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Diffstat (limited to 'release/src/router/busybox/shell/README')
| -rw-r--r-- | release/src/router/busybox/shell/README | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/release/src/router/busybox/shell/README b/release/src/router/busybox/shell/README new file mode 100644 index 00000000..59efe499 --- /dev/null +++ b/release/src/router/busybox/shell/README @@ -0,0 +1,108 @@ +Various bits of what is known about busybox shells, in no particular order. + +2008-02-14 +ash: does not restore tty pgrp if killed by HUP. Symptom: Midnight Commander +is backgrounded if you started ash under it, and then killed it with HUP. + +2007-11-23 +hush: fixed bogus glob handling; fixed exec <"$1"; added test and echo builtins + +2007-06-13 +hush: exec <"$1" doesn't do parameter subst + +2007-05-24 +hush: environment-related memory leak plugged, with net code size +decrease. + +2007-05-24 +hush: '( echo ${name )' will show syntax error message, but prompt +doesn't return (need to press <enter>). Pressing Ctrl-C, <enter>, +'( echo ${name )' again, Ctrl-C segfaults. + +2007-05-21 +hush: environment cannot be handled by libc routines as they are leaky +(by API design and thus unfixable): hush will leak memory in this script, +bash does not: +pid=$$ +while true; do + unset t; + t=111111111111111111111111111111111111111111111111111111111111111111111111 + export t + ps -o vsz,pid,comm | grep " $pid " +done +The fix is to not use setenv/putenv/unsetenv but manipulate env ourself. TODO. +hush: meanwhile, first three command subst bugs mentioned below are fixed. :) + +2007-05-06 +hush: more bugs spotted. Comparison with bash: +bash-3.2# echo "TEST`date;echo;echo`BEST" +TESTSun May 6 09:21:05 CEST 2007BEST [we dont strip eols] +bash-3.2# echo "TEST`echo '$(echo ZZ)'`BEST" +TEST$(echo ZZ)BEST [we execute inner echo] +bash-3.2# echo "TEST`echo "'"`BEST" +TEST'BEST [we totally mess up this one] +bash-3.2# echo `sleep 5` +[Ctrl-C should work, Ctrl-Z should do nothing][we totally mess up this one] +bash-3.2# if true; then +> [Ctrl-C] +bash-3.2# [we re-issue "> "] +bash-3.2# if echo `sleep 5`; then +> true; fi [we execute sleep before "> "] + +2007-05-04 +hush: made ctrl-Z/C work correctly for "while true; do true; done" +(namely, it backgrounds/interrupts entire "while") + +2007-05-03 +hush: new bug spotted: Ctrl-C on "while true; do true; done" doesn't +work right: +# while true; do true; done +[1] 0 true <-- pressing Ctrl-C several times... +[2] 0 true +[3] 0 true +Segmentation fault + +2007-05-03 +hush: update on "sleep 1 | exit 3; echo $?" bug. +parse_stream_outer() repeatedly calls parse_stream(). +parse_stream() is now fixed to stop on ';' in this example, +fixing it (parse_stream_outer() will call parse_stream() 1st time, +execute the parse tree, call parse_stream() 2nd time and execute the tree). +But it's not the end of story. +In more complex situations we _must_ parse way farther before executing. +Example #2: "{ sleep 1 | exit 3; echo $?; ...few_lines... } >file". +Because of redirection, we cannot execute 1st pipe before we parse it all. +We probably need to learn to store $var expressions in parse tree. +Debug printing of parse tree would be nice too. + +2007-04-28 +hush: Ctrl-C and Ctrl-Z for single NOFORK commands are working. +Memory and other resource leaks (opendir) are not addressed +(testcase is "rm -i" interrupted by ctrl-c). + +2007-04-21 +hush: "sleep 5 | sleep 6" + Ctrl-Z + fg seems to work. +"rm -i" + Ctrl-C, "sleep 5" + Ctrl-Z still doesn't work +for SH_STANDALONE case :( + +2007-04-21 +hush: fixed non-backgrounding of "sleep 1 &" and totally broken +"sleep 1 | sleep 2 &". Noticed a bug where successive jobs +get numbers 1,2,3 even when job #1 has exited before job# 2 is started. +(bash reuses #1 in this case) + +2007-04-21 +hush: "sleep 1 | exit 3; echo $?" prints 0 because $? is substituted +_before_ pipe gets executed!! run_list_real() already has "pipe;echo" +parsed and handed to it for execution, so it sees "pipe"; "echo 0". + +2007-04-21 +hush: removed setsid() and made job control sort-of-sometimes-work. +Ctrl-C in "rm -i" works now except for SH_STANDALONE case. +"sleep 1 | exit 3" + "echo $?" works, "sleep 1 | exit 3; echo $?" +shows exitcode 0 (should be 3). "sleep 1 | sleep 2 &" fails horribly. + +2007-04-14 +lash, hush: both do setsid() and as a result don't have ctty! +Ctrl-C doesn't work for any child (try rm -i), etc... +lash: bare ">file" doesn't create a file (hush works) |