Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -O2 -flto=auto -ffat-lto-objects -fexceptions -g
-grecord-gcc-switches -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1
-m64 -mtune=generic -fasynchronous-unwind-tables
-fstack-clash-protection -fcf-protection
uname output: Linux chatoyancy 5.18.17-200.fc36.x86_64 #1 SMP
PREEMPT_DYNAMIC Thu Aug 11 14:36:06 UTC 2022 x86_64 x86_64 x86_64
GNU/Linux
Machine Type: x86_64-redhat-linux-gnu
Bash Version: 5.1
Patch Level: 16
Release Status: release
Description:
In Bash versions from 4.3 to the current devel, after calling `trap'
for SIGINT in completion functions specified to `complete -F',
readline is left in a strange state where C-c does not respond and
the first character of the next user command is dropped. This is
caused by missing `rl_set_signals ()' after using `trap xxx INT' in
the completion functions.
Repeat-By:
Here is a reduced test case.
$ bash --norc
$ _cmd0() { trap - INT; } && complete -F _cmd0 cmd0
$ cmd0 a< here, press [TAB][C-c][RET]
bash: md0: command not found
$
In the above case, there is no response to [C-c] although we are
expecting [C-c] to print `^C' and clear the command line. Also, the
subsequent [RET] causes the execution of the command, but somehow
the first character of the command line is missing.
We can observe similar behaviors also with the following cases
(where the number 100 may be adjusted depending on the speed of
the machine so that C-c is received within the for loop).
$ _cmd1() { trap 'echo INT:$FUNCNAME' INT; for
((i=0;i<100;i++)); do true; done; trap - INT; } && complete -F
_cmd1 cmd1
$ cmd1 a[TAB][C-c]
$ _cmd2() { trap 'echo INT:$FUNCNAME; trap - INT' INT; for
((i=0;i<100;i++)); do true; done; trap - INT; } && complete -F
_cmd2 cmd2
$ cmd2 a[TAB][C-c]
$ _cmd3() { trap 'echo INT:$FUNCNAME; trap - INT; kill -INT $$' INT;
for ((i=0;i<100;i++)); do true; done; trap - INT; } && complete -F
_cmd3 cmd3
$ cmd3 a[TAB][C-c]
$ _cmd4() { compgen -F _cmd3 &>/dev/null; } && complete -F _cmd4 cmd4
$ cmd4 a[TAB][C-c]
Fix:
I attach a patch [0001-fix-rlsig-compfunctrap.patch.txt] that
explains an essential part of a possible fix.
* I would like to perform `rl_clear_signals ()' and `rl_set_signals
()' only when it is called from the built-in programmable
completion directly caused by the user key inputs but not when it
is called by `compgen', so we need a reliable way to test it (see
the code comment starting with XXX in the patch). The case where
`compgen -F xxx 2>/dev/null' is called inside another completion
function `yyy' with `complete -F yyy' should also be taken care of
(cf the test case of cmd4).
I excluded a concrete implementation for the test from the above
patch because this is not an essential part of the fix and also
there are multiple possible implementations. I attach an example
patch [0002-example-flags.patch.txt] of implementing it by adding
a parameter `flags' to `gen_compspec_completions' and
`gen_shell_function_matches'.
* The change in `pcomplete.c' solves test cases cmd1..cmd3, but test
cases cmd3 and cmd4 remain not working.
This is because `trap - INT; kill -INT $$' makes the control to
``longjmp'' from `jump_to_top_level () @ sig.c' to the top-level
`reader_loop () @ eval.c' without running the cleanup code in
`readline () @ lib/readline/readline.c', particularly
`rl_clear_signals ()'. Because of this missing call to
`rl_clear_signals ()', the next call to `rl_set_signals ()' in
`readline ()' does nothing, so the signals for readline are not
set up.
I initially naively thought we could also set up an unwind frame
in `readline ()' but realized that the unwind mechanism is
implemented in Bash, so readline cannot rely on it. Instead, the
patch clears the readline signals in `reader_loop ()'---the
longjmp destination.
--
Koichi
From e1b08619bbc0f4249271fc66c4049973b256b58d Mon Sep 17 00:00:00 2001
From: Koichi Murase
Date: Thu, 1 Sep 2022 19:04:22 +0900
Subject: [PATCH 1/4] fix readline signal setups after trap INT in compfunc
---
eval.c | 8
pcomplete.c | 13 +
2 files changed, 21 insertions(+)
diff --git a/eval.c b/eval.c
index 17fbf736..c0b45079 100644
--- a/eval.c
+++ b/eval.c
@@ -48,6 +48,10 @@
# include "bashhist.h"
#endif
+#if defined (READLINE)
+# include
+#endif
+
static void send_pwd_to_eterm PARAMS((void));
static sighandler alrm_catcher PARAMS((int));
@@ -119,6 +123,10 @@ reader_loop ()
current_command = (COMMAND *)NULL;
}
+#if defined (READLINE)
+ if (interactive_
