CVS commit: src

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sat Mar 29 01:06:37 UTC 2025

Modified Files:
        src/lib/libc/gen: isctype.c
        src/tests/lib/libc/gen: t_ctype.c

Log Message:
ctype(3): Summon a demon from caller's nose if abused out-of-line.

This way, applications which opt for the out-of-line functions will
crash with a potentially meaningful message to stderr if they pass
inputs on which the ctype(3) functions are undefined.  (If fd 2 is
something else, tough -- this is nasal demon country, and they fly
where they please, application intent be damned.)

This probably won't catch many applications -- but it might catch C++
applications at runtime that can't be caught at build-time because
they eschew the macros.

The cost is a single predicted-not-taken branch -- it's checking c
for membership in the interval [-1,0xff] when we're already computing
c + 1, so it can be a single unsigned-compare.  By deferring the
message and abort to an out-of-line function we avoid a stack frame
in the good case.  And this is for the unlikely, out-of-line versions
of the ctype(3) functions -- most applications get the inline macros.
So I'm not concerned by the prospect of a performance impact.

Update the tests so they recognize SIGABRT as noisy failure too, not
just SIGSEGV.

PR lib/58208: ctype(3) provides poor runtime feedback of abuse


To generate a diff of this commit:
cvs rdiff -u -r1.26 -r1.27 src/lib/libc/gen/isctype.c
cvs rdiff -u -r1.8 -r1.9 src/tests/lib/libc/gen/t_ctype.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.