[dragonfly.git] / sys / emulation / linux / i386 / linprocfs / linprocfs_vnops.c

/*
 * Copyright (c) 2000 Dag-Erling Coïdan Smørgrav
 * Copyright (c) 1999 Pierre Beyssac
 * Copyright (c) 1993, 1995 Jan-Simon Pendry
 * Copyright (c) 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 *
 *      @(#)procfs_vnops.c      8.18 (Berkeley) 5/21/95
 *
 * $FreeBSD: src/sys/i386/linux/linprocfs/linprocfs_vnops.c,v 1.3.2.5 2001/08/12 14:29:19 rwatson Exp $
 * $DragonFly: src/sys/emulation/linux/i386/linprocfs/linprocfs_vnops.c,v 1.42 2007/11/20 21:03:48 dillon Exp $
 */

/*
 * procfs vnode interface
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/fcntl.h>
#include <sys/proc.h>
#include <sys/priv.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/dirent.h>
#include <sys/malloc.h>
#include <sys/reg.h>
#include <sys/jail.h>
#include <vm/vm_zone.h>
#include "linprocfs.h"
#include <sys/pioctl.h>

#include <machine/limits.h>

extern struct vnode *procfs_findtextvp (struct proc *);

static int      linprocfs_access (struct vop_access_args *);
static int      linprocfs_badop (struct vop_generic_args *);
static int      linprocfs_bmap (struct vop_bmap_args *);
static int      linprocfs_close (struct vop_close_args *);
static int      linprocfs_getattr (struct vop_getattr_args *);
static int      linprocfs_inactive (struct vop_inactive_args *);
static int      linprocfs_ioctl (struct vop_ioctl_args *);
static int      linprocfs_lookup (struct vop_old_lookup_args *);
static int      linprocfs_open (struct vop_open_args *);
static int      linprocfs_print (struct vop_print_args *);
static int      linprocfs_readdir (struct vop_readdir_args *);
static int      linprocfs_readlink (struct vop_readlink_args *);
static int      linprocfs_reclaim (struct vop_reclaim_args *);
static int      linprocfs_setattr (struct vop_setattr_args *);

static int      linprocfs_readdir_proc(struct vop_readdir_args *);
static int      linprocfs_readdir_root(struct vop_readdir_args *);
static int      linprocfs_readdir_net(struct vop_readdir_args *ap);
static int      linprocfs_readdir_sys(struct vop_readdir_args *ap);
static int      linprocfs_readdir_syskernel(struct vop_readdir_args *ap);

/*
 * procfs vnode operations.
 */
struct vop_ops linprocfs_vnode_vops = {
        .vop_default =          vop_defaultop,
        .vop_access =           linprocfs_access,
        .vop_advlock =          (void *)linprocfs_badop,
        .vop_bmap =             linprocfs_bmap,
        .vop_close =            linprocfs_close,
        .vop_old_create =       (void *)linprocfs_badop,
        .vop_getattr =          linprocfs_getattr,
        .vop_inactive =         linprocfs_inactive,
        .vop_old_link =         (void *)linprocfs_badop,
        .vop_old_lookup =       linprocfs_lookup,
        .vop_old_mkdir =        (void *)linprocfs_badop,
        .vop_old_mknod =        (void *)linprocfs_badop,
        .vop_open =             linprocfs_open,
        .vop_pathconf =         vop_stdpathconf,
        .vop_print =            linprocfs_print,
        .vop_read =             (void *)linprocfs_rw,
        .vop_readdir =          linprocfs_readdir,
        .vop_readlink =         linprocfs_readlink,
        .vop_reclaim =          linprocfs_reclaim,
        .vop_old_remove =       (void *)linprocfs_badop,
        .vop_old_rename =       (void *)linprocfs_badop,
        .vop_old_rmdir =        (void *)linprocfs_badop,
        .vop_setattr =          linprocfs_setattr,
        .vop_old_symlink =      (void *)linprocfs_badop,
        .vop_write =            (void *)linprocfs_rw,
        .vop_ioctl =            linprocfs_ioctl
};

/*
 * This is a list of the valid names in the
 * process-specific sub-directories.  It is
 * used in linprocfs_lookup and linprocfs_readdir
 */
static struct proc_target {
        u_char  pt_type;
        u_char  pt_namlen;
        char    *pt_name;
        pfstype pt_pfstype;
        int     (*pt_valid) (struct proc *p);
} proc_targets[] = {
#define N(s) sizeof(s)-1, s
        /*        name          type            validp */
        { DT_DIR, N("."),       Pproc,          NULL },
        { DT_DIR, N(".."),      Proot,          NULL },
        { DT_REG, N("mem"),     Pmem,           NULL },

        { DT_LNK, N("exe"),     Pexe,           NULL },
        { DT_LNK, N("cwd"),     Pcwd,           NULL },
        { DT_LNK, N("root"),    Pprocroot,      NULL },
        { DT_LNK, N("fd"),      Pfd,            NULL },

        { DT_REG, N("stat"),    Pprocstat,      NULL },
        { DT_REG, N("status"),  Pprocstatus,    NULL },
        { DT_REG, N("maps"),    Pmaps,          NULL },
        { DT_REG, N("statm"),   Pstatm,         NULL },
#if 0
        { DT_REG, N("cmdline"), Pcmdline,       NULL },
        { DT_REG, N("environ"), Penviron,       NULL },
#endif
#undef N
};
static const int nproc_targets = sizeof(proc_targets) / sizeof(proc_targets[0]);

static pid_t atopid (const char *, u_int);

