PR/58208 CVS commit: src

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

The following reply was made to PR lib/58208; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/58208 CVS commit: src
Date: Sat, 29 Mar 2025 01:06:37 +0000

 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.