xref: /src/sys/miscfs/procfs/procfs_vfsops.c

/*	$NetBSD: procfs_vfsops.c,v 1.86.2.2 2014/05/22 11:41:05 yamt Exp $	*/

/*
 * 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. 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
 */

/*
 * Copyright (c) 1993 Jan-Simon Pendry
 *
 * 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
 */

/*
 * procfs VFS interface
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: procfs_vfsops.c,v 1.86.2.2 2014/05/22 11:41:05 yamt Exp $");

#if defined(_KERNEL_OPT)
#include "opt_compat_netbsd.h"
#endif

#include <sys/param.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/syslog.h>
#include <sys/mount.h>
#include <sys/dirent.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/kauth.h>
#include <sys/module.h>

#include <miscfs/genfs/genfs.h>

#include <miscfs/procfs/procfs.h>

#include <uvm/uvm_extern.h>			/* for PAGE_SIZE */

MODULE(MODULE_CLASS_VFS, procfs, NULL);

VFS_PROTOS(procfs);

static struct sysctllog *procfs_sysctl_log;

static kauth_listener_t procfs_listener;

/*
 * VFS Operations.
 *
 * mount system call
 */
/* ARGSUSED */
int
procfs_mount(
    struct mount *mp,
    const char *path,
    void *data,
    size_t *data_len)
{
	struct lwp *l = curlwp;
	struct procfsmount *pmnt;
	struct procfs_args *args = data;
	int error;

	if (args == NULL)
		return EINVAL;

	if (UIO_MX & (UIO_MX-1)) {
		log(LOG_ERR, "procfs: invalid directory entry size");
		return (EINVAL);
	}

	if (mp->mnt_flag & MNT_GETARGS) {
		if (*data_len < sizeof *args)
			return EINVAL;

		pmnt = VFSTOPROC(mp);
		if (pmnt == NULL)
			return EIO;
		args->version = PROCFS_ARGSVERSION;
		args->flags = pmnt->pmnt_flags;
		*data_len = sizeof *args;
		return 0;
	}

	if (mp->mnt_flag & MNT_UPDATE)
		return (EOPNOTSUPP);

	if (*data_len >= sizeof *args && args->version != PROCFS_ARGSVERSION)
		return EINVAL;

	pmnt = kmem_zalloc(sizeof(struct procfsmount), KM_SLEEP);

	mp->mnt_stat.f_namemax = PROCFS_MAXNAMLEN;
	mp->mnt_flag |= MNT_LOCAL;
	mp->mnt_data = pmnt;
	vfs_getnewfsid(mp);

	error = set_statvfs_info(path, UIO_USERSPACE, "procfs", UIO_SYSSPACE,
	    mp->mnt_op->vfs_name, mp, l);
	pmnt->pmnt_exechook = exechook_establish(procfs_revoke_vnodes, mp);
	if (*data_len >= sizeof *args)
		pmnt->pmnt_flags = args->flags;
	else
		pmnt->pmnt_flags = 0;

	mp->mnt_iflag |= IMNT_MPSAFE;
	return error;
}

/*
 * unmount system call
 */
int
procfs_unmount(struct mount *mp, int mntflags)
{
	int error;
	int flags = 0;

	if (mntflags & MNT_FORCE)
		flags |= FORCECLOSE;

	if ((error = vflush(mp, 0, flags)) != 0)
		return (error);

	exechook_disestablish(VFSTOPROC(mp)->pmnt_exechook);

	kmem_free(mp->mnt_data, sizeof(struct procfsmount));
	mp->mnt_data = NULL;

	return 0;
}

int
procfs_root(struct mount *mp, struct vnode **vpp)
{
	int error;

	error = procfs_allocvp(mp, vpp, 0, PFSroot, -1, NULL);
	if (error == 0) {
		error = vn_lock(*vpp, LK_EXCLUSIVE);
		if (error != 0) {
			vrele(*vpp);
			*vpp = NULL;
		}
	}

	return error;
}

/* ARGSUSED */
int
procfs_start(struct mount *mp, int flags)
{

	return (0);
}

/*
 * Get file system statistics.
 */
int
procfs_statvfs(struct mount *mp, struct statvfs *sbp)
{

	genfs_statvfs(mp, sbp);

