diff options
| author | Lancelot SIX <lancelot.six@amd.com> | 2021-12-13 07:48:48 -0600 |
|---|---|---|
| committer | Lancelot SIX <lancelot.six@amd.com> | 2021-12-17 03:56:25 -0500 |
| commit | 72994b6028360eccb5d25b39d2e18b386d091426 (patch) | |
| tree | 855d88a99f9ca5ddc6110d496f1a2d29e0a5e3bf | |
| parent | 27e3da31c31572fde3d6e244a68ea45fb874b038 (diff) | |
| download | gdb-72994b6028360eccb5d25b39d2e18b386d091426.zip gdb-72994b6028360eccb5d25b39d2e18b386d091426.tar.gz gdb-72994b6028360eccb5d25b39d2e18b386d091426.tar.bz2 | |
gdb/tui: install SIGWINCH only when connected to a TTY
PR26056 reports that when GDB is connected to non-TTY stdin/stdout, it
crashes when it receives a SIGWINCH signal.
This can be reproduced as follows:
$ gdb/gdb -nx -batch -ex 'run' --args sleep 60 </dev/null 2>&1 | cat
# from another terminal:
$ kill -WINCH %(pidof gdb)
When doing so, the process crashes in a call to rl_resize_terminal:
void
rl_resize_terminal (void)
{
_rl_get_screen_size (fileno (rl_instream), 1);
...
}
The problem is that at this point rl_instream has the value NULL.
The rl_instream variable is supposed to be initialized during a call to
readline_initialize_everything, which in a normal startup sequence is
called under this call chain:
tui_interp::init
tui_ensure_readline_initialized
rl_initialize
readline_initialize_everything
In tui_interp::init, we have the following sequence:
tui_initialize_io ();
tui_initialize_win (); // <- Installs SIGWINCH
if (gdb_stdout->isatty ())
tui_ensure_readline_initialized (); // <- Initializes rl_instream
This function unconditionally installs the SIGWINCH signal handler (this
is done by tui_initialize_win), and then if gdb_stdout is a TTY it
initializes readline. Therefore, if stdout is not a TTY, SIGWINCH is
installed but readline is not initialized. In such situation
rl_instream stays NULL, and when GDB receives a SIGWINCH it calls its
handler and in fine tries to access rl_instream leading to the crash.
This patch proposes to fix this issue by installing the SIGWINCH signal
handler only if GDB is connected to a TTY. Given that this
initialization it the only task of tui_initialize_win, this patch moves
tui_initialize_win just after the call to
tui_ensure_readline_initialized.
Tested on x86_64-linux.
Co-authored-by: Pedro Alves <pedro@palves.net>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=26056
Change-Id: I6458acef7b0d9beda2a10715d0345f02361076d9
| -rw-r--r-- | gdb/testsuite/gdb.base/sigwinch-notty.exp | 70 | ||||
| -rw-r--r-- | gdb/testsuite/lib/gdb.exp | 4 | ||||
| -rwxr-xr-x | gdb/testsuite/lib/notty-wrap | 24 | ||||
| -rw-r--r-- | gdb/tui/tui-interp.c | 10 |
4 files changed, 105 insertions, 3 deletions
diff --git a/gdb/testsuite/gdb.base/sigwinch-notty.exp b/gdb/testsuite/gdb.base/sigwinch-notty.exp new file mode 100644 index 0000000..9084c25 --- /dev/null +++ b/gdb/testsuite/gdb.base/sigwinch-notty.exp @@ -0,0 +1,70 @@ +# Copyright 2021 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +# Test that GDB does not crash when it is started without a terminal / +# without readline, and, it receives a SIGWINCH. Regression test for +# PR gdb/26056. + +if [target_info exists gdb,nosignals] { + verbose "Skipping $subdir/$gdb_test_file_name.exp because of nosignals." + continue +} + +# The testfile relies on "run" from the command line, so only works +# with "target native". +if { [target_info gdb_protocol] != "" } { + continue +} + +gdb_exit + +# Start GDB without a terminal, running sleep for a while. Before the +# sleep exits, we'll send a SIGWINCH. "show editing" to double check +# that readline is disabled. +save_vars { GDB GDBFLAGS } { + set GDB "$srcdir/lib/notty-wrap $GDB" + set GDBFLAGS "$GDBFLAGS -ex \"show editing\" -ex run --args sleep 3" + + gdb_spawn +} + +set gdb_pid [exp_pid -i $gdb_spawn_id] + +verbose -log "gdb_spawn_id=$gdb_spawn_id" +verbose -log "gdb_pid=$gdb_pid" + +after 1000 { + # Note, GDB is started under a shell, so PID is actually the + # shell's pid, not GDB's. Use "-PID" to send the signal to the + # whole process group and reach GDB, instead of just to the shell. + remote_exec host "kill -SIGWINCH -${gdb_pid}" +} + +# If GDB mishandles the SIGWINCH and crashes, that happens before we +# see the "inferior exited normally" message, so this will ERROR with +# eof. +gdb_test_multiple "" "wait for sleep exit" { + -re "Editing of command lines as they are typed is off.*$inferior_exited_re normally.*$gdb_prompt " { + pass $gdb_test_name + } +} + +gdb_test_multiple "" "wait for gdb exit" { + eof { + set wait_status [wait -i $gdb_spawn_id] + verbose -log "GDB process exited with wait status $wait_status" + pass $gdb_test_name + } +} diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp index 95220f6..b952c93 100644 --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -2096,7 +2096,9 @@ proc default_gdb_spawn { } { exit 1 } } - set res [remote_spawn host "$GDB $INTERNAL_GDBFLAGS $GDBFLAGS [host_info gdb_opts]"] + + # Put GDBFLAGS last so that tests can put "--args ..." in it. + set res [remote_spawn host "$GDB $INTERNAL_GDBFLAGS [host_info gdb_opts] $GDBFLAGS"] if { $res < 0 || $res == "" } { perror "Spawning $GDB failed." return 1 diff --git a/gdb/testsuite/lib/notty-wrap b/gdb/testsuite/lib/notty-wrap new file mode 100755 index 0000000..899c2dd --- /dev/null +++ b/gdb/testsuite/lib/notty-wrap @@ -0,0 +1,24 @@ +#!/bin/sh + +# Copyright (C) 2021 Free Software Foundation, Inc. +# +# This file is part of GDB. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see +# <http://www.gnu.org/licenses/>. + +# Wrap any passed-in program and args in a pipe, so that the program +# is started without a terminal. + +exec "$@" </dev/null 2>&1 | cat diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c index 0cd5b12..16859cb 100644 --- a/gdb/tui/tui-interp.c +++ b/gdb/tui/tui-interp.c @@ -242,9 +242,15 @@ tui_interp::init (bool top_level) atexit (tui_exit); tui_initialize_io (); - tui_initialize_win (); if (gdb_stdout->isatty ()) - tui_ensure_readline_initialized (); + { + tui_ensure_readline_initialized (); + + /* This installs the SIGWINCH signal handler. The handler needs to do + readline calls (to rl_resize_terminal), so it must not be installed + unless readline is properly initialized. */ + tui_initialize_win (); + } } /* Used as the command handler for the tui. */ |