/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software developed by the Computer Systems
 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
 * BG 91-66 and contributed to Berkeley.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */


/*
 * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
 * users of this code, so we've factored it out into a separate module.
 * Thus, we keep this grunge out of the other kvm applications (i.e.,
 * most other applications are interested only in open/close/read/nlist).
 */

#include <sys/param.h>
#define _WANT_UCRED     /* make ucred.h give us 'struct ucred' */
#include <sys/ucred.h>
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <sys/_task.h>
#include <sys/cpuset.h>
#include <sys/user.h>
#include <sys/proc.h>
#define _WANT_PRISON    /* make jail.h give us 'struct prison' */
#include <sys/jail.h>
#include <sys/exec.h>
#include <sys/stat.h>
#include <sys/sysent.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/file.h>
#include <sys/conf.h>
#define _WANT_KW_EXITCODE
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <nlist.h>
#include <kvm.h>

#include <sys/sysctl.h>

#include <limits.h>
#include <memory.h>
#include <paths.h>

#include "kvm_private.h"

#define KREAD(kd, addr, obj) \
        (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))

static int ticks;
static int hz;
static uint64_t cpu_tick_frequency;

/*
 * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
 * read/initialized before this function is ever called.
 */
static uint64_t
cputick2usec(uint64_t tick)
{
        if (cpu_tick_frequency == 0)
                return (0);
        return ((tick / cpu_tick_frequency) * 1000000ULL) +
            ((tick % cpu_tick_frequency) * 1000000ULL) / cpu_tick_frequency;
}

/*
 * Read proc's from memory file into buffer bp, which has space to hold
 * at most maxcnt procs.
 */
static int
kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
    struct kinfo_proc *bp, int maxcnt)
{
        int cnt = 0;
        struct kinfo_proc kinfo_proc, *kp;
        struct pgrp pgrp;
        struct session sess;
        struct cdev t_cdev;
        struct tty tty;
        struct vmspace vmspace;
        struct sigacts sigacts;
#if 0
        struct pstats pstats;
#endif
        struct ucred ucred;
        struct prison pr;
        struct thread mtd;
        struct proc proc;
        struct proc pproc;
        struct sysentvec sysent;
        char svname[KI_EMULNAMELEN];
        struct thread *td = NULL;
        bool first_thread;

        kp = &kinfo_proc;
        kp->ki_structsize = sizeof(kinfo_proc);
        /*
         * Loop on the processes, then threads within the process if requested.
         */
        if (what == KERN_PROC_ALL)
                what |= KERN_PROC_INC_THREAD;
        for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
                memset(kp, 0, sizeof *kp);
                if (KREAD(kd, (u_long)p, &proc)) {
                        _kvm_err(kd, kd->program, "can't read proc at %p", p);
                        return (-1);
                }
                if (proc.p_state == PRS_NEW)
                        continue;
                if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
                        kp->ki_uid = ucred.cr_uid;
                        kp->ki_ruid = ucred.cr_ruid;
                        kp->ki_svuid = ucred.cr_svuid;
                        kp->ki_rgid = ucred.cr_rgid;
                        kp->ki_svgid = ucred.cr_svgid;
                        kp->ki_cr_flags = 0;
                        if (ucred.cr_flags & CRED_FLAG_CAPMODE)
                                kp->ki_cr_flags |= KI_CRF_CAPABILITY_MODE;
                        if (1 + ucred.cr_ngroups > KI_NGROUPS) {
                                kp->ki_ngroups = KI_NGROUPS;
                                kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
                        } else
                                kp->ki_ngroups = 1 + ucred.cr_ngroups;
                        kp->ki_groups[0] = ucred.cr_gid;
                        kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups + 1,
                            (kp->ki_ngroups - 1) * sizeof(gid_t));
                        if (ucred.cr_prison != NULL) {
                                if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
                                        _kvm_err(kd, kd->program,
                                            "can't read prison at %p",
                                            ucred.cr_prison);
                                        return (-1);
                                }
                                kp->ki_jid = pr.pr_id;
                        }
                }

