dissertation/usr.bin/top/machine.c

/* $OpenBSD: machine.c,v 1.112 2022/09/10 16:58:51 cheloha Exp $	 */

/*-
 * Copyright (c) 1994 Thorsten Lockert <tholo@sigmasoft.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * AUTHOR:  Thorsten Lockert <tholo@sigmasoft.com>
 *          Adapted from BSD4.4 by Christos Zoulas <christos@ee.cornell.edu>
 *          Patch for process wait display by Jarl F. Greipsland <jarle@idt.unit.no>
 *	    Patch for -DORDER by Kenneth Stailey <kstailey@disclosure.com>
 *	    Patch for new swapctl(2) by Tobias Weingartner <weingart@openbsd.org>
 */

#include <sys/param.h>	/* DEV_BSIZE PZERO */
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/swap.h>
#include <sys/sysctl.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#include <errno.h>

#include "top.h"
#include "display.h"
#include "machine.h"
#include "utils.h"

static int	swapmode(int *, int *);
static char	*state_abbr(struct kinfo_proc *);
static char	*format_comm(struct kinfo_proc *);
static int	cmd_matches(struct kinfo_proc *, char *);
static char	**get_proc_args(struct kinfo_proc *);

/* get_process_info passes back a handle.  This is what it looks like: */

struct handle {
	struct kinfo_proc **next_proc;	/* points to next valid proc pointer */
};

/* what we consider to be process size: */
#define PROCSIZE(pp) ((pp)->p_vm_tsize + (pp)->p_vm_dsize + (pp)->p_vm_ssize)

/*
 *  These definitions control the format of the per-process area
 */
static char header[] =
	"  PID X        PRI NICE  SIZE   RES STATE     WAIT      TIME    CPU COMMAND";

/* offsets in the header line to start alternative columns */
#define UNAME_START 6
#define RTABLE_START 46

#define Proc_format \
	"%5d %-8.8s %3d %4d %5s %5s %-9s %-7.7s %6s %5.2f%% %s"

/* process state names for the "STATE" column of the display */
char	*state_abbrev[] = {
	"", "start", "run", "sleep", "stop", "zomb", "dead", "onproc"
};

/* these are for calculating cpu state percentages */
static struct cpustats	*cp_time;
static struct cpustats	*cp_old;
static struct cpustats	*cp_diff;

/* these are for detailing the process states */
int process_states[8];
char *procstatenames[] = {
	"", " starting, ", " running, ", " idle, ",
	" stopped, ", " zombie, ", " dead, ", " on processor, ",
	NULL
};

/* these are for detailing the cpu states */
int64_t *cpu_states;
char *cpustatenames[] = {
	"user", "nice", "sys", "spin", "intr", "idle", NULL
};

/* this is for tracking which cpus are online */
int *cpu_online;

/* these are for detailing the memory statistics */
int memory_stats[10];
char *memorynames[] = {
	"Real: ", "K/", "K act/tot ", "Free: ", "K ",
	"Cache: ", "K ",
	"Swap: ", "K/", "K",
	NULL
};

/* these are names given to allowed sorting orders -- first is default */
char	*ordernames[] = {
	"cpu", "size", "res", "time", "pri", "pid", "command", NULL
};

/* these are for keeping track of the proc array */
static int	nproc;
static int	onproc = -1;
static int	pref_len;
static struct kinfo_proc *pbase;
static struct kinfo_proc **pref;

/* these are for getting the memory statistics */
static int	pageshift;	/* log base 2 of the pagesize */

/* define pagetok in terms of pageshift */
#define pagetok(size) ((size) << pageshift)

int		ncpu;
int		ncpuonline;
int		fscale;

unsigned int	maxslp;

int
getfscale(void)
{
	int mib[] = { CTL_KERN, KERN_FSCALE };
	size_t size = sizeof(fscale);

