500 lines
14 KiB
C
500 lines
14 KiB
C
/* $NetBSD: kern_acct.c,v 1.99 2021/12/05 04:35:38 msaitoh Exp $ */
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/*-
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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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* 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. 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 8.8 (Berkeley) 5/14/95
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*/
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/*-
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* Copyright (c) 1994 Christopher G. Demetriou
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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 8.8 (Berkeley) 5/14/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_acct.c,v 1.99 2021/12/05 04:35:38 msaitoh Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/syslog.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/kmem.h>
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#include <sys/namei.h>
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#include <sys/errno.h>
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#include <sys/acct.h>
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#include <sys/resourcevar.h>
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#include <sys/ioctl.h>
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#include <sys/tty.h>
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#include <sys/kauth.h>
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#include <sys/syscallargs.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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* Lock to serialize system calls and kernel threads.
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*/
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krwlock_t acct_lock;
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/*
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* The global accounting state and related data. Gain the mutex before
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* accessing these variables.
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*/
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static enum {
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ACCT_STOP,
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ACCT_ACTIVE,
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ACCT_SUSPENDED
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} acct_state; /* The current accounting state. */
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static struct vnode *acct_vp; /* Accounting vnode pointer. */
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static kauth_cred_t acct_cred; /* Credential of accounting file
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owner (i.e root). Used when
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accounting file i/o. */
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static struct lwp *acct_dkwatcher; /* Free disk space checker. */
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/*
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* Values associated with enabling and disabling accounting
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*/
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int acctsuspend = 2; /* stop accounting when < 2% free space left */
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int acctresume = 4; /* resume when free space risen to > 4% */
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int acctchkfreq = 15; /* frequency (in seconds) to check space */
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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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static int
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acct_chkfree(void)
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{
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int error;
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struct statvfs *sb;
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fsblkcnt_t bavail;
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sb = kmem_alloc(sizeof(*sb), KM_SLEEP);
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error = VFS_STATVFS(acct_vp->v_mount, sb);
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if (error != 0) {
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kmem_free(sb, sizeof(*sb));
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return (error);
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}
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if (sb->f_bfree < sb->f_bresvd) {
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bavail = 0;
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} else {
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bavail = sb->f_bfree - sb->f_bresvd;
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}
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switch (acct_state) {
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case ACCT_SUSPENDED:
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if (bavail > acctresume * sb->f_blocks / 100) {
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acct_state = ACCT_ACTIVE;
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log(LOG_NOTICE, "Accounting resumed\n");
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}
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break;
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case ACCT_ACTIVE:
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if (bavail <= acctsuspend * sb->f_blocks / 100) {
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acct_state = ACCT_SUSPENDED;
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log(LOG_NOTICE, "Accounting suspended\n");
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}
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break;
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case ACCT_STOP:
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break;
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}
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kmem_free(sb, sizeof(*sb));
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return (0);
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}
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static void
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acct_stop(void)
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{
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int error;
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KASSERT(rw_write_held(&acct_lock));
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if (acct_vp != NULLVP && acct_vp->v_type != VBAD) {
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error = vn_close(acct_vp, FWRITE, acct_cred);
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#ifdef DIAGNOSTIC
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if (error != 0)
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printf("acct_stop: failed to close, errno = %d\n",
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error);
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#else
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__USE(error);
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#endif
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acct_vp = NULLVP;
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}
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if (acct_cred != NULL) {
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kauth_cred_free(acct_cred);
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acct_cred = NULL;
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}
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acct_state = ACCT_STOP;
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}
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/*
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* Periodically check the file system 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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static void
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acctwatch(void *arg)
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{
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int error;
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log(LOG_NOTICE, "Accounting started\n");
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rw_enter(&acct_lock, RW_WRITER);
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while (acct_state != ACCT_STOP) {
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if (acct_vp->v_type == VBAD) {
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log(LOG_NOTICE, "Accounting terminated\n");
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acct_stop();
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continue;
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}
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error = acct_chkfree();
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#ifdef DIAGNOSTIC
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if (error != 0)
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printf("acctwatch: failed to statvfs, error = %d\n",
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error);
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#else
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__USE(error);
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#endif
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rw_exit(&acct_lock);
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error = kpause("actwat", false, acctchkfreq * hz, NULL);
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rw_enter(&acct_lock, RW_WRITER);
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#ifdef DIAGNOSTIC
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if (error != 0 && error != EWOULDBLOCK)
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printf("acctwatch: sleep error %d\n", error);
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#endif
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}
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acct_dkwatcher = NULL;
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rw_exit(&acct_lock);
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kthread_exit(0);
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}
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void
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acct_init(void)
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{
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acct_state = ACCT_STOP;
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acct_vp = NULLVP;
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acct_cred = NULL;
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rw_init(&acct_lock);
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}
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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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int
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sys_acct(struct lwp *l, const struct sys_acct_args *uap, register_t *retval)
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{
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/* {
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syscallarg(const char *) path;
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} */
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struct pathbuf *pb;
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struct vnode *vp;
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int error;
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/* Make sure that the caller is root. */
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if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_ACCOUNTING,
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0, NULL, NULL, NULL)))
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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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* writing and make sure it's a 'normal'.
