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.
