NAME
vm_map_protect —
apply protection bits to a virtual
memory region
SYNOPSIS
#include
<sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
int
vm_map_protect(vm_map_t map,
vm_offset_t start, vm_offset_t
end, vm_prot_t new_prot,
vm_prot_t new_maxprot, int
flags);
DESCRIPTION
The
vm_map_protect()
function sets the protection bits and maximum protection bits of the address
region bounded by start and end
within the map map.
If the flags argument has the
VM_MAP_PROTECT_SET_PROT bit set, then the effective
protection is set to new_prot.
If the flags argument has the
VM_MAP_PROTECT_SET_MAXPROT bit set, then the maximum
protection is set to new_maxprot. Protection bits not
included into new_maxprot will be cleared from
existing entries.
The values specified by new_prot and new_maxprot are not allowed to include any protection bits that are not set in existing max_protection on every entry within the range. The operation will fail if this condition is violated. For instance, this prevents upgrading a shared mapping of a read-only file from read-only to read-write.
The specified range must not contain sub-maps.
IMPLEMENTATION NOTES
The function acquires a lock on the map for
the duration, by calling
vm_map_lock(9). Also, any in-progress wiring operation on the
map affecting the specified range will cause
vm_map_protect to sleep, waiting for completion.
RETURN VALUES
KERN_SUCCESS- The specified protection bits were set successfully.
KERN_INVALID_ARGUMENT- A sub-map entry was encountered in the range,
KERN_PROTECTION_FAILURE- The value of new_prot or new_maxprot exceed max_protection for an entry within the range.
KERN_PROTECTION_FAILURE- The map does not allow simultaneous setting of write and execute
permissions, but new_prot has both
VM_PROT_WRITEandVM_PROT_EXECUTEset. KERN_RESOURCE_SHORTAGE- A copy-on-write mapping is transitioned from read-only to read-write, and not enough swap space is available to back the copied pages.
KERN_OUT_OF_BOUNDS- Both new protection and new maximum protection updates were requested, but the specified new_prot is not a subset of new_maxprot.
SEE ALSO
AUTHORS
This manual page was written by Bruce M Simpson <bms@spc.org>.