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*/
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if (SCARG(uap, path) != NULL) {
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struct vattr va;
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size_t pad;
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error = pathbuf_copyin(SCARG(uap, path), &pb);
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if (error) {
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return error;
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}
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error = vn_open(NULL, pb, TRYEMULROOT, FWRITE|O_APPEND, 0,
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&vp, NULL, NULL);
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if (error != 0) {
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pathbuf_destroy(pb);
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return error;
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}
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if (vp->v_type != VREG) {
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VOP_UNLOCK(vp);
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error = EACCES;
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goto bad;
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}
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if ((error = VOP_GETATTR(vp, &va, l->l_cred)) != 0) {
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VOP_UNLOCK(vp);
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goto bad;
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}
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if ((pad = (va.va_size % sizeof(struct acct))) != 0) {
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u_quad_t size = va.va_size - pad;
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#ifdef DIAGNOSTIC
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printf("Size of accounting file not a multiple of "
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"%lu - incomplete record truncated\n",
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(unsigned long)sizeof(struct acct));
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#endif
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vattr_null(&va);
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va.va_size = size;
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error = VOP_SETATTR(vp, &va, l->l_cred);
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if (error != 0) {
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VOP_UNLOCK(vp);
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goto bad;
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}
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}
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VOP_UNLOCK(vp);
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}
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rw_enter(&acct_lock, RW_WRITER);
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/*
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* If accounting was previously enabled, kill the old space-watcher,
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* free credential for accounting file i/o,
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* ... (and, if no new file was specified, leave).
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*/
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acct_stop();
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if (SCARG(uap, path) == NULL)
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goto out;
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/*
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* Save the new accounting file vnode and credential,
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* and schedule the new free space watcher.
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*/
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acct_state = ACCT_ACTIVE;
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acct_vp = vp;
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acct_cred = l->l_cred;
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kauth_cred_hold(acct_cred);
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pathbuf_destroy(pb);
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error = acct_chkfree(); /* Initial guess. */
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if (error != 0) {
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acct_stop();
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goto out;
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}
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if (acct_dkwatcher == NULL) {
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error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
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acctwatch, NULL, &acct_dkwatcher, "acctwatch");
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if (error != 0)
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acct_stop();
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}
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out:
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rw_exit(&acct_lock);
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return (error);
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bad:
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vn_close(vp, FWRITE, l->l_cred);
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pathbuf_destroy(pb);
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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 lwp *l)
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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 rusage *r;
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int t, error = 0;
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struct rlimit orlim;
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struct proc *p = l->l_proc;
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if (acct_state != ACCT_ACTIVE)
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return 0;
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memset(&acct, 0, sizeof(acct)); /* to zerofill padded data */
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rw_enter(&acct_lock, RW_READER);
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/* If accounting isn't enabled, don't bother */
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if (acct_state != ACCT_ACTIVE)
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goto out;
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/*
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* Temporarily raise the file limit so that accounting can't
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* be stopped by the user.
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*
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* XXX We should think about the CPU limit, too.
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*/
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lim_privatise(p);
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orlim = p->p_rlimit[RLIMIT_FSIZE];
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/* Set current and max to avoid illegal values */
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p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
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p->p_rlimit[RLIMIT_FSIZE].rlim_max = RLIM_INFINITY;
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/*
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* Get process accounting information.
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*/
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/* (1) The name of the command that ran */
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strncpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm));
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/* (2) The amount of user and system time that was used */
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mutex_enter(p->p_lock);
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calcru(p, &ut, &st, NULL, NULL);
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mutex_exit(p->p_lock);
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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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acct.ac_btime = p->p_stats->p_start.tv_sec;
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getmicrotime(&tmp);
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timersub(&tmp, &p->p_stats->p_start, &tmp);
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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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timeradd(&ut, &st, &tmp);
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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 = kauth_cred_getuid(l->l_cred);
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acct.ac_gid = kauth_cred_getgid(l->l_cred);
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/* (7) The terminal from which the process was started */
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mutex_enter(&proc_lock);
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if ((p->p_lflag & PL_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
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acct.ac_tty = 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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mutex_exit(&proc_lock);
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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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/*
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* Now, just write the accounting information to the file.
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*/
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error = vn_rdwr(UIO_WRITE, acct_vp, (void *)&acct,
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sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT,
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acct_cred, NULL, NULL);
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if (error != 0)
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log(LOG_ERR, "Accounting: write failed %d\n", error);
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/* Restore limit - rather pointless since process is about to exit */
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p->p_rlimit[RLIMIT_FSIZE] = orlim;
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out:
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rw_exit(&acct_lock);
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return (error);
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}
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