Linux /proc filesystem.

Submitted by:	pb

7 files changed, 1843 insertions, 2 deletions

diff --git a/sys/miscfs/linprocfs/linprocfs.h b/sys/miscfs/linprocfs/linprocfs.h
new file mode 100644
index 000000000000..e7f70bcaf349
--- /dev/null
+++ b/sys/miscfs/linprocfs/linprocfs.h
@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 1993 Jan-Simon Pendry
+ * Copyright (c) 1993
+ *	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.h	8.9 (Berkeley) 5/14/95
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * The different types of node in a procfs filesystem
+ */
+typedef enum {
+	Proot,		/* the filesystem root */
+	Pself,		/* symbolic link for curproc */
+	Pproc,		/* a process-specific sub-directory */
+	Pexe,		/* the executable file */
+	Pmem,		/* the process's memory image */
+	Pmeminfo,
+	Pcpuinfo
+} pfstype;
+
+/*
+ * control data for the proc file system.
+ */
+struct pfsnode {
+	struct pfsnode	*pfs_next;	/* next on list */
+	struct vnode	*pfs_vnode;	/* vnode associated with this pfsnode */
+	pfstype		pfs_type;	/* type of procfs node */
+	pid_t		pfs_pid;	/* associated process */
+	u_short		pfs_mode;	/* mode bits for stat() */
+	u_long		pfs_flags;	/* open flags */
+	u_long		pfs_fileno;	/* unique file id */
+	pid_t		pfs_lockowner;	/* pfs lock owner */
+};
+
+#define PROCFS_NAMELEN 	8	/* max length of a filename component */
+
+/*
+ * Kernel stuff follows
+ */
+#ifdef _KERNEL
+#define CNEQ(cnp, s, len) \
+	 ((cnp)->cn_namelen == (len) && \
+	  (bcmp((s), (cnp)->cn_nameptr, (len)) == 0))
+
+#define KMEM_GROUP 2
+
+#define PROCFS_FILENO(pid, type) \
+	(((type) < Pproc) ? \
+			((type) + 2) : \
+			((((pid)+1) << 4) + ((int) (type))))
+
+/*
+ * Convert between pfsnode vnode
+ */
+#define VTOPFS(vp)	((struct pfsnode *)(vp)->v_data)
+#define PFSTOV(pfs)	((pfs)->pfs_vnode)
+
+typedef struct vfs_namemap vfs_namemap_t;
+struct vfs_namemap {
+	const char *nm_name;
+	int nm_val;
+};
+
+int vfs_getuserstr __P((struct uio *, char *, int *));
+vfs_namemap_t *vfs_findname __P((vfs_namemap_t *, char *, int));
+
+/* <machine/reg.h> */
+struct reg;
+struct fpreg;
+struct dbreg;
+
+#define PFIND(pid) ((pid) ? pfind(pid) : &proc0)
+
+void linprocfs_exit __P((struct proc *));
+int linprocfs_freevp __P((struct vnode *));
+int linprocfs_allocvp __P((struct mount *, struct vnode **, long, pfstype));
+struct vnode *linprocfs_findtextvp __P((struct proc *));
+int linprocfs_sstep __P((struct proc *));
+void linprocfs_fix_sstep __P((struct proc *));
+#if 0
+int linprocfs_read_regs __P((struct proc *, struct reg *));
+int linprocfs_write_regs __P((struct proc *, struct reg *));
+int linprocfs_read_fpregs __P((struct proc *, struct fpreg *));
+int linprocfs_write_fpregs __P((struct proc *, struct fpreg *));
+int linprocfs_read_dbregs __P((struct proc *, struct dbreg *));
+int linprocfs_write_dbregs __P((struct proc *, struct dbreg *));
+#endif
+int linprocfs_domeminfo __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
+int linprocfs_docpuinfo __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
+
+/* functions to check whether or not files should be displayed */
+int linprocfs_validfile __P((struct proc *));
+
+#define PROCFS_LOCKED	0x01
+#define PROCFS_WANT	0x02
+
+extern vop_t **linprocfs_vnodeop_p;
+
+int	linprocfs_root __P((struct mount *, struct vnode **));
+int	linprocfs_rw __P((struct vop_read_args *));
+#endif /* _KERNEL */
diff --git a/sys/miscfs/linprocfs/linprocfs_misc.c b/sys/miscfs/linprocfs/linprocfs_misc.c
new file mode 100644
index 000000000000..0302e8eee9b0
--- /dev/null
+++ b/sys/miscfs/linprocfs/linprocfs_misc.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 1993 Jan-Simon Pendry
+ * Copyright (c) 1993
+ *	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_status.c	8.4 (Berkeley) 6/15/94
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/proc.h>
+#include <sys/jail.h>
+#include <sys/vnode.h>
+#include <sys/tty.h>
+#include <sys/resourcevar.h>
+#include <miscfs/linprocfs/linprocfs.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_param.h>
+#include <sys/exec.h>
+
+#include <machine/md_var.h>
