KVM_KREAD(3KVM) Kernel VM Library Functions KVM_KREAD(3KVM)


NAME


kvm_kread, kvm_kwrite, kvm_uread, kvm_uwrite - copy data to or from a
kernel image or running system

SYNOPSIS


cc [ flag... ] file... -lkvm [ library...]
#include <kvm.h>

ssize_t kvm_kread(kvm_t *kd, uintptr_t addr, void *buf, size_t nbytes);


ssize_t kvm_kwrite(kvm_t *kd, uintptr_t addr, void *buf, size_t nbytes);


ssize_t kvm_uread(kvm_t *kd, uintptr_t addr, void *buf, size_t nbytes);


ssize_t kvm_uwrite(kvm_t *kd, uintptr_t addr, void *buf, size_t nbytes);


DESCRIPTION


The kvm_kread() function transfers data from the kernel address space to
the address space of the process. nbytes bytes of data are copied from
the kernel virtual address given by addr to the buffer pointed to by buf.


The kvm_kwrite() function is like kvm_kread(), except that the direction
of the transfer is reversed. To use this function, the kvm_open(3KVM)
call that returned kd must have specified write access.


The kvm_uread() function transfers data from the address space of the
processes specified in the most recent kvm_getu(3KVM) call. nbytes bytes
of data are copied from the user virtual address given by addr to the
buffer pointed to by buf.


The kvm_uwrite() function is like kvm_uread(), except that the direction
of the transfer is reversed. To use this function, the kvm_open(3KVM)
call that returned kd must have specified write access. The address is
resolved in the address space of the process specified in the most recent
kvm_getu(3KVM) call.

RETURN VALUES


On success, these functions return the number of bytes actually
transferred. On failure, they return -1.

ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Stable |
+--------------------+-----------------+
|MT-Level | Unsafe |
+--------------------+-----------------+

SEE ALSO


kvm_getu(3KVM), kvm_nlist(3KVM), kvm_open(3KVM), attributes(5)


May 2, 2002 KVM_KREAD(3KVM)