KVM_DUMP(3) BSD Library Functions Manual KVM_DUMP(3)NAME
kvm_dump_mkheader, kvm_dump_wrtheader, kvm_dump_inval — crash dump sup‐
port functions
LIBRARY
Kernel Data Access Library (libkvm, -lkvm)
SYNOPSIS
#include <kvm.h>
int
kvm_dump_mkheader(kvm_t *kd, off_t dump_off);
int
kvm_dump_wrtheader(kvm_t *kd, FILE *fp, int dumpsize);
int
kvm_dump_inval(kvm_t *kd);
DESCRIPTION
First note that the functions described here were designed to be used by
savecore(8).
The function kvm_dump_mkheader() checks if the physical memory file asso‐
ciated with kd contains a valid crash dump header as generated by a dump‐
ing kernel. When a valid header is found, kvm_dump_mkheader() initial‐
izes the internal kvm data structures as if a crash dump generated by the
savecore(8) program was opened. This has the intentional side effect of
enabling the address translation machinery.
A call to kvm_dump_mkheader() will most likely be followed by a call to
kvm_dump_wrtheader(). This function takes care of generating the generic
header, the CORE_CPU section and the section header of the CORE_DATA sec‐
tion. The data is written to the file pointed at by fp. The dumpsize
argument is only used to properly the set the segment size of the
CORE_DATA section. Note that this function assumes that fp is positioned
at file location 0. This function will not seek and therefore allows fp
to be a file pointer obtained by zopen().
The kvm_dump_inval() function clears the magic number in the physical
memory file associated with kd. The address translations must be enabled
for this to work (thus assuming that kvm_dump_mkheader() was called ear‐
lier in the sequence).
RETURN VALUES
All functions except kvm_dump_mkheader() return 0 on success, -1 on fail‐
ure. The function kvm_dump_mkheader() returns the size of the headers
present before the actual dumpdata starts. If no valid headers were
found but no fatal errors occurred, 0 is returned. On fatal errors the
return value is -1.
In the case of failure, kvm_geterr(3) can be used to retrieve the cause
of the error.
SEE ALSOkvm(3), kvm_open(3)HISTORY
These functions first appeared in NetBSD 1.2.
BSD March 17, 1996 BSD