	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]),
	    &fscale, &size, NULL, 0) == -1)
		return (-1);
	return fscale;
}

int
getncpu(void)
{
	int mib[] = { CTL_HW, HW_NCPU };
	int numcpu;
	size_t size = sizeof(numcpu);

	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]),
	    &numcpu, &size, NULL, 0) == -1)
		return (-1);

	return (numcpu);
}

int
getncpuonline(void)
{
	int mib[] = { CTL_HW, HW_NCPUONLINE };
	int numcpu;
	size_t size = sizeof(numcpu);

	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]),
	    &numcpu, &size, NULL, 0) == -1)
		return (-1);

	return (numcpu);
}

int
machine_init(struct statics *statics)
{
	int pagesize;

	ncpu = getncpu();
	if (ncpu == -1)
		return (-1);
	if (getfscale() == -1)
		return (-1);
	cpu_states = calloc(ncpu, CPUSTATES * sizeof(int64_t));
	if (cpu_states == NULL)
		err(1, NULL);
	cp_time = calloc(ncpu, sizeof(*cp_time));
	cp_old  = calloc(ncpu, sizeof(*cp_old));
	cp_diff = calloc(ncpu, sizeof(*cp_diff));
	if (cp_time == NULL || cp_old == NULL || cp_diff == NULL)
		err(1, NULL);
	cpu_online = calloc(ncpu, sizeof(*cpu_online));
	if (cpu_online == NULL)
		err(1, NULL);

	/*
	 * get the page size with "getpagesize" and calculate pageshift from
	 * it
	 */
	pagesize = getpagesize();
	pageshift = 0;
	while (pagesize > 1) {
		pageshift++;
		pagesize >>= 1;
	}

	/* we only need the amount of log(2)1024 for our conversion */
	pageshift -= LOG1024;

	/* fill in the statics information */
	statics->procstate_names = procstatenames;
	statics->cpustate_names = cpustatenames;
	statics->memory_names = memorynames;
	statics->order_names = ordernames;
	return (0);
}

char *
format_header(char *second_field, char *eighth_field)
{
	char *second_fieldp = second_field, *eighth_fieldp = eighth_field, *ptr;

	ptr = header + UNAME_START;
	while (*second_fieldp != '\0')
		*ptr++ = *second_fieldp++;
	ptr = header + RTABLE_START;
	while (*eighth_fieldp != '\0')
		*ptr++ = *eighth_fieldp++;
	return (header);
}

void
get_system_info(struct system_info *si)
{
	static int cpustats_mib[] = {CTL_KERN, KERN_CPUSTATS, /*fillme*/0};
	static int sysload_mib[] = {CTL_VM, VM_LOADAVG};
	static int uvmexp_mib[] = {CTL_VM, VM_UVMEXP};
	static int bcstats_mib[] = {CTL_VFS, VFS_GENERIC, VFS_BCACHESTAT};
	struct loadavg sysload;
	struct uvmexp uvmexp;
	struct bcachestats bcstats;
	double *infoloadp;
	size_t size;
	int i;
	int64_t *tmpstate;

	size = sizeof(*cp_time);
	for (i = 0; i < ncpu; i++) {
		cpustats_mib[2] = i;
		tmpstate = cpu_states + (CPUSTATES * i);
		if (sysctl(cpustats_mib, 3, &cp_time[i], &size, NULL, 0) == -1)
			warn("sysctl kern.cpustats failed");
		/* convert cpustats counts to percentages */
		(void) percentages(CPUSTATES, tmpstate, cp_time[i].cs_time,
		    cp_old[i].cs_time, cp_diff[i].cs_time);
		/* note whether the cpu is online */
		cpu_online[i] = (cp_time[i].cs_flags & CPUSTATS_ONLINE) != 0;
	}

	size = sizeof(sysload);
	if (sysctl(sysload_mib, 2, &sysload, &size, NULL, 0) == -1)
		warn("sysctl failed");
	infoloadp = si->load_avg;
	for (i = 0; i < 3; i++)
		*infoloadp++ = ((double) sysload.ldavg[i]) / sysload.fscale;


