Re: [PATCH] gdc 9, 10 and 11 bug fix

["Marc Aurèle La France" <tsi@tuyoix.net>]

On Tue, 17 May 2022, Marc Aurèle La France wrote:
> On Tue, 17 May 2022, Iain Buclaw wrote:
>> Excerpts from Marc Aurèle La France's message of Mai 17, 2022 5:31 pm:
>>> On Tue, 17 May 2022, Iain Buclaw wrote:
>>>> Excerpts from Marc Aurèle La France's message of Mai 16, 2022 11:34 pm:
>>>>> On Sun, 15 May 2022, Iain Buclaw wrote:
>>>>>> Excerpts from Marc Aurèle La France's message of Mai 12, 2022 10:29 pm:

>>>>>>> No compiler has any business rejecting files for the sole crime of
>>>>>>> being symlinked to.  The following applies, modulo patch fuzz, to the
>>>>>>> 9, 10 and 11 series of compilers.

>>>>>>> Given my use of shadow trees, this bug attempted to prevent me from
>>>>>>> building 12.1.0.  The D-based gdc in 12.1.0 and up does not exhibit
>>>>>>> this quirky behaviour.

>>>>>> Thanks, I've checked upstream and see the following change:

>>>>>> https://github.com/dlang/dmd/pull/11836/commits/ebda81e44fd0ca4b247a1860d9bef411c41c16cb

>>>>>> It should be fine to just backport that.

>>>>> Thanks for the pointer.

>>>>> I ended up with the three slightly different diffs below, one each for
>>>>> the 9, 10 and 11 branches.  Each was rebuilt using 8.5.0, then used to
>>>>> rebuild 12.1.0.  All of this ran smoothly without complaint, although I
>>>>> wouldn't want to do this on a 486...

>>>>> Signed-off-by: Marc Aurèle La France <tsi@tuyoix.net>

>>>>> For GCC 9   ----------  8< ----------
>>>>> 
>>>>> diff -aNpRruz -X /etc/diff.excludes gcc-9.4.0/gcc/d/dmd/root/filename.c 
>>>>> devel-9.4.0/gcc/d/dmd/root/filename.c
>>>>> --- gcc-9.4.0/gcc/d/dmd/root/filename.c	2021-06-01 01:53:04.716474774 
>>>>> -0600
>>>>> +++ devel-9.4.0/gcc/d/dmd/root/filename.c	2022-05-15 15:02:49.995441507 
>>>>> -0600
>>>>> @@ -475,53 +475,7 @@ const char *FileName::safeSearchPath(Strings *path, 
>>>>> const char *name)
>>>>>
>>>>>      return FileName::searchPath(path, name, false);
>>>>>  #elif POSIX
>>>>> -    /* Even with realpath(), we must check for // and disallow it
>>>>> -     */
>>>>> -    for (const char *p = name; *p; p++)
>>>>> -    {
>>>>> -        char c = *p;
>>>>> -        if (c == '/' && p[1] == '/')
>>>>> -        {
>>>>> -            return NULL;
>>>>> -        }
>>>>> -    }

>>>> I'd keep this check in, otherwise removing/replacing only the `if
>>>> (path)` branch looks OK to me.

>>> The corresponding D code doesn't care about double slashes and neither
>>> should this.  Also, the comment is misleading as realpath() would no
>>> longer be used here.

>> True, but the D front-end does check the path in other places now:

>> https://github.com/dlang/dmd/blob/e9ba29d71b557fe079e95ee6554f116b24159bab/src/dmd/root/filename.d#L787-L803

>> https://github.com/dlang/dmd/blob/e9ba29d71b557fe079e95ee6554f116b24159bab/src/dmd/expressionsem.d#L5984-L6007

>> If we remove all checks, then there'd be nothing to prevent either
>> import("/file") or import("../file") from being used.

> There is still no check for double slashes.  All I want here is to fix a C++ 
> -> D migration bug without leaving any detritus behind.

Anything more on this?

Marc.