KVM_GETPROCS(3) | Library Functions Manual | KVM_GETPROCS(3) |
kvm_getprocs
, kvm_getargv
,
kvm_getenvv
, kvm_getproc2
,
kvm_getargv2
, kvm_getenvv2
—
#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);
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:
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.
kvm_getprocs
(), kvm_getargv
(),
kvm_getenvv
(), kvm_getproc2
(),
kvm_getargv2
(), and
kvm_getenvv2
() all return NULL
on failure.
January 9, 2018 | NetBSD 9.2 |