	/* get total -- systemwide main memory usage structure */
	size = sizeof(uvmexp);
	if (sysctl(uvmexp_mib, 2, &uvmexp, &size, NULL, 0) == -1) {
		warn("sysctl failed");
		bzero(&uvmexp, sizeof(uvmexp));
	}
	size = sizeof(bcstats);
	if (sysctl(bcstats_mib, 3, &bcstats, &size, NULL, 0) == -1) {
		warn("sysctl failed");
		bzero(&bcstats, sizeof(bcstats));
	}
	/* convert memory stats to Kbytes */
	memory_stats[0] = -1;
	memory_stats[1] = pagetok(uvmexp.active);
	memory_stats[2] = pagetok(uvmexp.npages - uvmexp.free);
	memory_stats[3] = -1;
	memory_stats[4] = pagetok(uvmexp.free);
	memory_stats[5] = -1;
	memory_stats[6] = pagetok(bcstats.numbufpages);
	memory_stats[7] = -1;

	if (!swapmode(&memory_stats[8], &memory_stats[9])) {
		memory_stats[8] = 0;
		memory_stats[9] = 0;
	}

	/* set arrays and strings */
	si->cpustates = cpu_states;
	si->cpuonline = cpu_online;
	si->memory = memory_stats;
}

static struct handle handle;

struct kinfo_proc *
getprocs(int op, int arg, int *cnt)
{
	size_t size;
	int mib[6] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0,
	    sizeof(struct kinfo_proc), 0};
	static int maxslp_mib[] = {CTL_VM, VM_MAXSLP};
	static struct kinfo_proc *procbase;
	int st;

	mib[2] = op;
	mib[3] = arg;

	size = sizeof(maxslp);
	if (sysctl(maxslp_mib, 2, &maxslp, &size, NULL, 0) == -1) {
		warn("sysctl vm.maxslp failed");
		return (0);
	}
    retry:
	free(procbase);
	st = sysctl(mib, 6, NULL, &size, NULL, 0);
	if (st == -1) {
		/* _kvm_syserr(kd, kd->program, "kvm_getprocs"); */
		return (0);
	}
	size = 5 * size / 4;			/* extra slop */
	if ((procbase = malloc(size)) == NULL)
		return (0);
	mib[5] = (int)(size / sizeof(struct kinfo_proc));
	st = sysctl(mib, 6, procbase, &size, NULL, 0);
	if (st == -1) {
		if (errno == ENOMEM)
			goto retry;
		/* _kvm_syserr(kd, kd->program, "kvm_getprocs"); */
		return (0);
	}
	*cnt = (int)(size / sizeof(struct kinfo_proc));
	return (procbase);
}

static char **
get_proc_args(struct kinfo_proc *kp)
{
	static char	**s;
	static size_t	siz = 1023;
	int		mib[4];

	if (!s && !(s = malloc(siz)))
		err(1, NULL);

	mib[0] = CTL_KERN;
	mib[1] = KERN_PROC_ARGS;
	mib[2] = kp->p_pid;
	mib[3] = KERN_PROC_ARGV;
	for (;;) {
		size_t space = siz;
		if (sysctl(mib, 4, s, &space, NULL, 0) == 0)
			break;
		if (errno != ENOMEM)
			return NULL;
		siz *= 2;
		if ((s = realloc(s, siz)) == NULL)
			err(1, NULL);
	}
	return s;
}

static int
cmd_matches(struct kinfo_proc *proc, char *term)
{
	extern int	show_args;
	char		**args = NULL;

	if (!term) {
		/* No command filter set */
		return 1;
	} else {
		/* Filter set, process name needs to contain term */
		if (strstr(proc->p_comm, term))
			return 1;
		/* If showing arguments, search those as well */
		if (show_args) {
			args = get_proc_args(proc);

			if (args == NULL) {
				/* Failed to get args, so can't search them */
				return 0;
			}

