PRCTL(1) User Commands PRCTL(1)

prctl - get or set the resource controls of running processes, tasks, and projects 

prctl [-P] [-t [basic | privileged | system]]
     [-n name [-srx] [-v value] [-e | -d action] [-p pid]]
     [-i idtype] id...

The prctl utility allows the examination and modification of the resource controls associated with an active process, task, or project on the system. It allows access to the basic and privileged limits and the current usage on the specified entity.

See resource_controls(5) for a description of the resource controls supported in the current release of the Solaris operating system.

The following options are supported:

-d | -e action

Disables (-d) or enables (-e) the specified action on the resource control value specified by -v, -t, and -p. If any of the -v, -t, or -p options are unspecified, they match any value, privilege, or recipient pid. For example, specifying only -v modifies the first resource control with matching value, matching any privilege and recipient pid. If no matching resource control value is found, a new value is added as if -s were specified.

Actions:

all

This action is only available with -d. It disables all actions. This fails on resource control values that have the deny global flag.

deny

Indicates that the resource control attempts to deny granting the resource to the process, task, project, or zone on a request for resources in excess of the resource control value. deny actions can not be enabled if the resource control has the no-deny global flag. deny actions can not be disabled if the resource control has the deny global flag.

signal

This action is only available with -d. It deactivates the signal action.

signal=signum

In the signal=signum action, signum is a signal number (or string representation of a signal). Setting a signal action on a resource control with the no-local-action global flag fails. A limited set of signals can be sent. See NOTES for additional details.

-i idtype

Specifies the type of the id operands. Valid idtypes are process, task, project, or zone. Also allowed are pid, taskid, projid, and zoneid. The default id type, if the -i option is omitted, is process.

For a modify operation, the entity to which id operands are members is the target entity. For instance, setting a project resource control on an -i process sets the resource control on the project to which each given process argument is a member.

For a get operation, the resource controls are listed for all entities to which the id operands are members. For example, -i task taskid lists the task, project, and zone resource controls for the task, and for the project and zone to which that task is a member.

-n name

Specifies the name of the resource control to get or set. If the name is unspecified, all resource controls are retrieved.

-p pid

When manipulating (using -s, -r, -x, -d, or -e) a basic task project, or zone resource control values, a recipient pid can be specified using -p. When setting a new basic resource control or controls on a task, project, or zone, the -p option is required if the -i idtype option argument is not process.

-P

Display resource control values in space delimited format.

-r

Replaces the first resource control value (matching with the -t privilege) with the new value specified through the -v option.

-s

Set a new resource control value.

This option requires the -v option.

If you do not specify the -t option, basic privilege is used. If you want to set a basic task, process, or zone rctl, -p is required. If -e or -d are also specified, the action on the new rctl is set as well.

For compatibility with prior releases, this option is implied if -v is specified, without any of -e, -d, -r, or -x.

See resource_controls(5) for a description of unit modifiers and scaling factors you can use to express large values when setting a resource control value.

-t [ basic | privileged | system ]

Specifies which resource control type to set. Unless the "lowerable" flag is set for a resource control, only invocations by users (or setuid programs) who have privileges equivalent to those of root can modify privileged resource controls. See rctlblk_set_value(3C) for a description of the RCTL_GLOBAL_LOWERABLE flag. If the type is not specified, basic is assumed. For a get operation, the values of all resource control types, including system, are displayed if no type is specified.

-v value

Specifies the value for the resource control for a set operation. If no value is specified, then the modification (deletion, action enabling or disabling) is carried out on the lowest-valued resource control with the given type.

See resource_controls(5) for a description of unit modifiers and scaling factors you can use to express large values when setting a resource control value.

-x

Deletes the specified resource control value. If the delete option is not provided, the default operation of prctl is to modify a resource control value of matching value and privilege, or insert a new value with the given privilege. The matching criteria are discussed more fully in setrctl(2).

If none of the -s, -r, -x, -v, -d, or -e options are specified, the invocation is considered a get operation. Otherwise, it is considered a modify operation.

The following operand is supported:

id

The ID of the entity (process, task, project, or zone) to interrogate. If the invoking user's credentials are unprivileged and the entity being interrogated possesses different credentials, the operation fails. If no id is specified, an error message is returned.

