specific privilege names to a broad range of privileges. These may require some future tweaking. Sponsored by: nCircle Network Security, Inc. Obtained from: TrustedBSD Project Discussed on: arch@ Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri, Alex Lyashkov <umka at sevcity dot net>, Skip Ford <skip dot ford at verizon dot net>, Antoine Brodin <antoine dot brodin at laposte dot net>
555 lines
15 KiB
C
555 lines
15 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Copyright (c) 1994 Christopher G. Demetriou
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* Copyright (c) 2005 Robert N. M. Watson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/acct.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/mount.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/sx.h>
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#include <sys/sysctl.h>
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#include <sys/sysent.h>
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#include <sys/syslog.h>
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#include <sys/sysproto.h>
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#include <sys/tty.h>
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#include <sys/vnode.h>
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#include <security/mac/mac_framework.h>
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/*
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* The routines implemented in this file are described in:
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* Leffler, et al.: The Design and Implementation of the 4.3BSD
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* UNIX Operating System (Addison Welley, 1989)
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* on pages 62-63.
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*
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* Arguably, to simplify accounting operations, this mechanism should
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* be replaced by one in which an accounting log file (similar to /dev/klog)
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* is read by a user process, etc. However, that has its own problems.
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*/
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/*
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* Internal accounting functions.
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* The former's operation is described in Leffler, et al., and the latter
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* was provided by UCB with the 4.4BSD-Lite release
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*/
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static comp_t encode_comp_t(u_long, u_long);
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static void acctwatch(void);
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static void acct_thread(void *);
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static int acct_disable(struct thread *);
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/*
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* Accounting vnode pointer, saved vnode pointer, and flags for each.
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* acct_sx protects against changes to the active vnode and credentials
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* while accounting records are being committed to disk.
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*/
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static int acct_configured;
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static int acct_suspended;
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static struct vnode *acct_vp;
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static struct ucred *acct_cred;
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static int acct_flags;
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static struct sx acct_sx;
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SX_SYSINIT(acct, &acct_sx, "acct_sx");
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/*
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* State of the accounting kthread.
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*/
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static int acct_state;
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#define ACCT_RUNNING 1 /* Accounting kthread is running. */
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#define ACCT_EXITREQ 2 /* Accounting kthread should exit. */
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/*
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* Values associated with enabling and disabling accounting
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*/
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static int acctsuspend = 2; /* stop accounting when < 2% free space left */
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SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
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&acctsuspend, 0, "percentage of free disk space below which accounting stops");
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static int acctresume = 4; /* resume when free space risen to > 4% */
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SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
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&acctresume, 0, "percentage of free disk space above which accounting resumes");
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static int acctchkfreq = 15; /* frequency (in seconds) to check space */
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static int
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sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS)
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{
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int error, value;
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/* Write out the old value. */
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error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int));
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if (error || req->newptr == NULL)
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return (error);
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/* Read in and verify the new value. */
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error = SYSCTL_IN(req, &value, sizeof(int));
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if (error)
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return (error);
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if (value <= 0)
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return (EINVAL);
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acctchkfreq = value;
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return (0);
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}
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SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW,
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&acctchkfreq, 0, sysctl_acct_chkfreq, "I",
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"frequency for checking the free space");
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SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0,
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"Accounting configured or not");
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SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0,
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"Accounting suspended or not");
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/*
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* Accounting system call. Written based on the specification and
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* previous implementation done by Mark Tinguely.
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*
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* MPSAFE
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*/
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int
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acct(struct thread *td, struct acct_args *uap)
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{
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struct nameidata nd;
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int error, flags, vfslocked;
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error = priv_check(td, PRIV_ACCT);
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if (error)
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return (error);
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/*
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* If accounting is to be started to a file, open that file for
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* appending and make sure it's a 'normal'.
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*/
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if (uap->path != NULL) {
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NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE | AUDITVNODE1,
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UIO_USERSPACE, uap->path, td);
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flags = FWRITE | O_APPEND;
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error = vn_open(&nd, &flags, 0, -1);
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if (error)
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return (error);
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vfslocked = NDHASGIANT(&nd);
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NDFREE(&nd, NDF_ONLY_PNBUF);
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#ifdef MAC
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error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
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if (error) {
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VOP_UNLOCK(nd.ni_vp, 0, td);
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vn_close(nd.ni_vp, flags, td->td_ucred, td);
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VFS_UNLOCK_GIANT(vfslocked);
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return (error);
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}
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#endif
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VOP_UNLOCK(nd.ni_vp, 0, td);
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if (nd.ni_vp->v_type != VREG) {
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vn_close(nd.ni_vp, flags, td->td_ucred, td);
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VFS_UNLOCK_GIANT(vfslocked);
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return (EACCES);
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}
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VFS_UNLOCK_GIANT(vfslocked);
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#ifdef MAC
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} else {
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error = mac_check_system_acct(td->td_ucred, NULL);
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if (error)
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return (error);
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#endif
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}
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/*
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* Disallow concurrent access to the accounting vnode while we swap
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* it out, in order to prevent access after close.
