblock_input ();
 
       /* Scan dead buffer windows.  */
       for (; CONSP (dead_windows); dead_windows = XCDR (dead_windows))