	sbp->f_bsize = PAGE_SIZE;
	sbp->f_frsize = PAGE_SIZE;
	sbp->f_iosize = PAGE_SIZE;
	sbp->f_blocks = 1;
	sbp->f_files = maxproc;			/* approx */
	sbp->f_ffree = maxproc - nprocs;	/* approx */
	sbp->f_favail = maxproc - nprocs;	/* approx */

	return (0);
}

/*ARGSUSED*/
int
procfs_sync(
    struct mount *mp,
    int waitfor,
    kauth_cred_t uc)
{

	return (0);
}

/*ARGSUSED*/
int
procfs_vget(struct mount *mp, ino_t ino,
    struct vnode **vpp)
{
	return (EOPNOTSUPP);
}

void
procfs_init(void)
{
	procfs_hashinit();
}

void
procfs_reinit(void)
{
	procfs_hashreinit();
}

void
procfs_done(void)
{
	procfs_hashdone();
}

extern const struct vnodeopv_desc procfs_vnodeop_opv_desc;

const struct vnodeopv_desc * const procfs_vnodeopv_descs[] = {
	&procfs_vnodeop_opv_desc,
	NULL,
};

struct vfsops procfs_vfsops = {
	.vfs_name = MOUNT_PROCFS,
	.vfs_min_mount_data = sizeof (struct procfs_args),
	.vfs_mount = procfs_mount,
	.vfs_start = procfs_start,
	.vfs_unmount = procfs_unmount,
	.vfs_root = procfs_root,
	.vfs_quotactl = (void *)eopnotsupp,
	.vfs_statvfs = procfs_statvfs,
	.vfs_sync = procfs_sync,
	.vfs_vget = procfs_vget,
	.vfs_fhtovp = (void *)eopnotsupp,
	.vfs_vptofh = (void *)eopnotsupp,
	.vfs_init = procfs_init,
	.vfs_reinit = procfs_reinit,
	.vfs_done = procfs_done,
	.vfs_snapshot = (void *)eopnotsupp,
	.vfs_extattrctl = vfs_stdextattrctl,
	.vfs_suspendctl = (void *)eopnotsupp,
	.vfs_renamelock_enter = genfs_renamelock_enter,
	.vfs_renamelock_exit = genfs_renamelock_exit,
	.vfs_fsync = (void *)eopnotsupp,
	.vfs_opv_descs = procfs_vnodeopv_descs
};

static int
procfs_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
    void *arg0, void *arg1, void *arg2, void *arg3)
{
	struct proc *p;
	struct pfsnode *pfs;
	enum kauth_process_req req;
	int result;

	result = KAUTH_RESULT_DEFER;
	p = arg0;
	pfs = arg1;
	req = (enum kauth_process_req)(unsigned long)arg2;

	if (action != KAUTH_PROCESS_PROCFS)
		return result;

	/* Privileged; let secmodel handle that. */
	if (req == KAUTH_REQ_PROCESS_PROCFS_CTL)
		return result;

	switch (pfs->pfs_type) {
	case PFSregs:
	case PFSfpregs:
	case PFSmem:
		if (kauth_cred_getuid(cred) != kauth_cred_getuid(p->p_cred) ||
		    ISSET(p->p_flag, PK_SUGID))
			break;

		/*FALLTHROUGH*/
	default:
		result = KAUTH_RESULT_ALLOW;
		break;
	}

	return result;
}


static int
procfs_modcmd(modcmd_t cmd, void *arg)
{
	int error;

	switch (cmd) {
	case MODULE_CMD_INIT:
		error = vfs_attach(&procfs_vfsops);
		if (error != 0)
			break;
		sysctl_createv(&procfs_sysctl_log, 0, NULL, NULL,
			       CTLFLAG_PERMANENT,
			       CTLTYPE_NODE, "procfs",
			       SYSCTL_DESCR("Process file system"),
			       NULL, 0, NULL, 0,
			       CTL_VFS, 12, CTL_EOL);
		/*
		 * XXX the "12" above could be dynamic, thereby eliminating
		 * one more instance of the "number to vfs" mapping problem,
		 * but "12" is the order as taken from sys/mount.h
		 */

		procfs_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
		    procfs_listener_cb, NULL);

		break;
	case MODULE_CMD_FINI:
		error = vfs_detach(&procfs_vfsops);
		if (error != 0)
			break;
		sysctl_teardown(&procfs_sysctl_log);
		kauth_unlisten_scope(procfs_listener);
		break;
	default:
		error = ENOTTY;
		break;
	}

	return (error);
}