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*/
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sx_xlock(&acct_sx);
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/*
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* If accounting was previously enabled, kill the old space-watcher,
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* close the file, and (if no new file was specified, leave). Reset
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* the suspended state regardless of whether accounting remains
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* enabled.
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*/
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acct_suspended = 0;
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if (acct_vp != NULL) {
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vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
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error = acct_disable(td);
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VFS_UNLOCK_GIANT(vfslocked);
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}
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if (uap->path == NULL) {
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if (acct_state & ACCT_RUNNING) {
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acct_state |= ACCT_EXITREQ;
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wakeup(&acct_state);
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}
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sx_xunlock(&acct_sx);
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return (error);
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}
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/*
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* Save the new accounting file vnode, and schedule the new
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* free space watcher.
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*/
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acct_vp = nd.ni_vp;
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acct_cred = crhold(td->td_ucred);
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acct_flags = flags;
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if (acct_state & ACCT_RUNNING)
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acct_state &= ~ACCT_EXITREQ;
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else {
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/*
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* Try to start up an accounting kthread. We may start more
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* than one, but if so the extras will commit suicide as
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* soon as they start up.
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*/
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error = kthread_create(acct_thread, NULL, NULL, 0, 0,
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"accounting");
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if (error) {
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vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
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(void) vn_close(acct_vp, acct_flags, acct_cred, td);
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VFS_UNLOCK_GIANT(vfslocked);
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crfree(acct_cred);
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acct_configured = 0;
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acct_vp = NULL;
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acct_cred = NULL;
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acct_flags = 0;
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sx_xunlock(&acct_sx);
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log(LOG_NOTICE, "Unable to start accounting thread\n");
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return (error);
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}
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}
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acct_configured = 1;
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sx_xunlock(&acct_sx);
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log(LOG_NOTICE, "Accounting enabled\n");
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return (error);
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}
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/*
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* Disable currently in-progress accounting by closing the vnode, dropping
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* our reference to the credential, and clearing the vnode's flags.
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*/
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static int
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acct_disable(struct thread *td)
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{
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int error;
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sx_assert(&acct_sx, SX_XLOCKED);
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error = vn_close(acct_vp, acct_flags, acct_cred, td);
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crfree(acct_cred);
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acct_configured = 0;
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acct_vp = NULL;
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acct_cred = NULL;
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acct_flags = 0;
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log(LOG_NOTICE, "Accounting disabled\n");
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return (error);
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}
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/*
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* Write out process accounting information, on process exit.
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* Data to be written out is specified in Leffler, et al.
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* and are enumerated below. (They're also noted in the system
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* "acct.h" header file.)
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*/
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int
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acct_process(struct thread *td)
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{
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struct acct acct;
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struct timeval ut, st, tmp;
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struct plimit *newlim, *oldlim;
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struct proc *p;
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struct rusage *r;
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int t, ret, vfslocked;
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/*
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* Lockless check of accounting condition before doing the hard
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* work.
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*/
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if (acct_vp == NULL || acct_suspended)
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return (0);
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sx_slock(&acct_sx);
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/*
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* If accounting isn't enabled, don't bother. Have to check again
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* once we own the lock in case we raced with disabling of accounting
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* by another thread.
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*/
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if (acct_vp == NULL || acct_suspended) {
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sx_sunlock(&acct_sx);
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return (0);
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}
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p = td->td_proc;
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/*
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* Get process accounting information.
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*/
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PROC_LOCK(p);
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/* (1) The name of the command that ran */
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bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
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/* (2) The amount of user and system time that was used */
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calcru(p, &ut, &st);
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acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
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acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
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/* (3) The elapsed time the command ran (and its starting time) */
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tmp = boottime;
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timevaladd(&tmp, &p->p_stats->p_start);
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acct.ac_btime = tmp.tv_sec;
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microuptime(&tmp);
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timevalsub(&tmp, &p->p_stats->p_start);
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acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
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/* (4) The average amount of memory used */
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r = &p->p_stats->p_ru;
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tmp = ut;
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timevaladd(&tmp, &st);
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t = tmp.tv_sec * hz + tmp.tv_usec / tick;
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if (t)
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acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
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else
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acct.ac_mem = 0;
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/* (5) The number of disk I/O operations done */
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acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
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/* (6) The UID and GID of the process */
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acct.ac_uid = p->p_ucred->cr_ruid;
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acct.ac_gid = p->p_ucred->cr_rgid;
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/* (7) The terminal from which the process was started */
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SESS_LOCK(p->p_session);
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if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
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acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
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else
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acct.ac_tty = NODEV;
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SESS_UNLOCK(p->p_session);
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/* (8) The boolean flags that tell how the process terminated, etc. */
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acct.ac_flag = p->p_acflag;
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PROC_UNLOCK(p);
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/*
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* Eliminate any file size rlimit.
