Contents of /tags/mkinitrd-6_3_4/busybox/shell/ash_doc.txt
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Thu Dec 16 01:27:43 2010 UTC (13 years, 9 months ago) by niro
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Thu Dec 16 01:27:43 2010 UTC (13 years, 9 months ago) by niro
File MIME type: text/plain
File size: 4320 byte(s)
tagged 'mkinitrd-6_3_4'
1 | Wait + signals |
2 | |
3 | We had some bugs here which are hard to test in testsuite. |
4 | |
5 | Bug 1280 (http://busybox.net/bugs/view.php?id=1280): |
6 | was misbehaving in interactive ash. Correct behavior: |
7 | |
8 | $ sleep 20 & |
9 | $ wait |
10 | ^C |
11 | $ wait |
12 | ^C |
13 | $ wait |
14 | ^C |
15 | ... |
16 | |
17 | |
18 | Bug 1984 (http://busybox.net/bugs/view.php?id=1984): |
19 | traps were not triggering: |
20 | |
21 | trap_handler_usr () { |
22 | echo trap usr |
23 | } |
24 | trap_handler_int () { |
25 | echo trap int |
26 | } |
27 | trap trap_handler_usr USR1 |
28 | trap trap_handler_int INT |
29 | sleep 3600 & |
30 | echo "Please do: kill -USR1 $$" |
31 | echo "or: kill -INT $$" |
32 | while true; do wait; echo wait interrupted; done |
33 | |
34 | |
35 | Bug 189 (https://bugs.busybox.net/show_bug.cgi?id=189) |
36 | |
37 | func() { |
38 | sleep 1 |
39 | } |
40 | while (true); do |
41 | func |
42 | echo Looping |
43 | done |
44 | |
45 | ^C was observed to make ash processes geometrically multiply (!) instead |
46 | of exiting. (true) in subshell does not seem to matter, as another user |
47 | reports the same with: |
48 | |
49 | trap "echo USR1" USR1 |
50 | while true; do |
51 | echo Sleeping |
52 | sleep 5 |
53 | done |
54 | |
55 | Compat note. |
56 | Bash version 3.2.0(1) exits this script at the receipt of SIGINT |
57 | _only_ if it had two last children die from it. |
58 | The following trace was obtained while periodically running |
59 | "killall -SIGINT sleep; sleep 0.1; kill -SIGINT <bash_PID>": |
60 | |
61 | 23:48:32.376707 clone(...) = 13528 |
62 | 23:48:32.388706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) |
63 | 23:48:32.459761 --- SIGINT (Interrupt) @ 0 (0) --- |
64 | kill -SIGINT <bash_PID> is ignored, back to waiting: |
65 | 23:48:32.463706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13528 |
66 | sleep exited with 0 |
67 | 23:48:37.377557 --- SIGCHLD (Child exited) @ 0 (0) --- |
68 | 23:48:37.378451 clone(...) = 13538 |
69 | 23:48:37.390708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13538 |
70 | sleep was killed by "killall -SIGINT sleep" |
71 | 23:48:38.523944 --- SIGCHLD (Child exited) @ 0 (0) --- |
72 | 23:48:38.524861 clone(...) = 13542 |
73 | 23:48:38.538706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) |
74 | 23:48:38.624761 --- SIGINT (Interrupt) @ 0 (0) --- |
75 | kill -SIGINT <bash_PID> is ignored, back to waiting: |
76 | 23:48:38.628706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13542 |
77 | sleep exited with 0 |
78 | 23:48:43.525674 --- SIGCHLD (Child exited) @ 0 (0) --- |
79 | 23:48:43.526563 clone(...) = 13545 |
80 | 23:48:43.538709 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13545 |
81 | sleep was killed by "killall -SIGINT sleep" |
82 | 23:48:44.466848 --- SIGCHLD (Child exited) @ 0 (0) --- |
83 | 23:48:44.467735 clone(...) = 13549 |
84 | 23:48:44.481706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) |
85 | 23:48:44.567757 --- SIGINT (Interrupt) @ 0 (0) --- |
86 | kill -SIGINT <bash_PID> is ignored, back to waiting: |
87 | 23:48:44.571706 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 13549 |
88 | sleep exited with 0 |
89 | 23:48:49.468553 --- SIGCHLD (Child exited) @ 0 (0) --- |
90 | 23:48:49.469445 clone(...) = 13551 |
91 | 23:48:49.481708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13551 |
92 | sleep was killed by "killall -SIGINT sleep" |
93 | 23:48:50.515837 --- SIGCHLD (Child exited) @ 0 (0) --- |
94 | 23:48:50.516718 clone(...) = 13555 |
95 | 23:48:50.530706 waitpid(-1, 0xffc832ec, 0) = ? ERESTARTSYS (To be restarted) |
96 | 23:48:50.615761 --- SIGINT (Interrupt) @ 0 (0) --- |
97 | kill -SIGINT <bash_PID> is ignored, back to waiting: |
98 | 23:48:50.619705 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 13555 |
99 | sleep was killed by "killall -SIGINT sleep". |
100 | This is the second one in a row. Kill ourself: |
101 | 23:48:51.504604 kill(13515, SIGINT) = 0 |
102 | 23:48:51.504689 --- SIGINT (Interrupt) @ 0 (0) --- |
103 | 23:48:51.504915 +++ killed by SIGINT +++ |
104 | |
105 | As long as there is at least one "sleep 5" which exited successfully |
106 | (not killed by SIGINT), bash continues. This is not documented anywhere |
107 | AFAIKS. |
108 | |
109 | Why keyboard ^C acts differently? |
110 | |
111 | 00:08:07.655985 clone(...) = 14270 |
112 | 00:08:07.669707 waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 14270 |
113 | 00:08:12.656872 --- SIGCHLD (Child exited) @ 0 (0) --- |
114 | 00:08:12.657743 clone(...) = 14273 |
115 | 00:08:12.671708 waitpid(-1, [{WIFSIGNALED(s) && WTERMSIG(s) == SIGINT}], 0) = 14273 |
116 | 00:08:13.810778 --- SIGINT (Interrupt) @ 0 (0) --- |
117 | 00:08:13.818705 kill(14269, SIGINT) = 0 |
118 | 00:08:13.820103 --- SIGINT (Interrupt) @ 0 (0) --- |
119 | 00:08:13.820925 +++ killed by SIGINT +++ |
120 | |
121 | Perhaps because at the moment bash got SIGINT it had no children? |
122 | (it did not manage to spawn new sleep yet, see the trace) |