Example 1 Displaying Current Resource Control Settings

The following example displays current resource control settings for a task to which the current shell belongs:


 example$ ps -o taskid -p $$
TASKID
8
example$ prctl -i task 8
136150: /bin/ksh
NAME    PRIVILEGE       VALUE    FLAG   ACTION             RECIPIENT
task.max-cpu-time
        usage            8s
        system          18.4Es    inf   none                -
task.max-processes
        usage              30
        system          2.15G     max   deny                -
task.max-lwps
        usage              39
        system          2.15G     max   deny                -
project.max-contracts
        privileged      10.0K       -   deny                -
project.max-locked-memory
        usage               0B
        privileged       508MB      -   deny                -
project.max-port-ids
        privileged      8.19K       -   deny                -
project.max-shm-memory
        privileged       508MB      -   deny                -
project.max-shm-ids
        privileged        128       -   deny                -
project.max-msg-ids
        privileged        128       -   deny                -
project.max-sem-ids
        privileged        128       -   deny                -
project.max-crypto-memory
         usage            0B
privileged       508MB      -   deny                -
project.max-tasks
        usage               2
        system          2.15G     max   deny                -
project.max-processes
         usage             30
        system          2.15G     max   deny                -
project.max-lwps
         usage             39
        system          2.15G     max   deny                -
project.cpu-shares
        usage               1
        privileged          1       -   none                -
zone.max-shm-memory
        system          16.0EB    max   deny                -
zone.max-shm-ids
        system          16.8M     max   deny                -
zone.max-sem-ids
        system          16.8M     max   deny                -
zone.max-msg-ids
        system          16.8M     max   deny                -
zone.max-processes
        system          2.15G     max   deny                -
zone.max-lwps
        system          2.15G     max   deny                -
zone.cpu-shares
        privileged          1       -   none                -
zone.max-locked-memory
        usage               0B
        privileged       508MB      -   deny                -

Example 2 Displaying, Replacing, and Verifying the Value of a Specific Control

The following examples displays, replaces, and verifies the value of a specific control on an existing project:


example# prctl -n project.cpu-shares -i project group.staff
project: 10: group.staff
NAME    PRIVILEGE       VALUE    FLAG   ACTION               RECIPIENT
project.cpu-shares
        usage               1
        privileged          1       -   none                         -
        system          65.5K     max   none                         -
example# prctl -n project.cpu-shares -v 10 -r -i project group.staff
example# prctl -n project.cpu-shares -i project group.staff
project: 10: group.staff
NAME    PRIVILEGE       VALUE    FLAG   ACTION               RECIPIENT
project.cpu-shares
        usage              10
        privileged         10       -   none                         -
        system          65.5K     max   none                         -

Example 3 Adjusting Resources

The following example uses the project.max-locked-memory resource.

First, use id -p to find out which project the current shell is a member of:


/home/garfield> id -p
          uid=77880(garfield) gid=10(staff) projid=10(group.staff)

Using the target project, identify the resource limit value before the change:


/home/garfield> prctl -n project.max-locked-memory -i project \
                      group.staff
	project 10: group.staff
	project.max-locked-memory
            privileged         256MB       -    deny                  -
	    system            16.0EB     max    deny                  -
current limit is 256 Megabytes.

Next, adjust the project.max-locked-memory limit to 300 Megabytes for the target project:


# prctl -n project.max-locked-memory -v 300M -r -i project group.staff

The resource limit value after the change shows a new value of 300 Megabytes:


# prctl -n project.max-locked-memory -i project group.staff
	project 10:group.staff
	project.max-locked-memory
	    usage              200MG
     privileged         300MB       -    deny                           -
	   system            16.0EB     max    deny                           -

Example 4 Modifying CPU Caps for a Project

The prctl command can use the project.cpu-cap resource control (see resource_controls(5)) to set and modify CPU caps for a project. (The same resource control can be used in the /etc/project file. See project(4)) The following command modifies the CPU cap to limit user.smith to three CPUs:


# prctl -r -t privileged -n project.cpu-cap -v 300 -i project user.smith

The prctl -r option, used above, is used to dynamically change a CPU cap for a project or zone. For example, the following command will change the cap set in the preceding command to 80 percent:


# prctl -r -t privileged -n project.cpu-cap -v 80 -i project user.smith

To remove a CPU cap, enter:


# prctl -x -n project.cpu-cap $$

Example 5 Modifying CPU Caps for a Zone

The prctl command can use the zone.cpu-cap resource control (see resource_controls(5)) to set and modify CPU caps for a zone. (The same resource control can be manipulated using the zonecfg(1M) command.) The following command modifies the CPU cap to limit the global zone to 80 percent of a CPU:


# prctl -t privileged -n zone.cpu-cap -v 80 -i zone global

The cap can be lowered to 50% using:


# prctl -r -t privileged -n zone.cpu-cap -v 50 -i zone global

The following exit values are returned:

0

Success.

1

Fatal error encountered.

2

Invalid command line options were specified.

/proc/pid/*
Process information and control files

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability See below.

The command-line syntax is Committed. The human-readable output is Uncommitted. The parsable output is Committed.

rctladm(1M), zonecfg(1M), setrctl(2), rctlblk_get_local_action(3C), project(4), attributes(5), resource_controls(5)

The valid signals that can be set on a resource control block allowing local actions are SIGABRT, SIGXRES, SIGHUP, SIGSTOP, SIGTERM, and SIGKILL. Additionally, CPU time related controls can issue the SIGXCPU signal, and file size related controls can send the SIGXFSZ signal.
January 23, 2021 OmniOS