                switch(what & ~KERN_PROC_INC_THREAD) {

                case KERN_PROC_GID:
                        if (kp->ki_groups[0] != (gid_t)arg)
                                continue;
                        break;

                case KERN_PROC_PID:
                        if (proc.p_pid != (pid_t)arg)
                                continue;
                        break;

                case KERN_PROC_RGID:
                        if (kp->ki_rgid != (gid_t)arg)
                                continue;
                        break;

                case KERN_PROC_UID:
                        if (kp->ki_uid != (uid_t)arg)
                                continue;
                        break;

                case KERN_PROC_RUID:
                        if (kp->ki_ruid != (uid_t)arg)
                                continue;
                        break;
                }
                /*
                 * We're going to add another proc to the set.  If this
                 * will overflow the buffer, assume the reason is because
                 * nprocs (or the proc list) is corrupt and declare an error.
                 */
                if (cnt >= maxcnt) {
                        _kvm_err(kd, kd->program, "nprocs corrupt");
                        return (-1);
                }
                /*
                 * gather kinfo_proc
                 */
                kp->ki_paddr = p;
                kp->ki_addr = 0;        /* XXX uarea */
                /* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
                kp->ki_args = proc.p_args;
                kp->ki_numthreads = proc.p_numthreads;
                kp->ki_tracep = NULL;   /* XXXKIB do not expose ktr_io_params */
                kp->ki_textvp = proc.p_textvp;
                kp->ki_fd = proc.p_fd;
                kp->ki_pd = proc.p_pd;
                kp->ki_vmspace = proc.p_vmspace;
                if (proc.p_sigacts != NULL) {
                        if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
                                _kvm_err(kd, kd->program,
                                    "can't read sigacts at %p", proc.p_sigacts);
                                return (-1);
                        }
                        kp->ki_sigignore = sigacts.ps_sigignore;
                        kp->ki_sigcatch = sigacts.ps_sigcatch;
                }
#if 0
                if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
                        if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
                                _kvm_err(kd, kd->program,
                                    "can't read stats at %x", proc.p_stats);
                                return (-1);
                        }
                        kp->ki_start = pstats.p_start;

                        /*
                         * XXX: The times here are probably zero and need
                         * to be calculated from the raw data in p_rux and
                         * p_crux.
                         */
                        kp->ki_rusage = pstats.p_ru;
                        kp->ki_childstime = pstats.p_cru.ru_stime;
                        kp->ki_childutime = pstats.p_cru.ru_utime;
                        /* Some callers want child-times in a single value */
                        timeradd(&kp->ki_childstime, &kp->ki_childutime,
                            &kp->ki_childtime);
                }
#endif
                if (proc.p_oppid)
                        kp->ki_ppid = proc.p_oppid;
                else if (proc.p_pptr) {
                        if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
                                _kvm_err(kd, kd->program,
                                    "can't read pproc at %p", proc.p_pptr);
                                return (-1);
                        }
                        kp->ki_ppid = pproc.p_pid;
                } else
                        kp->ki_ppid = 0;
                if (proc.p_pgrp == NULL)
                        goto nopgrp;
                if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
                        _kvm_err(kd, kd->program, "can't read pgrp at %p",
                                 proc.p_pgrp);
                        return (-1);
                }
                kp->ki_pgid = pgrp.pg_id;
                kp->ki_jobc = -1;       /* Or calculate?  Arguably not. */
                if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
                        _kvm_err(kd, kd->program, "can't read session at %p",
                                pgrp.pg_session);
                        return (-1);
                }
                kp->ki_sid = sess.s_sid;
                (void)memcpy(kp->ki_login, sess.s_login,
                                                sizeof(kp->ki_login));
                if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
                        if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
                                _kvm_err(kd, kd->program,
                                         "can't read tty at %p", sess.s_ttyp);
                                return (-1);
                        }
                        if (tty.t_dev != NULL) {
                                if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
                                        _kvm_err(kd, kd->program,
                                                 "can't read cdev at %p",
                                                tty.t_dev);
                                        return (-1);
                                }
#if 0
                                kp->ki_tdev = t_cdev.si_udev;
#else
                                kp->ki_tdev = NODEV;
#endif
                        }
                        if (tty.t_pgrp != NULL) {
                                if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
                                        _kvm_err(kd, kd->program,
                                                 "can't read tpgrp at %p",
                                                tty.t_pgrp);
                                        return (-1);
                                }
                                kp->ki_tpgid = pgrp.pg_id;
                        } else
                                kp->ki_tpgid = -1;
                        if (tty.t_session != NULL) {
                                if (KREAD(kd, (u_long)tty.t_session, &sess)) {
                                        _kvm_err(kd, kd->program,
                                            "can't read session at %p",
                                            tty.t_session);
                                        return (-1);
                                }
                                kp->ki_tsid = sess.s_sid;
                        }
                } else {
nopgrp:
                        kp->ki_tdev = NODEV;
                }

