I'm in the process of setting up documentation & examples on how to
implement new static analysis checks.
If we're OK with turning new usages of these functions into errors, I
can help whoever is volunteering to do this.
Am 12.06.20 um 22:40 schrieb Jeff Gilbert:
> It would be great to have CI linting for these!
> On Fri, Jun 12, 2020 at 2:19 AM Henri Sivonen wrote:
>> This is an occasional re-reminder that anything in the C standard
>> library that is locale-sensitive is fundamentally broken and should
>> not be used.
>> Today's example is strerr(), which returns a string that is meant to
>> be rendered to the user, but the string isn't guaranteed to be UTF-8.
>> On Mon, Aug 27, 2018 at 3:04 PM Henri Sivonen wrote:
>>> Please don't use the functions from ctype.h and strings.h.
>>> In addition to these being locale-sensitive, the functions from
>>> ctype.h are defined to take (signed) int with the value space of
>>> *unsigned* char or EOF and other argument values are Undefined
>>> Behavior. Therefore, on platforms where char is signed, passing a char
>>> sign-extends to int and invokes UB if the most-significant bit of the
>>> char was set! Bug filed 15 years ago!
>>> https://bugzilla.mozilla.org/show_bug.cgi?id=216952 (I'm not aware of
>>> implementations doing anything surprising with this UB but there
>>> exists precedent for *compiler* writers looking at the standard
>>> *library* UB language and taking calls into standard library functions
>>> as optimization-guiding assertions about the values of their
>>> arguments, so better not risk it.)
>>> For isfoo(), please use mozilla::IsAsciiFoo() from mozilla/TextUtils.h.
>>> For tolower() and toupper(), please use ToLowerCaseASCII() and
>>> ToUpperCaseASCII() from nsUnicharUtils.h
>>> For strcasecmp() and strncasecmp(), please use their nsCRT::-prefixed
>>> versions from nsCRT.h.
>>> (Ideally, we should scrub these from vendored C code, too, since being
>>> in third-party code doesn't really make the above problems go away.)
>>> Henri Sivonen
>> Henri Sivonen
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