proc_compare(3) [netbsd man page]

PROC_COMPARE(3) 					   BSD Library Functions Manual 					   PROC_COMPARE(3)

NAME

     proc_compare -- compare two processes' interactivity

LIBRARY

     System Utilities Library (libutil, -lutil)

SYNOPSIS

     #include <sys/sysctl.h>

     int
     proc_compare(const struct kinfo_proc2 *p1, const struct kinfo_lwp *l1, const struct kinfo_proc2 *p2, const struct kinfo_lwp *l2);

DESCRIPTION

     The proc_compare() function compares two processes that are on the same terminal for their interactivity.	This means that the process
     returned is the one that has a better chance being the active foreground process on that tty.  This algorithm is used in the kernel for
     SIGINFO reporting and in userland by w(1).

     The algorithm used is as follows:
	   o   If one of them is runnable, it is preferred.
	   o   If both are runnable, the one with the largest CPU percent is preferred.
	   o   In a CPU percent tie, the one started more recently wins.
	   o   If none are runnable, and one of them is a zombie, the non-zombie is preferred
	   o   If both are zombies, the one started more recently wins.
	   o   If neither is a zombie, the one with the smaller sleep time wins.
	   o   In a tie, and one is sleeping in non-interruptible sleep, prefer that one.
	   o   If both are in the same state, the one started more recently is preferred.
     In all cases where the most recently started wins, if there was no winner, the one with the largest PID wins.

RETURN VALUES

     The proc_compare() function returns 0 if p1 is to be preferred and 1 if p2 is to be preferred.

SEE ALSO

     w(1)

HISTORY

     The proc_compare() was extracted from src/sys/kern/tty.c and src/usr.bin/w/proc_compare.c and merged in NetBSD 6.0.

BSD
								 October 20, 2011							       BSD

KVM_GETPROCS(3) 					   BSD Library Functions 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/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, int 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 struc-
     ture 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.

BSD
								 February 10, 2004							       BSD