Dave Bort
912acb5f24
A hint about how important a job is; used to rank jobs for the out-of-memory (OOM) killer. Change-Id: Ib49ea933fc6c1bd5d0bc2c2e05548d744974a79b
3.3 KiB
mx_object_get_property, mx_object_set_property
NAME
object_get_property - Ask for various properties of various kernel objects.
object_set_property - Set various properties of various kernel objects.
SYNOPSIS
#include <magenta/syscalls.h>
#include <magenta/syscalls/object.h>
mx_status_t mx_object_get_property(mx_handle_t handle, uint32_t property,
void* value, size_t size);
mx_status_t mx_object_set_property(mx_handle_t handle, uint32_t property,
const void* value, size_t size);
DESCRIPTION
mx_object_get_property() requests the value of a kernel object's property. Getting a property requires MX_RIGHT_GET_PROPERTY rights on the handle.
mx_object_set_property() modifies the value of a kernel object's property. Setting a property requires MX_RIGHT_SET_PROPERTY rights on the handle.
The handle parameter indicates the target kernel object. Different properties only work on certain types of kernel objects, as described below.
The property parameter indicates which property to get/set. Property values have the prefix MX_PROP_, and are described below.
The value parameter holds the property value, and must be a pointer to a buffer of size bytes. Different properties expect different value types/sizes as described below.
PROPERTIES
Property values have the prefix MX_PROP_, and are defined in
#include <magenta/syscalls/object.h>
MX_PROP_NUM_STATE_KINDS
handle type: Thread
value type: uint32_t
Allowed operations: get
For debugger usage.
TODO: Describe the details of this property.
MX_PROP_NAME
handle type: (Most types)
value type: char[MX_MAX_NAME_LEN]
Allowed operations: get, set
The name of the object, as a NUL-terminated string.
MX_PROP_REGISTER_FS
handle type: Thread
value type: uintptr_t
Allowed operations: set
The value of the x86 FS segment register.
Only defined for x86-64.
MX_PROP_PROCESS_DEBUG_ADDR
handle type: Process
value type: uintptr_t
Allowed operations: get, set
The value of ld.so's _dl_debug_addr.
MX_PROP_PROCESS_VDSO_BASE_ADDRESS
handle type: Process
value type: uintptr_t
Allowed operations: get
The base address of the vDSO mapping, or zero.
MX_PROP_JOB_IMPORTANCE
handle type: Job
value type: mx_job_importance_t
Allowed operations: get, set
A hint about how important a job is; used to rank jobs for the out-of-memory (OOM) killer.
Additional errors:
- MX_ERR_OUT_OF_RANGE: If the importance value is not valid
RETURN VALUE
mx_object_get_property() returns MX_OK on success. In the event of failure, a negative error value is returned.
ERRORS
MX_ERR_BAD_HANDLE: handle is not a valid handle
MX_ERR_WRONG_TYPE: handle is not an appropriate type for property
MX_ERR_ACCESS_DENIED: handle does not have the necessary rights for the operation
MX_ERR_INVALID_ARGS: value is an invalid pointer
MX_ERR_NO_MEMORY: Temporary out of memory failure
MX_ERR_BUFFER_TOO_SMALL: size is too small for property
MX_ERR_NOT_SUPPORTED: property does not exist