I fixed the bug in ksh that allows you delete a special builtin.
On Mon, Sep 29, 2014 at 5:25 PM, Dan Douglas <orm...@gmail.com> wrote: > Just a few points to add. > > On Monday, September 29, 2014 04:29:52 PM Stephane Chazelas wrote: > > 2014-09-29 09:04:00 -0600, Eric Blake: > > [...] > > > > "The function is named fname; the application shall ensure that it > is a > > > > name (see XBD Name) and that it is not the name of a special built-in > utility." > > > > > > > > > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_05 > > This doesn't normally matter because POSIX requires special builtins to > take > precedence over functions during command search, so even if you have such a > function defined it is impossible to call. Bash doesn't use the correct > search > order however. > > Mksh has the reverse bug. It allows defining the function (wrongly) but > then > calls the special builtin anyway (correctly). > > Another bug is in ksh93 whose `builtin` allows disabling special builtins > (which according to the manual, shouldn't work). > > $ ksh -c 'builtin -d set; function set { echo test; }; set' > test > > Bash's "enable" correctly disallows that. > > > I agree the requirement is on the application, and I can't see > > why POSIX should force a shell to reject a function whose name > > doesn't contain a valid identifier. > > ... > > Another thing you can do in bash is bypass its command name check by using > a > null zeroth word. > > $ { function } { echo test; }; <() }; } > test > > Ordinarily } would be uncallable, but apparently since bash only checks the > command name of the first word, calling with e.g. `<() }` or `$() }` works. > > -- > Dan Douglas
