HP-UX Reference (11i v3 07/02) - 4 File Formats (vol 8)

sd(4) sd(4)

LOCKING

These commands use a common locking mechanism for reading and modifying both root directories and

software depots. This mechanism allows multiple readers but only one writer on a root or depot.

The commands which modify software in an (alternate) root directory are restricted from simultaneous

modiﬁcation using fcntl(2) locking on the ﬁle

var/adm/sw/products/swlock

relative to the root directory (e.g. /var/adm/sw/products/swlock

The commands which modify software in a depot are restricted from simultaneous modiﬁcation using

fcntl(2) locking on the ﬁle

catalog/swlock

relative to the depot directory (e.g. /var/spool/sw/catalog/swlock

All commands set fcntl(2) read locks on roots and depots using the

swlock ﬁle mentioned above. When a

read lock is set, it prevents other commands from performing modiﬁcations (i.e. from setting write locks).

The

swacl command is restricted from simultaneous modiﬁcation of an ACL using fcntl(2) read and write

locks on the

_LOCK_FILE

associated with each ACL.

AUTHOR

Software Distributor was developed by the Hewlett-Packard Company.

swagent, swcopy, swin-

stall

, swlist, and swpackage were developed by the Hewlett-Packard Company and Mark H. Col-

burn (see pax(1)).