/*
 * set things up for doing i/o on
 * the pfsnode (vp).  (vp) is locked
 * on entry, and should be left locked
 * on exit.
 *
 * for procfs we don't need to do anything
 * in particular for i/o.  all that is done
 * is to support exclusive open on process
 * memory images.
 */
static int
linprocfs_open(struct vop_open_args *ap)
{
        struct pfsnode *pfs = VTOPFS(ap->a_vp);
        struct proc *p2;

        p2 = PFIND(pfs->pfs_pid);
        if (p2 == NULL)
                return (ENOENT);
        if (pfs->pfs_pid && !PRISON_CHECK(ap->a_cred, p2->p_ucred))
                return (ENOENT);

        switch (pfs->pfs_type) {
        case Pmem:
                if (((pfs->pfs_flags & FWRITE) && (ap->a_mode & O_EXCL)) ||
                    ((pfs->pfs_flags & O_EXCL) && (ap->a_mode & FWRITE)))
                        return (EBUSY);

                if (p_trespass(ap->a_cred, p2->p_ucred))
                        return (EPERM);

                if (ap->a_mode & FWRITE)
                        pfs->pfs_flags = ap->a_mode & (FWRITE|O_EXCL);

                break;
        default:
                break;
        }

        return (vop_stdopen(ap));
}

/*
 * close the pfsnode (vp) after doing i/o.
 * (vp) is not locked on entry or exit.
 *
 * nothing to do for procfs other than undo
 * any exclusive open flag (see _open above).
 */
static int
linprocfs_close(struct vop_close_args *ap)
{
        struct pfsnode *pfs = VTOPFS(ap->a_vp);
        struct proc *p;

        switch (pfs->pfs_type) {
        case Pmem:
                if ((ap->a_fflag & FWRITE) && (pfs->pfs_flags & O_EXCL))
                        pfs->pfs_flags &= ~(FWRITE|O_EXCL);
                /*
                 * If this is the last close, then it checks to see if
                 * the target process has PF_LINGER set in p_pfsflags,
                 * if this is *not* the case, then the process' stop flags
                 * are cleared, and the process is woken up.  This is
                 * to help prevent the case where a process has been
                 * told to stop on an event, but then the requesting process
                 * has gone away or forgotten about it.
                 */
                if ((ap->a_vp->v_opencount < 2)
                    && (p = pfind(pfs->pfs_pid))
                    && !(p->p_pfsflags & PF_LINGER)) {
                        p->p_stops = 0;
                        p->p_step = 0;
                        wakeup(&p->p_step);
                }
                break;
        default:
                break;
        }
        return (vop_stdclose(ap));
}

/*
 * do an ioctl operation on a pfsnode (vp).
 * (vp) is not locked on entry or exit.
 */
static int
linprocfs_ioctl(struct vop_ioctl_args *ap)
{
        struct pfsnode *pfs = VTOPFS(ap->a_vp);
        struct proc *procp;
        int error;
        int signo;
        struct procfs_status *psp;
        unsigned char flags;

        procp = pfind(pfs->pfs_pid);
        if (procp == NULL) {
                return ENOTTY;
        }

        if (p_trespass(ap->a_cred, procp->p_ucred))
                return EPERM;

        switch (ap->a_command) {
        case PIOCBIS:
          procp->p_stops |= *(unsigned int*)ap->a_data;
          break;
        case PIOCBIC:
          procp->p_stops &= ~*(unsigned int*)ap->a_data;
          break;
        case PIOCSFL:
          /*
           * NFLAGS is "non-suser_xxx flags" -- currently, only
           * PFS_ISUGID ("ignore set u/g id");
           */
#define NFLAGS  (PF_ISUGID)
          flags = (unsigned char)*(unsigned int*)ap->a_data;
          if (flags & NFLAGS && (error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0)))
            return error;
          procp->p_pfsflags = flags;
          break;
        case PIOCGFL:
          *(unsigned int*)ap->a_data = (unsigned int)procp->p_pfsflags;
        case PIOCSTATUS:
          psp = (struct procfs_status *)ap->a_data;
          psp->state = (procp->p_step == 0);
          psp->flags = procp->p_pfsflags;
          psp->events = procp->p_stops;
          if (procp->p_step) {
            psp->why = procp->p_stype;
            psp->val = procp->p_xstat;
          } else {
            psp->why = psp->val = 0;    /* Not defined values */
          }
          break;
        case PIOCWAIT:
          psp = (struct procfs_status *)ap->a_data;
          if (procp->p_step == 0) {
            error = tsleep(&procp->p_stype, PCATCH, "piocwait", 0);
            if (error)
              return error;
          }
          psp->state = 1;       /* It stopped */
          psp->flags = procp->p_pfsflags;
          psp->events = procp->p_stops;
          psp->why = procp->p_stype;    /* why it stopped */
          psp->val = procp->p_xstat;    /* any extra info */
          break;
        case PIOCCONT:  /* Restart a proc */
          if (procp->p_step == 0)
            return EINVAL;      /* Can only start a stopped process */
          if ((signo = *(int*)ap->a_data) != 0) {
            if (signo >= NSIG || signo <= 0)
              return EINVAL;
            ksignal(procp, signo);
          }
          procp->p_step = 0;
          wakeup(&procp->p_step);
          break;
        default:
          return (ENOTTY);
        }
        return 0;
}

