[ace-users] Mutex : frustration with file-based shm implementation

[Johnny Willemsen]

Hi,

Thanks for using the PRF form. For some more information, see
http://deuce.doc.wustl.edu/bugzilla/show_bug.cgi?id=2166. 

Regards,

Johnny Willemsen
Remedy IT
Postbus 101
2650 AC  Berkel en Rodenrijs
The Netherlands
www.theaceorb.nl / www.remedy.nl  

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> Paul D. Grodt
>  
> TECORE Wireless Systems 
> 
> Phone:      +1 410 872 6225
> Fax:          +1 410 872 6010
> email:   pgrodt at tecore.com
> 
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> -----Original Message-----
> From: Paul Grodt 
> Sent: Tuesday, July 31, 2007 1:31 PM
> To: 'ace-users at cs.wustl.edu'
> Subject: Mutex : frustration with file-based shm implementation
> 
>     ACE VERSION: 5.5.8
> 
>     HOST MACHINE and OPERATING SYSTEM:
> i686 RHEL 4, 2.6.9-42.0.10.ELsmp
> 
>     COMPILER NAME AND VERSION (AND PATCHLEVEL):
> $ gcc -v
> Using built-in specs.
> Target: i386-redhat-linux
> Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
> --infodir=
> /usr/share/info --enable-shared --enable-threads=posix
> --enable-checking=release
>  --with-system-zlib --enable-__cxa_atexit 
> --disable-libunwind-exceptions
> 
> --with-gxx-include-dir=/usr/include/c++/3.4.3 
> --enable-libgcj-multifile 
> --enable-languages=c,c++,java,f95 --enable-java-awt=gtk 
> --disable-dssi 
> --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre
> --with-cpu=generic 
> --host=i386-redhat-linux
> Thread model: posix
> gcc version 4.1.0 20060515 (Red Hat 4.1.0-18)
> 
>     THE $ACE_ROOT/ace/config.h FILE [if you use a link to a platform-
>     specific file, simply state which one]:
> ace/config-linux.h
> 
>     THE $ACE_ROOT/include/makeinclude/platform_macros.GNU FILE [if you
>     use a link to a platform-specific file, simply state which one
>     (unless this isn't used in this case, e.g., with Microsoft Visual
>     C++)]:
> $(ACE_ROOT)/include/makeinclude/platform_linux.GNU
> 
>     CONTENTS OF 
> $ACE_ROOT/bin/MakeProjectCreator/config/default.features
>     (used by MPC when you generate your own makefiles):
> DNE
>     AREA/CLASS/EXAMPLE AFFECTED:
> Mutex
> 
> Problem affects my application execution
> 
>     SYNOPSIS:
> Frustration with file-based mutex implementation in ACE
> 
>     DESCRIPTION:
> For each named mutex I specify, a file is created under that path.  I
> don't 
> understand why this is the default behavior in Linux.  I 
> believe I have
> it 
> traced to the line "ace/config-linux-common.h:35-39":
> 
> // Temporary fix because NPTL kernels do have shm_open but there is a
> problem
> // with shm_open/shm_unlink pairing in ACE which  needs to be 
> fixed when
> I have time.
> # if defined (ACE_HAS_SHM_OPEN)
> #   undef ACE_HAS_SHM_OPEN
> # endif /* ACE_HAS_SHM_OPEN */
> 
> My searching may be off, but I could find no bugtracking or detailed 
> information related to this comment.
> 
> To get the files out of the way, I am currently using a 
> wrapper function
> in my 
> code to write all Mutexes to /tmp/.ACE-*
> 
> I seem to be getting errors on followup executions when multiple users
> run on a 
> system (I believe one of our programs is also creating 
> mutexes while in
> SUID 
> mode), and further errors on followup executions following abnormal
> program 
> termination (though I suspect the latter is normal Linux behavior).
> 
> Can I safely deactivate this code segment, or what development must be
> done to
> resolve this issue in ACE?
> 
> 
> Paul Grodt
> 
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