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[pushed] TUI: don't let exceptions escape while handling readline key bindings
- From: Pedro Alves <palves at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 29 Oct 2014 14:47:56 +0000
- Subject: [pushed] TUI: don't let exceptions escape while handling readline key bindings
- Authentication-results: sourceware.org; auth=none
I noticed that with:
$ TERM=dumb ./gdb -q -nx
<c-x,a>
Cannot enable the TUI: terminal doesn't support cursor addressing [TERM=dumb]
(gdb)
The next key the user types is silently eaten.
The problem is that we're throwing an exception while in a readline
callback that isn't prepared for that:
(top-gdb) bt
#0 tui_enable () at /home/pedro/gdb/mygit/build/../src/gdb/tui/tui.c:388
#1 0x000000000051f47b in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/build/../src/gdb/tui/tui.c:101
#2 0x0000000000768d6f in _rl_dispatch_subseq (key=1, map=0xd069c0 <emacs_ctlx_keymap>, got_subseq=0) at /home/pedro/gdb/mygit/build/../src/readline/readline.c:774
#3 0x0000000000768acb in _rl_dispatch_callback (cxt=0x1ce6190) at /home/pedro/gdb/mygit/build/../src/readline/readline.c:686
#4 0x000000000078120b in rl_callback_read_char () at /home/pedro/gdb/mygit/build/../src/readline/callback.c:170
#5 0x0000000000619445 in rl_callback_read_char_wrapper (client_data=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/event-top.c:166
#6 0x000000000061981b in stdin_event_handler (error=0, client_data=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/event-top.c:372
#7 0x000000000061840e in handle_file_event (data=...) at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:762
#8 0x00000000006178f5 in process_event () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:339
#9 0x00000000006179bc in gdb_do_one_event () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:403
#10 0x0000000000617a0c in start_event_loop () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:428
Here, in _rl_dispatch_subseq:
769
770 rl_executing_keymap = map;
771
772 rl_dispatching = 1;
773 RL_SETSTATE(RL_STATE_DISPATCHING);
774 (*map[key].function)(rl_numeric_arg * rl_arg_sign, key);
775 RL_UNSETSTATE(RL_STATE_DISPATCHING);
776 rl_dispatching = 0;
777
778 /* If we have input pending, then the last command was a prefix
779 command. Don't change the state of rl_last_func. Otherwise,
GDB is called from line 774, but longjmp'ing at that point leaves
rl_dispatching and RL_STATE_DISPATCHING set.
Fix this by wrapping tui_rl_switch_mode in a TRY_CATCH.
gdb/
2014-10-29 Pedro Alves <palves@redhat.com>
* tui/tui.c (tui_rl_switch_mode): Wrap tui_enable/tui_disable in
TRY_CATCH.
---
gdb/ChangeLog | 5 +++++
gdb/tui/tui.c | 27 +++++++++++++++++++++------
2 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 6767931..88c18e0 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2014-10-29 Pedro Alves <palves@redhat.com>
+
+ * tui/tui.c (tui_rl_switch_mode): Wrap tui_enable/tui_disable in
+ TRY_CATCH.
+
2014-10-29 Joel Brobecker <brobecker@adacore.com>
* arm-tdep.c (arm_skip_stack_protector): Return early if
diff --git a/gdb/tui/tui.c b/gdb/tui/tui.c
index ca66ccd..cb85fb0 100644
--- a/gdb/tui/tui.c
+++ b/gdb/tui/tui.c
@@ -90,15 +90,30 @@ static Keymap tui_readline_standard_keymap;
static int
tui_rl_switch_mode (int notused1, int notused2)
{
- if (tui_active)
+ volatile struct gdb_exception ex;
+
+ /* Don't let exceptions escape. We're in the middle of a readline
+ callback that isn't prepared for that. */
+ TRY_CATCH (ex, RETURN_MASK_ALL)
{
- tui_disable ();
- rl_prep_terminal (0);
+ if (tui_active)
+ {
+ tui_disable ();
+ rl_prep_terminal (0);
+ }
+ else
+ {
+ /* If tui_enable throws, we'll re-prep below. */
+ rl_deprep_terminal ();
+ tui_enable ();
+ }
}
- else
+ if (ex.reason < 0)
{
- rl_deprep_terminal ();
- tui_enable ();
+ exception_print (gdb_stderr, ex);
+
+ if (!tui_active)
+ rl_prep_terminal (0);
}
/* Clear the readline in case switching occurred in middle of
--
1.9.3