KVM_READ(3)            FreeBSD Library Functions Manual            KVM_READ(3)

NAME
     kvm_read, kvm_read2, kvm_write - read or write kernel virtual memory

LIBRARY
     Kernel Data Access Library (libkvm, -lkvm)

SYNOPSIS
     #include <kvm.h>

     ssize_t
     kvm_read(kvm_t *kd, unsigned long addr, void *buf, size_t nbytes);

     ssize_t
     kvm_read2(kvm_t *kd, kvaddr_t addr, void *buf, size_t nbytes);

     ssize_t
     kvm_write(kvm_t *kd, unsigned long addr, const void *buf, size_t nbytes);

DESCRIPTION
     The kvm_read(), kvm_read2(), and kvm_write() functions are used to read
     and write kernel virtual memory (or a crash dump file).  See kvm_open(3)
     for information regarding opening kernel virtual memory and crash dumps.

     The kvm_read() and kvm_read2() functions transfer nbytes bytes of data
     from the kernel space address addr to buf.  Conversely, kvm_write()
     transfers data from buf to addr.  Unlike their SunOS counterparts, these
     functions cannot be used to read or write process address spaces.

     The kvm_read2() function uses a different type (kvaddr_t) for the addr
     argument to allow use of addresses larger than ULONG_MAX when examining
     non-native kernel images.

RETURN VALUES
     Upon success, the number of bytes actually transferred is returned.
     Otherwise, -1 is returned.

SEE ALSO
     kvm(3), kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_geterr(3),
     kvm_getprocs(3), kvm_nlist(3), kvm_open(3), kvm_openfiles(3)

FreeBSD 13.1-RELEASE-p6        November 27, 2015       FreeBSD 13.1-RELEASE-p6