man pages section 3: Extended Library Functions, Volume 2

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Updated: July 2014
 
 

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
Committed
MT-Level
Unsafe

See Also

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