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ash: fix TRACE commands

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This commit is contained in:
Denis Vlasenko 2009-03-19 23:09:58 +00:00
parent 653d8e79b2
commit b21f379639
2 changed files with 81 additions and 9 deletions
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13
shell/ash.c
View File

@ -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);
}

77
shell/ash_doc.txt
View File

@ -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)