Contents of /tags/mkinitrd-6_1_9/busybox/shell/README
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Wed Oct 28 00:26:51 2009 UTC (14 years, 11 months ago) by niro
File size: 4133 byte(s)
Wed Oct 28 00:26:51 2009 UTC (14 years, 11 months ago) by niro
File size: 4133 byte(s)
tagged 'mkinitrd-6_1_9'
1 | Various bits of what is known about busybox shells, in no particular order. |
2 | |
3 | 2008-02-14 |
4 | ash: does not restore tty pgrp if killed by HUP. Symptom: Midnight Commander |
5 | is backgrounded if you started ash under it, and then killed it with HUP. |
6 | |
7 | 2007-11-23 |
8 | hush: fixed bogus glob handling; fixed exec <"$1"; added test and echo builtins |
9 | |
10 | 2007-06-13 |
11 | hush: exec <"$1" doesn't do parameter subst |
12 | |
13 | 2007-05-24 |
14 | hush: environment-related memory leak plugged, with net code size |
15 | decrease. |
16 | |
17 | 2007-05-24 |
18 | hush: '( echo ${name )' will show syntax error message, but prompt |
19 | doesn't return (need to press <enter>). Pressing Ctrl-C, <enter>, |
20 | '( echo ${name )' again, Ctrl-C segfaults. |
21 | |
22 | 2007-05-21 |
23 | hush: environment cannot be handled by libc routines as they are leaky |
24 | (by API design and thus unfixable): hush will leak memory in this script, |
25 | bash does not: |
26 | pid=$$ |
27 | while true; do |
28 | unset t; |
29 | t=111111111111111111111111111111111111111111111111111111111111111111111111 |
30 | export t |
31 | ps -o vsz,pid,comm | grep " $pid " |
32 | done |
33 | The fix is to not use setenv/putenv/unsetenv but manipulate env ourself. TODO. |
34 | hush: meanwhile, first three command subst bugs mentioned below are fixed. :) |
35 | |
36 | 2007-05-06 |
37 | hush: more bugs spotted. Comparison with bash: |
38 | bash-3.2# echo "TEST`date;echo;echo`BEST" |
39 | TESTSun May 6 09:21:05 CEST 2007BEST [we dont strip eols] |
40 | bash-3.2# echo "TEST`echo '$(echo ZZ)'`BEST" |
41 | TEST$(echo ZZ)BEST [we execute inner echo] |
42 | bash-3.2# echo "TEST`echo "'"`BEST" |
43 | TEST'BEST [we totally mess up this one] |
44 | bash-3.2# echo `sleep 5` |
45 | [Ctrl-C should work, Ctrl-Z should do nothing][we totally mess up this one] |
46 | bash-3.2# if true; then |
47 | > [Ctrl-C] |
48 | bash-3.2# [we re-issue "> "] |
49 | bash-3.2# if echo `sleep 5`; then |
50 | > true; fi [we execute sleep before "> "] |
51 | |
52 | 2007-05-04 |
53 | hush: made ctrl-Z/C work correctly for "while true; do true; done" |
54 | (namely, it backgrounds/interrupts entire "while") |
55 | |
56 | 2007-05-03 |
57 | hush: new bug spotted: Ctrl-C on "while true; do true; done" doesn't |
58 | work right: |
59 | # while true; do true; done |
60 | [1] 0 true <-- pressing Ctrl-C several times... |
61 | [2] 0 true |
62 | [3] 0 true |
63 | Segmentation fault |
64 | |
65 | 2007-05-03 |
66 | hush: update on "sleep 1 | exit 3; echo $?" bug. |
67 | parse_stream_outer() repeatedly calls parse_stream(). |
68 | parse_stream() is now fixed to stop on ';' in this example, |
69 | fixing it (parse_stream_outer() will call parse_stream() 1st time, |
70 | execute the parse tree, call parse_stream() 2nd time and execute the tree). |
71 | But it's not the end of story. |
72 | In more complex situations we _must_ parse way farther before executing. |
73 | Example #2: "{ sleep 1 | exit 3; echo $?; ...few_lines... } >file". |
74 | Because of redirection, we cannot execute 1st pipe before we parse it all. |
75 | We probably need to learn to store $var expressions in parse tree. |
76 | Debug printing of parse tree would be nice too. |
77 | |
78 | 2007-04-28 |
79 | hush: Ctrl-C and Ctrl-Z for single NOFORK commands are working. |
80 | Memory and other resource leaks (opendir) are not addressed |
81 | (testcase is "rm -i" interrupted by ctrl-c). |
82 | |
83 | 2007-04-21 |
84 | hush: "sleep 5 | sleep 6" + Ctrl-Z + fg seems to work. |
85 | "rm -i" + Ctrl-C, "sleep 5" + Ctrl-Z still doesn't work |
86 | for SH_STANDALONE case :( |
87 | |
88 | 2007-04-21 |
89 | hush: fixed non-backgrounding of "sleep 1 &" and totally broken |
90 | "sleep 1 | sleep 2 &". Noticed a bug where successive jobs |
91 | get numbers 1,2,3 even when job #1 has exited before job# 2 is started. |
92 | (bash reuses #1 in this case) |
93 | |
94 | 2007-04-21 |
95 | hush: "sleep 1 | exit 3; echo $?" prints 0 because $? is substituted |
96 | _before_ pipe gets executed!! run_list_real() already has "pipe;echo" |
97 | parsed and handed to it for execution, so it sees "pipe"; "echo 0". |
98 | |
99 | 2007-04-21 |
100 | hush: removed setsid() and made job control sort-of-sometimes-work. |
101 | Ctrl-C in "rm -i" works now except for SH_STANDALONE case. |
102 | "sleep 1 | exit 3" + "echo $?" works, "sleep 1 | exit 3; echo $?" |
103 | shows exitcode 0 (should be 3). "sleep 1 | sleep 2 &" fails horribly. |
104 | |
105 | 2007-04-14 |
106 | lash, hush: both do setsid() and as a result don't have ctty! |
107 | Ctrl-C doesn't work for any child (try rm -i), etc... |
108 | lash: bare ">file" doesn't create a file (hush works) |