                (void)kvm_read(kd, (u_long)proc.p_vmspace,
                    (char *)&vmspace, sizeof(vmspace));
                kp->ki_size = vmspace.vm_map.size;
                /*
                 * Approximate the kernel's method of calculating
                 * this field.
                 */
#define         pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
                kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
                kp->ki_swrss = vmspace.vm_swrss;
                kp->ki_tsize = vmspace.vm_tsize;
                kp->ki_dsize = vmspace.vm_dsize;
                kp->ki_ssize = vmspace.vm_ssize;

                switch (what & ~KERN_PROC_INC_THREAD) {

                case KERN_PROC_PGRP:
                        if (kp->ki_pgid != (pid_t)arg)
                                continue;
                        break;

                case KERN_PROC_SESSION:
                        if (kp->ki_sid != (pid_t)arg)
                                continue;
                        break;

                case KERN_PROC_TTY:
                        if ((proc.p_flag & P_CONTROLT) == 0 ||
                             kp->ki_tdev != (dev_t)arg)
                                continue;
                        break;
                }
                if (proc.p_comm[0] != 0)
                        strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
                (void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
                    sizeof(sysent));
                (void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
                    sizeof(svname));
                if (svname[0] != 0)
                        strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
                kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
                kp->ki_pid = proc.p_pid;
                kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
                kp->ki_acflag = proc.p_acflag;
                kp->ki_lock = proc.p_lock;
                kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */

                /* Per-thread items; iterate as appropriate. */
                td = TAILQ_FIRST(&proc.p_threads);
                for (first_thread = true; cnt < maxcnt && td != NULL &&
                    (first_thread || (what & KERN_PROC_INC_THREAD));
                    first_thread = false) {
                        if (proc.p_state != PRS_ZOMBIE) {
                                if (KREAD(kd, (u_long)td, &mtd)) {
                                        _kvm_err(kd, kd->program,
                                            "can't read thread at %p", td);
                                        return (-1);
                                }
                                if (what & KERN_PROC_INC_THREAD)
                                        td = TAILQ_NEXT(&mtd, td_plist);
                        } else
                                td = NULL;
                        if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
                                (void)kvm_read(kd, (u_long)mtd.td_wmesg,
                                    kp->ki_wmesg, WMESGLEN);
                        else
                                memset(kp->ki_wmesg, 0, WMESGLEN);
                        if (proc.p_pgrp == NULL) {
                                kp->ki_kiflag = 0;
                        } else {
                                kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
                                if (sess.s_leader == p)
                                        kp->ki_kiflag |= KI_SLEADER;
                        }
                        if ((proc.p_state != PRS_ZOMBIE) &&
                            (mtd.td_blocked != 0)) {
                                kp->ki_kiflag |= KI_LOCKBLOCK;
                                if (mtd.td_lockname)
                                        (void)kvm_read(kd,
                                            (u_long)mtd.td_lockname,
                                            kp->ki_lockname, LOCKNAMELEN);
                                else
                                        memset(kp->ki_lockname, 0,
                                            LOCKNAMELEN);
                                kp->ki_lockname[LOCKNAMELEN] = 0;
                        } else
                                kp->ki_kiflag &= ~KI_LOCKBLOCK;
                        kp->ki_siglist = proc.p_siglist;
                        if (proc.p_state != PRS_ZOMBIE) {
                                SIGSETOR(kp->ki_siglist, mtd.td_siglist);
                                kp->ki_sigmask = mtd.td_sigmask;
                                kp->ki_swtime = (ticks - proc.p_swtick) / hz;
                                kp->ki_flag = proc.p_flag;
                                kp->ki_sflag = 0;
                                kp->ki_nice = proc.p_nice;
                                kp->ki_traceflag = proc.p_traceflag;
                                if (proc.p_state == PRS_NORMAL) {
                                        if (TD_ON_RUNQ(&mtd) ||
                                            TD_CAN_RUN(&mtd) ||
                                            TD_IS_RUNNING(&mtd)) {
                                                kp->ki_stat = SRUN;
                                        } else if (TD_GET_STATE(&mtd) ==
                                            TDS_INHIBITED) {
                                                if (P_SHOULDSTOP(&proc)) {
                                                        kp->ki_stat = SSTOP;
                                                } else if (
                                                    TD_IS_SLEEPING(&mtd)) {
                                                        kp->ki_stat = SSLEEP;
                                                } else if (TD_ON_LOCK(&mtd)) {
                                                        kp->ki_stat = SLOCK;
                                                } else {
                                                        kp->ki_stat = SWAIT;
                                                }
                                        }
                                } else {
                                        kp->ki_stat = SIDL;
                                }
                                /* Stuff from the thread */
                                kp->ki_pri.pri_level = mtd.td_priority;
                                kp->ki_pri.pri_native = mtd.td_base_pri;
                                kp->ki_lastcpu = mtd.td_lastcpu;
                                kp->ki_wchan = mtd.td_wchan;
                                kp->ki_oncpu = mtd.td_oncpu;
                                if (mtd.td_name[0] != '\0')
                                        strlcpy(kp->ki_tdname, mtd.td_name,
                                            sizeof(kp->ki_tdname));
                                else
                                        memset(kp->ki_tdname, 0,
                                            sizeof(kp->ki_tdname));
                                kp->ki_pctcpu = 0;
                                kp->ki_rqindex = 0;

                                /*
                                 * Note: legacy fields; wraps at NO_CPU_OLD
                                 * or the old max CPU value as appropriate
                                 */
                                if (mtd.td_lastcpu == NOCPU)
                                        kp->ki_lastcpu_old = NOCPU_OLD;
                                else if (mtd.td_lastcpu > MAXCPU_OLD)
                                        kp->ki_lastcpu_old = MAXCPU_OLD;
                                else
                                        kp->ki_lastcpu_old = mtd.td_lastcpu;

                                if (mtd.td_oncpu == NOCPU)
                                        kp->ki_oncpu_old = NOCPU_OLD;
                                else if (mtd.td_oncpu > MAXCPU_OLD)
                                        kp->ki_oncpu_old = MAXCPU_OLD;
                                else
                                        kp->ki_oncpu_old = mtd.td_oncpu;
                                kp->ki_tid = mtd.td_tid;
                        } else {
                                memset(&kp->ki_sigmask, 0,
                                    sizeof(kp->ki_sigmask));
                                kp->ki_stat = SZOMB;
                                kp->ki_tid = 0;
                        }

                        bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
                        ++bp;
                        ++cnt;
                }
        }
        return (cnt);
}

