From b21f379639386c68c182e55ae61c6f1e80159c4d Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Thu, 19 Mar 2009 23:09:58 +0000 Subject: ash: fix TRACE commands --- shell/ash_doc.txt | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 73 insertions(+), 4 deletions(-) (limited to 'shell/ash_doc.txt') diff --git a/shell/ash_doc.txt b/shell/ash_doc.txt index d8a48c114..2aa44434c 100644 --- a/shell/ash_doc.txt +++ b/shell/ash_doc.txt @@ -46,8 +46,77 @@ done of exiting. (true) in subshell does not seem to matter, as another user reports the same with: -while true -do - echo Kill me - sleep 1 +trap "echo USR1" USR1 +while true; do + echo Sleeping + sleep 5 done + +Compat note. +Bash version 3.2.0(1) exits this script at the receipt of SIGINT +_only_ if it had two last children die from it. +The following trace was obtained while periodically running +"killall -SIGINT sleep; sleep 0.1; kill -SIGINT ": + +23:48:32.376707 clone(...) = 13528 +23:48:32.388706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) +23:48:32.459761 --- SIGINT (Interrupt) @ 0 (0) --- + kill -SIGINT is ignored, back to waiting: +23:48:32.463706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13528 + sleep exited with 0 +23:48:37.377557 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:37.378451 clone(...) = 13538 +23:48:37.390708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13538 + sleep was killed by "killall -SIGINT sleep" +23:48:38.523944 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:38.524861 clone(...) = 13542 +23:48:38.538706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) +23:48:38.624761 --- SIGINT (Interrupt) @ 0 (0) --- + kill -SIGINT is ignored, back to waiting: +23:48:38.628706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13542 + sleep exited with 0 +23:48:43.525674 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:43.526563 clone(...) = 13545 +23:48:43.538709 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13545 + sleep was killed by "killall -SIGINT sleep" +23:48:44.466848 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:44.467735 clone(...) = 13549 +23:48:44.481706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) +23:48:44.567757 --- SIGINT (Interrupt) @ 0 (0) --- + kill -SIGINT is ignored, back to waiting: +23:48:44.571706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13549 + sleep exited with 0 +23:48:49.468553 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:49.469445 clone(...) = 13551 +23:48:49.481708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13551 + sleep was killed by "killall -SIGINT sleep" +23:48:50.515837 --- SIGCHLD (Child exited) @ 0 (0) --- +23:48:50.516718 clone(...) = 13555 +23:48:50.530706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) +23:48:50.615761 --- SIGINT (Interrupt) @ 0 (0) --- + kill -SIGINT is ignored, back to waiting: +23:48:50.619705 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13555 + sleep was killed by "killall -SIGINT sleep". + This is the second one in a row. Kill ourself: +23:48:51.504604 kill(13515, SIGINT) = 0 +23:48:51.504689 --- SIGINT (Interrupt) @ 0 (0) --- +23:48:51.504915 +++ killed by SIGINT +++ + +As long as there is at least one "sleep 5" which exited successfully +(not killed by SIGINT), bash continues. This is not documented anywhere +AFAIKS. + +Why keyboard ^C acts differently? + +00:08:07.655985 clone(...) = 14270 +00:08:07.669707 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 14270 +00:08:12.656872 --- SIGCHLD (Child exited) @ 0 (0) --- +00:08:12.657743 clone(...) = 14273 +00:08:12.671708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 14273 +00:08:13.810778 --- SIGINT (Interrupt) @ 0 (0) --- +00:08:13.818705 kill(14269, SIGINT) = 0 +00:08:13.820103 --- SIGINT (Interrupt) @ 0 (0) --- +00:08:13.820925 +++ killed by SIGINT +++ + +Perhaps because at the moment bash got SIGINT it had no children? +(it did not manage to spawn new sleep yet, see the trace) -- cgit v1.2.3