Re: trouble with NGPT + Linux 2.5.40 + glibc 2.2.93

Hello!

I finally found the cause of the SEGFAULT on RedHat 8.0 during _init() of NGPT,
which makes NGPT not usable at all under RedHat 8.0:

During our basic init process, we call sysconf() to get the number of
processors in the machine. Besides many other things, this does an sscanf(),
which is a locale-dependent function. Locales are thread specific, so it
calls 
        decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
which checks for __libc_internal_tsd_get. This variable is 0 in the standard C
library but this weak symbol will be overwritten by our own NGPT 
__libc_internal_tsd_get and it points now to libc_internal_tsd_get(), which
will be called. This function uses pth_get_current() and this finally has no
idea on any current thread, because we are still in the basic init step. So
pth_get_current() returns 0 and libc_internal_tsd_get() returns NULL too and
_NL_CURRENT() will access an invalid memory area.

We could simply correct this, if we set all entry points like
__libc_internal_tsd_get/libc_internal_tsd_get() to 0 and activate them
only after our basic initialisation. Or we could ignore the number of
processors for now and wait until the first pthread_create().

But also other functions like strtol() are locale dependent and should not
be used during init but NGPT uses this function to parse the environment
variables.

And BTW, the _init function of GLIBC was called already. At least this is
correct.

Bye, Uwe

-- 
Dr. Uwe Girlich              email: [email protected]
Philosys Software GmbH       www: www.philosys.de
Edisonstrasse 6              phone: +49 89 321407-44
D-85716 Unterschleissheim    fax: +49 89 321407-12