The coshell(1) command, which is required for libcoshell to be
useful, is not known to be shipped by any distribution. It was
removed by the ksh-community fork and hence also by 93u+m (in
2940b3f5). The coshell facility as a whole is obsolete and
insecure. For a long time now, the statically linked libcoshell
library has been 40+ kilobytes of dead weight in the ksh binary.
Prior discussion (ksh2020): https://github.com/att/ast/issues/619
src/lib/libcoshell/*:
- Removed.
src/cmd/ksh93/*:
- Remove the SHOPT_COSHELL compiler option (which was enabled) and
a lot of code that was conditional upon #ifdef SHOPT_COSHELL.
- init.c: e_version[]: Removing SHOPT_COSHELL changed the "J"
feature identifier in ${.sh.version} to a lowercase "j", which
was conditional upon SHOPT_BGX (background job extensions).
But src/cmd/ksh93/RELEASE documents (at 08-12-04, on line 1188):
| +SHOPT_BGX enables background job extensions. Noted by "J" in
| the version string when enabled. [...]
That is the only available documentation. So change that "j" back
to a "J", leaving the version string unchanged after this commit.
- jobs.c: job_walk(): We need to keep one 'job_waitsafe(SIGCHLD);'
call that was conditional upon SHOPT_COSHELL; removing it caused
a regression test failure in tests/sigchld.sh, 'SIGCHLD blocked
for script at end of pipeline' (which means that until now, a ksh
compiled without libcoshell had broken SIGCHLD handling.)
bin/package, src/cmd/INIT/package.sh:
- Don't export COSHELL variable.
3613da4240