external/cde
1
0
Fork 0
mirror of git://git.code.sf.net/p/cdesktopenv/code synced 2025-03-09 15:50:02 +00:00
Code Issues Releases Wiki Activity

Fix corner-case >&- redirection leak out of subshell

Browse source 
Reproducer:

    exec 9>&1
    ( { exec 9>&1; } 9>&- )
    echo "test" >&9 # => 9: cannot open [Bad file descriptor]

The 9>&- incorrectly persists beyond the { } block that it
was attached to *and* beyond the ( ) subshell. This is yet another
bug with non-forking subshells; forking it with something like
'ulimit -t unlimited' works around the bug.

In over a year we have not been able to find a real fix, but I came
up with a workaround that forks a virtual subshell whenever it
executes a code block with a >&- or <&- redirection attached. That
use case is obscure enough that it should not cause any performance
regression except in very rare corner cases.

src/cmd/ksh93/sh/xec.c: sh_exec(): TSETIO:
- This is where redirections attached to code blocks are handled.
  Check for a >&- or <&- redirection using bit flaggery from
  shnodes.h and fork if we're executing such in a virtual subshell.

Resolves: https://github.com/ksh93/ksh/issues/161
Thanks to @ko1nksm for the bug report.
This commit is contained in:
Martijn Dekker 2022-02-11 02:21:47 +00:00
parent 14a43a0a88
commit 6304dfce41
4 changed files with 53 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

2
src/cmd/ksh93/include/version.h
View file

@ -21,7 +21,7 @@
#define SH_RELEASE_FORK "93u+m" /* only change if you develop a new ksh93 fork */
#define SH_RELEASE_SVER "1.0.0-beta.2" /* semantic version number: https://semver.org */
#define SH_RELEASE_DATE "2022-02-08" /* must be in this format for $((.sh.version)) */
#define SH_RELEASE_DATE "2022-02-11" /* must be in this format for $((.sh.version)) */
#define SH_RELEASE_CPYR "(c) 2020-2022 Contributors to ksh " SH_RELEASE_FORK
/* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */