SUNOS: Samba grabs all semaphores, breaking other softwares (PR#9755)

Jeremy Allison jallison at
Tue Sep 15 16:48:37 GMT 1998

Ole.H.Nielsen at wrote:
> SAMBA grabs ALL available semaphores minus 1 on SunOS 4.1.3,
> where the kernel has 60, see /usr/include/sys/sem.h:
> #define SEMMNS  60              /* # of semaphores in system */
> This is a MAJOR PROBLEM to us, since our backup software
> (IBM ADSM) also needs available semaphores for the client
> part to work.  Hence we can choose between running SAMBA
> or running backups :-(

Hi Ole, nice to hear from you again.

> On AIX 4.2.1 we see just 1 or 2 semaphores taken by SAMBA,
> so this is a SunOS specific problem.  We'd really like to
> get this bug under control...

It's not actually a bug really, more a questionable
design decision.

The solution for Samba 1.9.18pXX is to set the number
of semaphores manually in shmem_sysv.c, ie. change
the lines:

#ifdef SEMMSL
#define SHMEM_HASH_SIZE 63

to be just :

#define SHMEM_HASH_SIZE <whatever you want here>

Samba-2 won't have this problem as it is much
more conservative about SYSV semaphore use. I'm
CC:ing this reply to the mailing list as I think
people might be interested in this answer.


	Jeremy Allison,
	Samba Team.
Buying an operating system without source is like buying
a self-assembly Space Shuttle with no instructions.

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