NAME
kvm —
kernel memory interface
LIBRARY
library “libkvm”
DESCRIPTION
Thekvm library provides a uniform interface for
accessing kernel virtual memory images, including live systems and crash
dumps. Access to live systems is via /dev/mem while
crash dumps can be examined via the core file generated by
savecore(8). The interface behaves identically in both cases. Memory
can be read and written, kernel symbol addresses can be looked up efficiently,
and information about user processes can be gathered.
kvm_open()
is first called to obtain a descriptor for all subsequent calls.
COMPATIBILITY
The kvm interface was first introduced in
SunOS. A considerable number of programs have been developed that use this
interface, making backward compatibility highly desirable. In most respects,
the Sun kvm interface is consistent and clean.
Accordingly, the generic portion of the interface (i.e.,
kvm_open(), kvm_close(),
kvm_read(), kvm_write(), and
kvm_nlist()) has been incorporated into the
BSD interface. Indeed, many
kvm applications (i.e., debuggers and statistical
monitors) use only this subset of the interface.
The process interface was not kept. This is not a portability issue since any code that manipulates processes is inherently machine dependent.
Finally, the Sun kvm error reporting
semantics are poorly defined. The library can be configured either to print
errors to stderr automatically, or to print no error messages at all. In the
latter case, the nature of the error cannot be determined. To overcome this,
the BSD interface includes a routine,
kvm_geterr(3), to return (not print out) the error message
corresponding to the most recent error condition on the given
descriptor.
SEE ALSO
kinfo(3), kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_geterr(3), kvm_getfiles(3), kvm_getloadavg(3), kvm_getprocs(3), kvm_getswapinfo(3), kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3)