+#include <machine/cputypes.h>
+
+struct proc;
+
+int
+linprocfs_domeminfo(curp, p, pfs, uio)
+	struct proc *curp;
+	struct proc *p;
+	struct pfsnode *pfs;
+	struct uio *uio;
+{
+	char *ps;
+	int xlen;
+	int error;
+	char psbuf[512];		/* XXX - conservative */
+	unsigned long memtotal, memfree, memshared;
+	unsigned long buffers, cached, swaptotal, swapfree;
+
+	if (uio->uio_rw != UIO_READ)
+		return (EOPNOTSUPP);
+
+	memtotal = 32768; memfree = 32768;
+	buffers = 16384; cached = 8192;
+	swaptotal = 32768; swapfree = 16384;
+	memshared = 0;
+
+	ps = psbuf;
+	ps += sprintf(ps,
+		"        total:    used:    free:  shared: buffers:  cached:\n"
+		"Mem:  %ld %ld %ld %ld %ld %ld\nSwap: %ld %ld %ld\n"
+		"MemTotal: %9ld kB\n"
+		"MemFree:  %9ld kB\n"
+		"MemShared:%9ld kB\n"
+		"Buffers:  %9ld kB\n"
+		"Cached:   %9ld kB\n"
+		"SwapTotal:%9ld kB\n"
+		"SwapFree: %9ld kB\n",
+		memtotal*1024, (memtotal-memfree)*1024, memfree*1024,
+		memshared*1024, buffers*1024, cached*1024,
+		swaptotal*1024, (swaptotal-swapfree)*1024, swapfree*1024,
+		memtotal, memfree, memshared, buffers, cached,
+		swaptotal, swapfree);
+
+	xlen = ps - psbuf;
+	xlen -= uio->uio_offset;
+	ps = psbuf + uio->uio_offset;
+	xlen = imin(xlen, uio->uio_resid);
+	if (xlen <= 0)
+		error = 0;
+	else
+		error = uiomove(ps, xlen, uio);
+	return (error);
+}
+
+int
+linprocfs_docpuinfo(curp, p, pfs, uio)
+	struct proc *curp;
+	struct proc *p;
+	struct pfsnode *pfs;
+	struct uio *uio;
+{
+	char *ps;
+	int xlen;
+	int error;
+	char psbuf[512];		/* XXX - conservative */
+	char *class;
+#if 0
+	extern char *cpu_model;		/* Yuck */
+#endif
+
+	if (uio->uio_rw != UIO_READ)
+		return (EOPNOTSUPP);
+
+	switch (cpu_class) {
+	case CPUCLASS_286:
+		class = "286";
+		break;
+	case CPUCLASS_386:
+		class = "386";
+		break;
+	case CPUCLASS_486:
+		class = "486";
+		break;
+	case CPUCLASS_586:
+		class = "586";
+		break;
+	case CPUCLASS_686:
+		class = "686";
+		break;
+	default:
+		class = "unknown";
+		break;
+	}
+
+	ps = psbuf;
+	ps += sprintf(ps,
+			"processor       : %d\n"
+			"cpu             : %.3s\n"
+			"model           : %.20s\n"
+			"vendor_id       : %.20s\n"
+			"stepping        : %d\n",
+			0, class, "unknown", cpu_vendor, cpu_id);
+
+	xlen = ps - psbuf;
+	xlen -= uio->uio_offset;
+	ps = psbuf + uio->uio_offset;
+	xlen = imin(xlen, uio->uio_resid);
+	if (xlen <= 0)
+		error = 0;
+	else
+		error = uiomove(ps, xlen, uio);
+	return (error);
+}
diff --git a/sys/miscfs/linprocfs/linprocfs_subr.c b/sys/miscfs/linprocfs/linprocfs_subr.c
new file mode 100644
index 000000000000..7944eebd57a4
--- /dev/null
+++ b/sys/miscfs/linprocfs/linprocfs_subr.c
@@ -0,0 +1,353 @@
+/*
+ * Copyright (c) 1993 Jan-Simon Pendry
+ * Copyright (c) 1993
+ *	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_subr.c	8.6 (Berkeley) 5/14/95
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+#include <miscfs/linprocfs/linprocfs.h>
+
+static struct pfsnode *pfshead;
+static int pfsvplock;
+
+extern int procfs_domem __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
+
+/*
+ * allocate a pfsnode/vnode pair.  the vnode is
+ * referenced, but not locked.
+ *
+ * the pid, pfs_type, and mount point uniquely
+ * identify a pfsnode.  the mount point is needed
+ * because someone might mount this filesystem
+ * twice.
+ *
+ * all pfsnodes are maintained on a singly-linked
+ * list.  new nodes are only allocated when they cannot
+ * be found on this list.  entries on the list are
+ * removed when the vfs reclaim entry is called.
+ *
+ * a single lock is kept for the entire list.  this is
+ * needed because the getnewvnode() function can block
+ * waiting for a vnode to become free, in which case there
+ * may be more than one process trying to get the same
+ * vnode.  this lock is only taken if we are going to
+ * call getnewvnode, since the kernel itself is single-threaded.
+ *
+ * if an entry is found on the list, then call vget() to
+ * take a reference.  this is done because there may be
+ * zero references to it and so it needs to removed from
+ * the vnode free list.