			while (*args != NULL) {
				if (strstr(*args, term))
					return 1;
				args++;
			}
		}
	}
	return 0;
}

struct handle *
get_process_info(struct system_info *si, struct process_select *sel,
    int (*compare) (const void *, const void *))
{
	int show_idle, show_system, show_threads, show_uid, show_pid, show_cmd;
	int show_rtableid, hide_rtableid, hide_uid;
	int total_procs, active_procs;
	struct kinfo_proc **prefp, *pp;
	int what = KERN_PROC_ALL;

	show_system = sel->system;
	show_threads = sel->threads;

	if (show_system)
		what = KERN_PROC_KTHREAD;
	if (show_threads)
		what |= KERN_PROC_SHOW_THREADS;

	if ((pbase = getprocs(what, 0, &nproc)) == NULL) {
		/* warnx("%s", kvm_geterr(kd)); */
		quit(23);
	}
	if (nproc > onproc)
		pref = reallocarray(pref, (onproc = nproc),
		    sizeof(struct kinfo_proc *));
	if (pref == NULL) {
		warnx("Out of memory.");
		quit(23);
	}
	/* get a pointer to the states summary array */
	si->procstates = process_states;

	/* set up flags which define what we are going to select */
	show_idle = sel->idle;
	show_uid = sel->uid != (uid_t)-1;
	hide_uid = sel->huid != (uid_t)-1;
	show_pid = sel->pid != (pid_t)-1;
	show_rtableid = sel->rtableid != -1;
	hide_rtableid = sel->hrtableid != -1;
	show_cmd = sel->command != NULL;

	/* count up process states and get pointers to interesting procs */
	total_procs = 0;
	active_procs = 0;
	memset((char *) process_states, 0, sizeof(process_states));
	prefp = pref;
	for (pp = pbase; pp < &pbase[nproc]; pp++) {
		/*
		 * When showing threads, we want to ignore the structure
		 * that represents the entire process, which has TID == -1
		 */
		if (show_threads && pp->p_tid == -1)
			continue;
		/*
		 * Place pointers to each valid proc structure in pref[].
		 * Process slots that are actually in use have a non-zero
		 * status field.
		 */
		if (pp->p_stat != 0) {
			total_procs++;
			process_states[(unsigned char) pp->p_stat]++;
			if ((pp->p_psflags & PS_ZOMBIE) == 0 &&
			    (show_idle || pp->p_pctcpu != 0 ||
			    pp->p_stat == SRUN) &&
			    (!hide_uid || pp->p_ruid != sel->huid) &&
			    (!show_uid || pp->p_ruid == sel->uid) &&
			    (!show_pid || pp->p_pid == sel->pid) &&
			    (!hide_rtableid || pp->p_rtableid != sel->hrtableid) &&
			    (!show_rtableid || pp->p_rtableid == sel->rtableid) &&
			    (!show_cmd || cmd_matches(pp, sel->command))) {
				*prefp++ = pp;
				active_procs++;
			}
		}
	}

	qsort((char *)pref, active_procs, sizeof(struct kinfo_proc *), compare);
	/* remember active and total counts */
	si->p_total = total_procs;
	si->p_active = pref_len = active_procs;

	/* pass back a handle */
	handle.next_proc = pref;
	return &handle;
}

char fmt[MAX_COLS];	/* static area where result is built */

static char *
state_abbr(struct kinfo_proc *pp)
{
	static char buf[10];

	if (ncpu > 1 && pp->p_cpuid != KI_NOCPU)
		snprintf(buf, sizeof buf, "%s/%llu",
		    state_abbrev[(unsigned char)pp->p_stat], pp->p_cpuid);
	else
		snprintf(buf, sizeof buf, "%s",
		    state_abbrev[(unsigned char)pp->p_stat]);
	return buf;
}

static char *
format_comm(struct kinfo_proc *kp)
{
	static char	buf[MAX_COLS];
	char		**p, **s;
	extern int	show_args;

