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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 * When debugging is on, debugging info will be written to ./trace and
* a quit signal will generate a core dump. * a quit signal will generate a core dump.
*/ */
#define DEBUG 0 #define DEBUG 2
/* Tweak debug output verbosity here */ /* Tweak debug output verbosity here */
#define DEBUG_TIME 0 #define DEBUG_TIME 0
#define DEBUG_PID 1 #define DEBUG_PID 1
@ -3834,7 +3834,8 @@ dowait(int wait_flags, struct job *job)
* NB: _not_ safe_waitpid, we need to detect EINTR */ * NB: _not_ safe_waitpid, we need to detect EINTR */
pid = waitpid(-1, &status, pid = waitpid(-1, &status,
(doing_jobctl ? (wait_flags | WUNTRACED) : wait_flags)); (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) if (pid <= 0)
return pid; return pid;
@ -8003,7 +8004,7 @@ dotrap(void)
want_exexit = evalstring(t, SKIPEVAL); want_exexit = evalstring(t, SKIPEVAL);
exitstatus = savestatus; exitstatus = savestatus;
if (want_exexit) { if (want_exexit) {
TRACE(("dotrap returns %d\n", skip)); TRACE(("dotrap returns %d\n", want_exexit));
return want_exexit; return want_exexit;
} }
} }
@ -8051,11 +8052,13 @@ evaltree(union node *n, int flags)
if (err) { if (err) {
/* if it was a signal, check for trap handlers */ /* if it was a signal, check for trap handlers */
if (exception_type == EXSIG) { 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; goto out;
} }
/* continue on the way 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; exception_handler = savehandler;
longjmp(exception_handler->loc, err); 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 of exiting. (true) in subshell does not seem to matter, as another user
reports the same with: reports the same with:
while true trap "echo USR1" USR1
do while true; do
echo Kill me echo Sleeping
sleep 1 sleep 5
done 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)