+ */
+int
+linprocfs_allocvp(mp, vpp, pid, pfs_type)
+	struct mount *mp;
+	struct vnode **vpp;
+	long pid;
+	pfstype pfs_type;
+{
+	struct proc *p = curproc;	/* XXX */
+	struct pfsnode *pfs;
+	struct vnode *vp;
+	struct pfsnode **pp;
+	int error;
+
+loop:
+	for (pfs = pfshead; pfs != 0; pfs = pfs->pfs_next) {
+		vp = PFSTOV(pfs);
+		if (pfs->pfs_pid == pid &&
+		    pfs->pfs_type == pfs_type &&
+		    vp->v_mount == mp) {
+			if (vget(vp, 0, p))
+				goto loop;
+			*vpp = vp;
+			return (0);
+		}
+	}
+
+	/*
+	 * otherwise lock the vp list while we call getnewvnode
+	 * since that can block.
+	 */
+	if (pfsvplock & PROCFS_LOCKED) {
+		pfsvplock |= PROCFS_WANT;
+		(void) tsleep((caddr_t) &pfsvplock, PINOD, "pfsavp", 0);
+		goto loop;
+	}
+	pfsvplock |= PROCFS_LOCKED;
+
+	/*
+	 * Do the MALLOC before the getnewvnode since doing so afterward
+	 * might cause a bogus v_data pointer to get dereferenced
+	 * elsewhere if MALLOC should block.
+	 */
+	MALLOC(pfs, struct pfsnode *, sizeof(struct pfsnode), M_TEMP, M_WAITOK);
+
+	if ((error = getnewvnode(VT_PROCFS, mp, linprocfs_vnodeop_p, vpp)) != 0) {
+		FREE(pfs, M_TEMP);
+		goto out;
+	}
+	vp = *vpp;
+
+	vp->v_data = pfs;
+
+	pfs->pfs_next = 0;
+	pfs->pfs_pid = (pid_t) pid;
+	pfs->pfs_type = pfs_type;
+	pfs->pfs_vnode = vp;
+	pfs->pfs_flags = 0;
+	pfs->pfs_lockowner = 0;
+	pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type);
+
+	switch (pfs_type) {
+	case Proot:	/* /proc = dr-xr-xr-x */
+		pfs->pfs_mode = (VREAD|VEXEC) |
+				(VREAD|VEXEC) >> 3 |
+				(VREAD|VEXEC) >> 6;
+		vp->v_type = VDIR;
+		vp->v_flag = VROOT;
+		break;
+
+	case Pself:	/* /proc/self = lr--r--r-- */
+		pfs->pfs_mode = (VREAD) |
+				(VREAD >> 3) |
+				(VREAD >> 6);
+		vp->v_type = VLNK;
+		break;
+
+	case Pproc:
+		pfs->pfs_mode = (VREAD|VEXEC) |
+				(VREAD|VEXEC) >> 3 |
+				(VREAD|VEXEC) >> 6;
+		vp->v_type = VDIR;
+		break;
+
+	case Pexe:
+	case Pmem:
+		pfs->pfs_mode = (VREAD|VWRITE) |
+				(VREAD) >> 3;;
+		vp->v_type = VREG;
+		break;
+
+	case Pmeminfo:
+	case Pcpuinfo:
+		pfs->pfs_mode = (VREAD) |
+				(VREAD >> 3) |
+				(VREAD >> 6);
+		vp->v_type = VREG;
+		break;
+
+	default:
+		panic("linprocfs_allocvp");
+	}
+
+	/* add to procfs vnode list */
+	for (pp = &pfshead; *pp; pp = &(*pp)->pfs_next)
+		continue;
+	*pp = pfs;
+
+out:
+	pfsvplock &= ~PROCFS_LOCKED;
+
+	if (pfsvplock & PROCFS_WANT) {
+		pfsvplock &= ~PROCFS_WANT;
+		wakeup((caddr_t) &pfsvplock);
+	}
+
+	return (error);
+}
+
+int
+linprocfs_freevp(vp)
+	struct vnode *vp;
+{
+	struct pfsnode **pfspp;
+	struct pfsnode *pfs = VTOPFS(vp);
+
+	for (pfspp = &pfshead; *pfspp != 0; pfspp = &(*pfspp)->pfs_next) {
+		if (*pfspp == pfs) {
+			*pfspp = pfs->pfs_next;
+			break;
+		}
+	}
+
+	FREE(vp->v_data, M_TEMP);
+	vp->v_data = 0;
+	return (0);
+}
+
+int
+linprocfs_rw(ap)
+	struct vop_read_args *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	struct uio *uio = ap->a_uio;
+	struct proc *curp = uio->uio_procp;
+	struct pfsnode *pfs = VTOPFS(vp);
+	struct proc *p;
+	int rtval;
+
+	p = PFIND(pfs->pfs_pid);
+	if (p == 0)
+		return (EINVAL);
+	if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE)
+		return (EACCES);
+
+	while (pfs->pfs_lockowner) {
+		tsleep(&pfs->pfs_lockowner, PRIBIO, "pfslck", 0);
+	}
+	pfs->pfs_lockowner = curproc->p_pid;
+
+	switch (pfs->pfs_type) {
+	case Pmem:
+		rtval = procfs_domem(curp, p, pfs, uio);
+		break;
+	case Pmeminfo:
+		rtval = linprocfs_domeminfo(curp, p, pfs, uio);
+		break;
+	case Pcpuinfo:
+		rtval = linprocfs_docpuinfo(curp, p, pfs, uio);
+		break;
+	default:
+		rtval = EOPNOTSUPP;
+		break;
+	}
+	pfs->pfs_lockowner = 0;
+	wakeup(&pfs->pfs_lockowner);
+	return rtval;
+}
+
+#if 0
+/*
+ * Get a string from userland into (buf).  Strip a trailing
+ * nl character (to allow easy access from the shell).
+ * The buffer should be *buflenp + 1 chars long.  vfs_getuserstr
+ * will automatically add a nul char at the end.
+ *
+ * Returns 0 on success or the following errors
+ *
+ * EINVAL:    file offset is non-zero.
+ * EMSGSIZE:  message is longer than kernel buffer
+ * EFAULT:    user i/o buffer is not addressable
+ */
+int
+vfs_getuserstr(uio, buf, buflenp)
+	struct uio *uio;
+	char *buf;
+	int *buflenp;
+{
+	int xlen;
+	int error;
+
+	if (uio->uio_offset != 0)
+		return (EINVAL);
+
+	xlen = *buflenp;
+
+	/* must be able to read the whole string in one go */
+	if (xlen < uio->uio_resid)
+		return (EMSGSIZE);
+	xlen = uio->uio_resid;
+
+	if ((error = uiomove(buf, xlen, uio)) != 0)
+		return (error);
+
+	/* allow multiple writes without seeks */
+	uio->uio_offset = 0;
+
+	/* cleanup string and remove trailing newline */
+	buf[xlen] = '\0';
+	xlen = strlen(buf);
+	if (xlen > 0 && buf[xlen-1] == '\n')
+		buf[--xlen] = '\0';
+	*buflenp = xlen;
+
+	return (0);
+}
+
+vfs_namemap_t *
+vfs_findname(nm, buf, buflen)
+	vfs_namemap_t *nm;
+	char *buf;
+	int buflen;
+{
+
+	for (; nm->nm_name; nm++)
+		if (bcmp(buf, nm->nm_name, buflen+1) == 0)
+			return (nm);
+
+	return (0);
+}
+#endif
+
+void
+linprocfs_exit(struct proc *p)
+{
+	struct pfsnode *pfs;
+	pid_t pid = p->p_pid;
+
+	/*
+	 * The reason for this loop is not obvious -- basicly,
+	 * linprocfs_freevp(), which is called via vgone() (eventually),
+	 * removes the specified procfs node from the pfshead list.
+	 * It does this by *pfsp = pfs->pfs_next, meaning that it
+	 * overwrites the node.  So when we do pfs = pfs->next, we
+	 * end up skipping the node that replaces the one that was
+	 * vgone'd.  Since it may have been the last one on the list,
+	 * it may also have been set to null -- but *our* pfs pointer,
+	 * here, doesn't see this.  So the loop starts from the beginning
+	 * again.
+	 *
+	 * This is not a for() loop because the final event
+	 * would be "pfs = pfs->pfs_next"; in the case where
+	 * pfs is set to pfshead again, that would mean that
+	 * pfshead is skipped over.
+	 *
+	 */
+	pfs = pfshead;
+	while (pfs) {
+		if (pfs->pfs_pid == pid) {
+			vgone(PFSTOV(pfs));
+			pfs = pfshead;
+		} else
+			pfs = pfs->pfs_next;
+	}
+}
diff --git a/sys/miscfs/linprocfs/linprocfs_vfsops.c b/sys/miscfs/linprocfs/linprocfs_vfsops.c
new file mode 100644
index 000000000000..1132194f468c
--- /dev/null
+++ b/sys/miscfs/linprocfs/linprocfs_vfsops.c
@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 1993 Jan-Simon Pendry
+ * Copyright (c) 1993
+ *	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_vfsops.c	8.7 (Berkeley) 5/10/95
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * procfs VFS interface
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+#include <sys/syslog.h>
+#include <sys/mount.h>
+#include <sys/vnode.h>
+#include <miscfs/linprocfs/linprocfs.h>
+
+static int	linprocfs_mount __P((struct mount *mp, char *path, caddr_t data,
+				  struct nameidata *ndp, struct proc *p));
+static int	linprocfs_statfs __P((struct mount *mp, struct statfs *sbp,
+				   struct proc *p));
+static int	linprocfs_unmount __P((struct mount *mp, int mntflags,
+				    struct proc *p));
+
+/*
+ * VFS Operations.
+ *
+ * mount system call
+ */
+/* ARGSUSED */
+static int
+linprocfs_mount(mp, path, data, ndp, p)
+	struct mount *mp;
+	char *path;
+	caddr_t data;
+	struct nameidata *ndp;
+	struct proc *p;
+{
+	size_t size;
+	int error;
+
+	if (mp->mnt_flag & MNT_UPDATE)
+		return (EOPNOTSUPP);
+
+	if (mp->mnt_vfc->vfc_refcount == 1 && (error = at_exit(linprocfs_exit))) {
+		printf("linprocfs:  cannot register linprocfs_exit with at_exit\n");
+		return(error);
+	}
+
+	mp->mnt_flag |= MNT_LOCAL;
+	mp->mnt_data = 0;
+	vfs_getnewfsid(mp);
+
+	(void) copyinstr(path, (caddr_t)mp->mnt_stat.f_mntonname, MNAMELEN, &size);
+	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
+
+	size = sizeof("linprocfs") - 1;
+	bcopy("linprocfs", mp->mnt_stat.f_mntfromname, size);
+	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
+	(void)linprocfs_statfs(mp, &mp->mnt_stat, p);
+
+	return (0);
+}
+
+/*
+ * unmount system call
+ */
+static int
+linprocfs_unmount(mp, mntflags, p)
+	struct mount *mp;
+	int mntflags;
+	struct proc *p;
+{
+	int error;
+	int flags = 0;
+
+	if (mntflags & MNT_FORCE)
+		flags |= FORCECLOSE;
+
+	error = vflush(mp, 0, flags);
+	if (error)
+		return (error);
+
+	if (mp->mnt_vfc->vfc_refcount == 1)
+		rm_at_exit(linprocfs_exit);
+
+	return (0);
+}
+
+int
+linprocfs_root(mp, vpp)
+	struct mount *mp;
+	struct vnode **vpp;
+{
+
+	return (linprocfs_allocvp(mp, vpp, 0, Proot));
+}
+
+/*
+ * Get file system statistics.
+ */
+static int
+linprocfs_statfs(mp, sbp, p)
+	struct mount *mp;
+	struct statfs *sbp;
+	struct proc *p;
+{
+	sbp->f_bsize = PAGE_SIZE;
+	sbp->f_iosize = PAGE_SIZE;
+	sbp->f_blocks = 1;	/* avoid divide by zero in some df's */
+	sbp->f_bfree = 0;
+	sbp->f_bavail = 0;
+	sbp->f_files = maxproc;			/* approx */
+	sbp->f_ffree = maxproc - nprocs;	/* approx */
+
+	if (sbp != &mp->mnt_stat) {
+		sbp->f_type = mp->mnt_vfc->vfc_typenum;
+		bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
+		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
+		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
+	}
+
+	return (0);
+}
+
+static struct vfsops linprocfs_vfsops = {
+	linprocfs_mount,
+	vfs_stdstart,
+	linprocfs_unmount,
+	linprocfs_root,
+	vfs_stdquotactl,
+	linprocfs_statfs,
+	vfs_stdsync,
+	vfs_stdvget,
+	vfs_stdfhtovp,
+	vfs_stdcheckexp,
+	vfs_stdvptofh,
+	vfs_stdinit,
+};
+
+VFS_SET(linprocfs_vfsops, linprocfs, VFCF_SYNTHETIC);
diff --git a/sys/miscfs/linprocfs/linprocfs_vnops.c b/sys/miscfs/linprocfs/linprocfs_vnops.c
new file mode 100644
index 000000000000..5e9e98a03fb5
--- /dev/null
+++ b/sys/miscfs/linprocfs/linprocfs_vnops.c
@@ -0,0 +1,994 @@
+/*
+ * 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
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * 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/signalvar.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/namei.h>
+#include <sys/dirent.h>
+#include <machine/reg.h>
+#include <vm/vm_zone.h>
+#include <miscfs/linprocfs/linprocfs.h>
+#include <sys/pioctl.h>
+
+extern struct vnode *procfs_findtextvp __P((struct proc *));
+extern int	procfs_kmemaccess __P((struct proc *));
+
+static int	linprocfs_access __P((struct vop_access_args *));
+static int	linprocfs_badop __P((void));
+static int	linprocfs_bmap __P((struct vop_bmap_args *));
+static int	linprocfs_close __P((struct vop_close_args *));
+static int	linprocfs_getattr __P((struct vop_getattr_args *));
+static int	linprocfs_inactive __P((struct vop_inactive_args *));
+static int	linprocfs_ioctl __P((struct vop_ioctl_args *));
+static int	linprocfs_lookup __P((struct vop_lookup_args *));
+static int	linprocfs_open __P((struct vop_open_args *));
+static int	linprocfs_print __P((struct vop_print_args *));
+static int	linprocfs_readdir __P((struct vop_readdir_args *));
+static int	linprocfs_readlink __P((struct vop_readlink_args *));
+static int	linprocfs_reclaim __P((struct vop_reclaim_args *));
+static int	linprocfs_setattr __P((struct vop_setattr_args *));
+
+/*
+ * 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) __P((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("exe"),	Pexe,		linprocfs_validfile },
+	{ DT_REG, N("mem"),	Pmem,		NULL },
+#undef N
+};
+static const int nproc_targets = sizeof(proc_targets) / sizeof(proc_targets[0]);
+
+static pid_t atopid __P((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(ap)
+	struct vop_open_args /* {
+		struct vnode *a_vp;
+		int  a_mode;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *ap;
+{
+	struct pfsnode *pfs = VTOPFS(ap->a_vp);
+	struct proc *p1, *p2;
+
+	p2 = PFIND(pfs->pfs_pid);
+	if (p2 == NULL)
+		return (ENOENT);
+	if (pfs->pfs_pid && !PRISON_CHECK(ap->a_p, p2))
+		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);
+
+		p1 = ap->a_p;
+		if (p_trespass(p1, p2) &&
+		    !procfs_kmemaccess(p1))
+			return (EPERM);
+
+		if (ap->a_mode & FWRITE)
+			pfs->pfs_flags = ap->a_mode & (FWRITE|O_EXCL);
+
+		return (0);
+
+	default:
+		break;
+	}
+
+	return (0);
+}
+
+/*
+ * 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(ap)
+	struct vop_close_args /* {
+		struct vnode *a_vp;
+		int  a_fflag;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *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);
+		/*
+		 * This rather complicated-looking code is trying to
+		 * determine if this was the last close on this particular
+		 * vnode.  While one would expect v_usecount to be 1 at
+		 * that point, it seems that (according to John Dyson)
+		 * the VM system will bump up the usecount.  So:  if the
+		 * usecount is 2, and VOBJBUF is set, then this is really
+		 * the last close.  Otherwise, if the usecount is < 2
+		 * then it is definitely the last close.
+		 * 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_usecount < 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 (0);
+}
+
+/*
+ * do an ioctl operation on a pfsnode (vp).
+ * (vp) is not locked on entry or exit.
+ */
+static int
+linprocfs_ioctl(ap)
+	struct vop_ioctl_args *ap;
+{
+	struct pfsnode *pfs = VTOPFS(ap->a_vp);
+	struct proc *procp, *p;
+	int error;
+	int signo;
+	struct procfs_status *psp;
+	unsigned char flags;
+
+	p = ap->a_p;
+	procp = pfind(pfs->pfs_pid);
+	if (procp == NULL) {
+		return ENOTTY;
+	}
+
+	if (p_trespass(p, procp))
+		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 = suser(p)))
+	    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, PWAIT | 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;
+	    psignal(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(ap)
+	struct vop_bmap_args /* {
+		struct vnode *a_vp;
+		daddr_t  a_bn;
+		struct vnode **a_vpp;
+		daddr_t *a_bnp;
+		int *a_runp;
+	} */ *ap;
+{
+
+	if (ap->a_vpp != NULL)
+		*ap->a_vpp = ap->a_vp;
+	if (ap->a_bnp != NULL)
+		*ap->a_bnp = ap->a_bn;
+	if (ap->a_runp != NULL)
+		*ap->a_runp = 0;
+	return (0);
+}
+
+/*
+ * linprocfs_inactive is called when the pfsnode
+ * is vrele'd and the reference count goes
+ * to zero.  (vp) will be on the vnode free
+ * list, so to get it back vget() must be
+ * used.
+ *
+ * (vp) is locked on entry, but must be unlocked on exit.
+ */
+static int
+linprocfs_inactive(ap)
+	struct vop_inactive_args /* {
+		struct vnode *a_vp;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+
+	VOP_UNLOCK(vp, 0, ap->a_p);
+
+	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(ap)
+	struct vop_reclaim_args /* {
+		struct vnode *a_vp;
+	} */ *ap;
+{
+
+	return (linprocfs_freevp(ap->a_vp));
+}
+
+/*
+ * _print is used for debugging.
+ * just print a readable description
+ * of (vp).
+ */
+static int
+linprocfs_print(ap)
+	struct vop_print_args /* {
+		struct vnode *a_vp;
+	} */ *ap;
+{
+	struct pfsnode *pfs = VTOPFS(ap->a_vp);
+
+	printf("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()
+{
+
+	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(ap)
+	struct vop_getattr_args /* {
+		struct vnode *a_vp;
+		struct vattr *a_vap;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *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_cred == NULL ||
+		    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;
+
+	/*
+	 * If the process has exercised some setuid or setgid
+	 * privilege, then rip away read/write permission so
+	 * that only root can gain access.
+	 */
+	switch (pfs->pfs_type) {
+	case Pmem:
+		/* Retain group kmem readablity. */
+		if (procp->p_flag & P_SUGID)
+			vap->va_mode &= ~(VREAD|VWRITE);
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * 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:
+		/*
+		 * 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 =
+		    snprintf(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:
+		error = EOPNOTSUPP;
+		break;
+
+	case Pmeminfo:
+	case Pcpuinfo:
+		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;
+		vap->va_gid = KMEM_GROUP;
+		break;
+
+	default:
+		panic("linprocfs_getattr");
+	}
+
+	return (error);
+}
+
+static int
+linprocfs_setattr(ap)
+	struct vop_setattr_args /* {
+		struct vnode *a_vp;
+		struct vattr *a_vap;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *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(ap)
+	struct vop_access_args /* {
+		struct vnode *a_vp;
+		int a_mode;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *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, ap->a_cred, ap->a_p);
+	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.
+ *
+ * unless you want to get a migraine, just make sure your
+ * filesystem doesn't do any locking of its own.  otherwise
+ * read and inwardly digest ufs_lookup().
