PROTECT(1) General Commands Manual PROTECT(1)
NAME
protect -- protect processes from being killed when swap space is ex-
hausted
SYNOPSIS
protect [-i] command
protect [-cdi] -g pgrp
protect [-cdi] -p pid
DESCRIPTION
The protect command is used to mark processes as protected. The kernel
does not kill protected processes when swap space is exhausted. Note
that this protected state is not inherited by child processes by de-
fault.
The options are:
-c Remove protection from the specified processes.
-d Apply the operation to all current children of the specified
processes.
-i Apply the operation to all future children of the specified
processes.
-g pgrp Apply the operation to all processes in the specified process
group.
-p pid Apply the operation to the specified process.
command Execute command as a protected process.
Note that only one of the -p or -g flags may be specified when adjust-
ing the state of existing processes.
Daemons can be protected on startup using <name>_oomprotect option from
rc.conf(5).
EXIT STATUS
The protect utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
Mark the Xorg server as protected:
pgrep Xorg | xargs protect -p
Protect all ssh sessions and their child processes:
pgrep sshd | xargs protect -dip
Remove protection from all current and future processes:
protect -cdi -p 1
Using ps(1) to check if the protect flag has been applied to the
process:
ps -O flags,flags2 -p 64430
PID F F2 TT STAT TIME COMMAND
64430 10104002 00000001 5 S+ 0:00.00 ./main
^P ^PI
In the above example P points at the protected flag and PI points at
the inheritance flag. The process is protected if P bit is set to 1.
All children of this process will also be protected if PI bit is set to
1.
DIAGNOSTICS
protect: procctl: Operation not permitted The protect command does not
have the required permissions to protect selected processes. There are
many reasons why this could be the case, e.g.:
- protect is not executed by root.
- protect is executed inside a jail(8), which is not supported at the
moment.
SEE ALSO
ps(1), procctl(2), rc.conf(5)
BUGS
If you protect a runaway process that allocates all memory the system
will deadlock.
FreeBSD 13.2 July 12, 2022 PROTECT(1)