/*
 * do block mapping for pfsnode (vp).
 * since we don't use the buffer cache
 * for procfs this function should never
 * be called.  in any case, it's not clear
 * what part of the kernel ever makes use
 * of this function.  for sanity, this is the
 * usual no-op bmap, although returning
 * (EIO) would be a reasonable alternative.
 */
static int
linprocfs_bmap(struct vop_bmap_args *ap)
{
        if (ap->a_doffsetp != NULL)
                *ap->a_doffsetp = ap->a_loffset;
        if (ap->a_runp != NULL)
                *ap->a_runp = 0;
        if (ap->a_runb != NULL)
                *ap->a_runb = 0;
        return (0);
}

/*
 * linprocfs_inactive is called when the pfsnode
 * is vrele'd and the reference count is about
 * to go to zero.  (vp) will be on the vnode free
 * list, so to get it back vget() must be
 * used.
 *
 * (vp) is locked on entry and must remain locked
 *      on exit.
 */
static int
linprocfs_inactive(struct vop_inactive_args *ap)
{
        /*struct vnode *vp = ap->a_vp;*/

        return (0);
}

/*
 * _reclaim is called when getnewvnode()
 * wants to make use of an entry on the vnode
 * free list.  at this time the filesystem needs
 * to free any private data and remove the node
 * from any private lists.
 */
static int
linprocfs_reclaim(struct vop_reclaim_args *ap)
{
        return (linprocfs_freevp(ap->a_vp));
}

/*
 * _print is used for debugging.
 * just print a readable description
 * of (vp).
 */
static int
linprocfs_print(struct vop_print_args *ap)
{
        struct pfsnode *pfs = VTOPFS(ap->a_vp);

        kprintf("tag VT_PROCFS, type %d, pid %ld, mode %x, flags %lx\n",
            pfs->pfs_type, (long)pfs->pfs_pid, pfs->pfs_mode, pfs->pfs_flags);
        return (0);
}

/*
 * generic entry point for unsupported operations
 */
static int
linprocfs_badop(struct vop_generic_args *ap __unused)
{

        return (EIO);
}

/*
 * Invent attributes for pfsnode (vp) and store
 * them in (vap).
 * Directories lengths are returned as zero since
 * any real length would require the genuine size
 * to be computed, and nothing cares anyway.
 *
 * this is relatively minimal for procfs.
 */
static int
linprocfs_getattr(struct vop_getattr_args *ap)
{
        struct pfsnode *pfs = VTOPFS(ap->a_vp);
        struct vattr *vap = ap->a_vap;
        struct proc *procp;
        int error;

        /*
         * First make sure that the process and its credentials 
         * still exist.
         */
        switch (pfs->pfs_type) {
        case Proot:
        case Pself:
                procp = 0;
                break;

        default:
                procp = PFIND(pfs->pfs_pid);
                if (procp == 0 || procp->p_ucred == NULL)
                        return (ENOENT);
        }

        error = 0;

        /* start by zeroing out the attributes */
        VATTR_NULL(vap);

        /* next do all the common fields */
        vap->va_type = ap->a_vp->v_type;
        vap->va_mode = pfs->pfs_mode;
        vap->va_fileid = pfs->pfs_fileno;
        vap->va_flags = 0;
        vap->va_blocksize = PAGE_SIZE;
        vap->va_bytes = vap->va_size = 0;
        vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];

        /*
         * Make all times be current TOD.
         * It would be possible to get the process start
         * time from the p_stat structure, but there's
         * no "file creation" time stamp anyway, and the
         * p_stat structure is not addressible if u. gets
         * swapped out for that process.
         */
        nanotime(&vap->va_ctime);
        vap->va_atime = vap->va_mtime = vap->va_ctime;

        /*
         * now do the object specific fields
         *
         * The size could be set from struct reg, but it's hardly
         * worth the trouble, and it puts some (potentially) machine
         * dependent data into this machine-independent code.  If it
         * becomes important then this function should break out into
         * a per-file stat function in the corresponding .c file.
         */

        vap->va_nlink = 1;
        if (procp) {
                vap->va_uid = procp->p_ucred->cr_uid;
                vap->va_gid = procp->p_ucred->cr_gid;
        }

        switch (pfs->pfs_type) {
        case Proot:
        case Pnet:
        case Psys:
        case Psyskernel:
                /*
                 * Set nlink to 1 to tell fts(3) we don't actually know.
                 */
                vap->va_nlink = 1;
                vap->va_uid = 0;
                vap->va_gid = 0;
                vap->va_size = vap->va_bytes = DEV_BSIZE;
                break;

        case Pself: {
                char buf[16];           /* should be enough */
                vap->va_uid = 0;
                vap->va_gid = 0;
                vap->va_size = vap->va_bytes =
                    ksnprintf(buf, sizeof(buf), "%ld", (long)curproc->p_pid);
                break;
        }

        case Pproc:
                vap->va_nlink = nproc_targets;
                vap->va_size = vap->va_bytes = DEV_BSIZE;
                break;

        case Pexe: {
                char *fullpath, *freepath;
                error = cache_fullpath(procp, &procp->p_textnch, &fullpath, &freepath);
                /* error = vn_fullpath(procp, NULL, &fullpath, &freepath); */
                if (error == 0) {
                        vap->va_size = strlen(fullpath);
                        kfree(freepath, M_TEMP);
                } else {
                        vap->va_size = sizeof("unknown") - 1;
                        error = 0;
                }
                vap->va_bytes = vap->va_size;
                break;
        }
        case Pcwd: {
                char *fullpath, *freepath;
                error = cache_fullpath(procp, &procp->p_fd->fd_ncdir, &fullpath, &freepath);
                if (error == 0) {
                        vap->va_size = strlen(fullpath);
                        kfree(freepath, M_TEMP);
                } else {
                        vap->va_size = sizeof("unknown") - 1;
                        error = 0;
                }
                vap->va_bytes = vap->va_size;
                break;
        }
        case Pprocroot: {
                struct nchandle *nchp;
                char *fullpath, *freepath;
                nchp = jailed(procp->p_ucred) ? &procp->p_fd->fd_njdir : &procp->p_fd->fd_nrdir;
                error = cache_fullpath(procp, nchp, &fullpath, &freepath);
                if (error == 0) {
                        vap->va_size = strlen(fullpath);
                        kfree(freepath, M_TEMP);
                } else {
                        vap->va_size = sizeof("unknown") - 1;
                        error = 0;
                }
                vap->va_bytes = vap->va_size;
                break;
        }
        case Pfd: {
                if (procp == curproc) {
                        vap->va_size = sizeof("/dev/fd") - 1;
                        error = 0;      
                } else {
                        vap->va_size = sizeof("unknown") - 1;
                        error = 0;
                }
                vap->va_bytes = vap->va_size;
                break;
        }

        case Pmeminfo:
        case Pcpuinfo:
        case Pstat:
        case Puptime:
        case Pversion:
        case Ploadavg:
        case Pnetdev:
        case Pdevices:
        case Posrelease:
        case Postype:
        case Ppidmax:
                vap->va_bytes = vap->va_size = 0;
                vap->va_uid = 0;
                vap->va_gid = 0;
                break;
                
        case Pmem:
                /*
                 * If we denied owner access earlier, then we have to
                 * change the owner to root - otherwise 'ps' and friends
                 * will break even though they are setgid kmem. *SIGH*
                 */
                if (procp->p_flag & P_SUGID)
                        vap->va_uid = 0;
                else
                        vap->va_uid = procp->p_ucred->cr_uid;
                break;

        case Pprocstat:
        case Pprocstatus:
        case Pcmdline:
        case Penviron:
        case Pmaps:
        case Pstatm:
                vap->va_bytes = vap->va_size = 0;
                /* uid, gid are already set */
                break;

        default:
                panic("linprocfs_getattr");
        }

        return (error);
}

static int
linprocfs_setattr(struct vop_setattr_args *ap)
{

        if (ap->a_vap->va_flags != VNOVAL)
                return (EOPNOTSUPP);

        /*
         * just fake out attribute setting
         * it's not good to generate an error
         * return, otherwise things like creat()
         * will fail when they try to set the
         * file length to 0.  worse, this means
         * that echo $note > /proc/$pid/note will fail.
         */

        return (0);
}

/*
 * implement access checking.
 *
 * something very similar to this code is duplicated
 * throughout the 4bsd kernel and should be moved
 * into kern/vfs_subr.c sometime.
 *
 * actually, the check for super-user is slightly
 * broken since it will allow read access to write-only
 * objects.  this doesn't cause any particular trouble
 * but does mean that the i/o entry points need to check
 * that the operation really does make sense.
 */
static int
linprocfs_access(struct vop_access_args *ap)
{
        struct vattr *vap;
        struct vattr vattr;
        int error;

        /*
         * If you're the super-user,
         * you always get access.
         */
        if (ap->a_cred->cr_uid == 0)
                return (0);

        vap = &vattr;
        error = VOP_GETATTR(ap->a_vp, vap);
        if (error)
                return (error);

        /*
         * Access check is based on only one of owner, group, public.
         * If not owner, then check group. If not a member of the
         * group, then check public access.
         */
        if (ap->a_cred->cr_uid != vap->va_uid) {
                gid_t *gp;
                int i;

                ap->a_mode >>= 3;
                gp = ap->a_cred->cr_groups;
                for (i = 0; i < ap->a_cred->cr_ngroups; i++, gp++)
                        if (vap->va_gid == *gp)
                                goto found;
                ap->a_mode >>= 3;
found:
                ;
        }

        if ((vap->va_mode & ap->a_mode) == ap->a_mode)
                return (0);

        return (EACCES);
}

/*
 * lookup.  this is incredibly complicated in the general case, however
 * for most pseudo-filesystems very little needs to be done.
 */
static int
linprocfs_lookup(struct vop_old_lookup_args *ap)
{
        struct componentname *cnp = ap->a_cnp;
        struct vnode **vpp = ap->a_vpp;
        struct vnode *dvp = ap->a_dvp;
        char *pname = cnp->cn_nameptr;
        struct proc_target *pt;
        pid_t pid;
        struct pfsnode *pfs;
        struct proc *p;
        int i;
        int error;

        *vpp = NULL;

        if (cnp->cn_nameiop == NAMEI_DELETE || 
            cnp->cn_nameiop == NAMEI_RENAME ||
            cnp->cn_nameiop == NAMEI_CREATE) {
                return (EROFS);
        }

        error = 0;

        if (cnp->cn_namelen == 1 && *pname == '.') {
                *vpp = dvp;
                vref(*vpp);
                goto out;
        }

        pfs = VTOPFS(dvp);
        switch (pfs->pfs_type) {
        case Psys:
                if (cnp->cn_flags & CNP_ISDOTDOT) {
                        error = linprocfs_root(dvp->v_mount, vpp);
                        goto out;
                }
                if (CNEQ(cnp, "kernel", 6)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Psyskernel);
                        goto out;
                }               
                break;
        case Pnet:
                if (cnp->cn_flags & CNP_ISDOTDOT) {
                        error = linprocfs_root(dvp->v_mount, vpp);
                        goto out;
                }
                if (CNEQ(cnp, "dev", 3)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pnetdev);
                        goto out;
                }               
                break;
        case Psyskernel:
                if (cnp->cn_flags & CNP_ISDOTDOT) {
                        /* XXX: this is wrong, wrong, wrong. */
                        error = linprocfs_root(dvp->v_mount, vpp);
                        goto out;
                }
                if (CNEQ(cnp, "osrelease", 9)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Posrelease);
                        goto out;
                }
                if (CNEQ(cnp, "ostype", 6)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Postype);
                        goto out;
                }
                if (CNEQ(cnp, "pid_max", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Ppidmax);
                        goto out;
                }
                if (CNEQ(cnp, "version", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pversion);
                        goto out;
                }
                break;
                
        case Proot:
                if (cnp->cn_flags & CNP_ISDOTDOT)
                        return (EIO);

                if (CNEQ(cnp, "self", 4)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pself);
                        goto out;
                }
                if (CNEQ(cnp, "meminfo", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pmeminfo);
                        goto out;
                }
                if (CNEQ(cnp, "cpuinfo", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pcpuinfo);
                        goto out;
                }
                if (CNEQ(cnp, "stat", 4)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pstat);
                        goto out;
                }
                if (CNEQ(cnp, "uptime", 6)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Puptime);
                        goto out;
                }
                if (CNEQ(cnp, "version", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pversion);
                        goto out;
                }
                if (CNEQ(cnp, "loadavg", 7)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Ploadavg);
                        goto out;
                }
                if (CNEQ(cnp, "net", 3)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Pnet);
                        goto out;
                }
                if (CNEQ(cnp, "sys", 3)) {
                        error = linprocfs_allocvp(dvp->v_mount, vpp, 0, Psys);
                        goto out;
                }

                pid = atopid(pname, cnp->cn_namelen);
                if (pid == NO_PID)
                        break;

                p = PFIND(pid);
                if (p == 0)
                        break;

                if (!PRISON_CHECK(ap->a_cnp->cn_cred, p->p_ucred))
                        break;

                if (ps_showallprocs == 0 && ap->a_cnp->cn_cred->cr_uid != 0 &&
                    ap->a_cnp->cn_cred->cr_uid != p->p_ucred->cr_uid)
                        break;

                error = linprocfs_allocvp(dvp->v_mount, vpp, pid, Pproc);
                goto out;

        case Pproc:
                if (cnp->cn_flags & CNP_ISDOTDOT) {
                        error = linprocfs_root(dvp->v_mount, vpp);
                        goto out;
                }

                p = PFIND(pfs->pfs_pid);
                if (p == 0)
                        break;

                if (!PRISON_CHECK(ap->a_cnp->cn_cred, p->p_ucred))
                        break;

                if (ps_showallprocs == 0 && ap->a_cnp->cn_cred->cr_uid != 0 &&
                    ap->a_cnp->cn_cred->cr_uid != p->p_ucred->cr_uid)
                        break;

                for (pt = proc_targets, i = 0; i < nproc_targets; pt++, i++) {
                        if (cnp->cn_namelen == pt->pt_namlen &&
                            bcmp(pt->pt_name, pname, cnp->cn_namelen) == 0 &&
                            (pt->pt_valid == NULL || (*pt->pt_valid)(p)))
                                goto found;
                }
                break;

        found:
                error = linprocfs_allocvp(dvp->v_mount, vpp, pfs->pfs_pid,
                                        pt->pt_pfstype);
                goto out;

        default:
                error = ENOTDIR;
                goto out;
        }

        if (cnp->cn_nameiop == NAMEI_LOOKUP)
                error = ENOENT;
        else
                error = EROFS;

        /*
         * If no error occured *vpp will hold a referenced locked vnode.
         * dvp was passed to us locked and *vpp must be returned locked
         * so if dvp != *vpp and CNP_LOCKPARENT is not set, unlock dvp.
         */
out:
        if (error == 0) {
                if (*vpp != dvp && (cnp->cn_flags & CNP_LOCKPARENT) == 0) {
                        cnp->cn_flags |= CNP_PDIRUNLOCK;
                        vn_unlock(dvp);
                }
        }
        return (error);
}

/*
 * Does this process have a text file?
 */
int
linprocfs_validfile(struct proc *p)
{

        return (procfs_findtextvp(p) != NULLVP);
}

/*
 * readdir() returns directory entries from pfsnode (vp).
 *
 * We generate just one directory entry at a time, as it would probably
 * not pay off to buffer several entries locally to save uiomove calls.
 *
 * linprocfs_readdir(struct vnode *a_vp, struct uio *a_uio,
 *                   struct ucred *a_cred, int *a_eofflag,
 *                   int *a_ncookies, off_t **a_cookies)
 */
static int
linprocfs_readdir(struct vop_readdir_args *ap)
{
        struct pfsnode *pfs;
        int error;

        if (ap->a_uio->uio_offset < 0 || ap->a_uio->uio_offset > INT_MAX)
                return (EINVAL);

        pfs = VTOPFS(ap->a_vp);
        if ((error = vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY)) != 0)
                return (error);

        switch (pfs->pfs_type) {
        case Pproc:
                /*
                 * This is for the process-specific sub-directories.
                 * all that is needed to is copy out all the entries
                 * from the procent[] table (top of this file).
                 */
                error = linprocfs_readdir_proc(ap);
                break;
        case Proot:
                /*
                 * This is for the root of the procfs filesystem
                 * what is needed is a special entry for "self"
                 * followed by an entry for each process on allproc
                 */
                error = linprocfs_readdir_root(ap);
                break;
        case Pnet:
                error = linprocfs_readdir_net(ap);
                break;
        case Psys:
                error = linprocfs_readdir_sys(ap);
                break;
        case Psyskernel:
                error = linprocfs_readdir_syskernel(ap);
                break;
        default:
                error = ENOTDIR;
                break;
        }
        vn_unlock(ap->a_vp);

