NAME

     procctl — control processes

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/procctl.h>

     int
     procctl(idtype_t idtype, id_t id, int cmd, void *arg);

DESCRIPTION

     The procctl() system call provides for control over processes.  The idtype and id arguments
     specify the set of processes to control.  If multiple processes match the identifier,
     procctl will make a “best effort” to control as many of the selected processes as possible.
     An error is only returned if no selected processes successfully complete the request.  The
     following identifier types are supported:

     P_PID      Control the process with the process ID id.

     P_PGID     Control processes belonging to the process group with the ID id.

     The control request to perform is specified by the cmd argument.  The following commands are
     supported:

     PROC_SPROTECT     Set process protection state.  This is used to mark a process as protected
                       from being killed if the system exhausts available memory and swap.  The
                       arg parameter must point to an integer containing an operation and zero or
                       more optional flags.  The following operations are supported:

                       PPROT_SET       Mark the selected processes as protected.

                       PPROT_CLEAR     Clear the protected state of selected processes.

                       The following optional flags are supported:

                       PPROT_DESCEND   Apply the requested operation to all child processes of
                                       each selected process in addition to each selected
                                       process.

                       PPROT_INHERIT   When used with PPROT_SET, mark all future child processes
                                       of each selected process as protected.  Future child
                                       processes will also mark all of their future child
                                       processes.

RETURN VALUES

     If an error occurs, a value of -1 is returned and errno is set to indicate the error.

ERRORS

     The procctl() system call will fail if:

     [EFAULT]           The arg points outside the process's allocated address space.

     [EINVAL]           The cmd argument specifies an unsupported command.

                        The idtype argument specifies an unsupported identifier type.

     [EPERM]            The calling process does not have permission to perform the requested
                        operation on any of the selected processes.

     [ESRCH]            No processes matched the requested idtype and id.

     [EINVAL]           An invalid operation or flag was passed in arg for a PROC_SPROTECT
                        command.

SEE ALSO

     ptrace(2)

HISTORY

     The procctl() function appeared in FreeBSD 10.