kvm_getprocs(3) - NetBSD Manual Pages

Command:
Section:
Arch:
Collection:
>>>
KVM_GETPROCS(3)           NetBSD Programmer's Manual           KVM_GETPROCS(3)


NAME

     kvm_getprocs, kvm_getargv, kvm_getenvv - access user process state


LIBRARY

     Kernel Data Access Library (libkvm, -lkvm)


SYNOPSIS

     #include <kvm.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);


DESCRIPTION

     kvm_getprocs() returns a (sub-)set of active processes in the kernel in-
     dicated by kd.  The op and arg arguments constitute a predicate which
     limits the set of processes returned.  The value of op describes the fil-
     tering 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 arg
           KERN_PROC_TTY         processes with tty arg
           KERN_PROC_UID         processes with effective user id arg
           KERN_PROC_RUID        processes with real user 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 struc-
     tures.  This memory is locally allocated, and subsequent calls to
     kvm_getprocs() and kvm_close() will overwrite this storage.

     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 con-
     trol 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 ar-
     gument 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 pro-
     cess.


RETURN VALUES

     kvm_getprocs(), kvm_getargv(), and kvm_getenvv(), all return NULL on
     failure.


BUGS

     These routines do not belong in the kvm interface.


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)

NetBSD 1.4                       June 4, 1993                                2