	if (!show_args)
		return (kp->p_comm);

	s = get_proc_args(kp);
	if (s == NULL)
		return kp->p_comm;

	buf[0] = '\0';
	for (p = s; *p != NULL; p++) {
		if (p != s)
			strlcat(buf, " ", sizeof(buf));
		strlcat(buf, *p, sizeof(buf));
	}
	if (buf[0] == '\0')
		return (kp->p_comm);
	return (buf);
}

void
skip_processes(struct handle *hndl, int n)
{
	hndl->next_proc += n;
}

char *
format_next_process(struct handle *hndl, const char *(*get_userid)(uid_t, int),
    int rtable, pid_t *pid)
{
	struct kinfo_proc *pp;
	int cputime;
	double pct;
	char second_buf[16], eighth_buf[8];

	/* find and remember the next proc structure */
	pp = *(hndl->next_proc++);

	cputime = pp->p_rtime_sec + ((pp->p_rtime_usec + 500000) / 1000000);

	/* calculate the base for cpu percentages */
	pct = (double)pp->p_pctcpu / fscale;

	if (get_userid == NULL)
		snprintf(second_buf, sizeof(second_buf), "%8d", pp->p_tid);
	else
		strlcpy(second_buf, (*get_userid)(pp->p_ruid, 0),
		    sizeof(second_buf));

	if (rtable)
		snprintf(eighth_buf, sizeof(eighth_buf), "%7d", pp->p_rtableid);
	else
		strlcpy(eighth_buf, pp->p_wmesg[0] ? pp->p_wmesg : "-",
		    sizeof(eighth_buf));

	/* format this entry */
	snprintf(fmt, sizeof(fmt), Proc_format, pp->p_pid, second_buf,
	    pp->p_priority - PZERO, pp->p_nice - NZERO,
	    format_k(pagetok(PROCSIZE(pp))),
	    format_k(pagetok(pp->p_vm_rssize)),
	    (pp->p_stat == SSLEEP && pp->p_slptime > maxslp) ?
	    "idle" : state_abbr(pp),
	    eighth_buf, format_time(cputime), 100.0 * pct,
	    printable(format_comm(pp)));

	*pid = pp->p_pid;
	/* return the result */
	return (fmt);
}

/* comparison routine for qsort */
static unsigned char sorted_state[] =
{
	0,			/* not used		 */
	4,			/* start		 */
	5,			/* run			 */
	2,			/* sleep		 */
	3,			/* stop			 */
	1			/* zombie		 */
};

extern int rev_order;

/*
 *  proc_compares - comparison functions for "qsort"
 */

/*
 * First, the possible comparison keys.  These are defined in such a way
 * that they can be merely listed in the source code to define the actual
 * desired ordering.
 */

#define ORDERKEY_PCTCPU \
	if ((result = (int)(p2->p_pctcpu - p1->p_pctcpu)) == 0)
#define ORDERKEY_CPUTIME \
	if ((result = p2->p_rtime_sec - p1->p_rtime_sec) == 0) \
		if ((result = p2->p_rtime_usec - p1->p_rtime_usec) == 0)
#define ORDERKEY_STATE \
	if ((result = sorted_state[(unsigned char)p2->p_stat] - \
	    sorted_state[(unsigned char)p1->p_stat])  == 0)
#define ORDERKEY_PRIO \
	if ((result = p2->p_priority - p1->p_priority) == 0)
#define ORDERKEY_RSSIZE \
	if ((result = p2->p_vm_rssize - p1->p_vm_rssize) == 0)
#define ORDERKEY_MEM \
	if ((result = PROCSIZE(p2) - PROCSIZE(p1)) == 0)
#define ORDERKEY_PID \
	if ((result = p1->p_pid - p2->p_pid) == 0)
#define ORDERKEY_CMD \
	if ((result = strcmp(p1->p_comm, p2->p_comm)) == 0)

