Using the <tt>prctl</tt> Command - System Administration Guide: Virtualization Using the Solaris Operating System

Using the `prctl` Command

Use the prctl command to make runtime interrogations of and modifications to the resource controls associated with an active process, task, or project on the system. See the prctl(1) man page for more information.

How to Use the `prctl` Command to Display Default Resource Control Values

This procedure must be used on a system on which no resource controls have been set or changed. There can be only non-default entries in the /etc/system file or in the project database.

Use the prctl command on any process, such as the current shell that is running.

# prctl $$
process: 100337: -sh
NAME    PRIVILEGE       VALUE    FLAG   ACTION                   RECIPIENT
process.max-port-events
        privileged      65.5K       -   deny                             -
        system          2.15G     max   deny                             -
process.crypto-buffer-limit
        system          16.0EB    max   deny                             -
process.max-crypto-sessions
        system          18.4E     max   deny                             -
process.add-crypto-sessions
        privileged        100       -   deny                             -
        system          18.4E     max   deny                             -
process.min-crypto-sessions
        privileged         20       -   deny                             -
        system          18.4E     max   deny                             -
process.max-msg-messages
        privileged      8.19K       -   deny                             -
        system          4.29G     max   deny                             -
process.max-msg-qbytes
        privileged      64.0KB      -   deny                             -
        system          16.0EB    max   deny                             -
process.max-sem-ops
        privileged        512       -   deny                             -
        system          2.15G     max   deny                             -
process.max-sem-nsems
        privileged        512       -   deny                             -
        system          32.8K     max   deny                             -
process.max-address-space
        privileged      16.0EB    max   deny                             -
        system          16.0EB    max   deny                             -
process.max-file-descriptor
        basic             256       -   deny                        100337
        privileged      65.5K       -   deny                             -
        system          2.15G     max   deny                             -
process.max-core-size
        privileged      8.00EB    max   deny                             -
        system          8.00EB    max   deny                             -
process.max-stack-size
        basic           8.00MB      -   deny                        100337
        privileged      8.00EB      -   deny                             -
        system          8.00EB    max   deny                             -
process.max-data-size
        privileged      16.0EB    max   deny                             -
        system          16.0EB    max   deny                             -
process.max-file-size
        privileged      8.00EB    max   deny,signal=XFSZ                 -
        system          8.00EB    max   deny                             -
process.max-cpu-time
        privileged      18.4Es    inf   signal=XCPU                      -
        system          18.4Es    inf   none                             -
task.max-cpu-time
        system          18.4Es    inf   none                             -
task.max-lwps
        system          2.15G     max   deny                             -
project.max-contracts
        privileged      10.0K       -   deny                             -
        system          2.15G     max   deny                             -
project.max-device-locked-memory
        privileged       499MB      -   deny                             -
        system          16.0EB    max   deny                             -
project.max-port-ids
        privileged      8.19K       -   deny                             -
        system          65.5K     max   deny                             -
project.max-shm-memory
        privileged      1.95GB      -   deny                             -
        system          16.0EB    max   deny                             -
project.max-shm-ids
        privileged        128       -   deny                             -
        system          16.8M     max   deny                             -
project.max-msg-ids
        privileged        128       -   deny                             -
        system          16.8M     max   deny                             -
project.max-sem-ids
        privileged        128       -   deny                             -
        system          16.8M     max   deny                             -
project.max-tasks
        system          2.15G     max   deny                             -
project.max-lwps
        system          2.15G     max   deny                             -
project.cpu-shares
        privileged          1       -   none                             -
        system          65.5K     max   none                             -
zone.max-lwps
        system          2.15G     max   deny                             -
zone.cpu-shares
        privileged          1       -   none                             -
        system          65.5K     max   none                             -

How to Use the `prctl` Command to Display Information for a Given Resource Control

Display the maximum file descriptor for the current shell that is running.

# prctl -n process.max-file-descriptor $$
process: 110453: -sh
NAME    PRIVILEGE       VALUE    FLAG   ACTION       RECIPIENT
process.max-file-descriptor
        basic             256       -   deny            110453
        privileged      65.5K       -   deny                 -
        system          2.15G     max   deny

How to Use `prctl` to Temporarily Change a Value

This example procedure uses the prctl command to temporarily add a new privileged value to deny the use of more than three LWPs per project for the x-files project. The result is comparable to the result in How to Set the Maximum Number of LWPs for Each Task in a Project.

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.
Use newtask to join the x-files project.
```
# newtask -p x-files
```
Use the id command with the -p option to verify that the correct project has been joined.
```
# id -p
uid=0(root) gid=1(other) projid=101(x-files)
```
Add a new privileged value for project.max-lwps that limits the number of LWPs to three.
```
# prctl -n project.max-lwps -t privileged -v 3 -e deny -i project x-files
```

Verify the result.

# prctl -n project.max-lwps -i project x-files
process: 111108: csh
NAME    PRIVILEGE    VALUE    FLAG   ACTION            RECIPIENT
project.max-lwps
        privileged       3       -   deny                      -
        system       2.15G     max   deny                      -

How to Use `prctl` to Lower a Resource Control Value

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.
Use the prctl command with the -r option to change the lowest value of the process.max-file-descriptor resource control.
```
# prctl -n process.max-file-descriptor -r -v 128 $$
```

How to Use `prctl` to Display, Replace, and Verify the Value of a Control on a Project

Become superuser or assume an equivalent role.
Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.

Display the value of project.cpu-shares in the project group.staff.

# prctl -n project.cpu-shares -i project group.staff
project: 2: group.staff
NAME    PRIVILEGE       VALUE    FLAG   ACTION     RECIPIENT
project.cpu-shares
        privileged          1       -   none               -
        system          65.5K     max   none

Replace the current project.cpu-shares value 1 with the value 10.

# prctl -n project.cpu-shares -v 10 -r -i project group.staff

Display the value of project.cpu-shares in the project group.staff.

# prctl -n project.cpu-shares -i project group.staff
project: 2: group.staff
NAME    PRIVILEGE       VALUE    FLAG   ACTION     RECIPIENT
project.cpu-shares
        privileged         10       -   none               -
        system          65.5K     max   none

Using the prctl Command

How to Use the prctl Command to Display Default Resource Control Values

How to Use the prctl Command to Display Information for a Given Resource Control

How to Use prctl to Temporarily Change a Value

How to Use prctl to Lower a Resource Control Value