+ */
+static int
+linprocfs_lookup(ap)
+	struct vop_lookup_args /* {
+		struct vnode * a_dvp;
+		struct vnode ** a_vpp;
+		struct componentname * a_cnp;
+	} */ *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 *curp = cnp->cn_proc;
+	struct proc_target *pt;
+	struct vnode *fvp;
+	pid_t pid;
+	struct pfsnode *pfs;
+	struct proc *p;
+	int i;
+
+	*vpp = NULL;
+
+	if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
+		return (EROFS);
+
+	if (cnp->cn_namelen == 1 && *pname == '.') {
+		*vpp = dvp;
+		VREF(dvp);
+		/* vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, curp); */
+		return (0);
+	}
+
+	pfs = VTOPFS(dvp);
+	switch (pfs->pfs_type) {
+	case Proot:
+		if (cnp->cn_flags & ISDOTDOT)
+			return (EIO);
+
+		if (CNEQ(cnp, "self", 4))
+			return (linprocfs_allocvp(dvp->v_mount, vpp, 0, Pself));
+		if (CNEQ(cnp, "meminfo", 7))
+			return (linprocfs_allocvp(dvp->v_mount, vpp, 0, Pmeminfo));
+		if (CNEQ(cnp, "cpuinfo", 7))
+			return (linprocfs_allocvp(dvp->v_mount, vpp, 0, Pcpuinfo));
+
+		pid = atopid(pname, cnp->cn_namelen);
+		if (pid == NO_PID)
+			break;
+
+		p = PFIND(pid);
+		if (p == 0)
+			break;
+
+		return (linprocfs_allocvp(dvp->v_mount, vpp, pid, Pproc));
+
+	case Pproc:
+		if (cnp->cn_flags & ISDOTDOT)
+			return (linprocfs_root(dvp->v_mount, vpp));
+
+		p = PFIND(pfs->pfs_pid);
+		if (p == 0)
+			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:
+		if (pt->pt_pfstype == Pexe) {
+			fvp = procfs_findtextvp(p);
+			/* We already checked that it exists. */
+			VREF(fvp);
+			vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY, curp);
+			*vpp = fvp;
+			return (0);
+		}
+
+		return (linprocfs_allocvp(dvp->v_mount, vpp, pfs->pfs_pid,
+		    pt->pt_pfstype));
+
+	default:
+		return (ENOTDIR);
+	}
+
+	return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS);
+}
+
+/*
+ * Does this process have a text file?
+ */
+int
+linprocfs_validfile(p)
+	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.
+ */
+static int
+linprocfs_readdir(ap)
+	struct vop_readdir_args /* {
+		struct vnode *a_vp;
+		struct uio *a_uio;
+		struct ucred *a_cred;
+		int *a_eofflag;
+		int *a_ncookies;
+		u_long **a_cookies;
+	} */ *ap;
+{
+	struct uio *uio = ap->a_uio;
+	struct dirent d;
+	struct dirent *dp = &d;
+	struct pfsnode *pfs;
+	int count, error, i, off;
+	static u_int delen;
+
+	if (!delen) {
+
+		d.d_namlen = PROCFS_NAMELEN;
+		delen = GENERIC_DIRSIZ(&d);
+	}
+
+	pfs = VTOPFS(ap->a_vp);
+
+	off = (int)uio->uio_offset;
+	if (off != uio->uio_offset || off < 0 || 
+	    off % delen != 0 || uio->uio_resid < delen)
+		return (EINVAL);
+
+	error = 0;
+	count = 0;
+	i = off / delen;
+
+	switch (pfs->pfs_type) {
+	/*
+	 * 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).
+	 */
+	case Pproc: {
+		struct proc *p;
+		struct proc_target *pt;
+
+		p = PFIND(pfs->pfs_pid);
+		if (p == NULL)
+			break;
+		if (!PRISON_CHECK(curproc, p))
+			break;
+
+		for (pt = &proc_targets[i];
+		     uio->uio_resid >= delen && i < nproc_targets; pt++, i++) {
+			if (pt->pt_valid && (*pt->pt_valid)(p) == 0)
+				continue;
+
+			dp->d_reclen = delen;
+			dp->d_fileno = PROCFS_FILENO(pfs->pfs_pid, pt->pt_pfstype);
+			dp->d_namlen = pt->pt_namlen;
+			bcopy(pt->pt_name, dp->d_name, pt->pt_namlen + 1);
+			dp->d_type = pt->pt_type;
+
+			if ((error = uiomove((caddr_t)dp, delen, uio)) != 0)
+				break;
+		}
+
+	    	break;
+	    }
+
+	/*
+	 * 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
+#ifdef PROCFS_ZOMBIE
+	 * and zombproc.
+#endif
+	 */
+
+	case Proot: {
+#ifdef PROCFS_ZOMBIE
+		int doingzomb = 0;
+#endif
+		int pcnt = 0;
+		volatile struct proc *p = allproc.lh_first;
+
+		for (; p && uio->uio_resid >= delen; i++, pcnt++) {
+			bzero((char *) dp, delen);
+			dp->d_reclen = delen;
+
+			switch (i) {
+			case 0:		/* `.' */
+			case 1:		/* `..' */
+				dp->d_fileno = PROCFS_FILENO(0, Proot);
+				dp->d_namlen = i + 1;
+				bcopy("..", dp->d_name, dp->d_namlen);
+				dp->d_name[i + 1] = '\0';
+				dp->d_type = DT_DIR;
+				break;
+
+			case 2:
+				dp->d_fileno = PROCFS_FILENO(0, Pself);
+				dp->d_namlen = 4;
+				bcopy("self", dp->d_name, 5);
+				dp->d_type = DT_LNK;
+				break;
+
+			case 3:
+				dp->d_fileno = PROCFS_FILENO(0, Pmeminfo);
+				dp->d_namlen = 7;
+				bcopy("meminfo", dp->d_name, 8);
+				dp->d_type = DT_REG;
+				break;