        return (error);
}

static int
linprocfs_readdir_proc(struct vop_readdir_args *ap)
{
        struct pfsnode *pfs;
        int error, i, retval;
        struct proc *p;
        struct proc_target *pt;
        struct uio *uio = ap->a_uio;

        pfs = VTOPFS(ap->a_vp);
        p = PFIND(pfs->pfs_pid);
        if (p == NULL)
                return(0);
        if (!PRISON_CHECK(ap->a_cred, p->p_ucred))
                return(0);

        error = 0;
        i = uio->uio_offset;

        for (pt = &proc_targets[i];
             !error && uio->uio_resid > 0 && i < nproc_targets; pt++, i++) {
                if (pt->pt_valid && (*pt->pt_valid)(p) == 0)
                        continue;

                retval = vop_write_dirent(&error, uio,
                    PROCFS_FILENO(pfs->pfs_pid, pt->pt_pfstype), pt->pt_type,
                    pt->pt_namlen, pt->pt_name);
                if (retval)
                        break;
        }

        uio->uio_offset = i;

        return(error);
}

struct linprocfs_readdir_root_info {
        int error;
        int pcnt;
        int i;
        struct uio *uio;
        struct ucred *cred;
};

/*
 * Scan the root directory by scanning all process
 */
static int linprocfs_readdir_root_callback(struct proc *p, void *data);

static int
linprocfs_readdir_root(struct vop_readdir_args *ap)
{
        struct linprocfs_readdir_root_info info;
        struct uio *uio = ap->a_uio;
        int res = 0;

        info.error = 0;
        info.i = uio->uio_offset;
        info.pcnt = 0;
        info.uio = uio;
        info.cred = ap->a_cred;

        while (info.pcnt < 11) {
                res = linprocfs_readdir_root_callback(NULL, &info);
                if (res < 0)
                        break;
        }
        if (res >= 0)
                allproc_scan(linprocfs_readdir_root_callback, &info);

        uio->uio_offset = info.i;
        return(info.error);
}

static int
linprocfs_readdir_root_callback(struct proc *p, void *data)
{
        struct linprocfs_readdir_root_info *info = data;
        int retval;
        struct uio *uio = info->uio;
        ino_t d_ino;
        const char *d_name;
        char d_name_pid[20];
        size_t d_namlen;
        uint8_t d_type;

        switch (info->pcnt) {
        case 0:         /* `.' */
                d_ino = PROCFS_FILENO(0, Proot);
                d_name = ".";
                d_namlen = 1;
                d_type = DT_DIR;
                break;
        case 1:         /* `..' */
                d_ino = PROCFS_FILENO(0, Proot);
                d_name = "..";
                d_namlen = 2;
                d_type = DT_DIR;
                break;

        case 2:
                d_ino = PROCFS_FILENO(0, Proot);
                d_namlen = 4;
                d_name = "self";
                d_type = DT_LNK;
                break;

        case 3:
                d_ino = PROCFS_FILENO(0, Pmeminfo);
                d_namlen = 7;
                d_name = "meminfo";
                d_type = DT_REG;
                break;

        case 4:
                d_ino = PROCFS_FILENO(0, Pcpuinfo);
                d_namlen = 7;
                d_name = "cpuinfo";
                d_type = DT_REG;
                break;

        case 5:
                d_ino = PROCFS_FILENO(0, Pstat);
                d_namlen = 4;
                d_name = "stat";
                d_type = DT_REG;
                break;
                    
        case 6:
                d_ino = PROCFS_FILENO(0, Puptime);
                d_namlen = 6;
                d_name = "uptime";
                d_type = DT_REG;
                break;

        case 7:
                d_ino = PROCFS_FILENO(0, Pversion);
                d_namlen = 7;
                d_name = "version";
                d_type = DT_REG;
                break;

        case 8:
                d_ino = PROCFS_FILENO(0, Ploadavg);
                d_namlen = 7;
                d_name = "loadavg";
                d_type = DT_REG;
                break;
        case 9:
                d_ino = PROCFS_FILENO(0, Pnet);
                d_namlen = 3;
                d_name = "net";
                d_type = DT_DIR;
                break;
        case 10:
                d_ino = PROCFS_FILENO(0, Psys);
                d_namlen = 3;
                d_name = "sys";
                d_type = DT_DIR;
                break;
#if 0
        case 11:
                d_ino = PROCFS_FILENO(0, Pdevices);
                d_namlen = 7;
                d_name = "devices";
                d_type = DT_REG;
                break;          
#endif
        default:
                /*
                 * Ignore processes that aren't in our prison
                 */
                if (PRISON_CHECK(info->cred, p->p_ucred) == 0)
                        return(0);

                /*
                 * Ignore processes that we do not want to be visible.
                 */
                if (ps_showallprocs == 0 && 
                    info->cred->cr_uid != 0 &&
                    info->cred->cr_uid != p->p_ucred->cr_uid) {
                        return(0);
                }

                /*
                 * Skip processes we have already read (optimization)
                 */
                if (info->pcnt < info->i) {
                        ++info->pcnt;
                        return(0);
                }
                d_ino = PROCFS_FILENO(p->p_pid, Pproc);
                d_namlen = ksnprintf(d_name_pid, sizeof(d_name_pid),
                    "%ld", (long)p->p_pid);
                d_name = d_name_pid;
                d_type = DT_DIR;
                break;
        }

        /*
         * Skip processes we have already read
         */
        if (info->pcnt < info->i) {
                ++info->pcnt;
                return(0);
        }
        retval = vop_write_dirent(&info->error, info->uio, 
                                  d_ino, d_type, d_namlen, d_name);
        if (retval == 0) {
                ++info->pcnt;   /* iterate proc candidates scanned */
                ++info->i;      /* iterate entries written */
        }
        if (retval || info->error || uio->uio_resid <= 0)
                return(-1);
        return(0);
}

/*
 * Scan the root directory by scanning all process
 */
static int linprocfs_readdir_net_callback(struct proc *p, void *data);

static int
linprocfs_readdir_net(struct vop_readdir_args *ap)
{
        struct linprocfs_readdir_root_info info;
        struct uio *uio = ap->a_uio;
        int res;

        info.error = 0;
        info.i = uio->uio_offset;
        info.pcnt = 0;
        info.uio = uio;
        info.cred = ap->a_cred;

        while (info.pcnt < 3) {
                res = linprocfs_readdir_net_callback(NULL, &info);
                if (res < 0)
                        break;
        }

        uio->uio_offset = info.i;
        return(info.error);
}

static int
linprocfs_readdir_net_callback(struct proc *p, void *data)
{
        struct linprocfs_readdir_root_info *info = data;
        int retval;
        struct uio *uio = info->uio;
        ino_t d_ino;
        const char *d_name;
        size_t d_namlen;
        uint8_t d_type;

        switch (info->pcnt) {
        case 0:         /* `.' */
                d_ino = PROCFS_FILENO(0, Pnet);
                d_name = ".";
                d_namlen = 1;
                d_type = DT_DIR;
                break;
        case 1:         /* `..' */
                d_ino = PROCFS_FILENO(0, Proot);
                d_name = "..";
                d_namlen = 2;
                d_type = DT_DIR;
                break;

        case 2:
                d_ino = PROCFS_FILENO(0, Pnet);
                d_namlen = 3;
                d_name = "dev";
                d_type = DT_REG;
                break;
        default:
                d_ino = 0;
                d_namlen = 0;
                d_name = NULL;
                d_type = DT_REG;
                break;
        }

        /*
         * Skip processes we have already read
         */
        if (info->pcnt < info->i) {
                ++info->pcnt;
                return(0);
        }
        retval = vop_write_dirent(&info->error, info->uio, 
                                  d_ino, d_type, d_namlen, d_name);
        if (retval == 0) {
                ++info->pcnt;   /* iterate proc candidates scanned */
                ++info->i;      /* iterate entries written */
        }
        if (retval || info->error || uio->uio_resid <= 0)
                return(-1);
        return(0);
}







/*
 * Scan the root directory by scanning all process
 */
static int linprocfs_readdir_sys_callback(struct proc *p, void *data);

static int
linprocfs_readdir_sys(struct vop_readdir_args *ap)
{
        struct linprocfs_readdir_root_info info;
        struct uio *uio = ap->a_uio;
        int res;

        info.error = 0;
        info.i = uio->uio_offset;
        info.pcnt = 0;
        info.uio = uio;
        info.cred = ap->a_cred;

        while (info.pcnt < 3) {
                res = linprocfs_readdir_sys_callback(NULL, &info);
                if (res < 0)
                        break;
        }

        uio->uio_offset = info.i;
        return(info.error);
}

static int
linprocfs_readdir_sys_callback(struct proc *p, void *data)
{
        struct linprocfs_readdir_root_info *info = data;
        int retval;
        struct uio *uio = info->uio;
        ino_t d_ino;
        const char *d_name;
        size_t d_namlen;
        uint8_t d_type;

        switch (info->pcnt) {
        case 0:         /* `.' */
                d_ino = PROCFS_FILENO(0, Psys);
                d_name = ".";
                d_namlen = 1;
                d_type = DT_DIR;
                break;
        case 1:         /* `..' */
                d_ino = PROCFS_FILENO(0, Proot);
                d_name = "..";
                d_namlen = 2;
                d_type = DT_DIR;
                break;

        case 2:
                d_ino = PROCFS_FILENO(0, Psyskernel);
                d_namlen = 6;
                d_name = "kernel";
                d_type = DT_DIR;
                break;
        default:
                d_ino = 0;
                d_namlen = 0;
                d_name = NULL;
                d_type = DT_REG;
                break;
        }

        /*
         * Skip processes we have already read
         */
        if (info->pcnt < info->i) {
                ++info->pcnt;
                return(0);
        }
        retval = vop_write_dirent(&info->error, info->uio, 
                                  d_ino, d_type, d_namlen, d_name);
        if (retval == 0) {
                ++info->pcnt;   /* iterate proc candidates scanned */
                ++info->i;      /* iterate entries written */
        }
        if (retval || info->error || uio->uio_resid <= 0)
                return(-1);
        return(0);
}