/*
 * Build proc info array by reading in proc list from a crash dump.
 * Return number of procs read.  maxcnt is the max we will read.
 */
static int
kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
    u_long a_zombproc, int maxcnt)
{
        struct kinfo_proc *bp = kd->procbase;
        int acnt, zcnt = 0;
        struct proc *p;

        if (KREAD(kd, a_allproc, &p)) {
                _kvm_err(kd, kd->program, "cannot read allproc");
                return (-1);
        }
        acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
        if (acnt < 0)
                return (acnt);

        if (a_zombproc != 0) {
                if (KREAD(kd, a_zombproc, &p)) {
                        _kvm_err(kd, kd->program, "cannot read zombproc");
                        return (-1);
                }
                zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
                if (zcnt < 0)
                        zcnt = 0;
        }

        return (acnt + zcnt);
}

struct kinfo_proc *
kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
{
        int mib[4], st, nprocs;
        size_t size, osize;
        int temp_op;

        if (kd->procbase != 0) {
                free((void *)kd->procbase);
                /*
                 * Clear this pointer in case this call fails.  Otherwise,
                 * kvm_close() will free it again.
                 */
                kd->procbase = 0;
        }
        if (ISALIVE(kd)) {
                size = 0;
                mib[0] = CTL_KERN;
                mib[1] = KERN_PROC;
                mib[2] = op;
                mib[3] = arg;
                temp_op = op & ~KERN_PROC_INC_THREAD;
                st = sysctl(mib,
                    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
                    3 : 4, NULL, &size, NULL, 0);
                if (st == -1) {
                        _kvm_syserr(kd, kd->program, "kvm_getprocs");
                        return (0);
                }
                /*
                 * We can't continue with a size of 0 because we pass
                 * it to realloc() (via _kvm_realloc()), and passing 0
                 * to realloc() results in undefined behavior.
                 */
                if (size == 0) {
                        /*
                         * XXX: We should probably return an invalid,
                         * but non-NULL, pointer here so any client
                         * program trying to dereference it will
                         * crash.  However, _kvm_freeprocs() calls
                         * free() on kd->procbase if it isn't NULL,
                         * and free()'ing a junk pointer isn't good.
                         * Then again, _kvm_freeprocs() isn't used
                         * anywhere . . .
                         */
                        kd->procbase = _kvm_malloc(kd, 1);
                        goto liveout;
                }
                do {
                        size += size / 10;
                        kd->procbase = (struct kinfo_proc *)
                            _kvm_realloc(kd, kd->procbase, size);
                        if (kd->procbase == NULL)
                                return (0);
                        osize = size;
                        st = sysctl(mib, temp_op == KERN_PROC_ALL ||
                            temp_op == KERN_PROC_PROC ? 3 : 4,
                            kd->procbase, &size, NULL, 0);
                } while (st == -1 && errno == ENOMEM && size == osize);
                if (st == -1) {
                        _kvm_syserr(kd, kd->program, "kvm_getprocs");
                        return (0);
                }
                /*
                 * We have to check the size again because sysctl()
                 * may "round up" oldlenp if oldp is NULL; hence it
                 * might've told us that there was data to get when
                 * there really isn't any.
                 */
                if (size > 0 &&
                    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
                        _kvm_err(kd, kd->program,
                            "kinfo_proc size mismatch (expected %zu, got %d)",
                            sizeof(struct kinfo_proc),
                            kd->procbase->ki_structsize);
                        return (0);
                }
liveout:
                nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
        } else {
                struct nlist nl[6], *p;
                struct nlist nlz[2];

                nl[0].n_name = "_nprocs";
                nl[1].n_name = "_allproc";
                nl[2].n_name = "_ticks";
                nl[3].n_name = "_hz";
                nl[4].n_name = "_cpu_tick_frequency";
                nl[5].n_name = 0;

                nlz[0].n_name = "_zombproc";
                nlz[1].n_name = 0;

                if (!kd->arch->ka_native(kd)) {
                        _kvm_err(kd, kd->program,
                            "cannot read procs from non-native core");
                        return (0);
                }

