NAME
kvm_getprocs,
kvm_getargv,
kvm_getenvv —
access user process
state
LIBRARY
Kernel Data Access Library (libkvm, -lkvm)
SYNOPSIS
#include <kvm.h>
#include <sys/param.h>
#include <sys/sysctl.h>
struct kinfo_proc *
kvm_getprocs(
kvm_t
*kd,
int op,
int arg,
int *cnt);
char **
kvm_getargv(
kvm_t
*kd,
const struct
kinfo_proc *p,
int
nchr);
char **
kvm_getenvv(
kvm_t
*kd,
const struct
kinfo_proc *p,
int
nchr);
struct kinfo_proc2 *
kvm_getproc2(
kvm_t
*kd,
int op,
int arg,
size_t elemsize,
int *cnt);
char **
kvm_getargv2(
kvm_t
*kd,
const struct
kinfo_proc2 *p,
int
nchr);
char **
kvm_getenvv2(
kvm_t
*kd,
const struct
kinfo_proc2 *p,
int
nchr);
DESCRIPTION
kvm_getprocs() returns a (sub-)set of active processes in the
kernel indicated by
kd. The
op and
arg arguments constitute a predicate which limits the
set of processes returned. The value of
op describes the
filtering predicate as follows:
- KERN_PROC_ALL
- all processes
- KERN_PROC_PID
- processes with process id arg
- KERN_PROC_PGRP
- processes with process group arg
- KERN_PROC_SESSION
- processes with session id arg
- KERN_PROC_TTY
- processes with tty device arg
- KERN_PROC_UID
- processes with effective user id
arg
- KERN_PROC_RUID
- processes with real user id arg
- KERN_PROC_GID
- processes with effective group id
arg
- KERN_PROC_RGID
- processes with real group id arg
The number of processes found is returned in the reference parameter
cnt. The processes are returned as a contiguous array of
kinfo_proc structures. This memory is locally allocated, and
subsequent calls to
kvm_getprocs() and
kvm_close() will overwrite this storage.
If the
op argument for
kvm_getprocs() is
KERN_PROC_TTY,
arg can also be
KERN_PROC_TTY_NODEV to select processes with no controlling
tty and
KERN_PROC_TTY_REVOKE to select processes which have
had their controlling tty revoked.
kvm_getargv() returns a null-terminated argument vector that
corresponds to the command line arguments passed to process indicated by
p. Most likely, these arguments correspond to the values
passed to
exec(3) on process
creation. This information is, however, deliberately under control of the
process itself. Note that the original command name can be found, unaltered,
in the p_comm field of the process structure returned by
kvm_getprocs().
The
nchr argument indicates the maximum number of
characters, including null bytes, to use in building the strings. If this
amount is exceeded, the string causing the overflow is truncated and the
partial result is returned. This is handy for programs like
ps(1) and
w(1) that print only a one line
summary of a command and should not copy out large amounts of text only to
ignore it. If
nchr is zero, no limit is imposed and all
argument strings are returned in their entirety.
The memory allocated to the argv pointers and string storage is owned by the kvm
library. Subsequent
kvm_getprocs() and
kvm_close(3) calls will
clobber this storage.
The
kvm_getenvv() function is similar to
kvm_getargv() but returns the vector of environment strings.
This data is also alterable by the process.
kvm_getproc2() is similar to
kvm_getprocs()
but returns an array of
kinfo_proc2 structures.
Additionally, only the first
elemsize bytes of each
array entry are returned. If the size of the
kinfo_proc2
structure increases in size in a future release of
NetBSD the kernel will only return the requested
amount of data for each array entry and programs that use
kvm_getproc2() will continue to function without the need
for recompilation.
The
kvm_getargv2() and
kvm_getenvv2() are
equivalents to the
kvm_getargv() and
kvm_getenvv() functions but use a
kinfo_proc2 structure to specify the process.
If called against an active kernel, the
kvm_getproc2(),
kvm_getargv2(), and
kvm_getenvv2()
functions will use the
sysctl(3)
interface and do not require access to the kernel memory device file or swap
device.
RETURN VALUES
kvm_getprocs(),
kvm_getargv(),
kvm_getenvv(),
kvm_getproc2(),
kvm_getargv2(), and
kvm_getenvv2() all
return
NULL
on failure.
SEE ALSO
kvm(3),
kvm_close(3),
kvm_geterr(3),
kvm_nlist(3),
kvm_open(3),
kvm_openfiles(3),
kvm_read(3),
kvm_write(3)
BUGS
These routines do not belong in the kvm interface.