A note about HAVE_MMAP

COLLOT Jean-Yves jean-yves.collot at cofiroute.fr
Wed Sep 29 13:15:04 GMT 2004


I don't really understand what you are referring to, but I am positive that
there is not any use of HAVE_MMAP in any C file of Samba/VMS version 2.2.8.
There is no any call to mmap() either, and the "mmap" parameter of SMB.CONF
is used only for setting (or unsetting) flags when calling TDB_xxxx
routines, those flags being ignored by the new Dave Jones' specific TDB
routines.

JY

-----Message d'origine-----
De : wb8tyw at qsl.net [mailto:wb8tyw at qsl.net] 
Envoyé : mercredi 29 septembre 2004 14:57
À : samba-vms at lists.samba.org
Objet : Re: A note about HAVE_MMAP

In article <CF0913E9C3D53D4E94DE47FDE25C633D05049090 at hermes.cofiroute.com>,
COLLOT Jean-Yves <jean-yves.collot at cofiroute.fr> writes:

> Since Dave Jones provided a new, VMS-specific TDB set of routines,
defining
> HAVE_MMAP or not has no more impact on Samba/VMS.

What about the file transfer section of SAMBA where if HAVE_MMAP is set, and
the smb.conf setting for it is enabled, it sometimes bypasses the stm_read()
and stm_write(), and vms_lseek() routines completely and does random direct
read/writes to the file on the host.

This works correctly only on the STREAM and FIXed format files.  For VFC
files
when the MMAP bypasses those routines, file corruption will appear to be
present on reads, and writes can corrupt the file.

It took me a while to find that in the SAMBA 2.0.6 release.

There still has been no feedback to this mailing list if disabling mmap in
the smb.conf file had any effect on the observed corruption of VFC files.

-John
wb8tyw at qsl.network
Personal Opinion Only

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