                if (kvm_nlist(kd, nl) != 0) {
                        for (p = nl; p->n_type != 0; ++p)
                                ;
                        _kvm_err(kd, kd->program,
                                 "%s: no such symbol", p->n_name);
                        return (0);
                }
                (void) kvm_nlist(kd, nlz);      /* attempt to get zombproc */
                if (KREAD(kd, nl[0].n_value, &nprocs)) {
                        _kvm_err(kd, kd->program, "can't read nprocs");
                        return (0);
                }
                /*
                 * If returning all threads, we don't know how many that
                 * might be.  Presume that there are, on average, no more
                 * than 10 threads per process.
                 */
                if (op == KERN_PROC_ALL || (op & KERN_PROC_INC_THREAD))
                        nprocs *= 10;           /* XXX */
                if (KREAD(kd, nl[2].n_value, &ticks)) {
                        _kvm_err(kd, kd->program, "can't read ticks");
                        return (0);
                }
                if (KREAD(kd, nl[3].n_value, &hz)) {
                        _kvm_err(kd, kd->program, "can't read hz");
                        return (0);
                }
                if (KREAD(kd, nl[4].n_value, &cpu_tick_frequency)) {
                        _kvm_err(kd, kd->program,
                            "can't read cpu_tick_frequency");
                        return (0);
                }
                size = nprocs * sizeof(struct kinfo_proc);
                kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
                if (kd->procbase == NULL)
                        return (0);

                nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
                                      nlz[0].n_value, nprocs);
                if (nprocs <= 0) {
                        _kvm_freeprocs(kd);
                        nprocs = 0;
                }
#ifdef notdef
                else {
                        size = nprocs * sizeof(struct kinfo_proc);
                        kd->procbase = realloc(kd->procbase, size);
                }
#endif
        }
        *cnt = nprocs;
        return (kd->procbase);
}

void
_kvm_freeprocs(kvm_t *kd)
{

        free(kd->procbase);
        kd->procbase = NULL;
}

void *
_kvm_realloc(kvm_t *kd, void *p, size_t n)
{
        void *np;

        np = reallocf(p, n);
        if (np == NULL)
                _kvm_err(kd, kd->program, "out of memory");
        return (np);
}

/*
 * Get the command args or environment.
 */
static char **
kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
{
        int oid[4];
        int i;
        size_t bufsz;
        static int buflen;
        static char *buf, *p;
        static char **bufp;
        static int argc;
        char **nbufp;

        if (!ISALIVE(kd)) {
                _kvm_err(kd, kd->program,
                    "cannot read user space from dead kernel");
                return (NULL);
        }

        if (nchr == 0 || nchr > ARG_MAX)
                nchr = ARG_MAX;
        if (buflen == 0) {
                buf = malloc(nchr);
                if (buf == NULL) {
                        _kvm_err(kd, kd->program, "cannot allocate memory");
                        return (NULL);
                }
                argc = 32;
                bufp = malloc(sizeof(char *) * argc);
                if (bufp == NULL) {
                        free(buf);
                        buf = NULL;
                        _kvm_err(kd, kd->program, "cannot allocate memory");
                        return (NULL);
                }
                buflen = nchr;
        } else if (nchr > buflen) {
                p = realloc(buf, nchr);
                if (p != NULL) {
                        buf = p;
                        buflen = nchr;
                }
        }
        oid[0] = CTL_KERN;
        oid[1] = KERN_PROC;
        oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
        oid[3] = kp->ki_pid;
        bufsz = buflen;
        if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
                /*
                 * If the supplied buf is too short to hold the requested
                 * value the sysctl returns with ENOMEM. The buf is filled
                 * with the truncated value and the returned bufsz is equal
                 * to the requested len.
                 */
                if (errno != ENOMEM || bufsz != (size_t)buflen)
                        return (NULL);
                buf[bufsz - 1] = '\0';
                errno = 0;
        } else if (bufsz == 0)
                return (NULL);
        i = 0;
        p = buf;
        do {
                bufp[i++] = p;
                p += strlen(p) + 1;
                if (i >= argc) {
                        argc += argc;
                        nbufp = realloc(bufp, sizeof(char *) * argc);
                        if (nbufp == NULL)
                                return (NULL);
                        bufp = nbufp;
                }
        } while (p < buf + bufsz);
        bufp[i++] = 0;
        return (bufp);
}

char **
kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
{
        return (kvm_argv(kd, kp, 0, nchr));
}

char **
kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
{
        return (kvm_argv(kd, kp, 1, nchr));
}