useracc(9) [freebsd man page]

KERNACC(9)						   BSD Kernel Developer's Manual						KERNACC(9)

NAME

     kernacc, useracc -- check memory regions for accessibility

SYNOPSIS

     #include <sys/param.h>
     #include <sys/proc.h>
     #include <vm/vm.h>
     #include <vm/vm_extern.h>

     int
     kernacc(void *addr, int len, int rw);

     int
     useracc(void *addr, int len, int rw);

DESCRIPTION

     The kernacc() and useracc() functions check whether operations of the type specified in rw are permitted in the range of virtual addresses
     given by addr and len.  The possible values of rw are any bitwise combination of VM_PROT_READ, VM_PROT_WRITE and VM_PROT_EXECUTE.	kernacc()
     checks addresses in the kernel address space, while useracc() considers addr to represent an user space address.  The process context to use
     for this operation is taken from the global variable curproc.

RETURN VALUES

     Both functions return boolean true if the type of access specified by rw is permitted.  Otherwise boolean false is returned.

BUGS

     The process pointer should be passed in as an argument to useracc().

BSD
								   June 16, 1996							       BSD

VSLOCK(9)						   BSD Kernel Developer's Manual						 VSLOCK(9)

NAME

     vslock, vsunlock -- lock/unlock user space addresses in memory

SYNOPSIS

     #include <sys/param.h>
     #include <sys/proc.h>
     #include <vm/vm.h>
     #include <vm/vm_extern.h>

     int
     vslock(void *addr, size_t len);

     void
     vsunlock(void *addr, size_t len);

DESCRIPTION

     The vslock() and vsunlock() functions respectively lock and unlock a range of addresses belonging to the currently running process into mem-
     ory.  The actual amount of memory locked is a multiple of the machine's page size.  The starting page number is computed by truncating addr
     to the nearest preceding page boundary, and by rounding up addr + len to the next page boundary.  The process context to use for this opera-
     tion is taken from the global variable curproc.

RETURN VALUES

     The vslock() function will return 0 on success, otherwise it will return one of the errors listed below.

ERRORS

     The vslock() function will fail if:

     [EINVAL]		The addr and len parameters specify a memory range that wraps around the end of the machine address space.

     [ENOMEM]		The size of the specified address range exceeds the system limit on locked memory.

     [ENOMEM]		Locking the requested address range would cause the process to exceed its per-process locked memory limit.

     [EFAULT]		Some portion of the indicated address range is not allocated.  There was an error faulting/mapping a page.

BSD
								  August 10, 2004							       BSD