PROTECT(1)              FreeBSD General Commands Manual             PROTECT(1)

NAME

     protect - protect processes from being killed when swap space is
     exhausted

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 default.

     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 adjusting
     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 15.1-STABLE-HBSD         July 12, 2022                      PROTECT(1)