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047cb3303c
Functions can now be correctly redefined and unset in subshell
environments (such as ( ... ), $(command substitutions), etc).
Before this fix, attempts to do this were silently ignored (!!!),
causing the wrong code (i.e.: the function by the same name from
the parent shell environment) to be executed.
Redefining and unsetting functions within "shared" command
substitutions of the form '${ ...; }' is also fixed.
Prior discussion: https://github.com/att/ast/issues/73
src/cmd/ksh93/sh/parse.c:
- A fix from George Koelher (URL above). He writes:
| The parser can set t->comnamp to the wrong function.
| Suppose that the shell has executed
| foo() { echo WRONG; }
| and is now parsing
| (foo() { echo ok; } && foo)
| The parser was setting t->comnamp to the wrong foo. [This
| fix] doesn't set t->comnamp unless it was a builtin. Now the
| subshell can't call t->comnamp, so it looks for foo and finds
| the ok foo in the subshell's function tree.
src/cmd/ksh93/bltins/typeset.c:
- Unsetting functions in a virtual/non-forked subshell still
doesn't work: nv_open() fails to find the function. To work
around this problem, make 'unset -f' fork the subshell into its
own process with sh_subfork().
- The workaround exposed another bug: if we unset a function in a
subshell tree that overrode a function by the same name in the
main shell, then nv_delete() exposes the function from the main
shell scope. Since 'unset -f' now always forks a subshell, the
fix is to simply walk though troot's parent views and delete any
such zombie functions as well. (Without this, the 4 'more fun'
tests in tests/subshell.sh fail.)
src/cmd/ksh93/sh/subshell.c: sh_subfuntree():
- Fix function (re)definitions and unsetting in "shared" command
substitutions of the form '${ commandlist; }' (i.e.: if
sp->shp->subshare is true). Though internally this is a weird
form of virtual subshell, the manual page says it does not
execute in a subshell (meaning, all changes must survive it), so
a subshell function tree must not be created for these.
src/cmd/ksh93/tests/subshell.sh:
- Add regression tests related to these bugfixes. Test unsetting
and redefining a function in all three forms of virtual subshell.
(cherry picked from commit dde387825ab1bbd9f2eafc5dc38d5fd0bf9c3652)
104 lines
4.4 KiB
Text
104 lines
4.4 KiB
Text
This documents significant changes in the 93u+m branch of AT&T ksh93.
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For full details, see the git log at:
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https://github.com/modernish/ksh
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Any uppercase BUG_* names are modernish shell bug IDs.
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2020-05-29:
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- Fix BUG_FNSUBSH: functions can now be correctly redefined and unset in
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subshell environments (such as ( ... ), $(command substitutions), etc).
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Before this fix, this was silently ignored, causing the function by the
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same name from the parent shell environment to be executed instead.
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fn() { echo mainsh; }
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(fn() { echo subsh; }; fn); fn
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This now correctly outputs "subsh mainsh" instead of "mainsh mainsh".
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ls() { echo "ls executed"; }
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(unset -f ls; ls); ls
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This now correctly lists your directory and then prints "ls executed",
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instead of printing "ls executed" twice.
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2020-05-21:
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- Fix truncating of files with the combined redirections '<>;file' and
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'<#pattern'. The bug was caused by out-of-sync streams.
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Details and discussion: https://github.com/att/ast/issues/61
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- Patched code injection vulerability CVE-2019-14868. As a result, you can
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no longer use expressions in imported numeric environment variables; only
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integer literals are allowed.
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2020-05-20:
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- Fix BUG_ISSETLOOP. Expansions like ${var+set} remained static when used
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within a 'for', 'while' or 'until' loop; the expansions din't change along
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with the state of the variable, so they could not be used to check whether a
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variable is set within a loop if the state of that variable changed in the
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course of the loop.
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- Fix BUG_IFSISSET. ${IFS+s} always yielded 's', and [[ -v IFS ]] always
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yielded true, even if IFS is unset. This applied to IFS only.
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2020-05-19:
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- Fix 'command -p'. The -p option causes the operating system's standard
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utilities path (as output by 'getconf PATH') to be searched instead of $PATH.
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Before this fix, this was broken on non-interactive shells as the internal
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variable holding the default PATH value was not correctly initialised.
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2020-05-16:
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- Fix 'test -t 1', '[ -t 1 ]', '[[ -t 1 ]]' in command substitutions.
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Standard output (file descriptor 1) tested as being on a terminal within a
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command substitution, which makes no sense as the command substitution is
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supposed to be catching standard output.
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v=$(echo begincomsub
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[ -t 1 ] && echo oops
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echo endcomsub)
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echo "$v"
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This now does not output "oops".
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2020-05-14:
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- Fix syncing history when print -s -f is used. For example, the
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following now correctly adds a 'cd' command to the history:
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print -s -f 'cd -- %q\n' "$PWD"
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Ref.: https://github.com/att/ast/issues/425
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https://github.com/att/ast/pull/442
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- Fix BUG_PUTIOERR: Output builtins now correctly detect and report
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input/output errors. This allows scripts to check for a nonzero exit
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status on the 'print', 'printf' and 'echo' builtins and prevent possible
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infinite loops if SIGPIPE is ignored.
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- Add a convenient bin/run_ksh_tests script to the source tree that
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sets up the necessary environment and runs the ksh regression tests.
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2020-05-13:
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- Fix BUG_CASELIT: an undocumented 'case' pattern matching misbehaviour that
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goes back to the original Bourne shell, but wasn't discovered until 2018.
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If a pattern doesn't match as a pattern, it was tried again as a literal
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string. This broke common validation use cases, e.g.:
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n='[0-9]'
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case $n in
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( [0-9] ) echo "$n is a number" ;;
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esac
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would output "[0-9] is a number" as the literal string fallback matches the
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pattern. As this misbehaviour was never documented anywhere (not for Bourne,
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ksh88, or ksh93), and it was never replicated in other shells (not even in
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ksh88 clones pdksh and mksh), it is unlikely any scripts rely on it.
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Of course, a literal string fallback, should it be needed, is trivial to
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implement correctly without this breakage:
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case $n in
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( [0-9] | "[0-9]") echo "$n is a number or the number pattern" ;;
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esac
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Ref.: https://github.com/att/ast/issues/476
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- Fix BUG_REDIRIO: ksh used to redirect standard output by default when no
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file descriptor was specified with the rarely used '<>' reading/writing
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redirection operator. It now redirects standard input by default, as POSIX
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specifies and as all other POSIX shells do. To redirect standard output
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for reading and writing, you now need '1<>'.
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Ref.: https://github.com/att/ast/issues/75
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http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_07_07
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