Originally posted by: SystemAdmin

Hi,

Maybe someone knows the answer to this, but I was unable to find a reason for it in the manuals. I have been checking for SUID and SGID programs and have found a number of log and lock files with the SGID bit set. I cannot think of a reason for this action; what can you suggest?

For example, here are two files that I found:

-rw-rwSrw- 1 chahy staff 0 Dec 1 00:05 /exe_suppe3/log/chahy.log

----r-sr-- 1 root system 0 Nov 17 14:33 Spmi.lock

Regards,
George
#AIX-Forum

Originally posted by: Srikrishan

Hi,

SGID bit is used for mandatory locking(see man page of fcntl for details).

In some cases one want to have exclusive access to a part(or whole) of file he can either use advisory locking where each process has to check and get a lock before doing an operation on a file but the process can also skip the checking/locking part and directly write to the file.

OR

he can use mandatory locking where no other process can do conflicting operations on a file, for mandatory locking that SGID bit should be set for a file(in addition to other requirements mentioned in the man page)

Thanks
Sri
#AIX-Forum

Originally posted by: SystemAdmin

Hi Sri,

Many thanks for your assistance. I had trouble finding an AIX man page for fcntl, but there was plenty of material on the web. I couldn't get the locking to work from the shell; but that is probably not its intended use.

Thanks again,
George
#AIX-Forum

Originally posted by: Srikrishan

here are the man pages
http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/fcntl.htm

Thanks
Sri
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