Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name

[Florian Weimer]

* Samuel Thibault via Libc-alpha:

> Florian Weimer, le sam. 01 janv. 2022 18:27:49 +0100, a ecrit:
>> > @@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int 
>> > flags)
>> >    size_t amount_read;
>> >    int fd;
>> >  
>> > -  if (&trivfs_server_name && trivfs_server_name
>> > -      && trivfs_server_name[0] == 'r'
>> > -      && trivfs_server_name[1] == 'a'
>> > -      && trivfs_server_name[2] == 'n'
>> > -      && trivfs_server_name[3] == 'd'
>> > -      && trivfs_server_name[4] == 'o'
>> > -      && trivfs_server_name[5] == 'm'
>> > -      && trivfs_server_name[6] == '\0')
>> > +  if (&__trivfs_server_name && __trivfs_server_name
>> > +      && __trivfs_server_name[0] == 'r'
>> > +      && __trivfs_server_name[1] == 'a'
>> > +      && __trivfs_server_name[2] == 'n'
>> > +      && __trivfs_server_name[3] == 'd'
>> > +      && __trivfs_server_name[4] == 'o'
>> > +      && __trivfs_server_name[5] == 'm'
>> > +      && __trivfs_server_name[6] == '\0')
>> >      /* We are random, don't try to read ourselves!  */
>> >      return length;
>> 
>> How does this work?  It's a new synbol name, so there's no definition,
>> so the weak reference is always null.
>
> It is peeking it from the program.
>
> Basically the problem is that the random translator uses glibc, whose
> malloc implementation started using /dev/random in glibc 2.34, thus
> reading itself.

I still don't understand.  Why isn't the condition always false?