+
+			case 4:
+				dp->d_fileno = PROCFS_FILENO(0, Pcpuinfo);
+				dp->d_namlen = 7;
+				bcopy("cpuinfo", dp->d_name, 8);
+				dp->d_type = DT_REG;
+				break;
+
+			default:
+				while (pcnt < i) {
+					p = p->p_list.le_next;
+					if (!p)
+						goto done;
+					if (!PRISON_CHECK(curproc, p))
+						continue;
+					pcnt++;
+				}
+				while (!PRISON_CHECK(curproc, p)) {
+					p = p->p_list.le_next;
+					if (!p)
+						goto done;
+				}
+				dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc);
+				dp->d_namlen = sprintf(dp->d_name, "%ld",
+				    (long)p->p_pid);
+				dp->d_type = DT_REG;
+				p = p->p_list.le_next;
+				break;
+			}
+
+			if ((error = uiomove((caddr_t)dp, delen, uio)) != 0)
+				break;
+		}
+	done:
+
+#ifdef PROCFS_ZOMBIE
+		if (p == 0 && doingzomb == 0) {
+			doingzomb = 1;
+			p = zombproc.lh_first;
+			goto again;
+		}
+#endif
+
+		break;
+
+	    }
+
+	default:
+		error = ENOTDIR;
+		break;
+	}
+
+	uio->uio_offset = i * delen;
+
+	return (error);
+}
+
+/*
+ * readlink reads the link of `self'
+ */
+static int
+linprocfs_readlink(ap)
+	struct vop_readlink_args *ap;
+{
+	char buf[16];		/* should be enough */
+	int len;
+
+	if (VTOPFS(ap->a_vp)->pfs_fileno != PROCFS_FILENO(0, Pself))
+		return (EINVAL);
+
+	len = snprintf(buf, sizeof(buf), "%ld", (long)curproc->p_pid);
+
+	return (uiomove((caddr_t)buf, len, ap->a_uio));
+}
+
+/*
+ * convert decimal ascii to pid_t
+ */
+static pid_t
+atopid(b, len)
+	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);
+}
+
+/*
+ * procfs vnode operations.
+ */
+vop_t **linprocfs_vnodeop_p;
+static struct vnodeopv_entry_desc linprocfs_vnodeop_entries[] = {
+	{ &vop_default_desc,		(vop_t *) vop_defaultop },
+	{ &vop_access_desc,		(vop_t *) linprocfs_access },
+	{ &vop_advlock_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_bmap_desc,		(vop_t *) linprocfs_bmap },
+	{ &vop_close_desc,		(vop_t *) linprocfs_close },
+	{ &vop_create_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_getattr_desc,		(vop_t *) linprocfs_getattr },
+	{ &vop_inactive_desc,		(vop_t *) linprocfs_inactive },
+	{ &vop_link_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_lookup_desc,		(vop_t *) linprocfs_lookup },
+	{ &vop_mkdir_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_mknod_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_open_desc,		(vop_t *) linprocfs_open },
+	{ &vop_pathconf_desc,		(vop_t *) vop_stdpathconf },
+	{ &vop_print_desc,		(vop_t *) linprocfs_print },
+	{ &vop_read_desc,		(vop_t *) linprocfs_rw },
+	{ &vop_readdir_desc,		(vop_t *) linprocfs_readdir },
+	{ &vop_readlink_desc,		(vop_t *) linprocfs_readlink },
+	{ &vop_reclaim_desc,		(vop_t *) linprocfs_reclaim },
+	{ &vop_remove_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_rename_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_rmdir_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_setattr_desc,		(vop_t *) linprocfs_setattr },
+	{ &vop_symlink_desc,		(vop_t *) linprocfs_badop },
+	{ &vop_write_desc,		(vop_t *) linprocfs_rw },
+	{ &vop_ioctl_desc,		(vop_t *) linprocfs_ioctl },
+	{ NULL, NULL }
+};
+static struct vnodeopv_desc linprocfs_vnodeop_opv_desc =
+	{ &linprocfs_vnodeop_p, linprocfs_vnodeop_entries };
+
+VNODEOP_SET(linprocfs_vnodeop_opv_desc);
diff --git a/sys/modules/Makefile b/sys/modules/Makefile
index 50510515ed06..63e96818f178 100644
--- a/sys/modules/Makefile
+++ b/sys/modules/Makefile
@@ -3,8 +3,8 @@
 # XXX present but broken: ip_mroute_mod pcic
 
 SUBDIR=	aha amr an aue ccd cd9660 coda cue dc fdesc fxp if_disc if_ef if_ppp \
-	if_sl if_tun ipfilter ipfw joy kernfs kue md mfs mii mlx msdos \
-	ncp netgraph nfs ntfs nullfs \
+	if_sl if_tun ipfilter ipfw joy kernfs kue linprocfs \
+	md mfs mii mlx msdos ncp netgraph nfs ntfs nullfs \
 	nwfs portal procfs rl sf sis sk ste ti tl \
 	ugen uhid ukbd ulpt umapfs umass umodem ums union urio usb \
 	vn vpo vr wb xl
diff --git a/sys/modules/linprocfs/Makefile b/sys/modules/linprocfs/Makefile
new file mode 100644
index 000000000000..60434cd4c48a
--- /dev/null
+++ b/sys/modules/linprocfs/Makefile
@@ -0,0 +1,11 @@
+# $FreeBSD$
+
+.PATH:	${.CURDIR}/../../miscfs/linprocfs
+KMOD=	linprocfs
+SRCS=	vnode_if.h linprocfs_misc.c linprocfs_subr.c \
+		linprocfs_vfsops.c linprocfs_vnops.c
+NOMAN=
+VFS_KLD=
+CFLAGS+= -DLINPROCFS
+
+.include <bsd.kmod.mk>