/* remove one level of indirection and set sort order */
#define SETORDER do { \
		if (rev_order) { \
			p1 = *(struct kinfo_proc **) v2; \
			p2 = *(struct kinfo_proc **) v1; \
		} else { \
			p1 = *(struct kinfo_proc **) v1; \
			p2 = *(struct kinfo_proc **) v2; \
		} \
	} while (0)

/* compare_cpu - the comparison function for sorting by cpu percentage */
static int
compare_cpu(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_PRIO
	ORDERKEY_RSSIZE
	ORDERKEY_MEM
		;
	return (result);
}

/* compare_size - the comparison function for sorting by total memory usage */
static int
compare_size(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_MEM
	ORDERKEY_RSSIZE
	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_PRIO
		;
	return (result);
}

/* compare_res - the comparison function for sorting by resident set size */
static int
compare_res(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_RSSIZE
	ORDERKEY_MEM
	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_PRIO
		;
	return (result);
}

/* compare_time - the comparison function for sorting by CPU time */
static int
compare_time(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_CPUTIME
	ORDERKEY_PCTCPU
	ORDERKEY_STATE
	ORDERKEY_PRIO
	ORDERKEY_MEM
	ORDERKEY_RSSIZE
		;
	return (result);
}

/* compare_prio - the comparison function for sorting by CPU time */
static int
compare_prio(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_PRIO
	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_RSSIZE
	ORDERKEY_MEM
		;
	return (result);
}

static int
compare_pid(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_PID
	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_PRIO
	ORDERKEY_RSSIZE
	ORDERKEY_MEM
		;
	return (result);
}

static int
compare_cmd(const void *v1, const void *v2)
{
	struct kinfo_proc *p1, *p2;
	int result;

	SETORDER;

	ORDERKEY_CMD
	ORDERKEY_PCTCPU
	ORDERKEY_CPUTIME
	ORDERKEY_STATE
	ORDERKEY_PRIO
	ORDERKEY_RSSIZE
	ORDERKEY_MEM
		;
	return (result);
}


int (*proc_compares[])(const void *, const void *) = {
	compare_cpu,
	compare_size,
	compare_res,
	compare_time,
	compare_prio,
	compare_pid,
	compare_cmd,
	NULL
};

/*
 * proc_owner(pid) - returns the uid that owns process "pid", or -1 if
 *		the process does not exist.
 *		It is EXTREMELY IMPORTANT that this function work correctly.
 *		If top runs setuid root (as in SVR4), then this function
 *		is the only thing that stands in the way of a serious
 *		security problem.  It validates requests for the "kill"
 *		and "renice" commands.
 */
uid_t
proc_owner(pid_t pid)
{
	struct kinfo_proc **prefp, *pp;
	int cnt;

	prefp = pref;
	cnt = pref_len;
	while (--cnt >= 0) {
		pp = *prefp++;
		if (pp->p_pid == pid)
			return ((uid_t)pp->p_ruid);
	}
	return (uid_t)(-1);
}

/*
 * swapmode is rewritten by Tobias Weingartner <weingart@openbsd.org>
 * to be based on the new swapctl(2) system call.
 */
static int
swapmode(int *used, int *total)
{
	struct swapent *swdev;
	int nswap, rnswap, i;

	nswap = swapctl(SWAP_NSWAP, 0, 0);
	if (nswap == 0)
		return 0;

	swdev = calloc(nswap, sizeof(*swdev));
	if (swdev == NULL)
		return 0;

	rnswap = swapctl(SWAP_STATS, swdev, nswap);
	if (rnswap == -1) {
		free(swdev);
		return 0;
	}

	/* if rnswap != nswap, then what? */

	/* Total things up */
	*total = *used = 0;
	for (i = 0; i < nswap; i++) {
		if (swdev[i].se_flags & SWF_ENABLE) {
			*used += (swdev[i].se_inuse / (1024 / DEV_BSIZE));
			*total += (swdev[i].se_nblks / (1024 / DEV_BSIZE));
		}
	}
	free(swdev);
	return 1;
}