OpenBSD-4.6/lib/libkvm/kvm_getfiles.3

.\"	$OpenBSD: kvm_getfiles.3,v 1.12 2009/06/07 03:09:34 millert Exp $
.\"	$NetBSD: kvm_getfiles.3,v 1.3 1996/03/18 22:33:23 thorpej Exp $
.\"
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.\"     @(#)kvm_getfiles.3	8.2 (Berkeley) 4/19/94
.\"
.Dd $Mdocdate: June 7 2009 $
.Dt KVM_GETFILES 3
.Os
.Sh NAME
.Nm kvm_getfiles
.Nd survey open files
.Sh SYNOPSIS
.Fd #include <kvm.h>
.Fd #include <sys/types.h>
.Fd #define _KERNEL
.Fd #include <sys/file.h>
.Fd #undef _KERNEL
.\" .Fa kvm_t *kd
.Ft char *
.Fn kvm_getfiles "kvm_t *kd" "int op" "int arg" "int *cnt"
.Ft struct kinfo_file2 *
.Fn kvm_getfile2 "kvm_t *kd" "int op" "int arg" "size_t elemsize" "int *cnt"
.Sh DESCRIPTION
.Fn kvm_getfiles
returns a (sub-)set of the open files in the kernel indicated by
.Fa kd .
The
.Fa op
and
.Fa arg
arguments constitute a predicate which limits the set of files
returned.
No predicates are currently defined.
.Pp
The number of processes found is returned in the reference parameter
.Fa cnt .
The files are returned as a contiguous array of file structures,
preceded by the address of the first file entry in the kernel.
This memory is owned by kvm and is not guaranteed to be persistent across
subsequent kvm library calls.
Data should be copied out if it needs to be saved.
.Pp
.Fn kvm_getfile2
is similar to
.Fn kvm_getfiles
but returns an array of
.Vt kinfo_file2
structures.
Additionally, only the first
.Fa elemsize
bytes of each array entry are returned.
If the size of the
.Vt kinfo_file2
structure increases in size in a future release of
.Ox ,
the kernel will only return the requested amount of data for
each array entry and programs that use
.Fn kvm_getfile2
will continue to function without the need for recompilation.
The
.Fa op
and
.Fa arg
arguments constitute a predicate which limits the set of processes returned.
The value of
.Fa op
describes the filtering predicate as follows:
.Pp
.Bl -tag -width 20n -offset indent -compact
.It Dv KERN_FILE_BYFILE
all open files
.It Dv KERN_PROC_BYPID
files opened by process ID
.Fa arg
(\-1 for all processes)
.It Dv KERN_FILE_BYUID
files opened by processes with effective user ID
.Fa arg
.El
.Pp
Files associated with a process will include information about
the process that has the file open.
.Pp
The files are returned as a contiguous array of
.Vt kinfo_file2
structures.
The number of structures found is returned in the reference parameter
.Fa cnt .
This memory is owned by kvm and will be overwritten by subsequent calls to
.Fn kvm_getfile2
and destroyed by
.Fn kvm_close .
Data should be copied out if it needs to be saved.
.Sh RETURN VALUES
.Fn kvm_getfiles
and
.Fn kvm_getfile2
will return
.Dv NULL
on failure.
.Sh SEE ALSO
.Xr kvm 3 ,
.Xr kvm_close 3 ,
.Xr kvm_geterr 3 ,
.Xr kvm_nlist 3 ,
.Xr kvm_open 3 ,
.Xr kvm_openfiles 3 ,
.Xr kvm_read 3 ,
.Xr kvm_write 3
.Sh BUGS
This routine does not belong in the kvm interface.