Ping 4: [PATCH] more out of bounds checking improvements

[Martin Sebor <msebor@gmail.com>]

Florian reminded me that this patch (first posted on 10/26 last
year) is still outstanding so I'd like to try to ping it again.

Florian and Joseph provided some initial comments but not a formal
approval.

Martin

On 1/10/21 1:44 PM, Martin Sebor wrote:
> Ping: still looking for an approval of the patch below before
> tomorrow's freeze:
> https://sourceware.org/pipermail/libc-alpha/2020-December/120586.html
> 
> On 1/4/21 8:54 AM, Martin Sebor wrote:
>> Joseph or anyone else: is the patch below okay to commit?  I'd like
>> to include it in the upcoming release.
>>
>> https://sourceware.org/pipermail/libc-alpha/2020-December/120586.html
>>
>> On 12/18/20 9:56 AM, Martin Sebor wrote:
>>> Ping: Does the last patch look good enough to commit?
>>> https://sourceware.org/pipermail/libc-alpha/2020-December/120586.html
>>>
>>> On 12/9/20 2:46 PM, Martin Sebor wrote:
>>>> On 10/26/20 10:08 AM, Joseph Myers wrote:
>>>>> On Mon, 26 Oct 2020, Martin Sebor via Libc-alpha wrote:
>>>>>
>>>>>> The patch introduces the _L_tmpnam macro to avoid polluting
>>>>>> the POSIX <unistd.h> namespace with L_tmpnam when the latter is
>>>>>> only supposed to be defined in <stdio.h>.  This in turn causes
>>>>>> the a number of POSIX conformance test failures that I haven't
>>>>>> been able to figure how to deal with and need some help with.
>>>>>>
>>>>>> In file included from ../include/unistd.h:2,
>>>>>>                   from /tmp/tmpzm39v4n3/test.c:1:
>>>>>> ../posix/unistd.h:1159:32: error: ‘_L_ctermid’ undeclared here 
>>>>>> (not in a
>>>>>> function)
>>>>>>   extern char *ctermid (char __s[_L_ctermid]) __THROW
>>>>>>                                  ^~~~~~~~~~
>>>>>>
>>>>>> I expected adding the new macros to stdio-common/stdio_lim.h.in
>>>>>> would do the trick but clearly something else is needed and I'm
>>>>>> at a lost as to what that might be.  I haven't been able to find
>>>>>
>>>>> <unistd.h> doesn't include <bits/stdio_lim.h>, and you're making
>>>>> <unistd.h> use _L_ctermid, and you're only defining _L_ctermid in
>>>>> <bits/stdio_lim.h>.  You need to define it in a header that <unistd.h>
>>>>> includes - which also needs to be one whose contents are 
>>>>> namespace-clean
>>>>> for inclusion in <unistd.h> (which <bits/stdio_lim.h> isn't).
>>>>>
>>>>> The obvious way would be to have a new installed (i.e. add to 
>>>>> "headers" in
>>>>> the relevant Makefile) header for the new macros that can be 
>>>>> included in
>>>>> both <stdio.h> and <unistd.h>.  Suggestion: the existing scheme for
>>>>> automatic generation of bits/stdio_lim.h is overly complicated, it 
>>>>> would
>>>>> be better to use sysdeps headers in the normal way like for other 
>>>>> bits/
>>>>> headers where the values may depend on the glibc configuration (and 
>>>>> then
>>>>> to have testcases that verify consistently of OPEN_MAX and 
>>>>> FOPEN_MAX / of
>>>>> PATH_MAX and FILENAME_MAX, when both are defined).
>>>>
>>>> I don't know enough about the Glibc build infrastructure to
>>>> understand your suggestion but either approach sounds more involved
>>>> than I have cycles for so I propose the scaled patch instead, without
>>>> the ctermid and cuserid changes (and without the nonnull attribute
>>>> on readv/writev(*)).  Hopefully someone with more experience with
>>>> the existing scheme will find a way to define the two macros and
>>>> make use of them to enable the detection for these two functions
>>>> as well.
>>>>
>>>> Martin
>>>>
>>>> [*] I'll submit that patch separately.
>>>
>>
>