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*/
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newlim = lim_alloc();
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PROC_LOCK(p);
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oldlim = p->p_limit;
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lim_copy(newlim, oldlim);
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newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
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p->p_limit = newlim;
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PROC_UNLOCK(p);
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lim_free(oldlim);
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/*
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* Write the accounting information to the file.
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*/
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vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
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VOP_LEASE(acct_vp, td, acct_cred, LEASE_WRITE);
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ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct),
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(off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED,
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(int *)0, td);
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VFS_UNLOCK_GIANT(vfslocked);
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sx_sunlock(&acct_sx);
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return (ret);
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}
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/*
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* Encode_comp_t converts from ticks in seconds and microseconds
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* to ticks in 1/AHZ seconds. The encoding is described in
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* Leffler, et al., on page 63.
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*/
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#define MANTSIZE 13 /* 13 bit mantissa. */
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#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
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#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
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static comp_t
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encode_comp_t(u_long s, u_long us)
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{
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int exp, rnd;
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exp = 0;
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rnd = 0;
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s *= AHZ;
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s += us / (1000000 / AHZ); /* Maximize precision. */
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while (s > MAXFRACT) {
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rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
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s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
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exp++;
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}
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/* If we need to round up, do it (and handle overflow correctly). */
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if (rnd && (++s > MAXFRACT)) {
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s >>= EXPSIZE;
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exp++;
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}
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/* Clean it up and polish it off. */
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exp <<= MANTSIZE; /* Shift the exponent into place */
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exp += s; /* and add on the mantissa. */
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return (exp);
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}
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/*
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* Periodically check the filesystem to see if accounting
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* should be turned on or off. Beware the case where the vnode
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* has been vgone()'d out from underneath us, e.g. when the file
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* system containing the accounting file has been forcibly unmounted.
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*/
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/* ARGSUSED */
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static void
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acctwatch(void)
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{
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struct statfs sb;
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int vfslocked;
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sx_assert(&acct_sx, SX_XLOCKED);
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/*
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* If accounting was disabled before our kthread was scheduled,
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* then acct_vp might be NULL. If so, just ask our kthread to
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* exit and return.
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*/
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if (acct_vp == NULL) {
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acct_state |= ACCT_EXITREQ;
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return;
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}
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/*
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* If our vnode is no longer valid, tear it down and signal the
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* accounting thread to die.
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*/
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vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
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if (acct_vp->v_type == VBAD) {
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(void) acct_disable(NULL);
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VFS_UNLOCK_GIANT(vfslocked);
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acct_state |= ACCT_EXITREQ;
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return;
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}
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/*
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* Stopping here is better than continuing, maybe it will be VBAD
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* next time around.
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*/
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if (VFS_STATFS(acct_vp->v_mount, &sb, curthread) < 0) {
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
return;
|
|
}
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
if (acct_suspended) {
|
|
if (sb.f_bavail > (int64_t)(acctresume * sb.f_blocks /
|
|
100)) {
|
|
acct_suspended = 0;
|
|
log(LOG_NOTICE, "Accounting resumed\n");
|
|
}
|
|
} else {
|
|
if (sb.f_bavail <= (int64_t)(acctsuspend * sb.f_blocks /
|
|
100)) {
|
|
acct_suspended = 1;
|
|
log(LOG_NOTICE, "Accounting suspended\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The main loop for the dedicated kernel thread that periodically calls
|
|
* acctwatch().
|
|
*/
|
|
static void
|
|
acct_thread(void *dummy)
|
|
{
|
|
u_char pri;
|
|
|
|
/* This is a low-priority kernel thread. */
|
|
pri = PRI_MAX_KERN;
|
|
mtx_lock_spin(&sched_lock);
|
|
sched_prio(curthread, pri);
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
/* If another accounting kthread is already running, just die. */
|
|
sx_xlock(&acct_sx);
|
|
if (acct_state & ACCT_RUNNING) {
|
|
sx_xunlock(&acct_sx);
|
|
kthread_exit(0);
|
|
}
|
|
acct_state |= ACCT_RUNNING;
|
|
|
|
/* Loop until we are asked to exit. */
|
|
while (!(acct_state & ACCT_EXITREQ)) {
|
|
|
|
/* Perform our periodic checks. */
|
|
acctwatch();
|
|
|
|
/*
|
|
* We check this flag again before sleeping since the
|
|
* acctwatch() might have shut down accounting and asked us
|
|
* to exit.
|
|
*/
|
|
if (!(acct_state & ACCT_EXITREQ)) {
|
|
sx_xunlock(&acct_sx);
|
|
tsleep(&acct_state, pri, "-", acctchkfreq * hz);
|
|
sx_xlock(&acct_sx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Acknowledge the exit request and shutdown. We clear both the
|
|
* exit request and running flags.
|
|
*/
|
|
acct_state = 0;
|
|
sx_xunlock(&acct_sx);
|
|
kthread_exit(0);
|
|
}
|