diff options
| -rw-r--r-- | shell/ash.c | 13 | ||||
| -rw-r--r-- | shell/ash_doc.txt | 77 |
2 files changed, 81 insertions, 9 deletions
diff --git a/shell/ash.c b/shell/ash.c index a8383d805..d969b20a2 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -39,7 +39,7 @@ * When debugging is on, debugging info will be written to ./trace and * a quit signal will generate a core dump. */ -#define DEBUG 0 +#define DEBUG 2 /* Tweak debug output verbosity here */ #define DEBUG_TIME 0 #define DEBUG_PID 1 @@ -3834,7 +3834,8 @@ dowait(int wait_flags, struct job *job) * NB: _not_ safe_waitpid, we need to detect EINTR */ pid = waitpid(-1, &status, (doing_jobctl ? (wait_flags | WUNTRACED) : wait_flags)); - TRACE(("wait returns pid=%d, status=0x%x\n", pid, status)); + TRACE(("wait returns pid=%d, status=0x%x, errno=%d(%s)\n", + pid, status, errno, strerror(errno))); if (pid <= 0) return pid; @@ -8003,7 +8004,7 @@ dotrap(void) want_exexit = evalstring(t, SKIPEVAL); exitstatus = savestatus; if (want_exexit) { - TRACE(("dotrap returns %d\n", skip)); + TRACE(("dotrap returns %d\n", want_exexit)); return want_exexit; } } @@ -8051,11 +8052,13 @@ evaltree(union node *n, int flags) if (err) { /* if it was a signal, check for trap handlers */ if (exception_type == EXSIG) { - TRACE(("exception %d (EXSIG) in evaltree, err=%d\n", exception, err)); + TRACE(("exception %d (EXSIG) in evaltree, err=%d\n", + exception_type, err)); goto out; } /* continue on the way out */ - TRACE(("exception %d in evaltree, propagating err=%d\n", exception, err)); + TRACE(("exception %d in evaltree, propagating err=%d\n", + exception_type, err)); exception_handler = savehandler; longjmp(exception_handler->loc, err); } 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 <bash_PID>": + +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 <bash_PID> 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 <bash_PID> 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 <bash_PID> 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 <bash_PID> 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) |