.TH "UNLOCKSF" 1csound CARL
.SH NAME
locksf, unlocksf 
- lock/unlock a sound file system
.SH SYNOPSIS
.B locksf 
filesystem [message]
.sp
.B unlocksf 
filesystem [message]
.RS .5i
.nf
filesystems at CARL:
    /snd
    /snd1
.fi
The message part of the command is all arguments past the filesystem arg.
.RE
.SH DESCRIPTION
.B locksf
causes the named filesystem to be 
.I masterlocked.  
.B unlocksf
does the inverse action.
.PP
This is the sound file
system's version of single-user mode.  When a filesystem is masterlocked,
only members of a special group (the disk group at CARL) are able to
access files on the locked filesystem.  All other users receive a notice
that that filesystem is locked.  Only members of the disk group can 
masterlock/unlock a filesystem.  Certain fatal errors in sound file programs
can also cause the filesystem that the program was accessing to be masterlocked
in order to keep continued access from making the filesystem unrecoverable.
.PP
To set up a disk group, edit the file /etc/group to contain a line of
the form:
.RS .5i
disk::11:dgl,frm,root,disk,rusty
.RE
Notice that there is a pseudouser named 
.I disk, 
who is also in the disk group.
The 
.I disk 
pseudouser owns all the programs that run under the 
.I csound 
system,
and is the equivalent of 
.I root 
to the 
.I csound 
system.
.PP
The action of 
.B locksf
and
.B unlocksf 
is to manage a file in
the root directory of each sound filesystem named MASTERLOCK.  
(E.g., at CARL, /snd/MASTERLOCK).  
The existence of this file signals a locked
system.  All sound file programs check the existence
of this file automatically.
If a program detects the existence of this file, it then
checks to see if the user belongs
to the disk superuser group or is root.  If so, the program will print
"lock: sesame." as a reminder to the superuser that the system is locked
and to proceed with caution, and then allow the superuser to continue.
If the person running the program is not
in the superuser group, the message "The system has been MASTERLOCKED"
is printed.
It also prints the contents of the masterlock file.  Fatal errors that
create the masterlock file also put a diagnostic in it.
.PP
When running the 
.B locksf 
program, the 3rd. through nth. arguments are taken
as a diagnostic message and placed in the masterlock file.
.PP
All programs that write the masterlock file do so in append mode, so as
to enable catching a sequence of errors.
.PP
The 
.B dumpsf 
program can masterlock the filesystem 
during the time it is dumping.
.SH FILES
<filesystem>/MASTERLOCK
.SH AUTHOR
Gareth Loy
.SH SEE ALSO
sndin(1csound), sndout(1csound), dumpsf(1csound).
.SH DIAGNOSTICS
Attempts to run 
.B locksf 
or 
.B unlocksf 
by other than the superusers results
in a "Sorry." message, and no action.
.PP
Running 
.B locksf 
by itself generates a terse usage message.