kvm_open, kvm_close - specify a kernel to examine
kvm_t *kvm_open(namelist, corefile, swapfile, flag, errstr)
char *namelist, *corefile, *swapfile;
kvm_open() initializes a set of file descriptors to be used in subse-
quent calls to kernel VM routines. It returns a pointer to a kernel
identifier that must be used as the kd argument in subsequent kernel VM
The namelist argument specifies an unstripped executable file whose
symbol table will be used to locate various offsets in corefile. If
namelist is NULL, the symbol table of the currently running kernel is
used to determine offsets in the core image. In this case, it is up to
the implementation to select an appropriate way to resolve symbolic
references (for instance, using /vmunix as a default namelist file).
corefile specifies a file that contains an image of physical memory,
for instance, a kernel crash dump file (see savecore(8)) or the special
device /dev/mem. If corefile is NULL, the currently running kernel is
accessed (using /dev/mem and /dev/kmem).
swapfile specifies a file that represents the swap device. If both
corefile and swapfile are NULL, the swap device of the ``currently run-
ning kernel'' is accessed. Otherwise, if swapfile is NULL, kvm_open()
may succeed but subsequent kvm_getu(3K) function calls may fail if the
desired information is swapped out.
flag is used to specify read or write access for corefile and may have
one of the following values:
O_RDONLY open for reading
O_RDWR open for reading and writing
errstr is used to control error reporting. If it is a NULL pointer, no
error messages will be printed. If it is non-NULL, it is assumed to be
the address of a string that will be used to prefix error messages gen-
erated by kvm_open. Errors are printed to stderr. A useful value to
supply for errstr would be argv. This has the effect of printing
the process name in front of any error messages.
kvm_close() closes all file descriptors that were associated with kd.
These files are also closed on exit(2v) and execve(2V). kvm_close()
also resets the proc pointer associated with kvm_nextproc(3K) and
flushes any cached kernel data.
kmv_open() returns a non-NULL value suitable for use with subsequent
kernel VM function calls. On failure, it returns NULL and no files are
0 on success.
-1 on failure.
execve(2V), exit(2v), kvm_getu(3K), kvm_nextproc(3K), kvm_nlist(3K),
21 January 1990 KVM_OPEN(3K)