/*
 * Scan the root directory by scanning all process
 */
static int linprocfs_readdir_syskernel_callback(struct proc *p, void *data);

static int
linprocfs_readdir_syskernel(struct vop_readdir_args *ap)
{
        struct linprocfs_readdir_root_info info;
        struct uio *uio = ap->a_uio;
        int res;

        info.error = 0;
        info.i = uio->uio_offset;
        info.pcnt = 0;
        info.uio = uio;
        info.cred = ap->a_cred;

        while (info.pcnt < 6) {
                res = linprocfs_readdir_syskernel_callback(NULL, &info);
                if (res < 0)
                        break;
        }

        uio->uio_offset = info.i;
        return(info.error);
}

static int
linprocfs_readdir_syskernel_callback(struct proc *p, void *data)
{
        struct linprocfs_readdir_root_info *info = data;
        int retval;
        struct uio *uio = info->uio;
        ino_t d_ino;
        const char *d_name;
        size_t d_namlen;
        uint8_t d_type;

        switch (info->pcnt) {
        case 0:         /* `.' */
                d_ino = PROCFS_FILENO(0, Psyskernel);
                d_name = ".";
                d_namlen = 1;
                d_type = DT_DIR;
                break;
        case 1:         /* `..' */
                d_ino = PROCFS_FILENO(0, Psys);
                d_name = "..";
                d_namlen = 2;
                d_type = DT_DIR;
                break;

        case 2:
                d_ino = PROCFS_FILENO(0, Posrelease);
                d_namlen = 9;
                d_name = "osrelease";
                d_type = DT_REG;
                break;

        case 3:
                d_ino = PROCFS_FILENO(0, Postype);
                d_namlen = 4;
                d_name = "ostype";
                d_type = DT_REG;
                break;

        case 4:
                d_ino = PROCFS_FILENO(0, Pversion);
                d_namlen = 7;
                d_name = "version";
                d_type = DT_REG;
                break;

        case 5:
                d_ino = PROCFS_FILENO(0, Ppidmax);
                d_namlen = 7;
                d_name = "pid_max";
                d_type = DT_REG;
                break;
        default:
                d_ino = 0;
                d_namlen = 0;
                d_name = NULL;
                d_type = DT_REG;
                break;
        }

        /*
         * Skip processes we have already read
         */
        if (info->pcnt < info->i) {
                ++info->pcnt;
                return(0);
        }
        retval = vop_write_dirent(&info->error, info->uio, 
                                  d_ino, d_type, d_namlen, d_name);
        if (retval == 0) {
                ++info->pcnt;   /* iterate proc candidates scanned */
                ++info->i;      /* iterate entries written */
        }
        if (retval || info->error || uio->uio_resid <= 0)
                return(-1);
        return(0);
}

/*
 * readlink reads the link of `self' or `exe'
 */
static int
linprocfs_readlink(struct vop_readlink_args *ap)
{
        char buf[16];           /* should be enough */
        struct proc *procp;
        struct vnode *vp = ap->a_vp;
        struct nchandle *nchp;
        struct pfsnode *pfs = VTOPFS(vp);
        char *fullpath, *freepath;
        int error, len;

        switch (pfs->pfs_type) {
        case Pself:
                if (pfs->pfs_fileno != PROCFS_FILENO(0, Pself))
                        return (EINVAL);

                len = ksnprintf(buf, sizeof(buf), "%ld", (long)curproc->p_pid);

                return (uiomove(buf, len, ap->a_uio));
        /*
         * There _should_ be no way for an entire process to disappear
         * from under us...
         */
        case Pexe:
                procp = PFIND(pfs->pfs_pid);
                if (procp == NULL || procp->p_ucred == NULL) {
                        kprintf("linprocfs_readlink: pid %d disappeared\n",
                            pfs->pfs_pid);
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                }
                error = cache_fullpath(procp, &procp->p_textnch, &fullpath, &freepath);
                if (error != 0)
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                error = uiomove(fullpath, strlen(fullpath), ap->a_uio);
                kfree(freepath, M_TEMP);
                return (error);
        case Pcwd:
                procp = PFIND(pfs->pfs_pid);
                if (procp == NULL || procp->p_ucred == NULL) {
                        kprintf("linprocfs_readlink: pid %d disappeared\n",
                            pfs->pfs_pid);
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                }
                error = cache_fullpath(procp, &procp->p_fd->fd_ncdir, &fullpath, &freepath);
                if (error != 0)
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                error = uiomove(fullpath, strlen(fullpath), ap->a_uio);
                kfree(freepath, M_TEMP);
                return (error);
        case Pprocroot:
                procp = PFIND(pfs->pfs_pid);
                if (procp == NULL || procp->p_ucred == NULL) {
                        kprintf("linprocfs_readlink: pid %d disappeared\n",
                            pfs->pfs_pid);
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                }
                nchp = jailed(procp->p_ucred) ? &procp->p_fd->fd_njdir : &procp->p_fd->fd_nrdir;
                error = cache_fullpath(procp, nchp, &fullpath, &freepath);
                if (error != 0)
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                error = uiomove(fullpath, strlen(fullpath), ap->a_uio);
                kfree(freepath, M_TEMP);
                return (error);
        case Pfd:
                procp = PFIND(pfs->pfs_pid);
                if (procp == NULL || procp->p_ucred == NULL) {
                        kprintf("linprocfs_readlink: pid %d disappeared\n",
                            pfs->pfs_pid);
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                }
                if (procp == curproc) {
                        return (uiomove("/dev/fd", sizeof("/dev/fd") - 1,
                            ap->a_uio));
                } else {
                        return (uiomove("unknown", sizeof("unknown") - 1,
                            ap->a_uio));
                }
                /* notreached */
                break;
        default:
                return (EINVAL);
        }
}

/*
 * convert decimal ascii to pid_t
 */
static pid_t
atopid(const char *b, u_int len)
{
        pid_t p = 0;

        while (len--) {
                char c = *b++;
                if (c < '0' || c > '9')
                        return (NO_PID);
                p = 10 * p + (c - '0');
                if (p > PID_MAX)
                        return (NO_PID);
        }

        return (p);
}