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Diffstat (limited to 'sys/kern/kern_acct.c')
| -rw-r--r-- | sys/kern/kern_acct.c | 646 |
1 files changed, 646 insertions, 0 deletions
diff --git a/sys/kern/kern_acct.c b/sys/kern/kern_acct.c new file mode 100644 index 0000000..3362112 --- /dev/null +++ b/sys/kern/kern_acct.c @@ -0,0 +1,646 @@ +/*- + * Copyright (c) 1982, 1986, 1989, 1993 + * The Regents of the University of California. All rights reserved. + * (c) UNIX System Laboratories, Inc. + * Copyright (c) 2005 Robert N. M. Watson + * All rights reserved. + * + * All or some portions of this file are derived from material licensed + * to the University of California by American Telephone and Telegraph + * Co. or Unix System Laboratories, Inc. and are reproduced herein with + * the permission of UNIX System Laboratories, Inc. + * + * 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. + * 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. + * + * Copyright (c) 1994 Christopher G. Demetriou + * + * 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. + * + * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/acct.h> +#include <sys/fcntl.h> +#include <sys/kernel.h> +#include <sys/kthread.h> +#include <sys/limits.h> +#include <sys/lock.h> +#include <sys/mount.h> +#include <sys/mutex.h> +#include <sys/namei.h> +#include <sys/priv.h> +#include <sys/proc.h> +#include <sys/resourcevar.h> +#include <sys/sched.h> +#include <sys/sx.h> +#include <sys/sysctl.h> +#include <sys/sysent.h> +#include <sys/syslog.h> +#include <sys/sysproto.h> +#include <sys/tty.h> +#include <sys/vnode.h> + +#include <security/mac/mac_framework.h> + +/* + * The routines implemented in this file are described in: + * Leffler, et al.: The Design and Implementation of the 4.3BSD + * UNIX Operating System (Addison Welley, 1989) + * on pages 62-63. + * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction + * compt_t representation described in the above reference was replaced + * with that of IEEE-754 floats. + * + * Arguably, to simplify accounting operations, this mechanism should + * be replaced by one in which an accounting log file (similar to /dev/klog) + * is read by a user process, etc. However, that has its own problems. + */ + +/* Floating point definitions from <float.h>. */ +#define FLT_MANT_DIG 24 /* p */ +#define FLT_MAX_EXP 128 /* emax */ + +/* + * Internal accounting functions. + * The former's operation is described in Leffler, et al., and the latter + * was provided by UCB with the 4.4BSD-Lite release + */ +static uint32_t encode_timeval(struct timeval); +static uint32_t encode_long(long); +static void acctwatch(void); +static void acct_thread(void *); +static int acct_disable(struct thread *, int); + +/* + * Accounting vnode pointer, saved vnode pointer, and flags for each. + * acct_sx protects against changes to the active vnode and credentials + * while accounting records are being committed to disk. + */ +static int acct_configured; +static int acct_suspended; +static struct vnode *acct_vp; +static struct ucred *acct_cred; +static int acct_flags; +static struct sx acct_sx; + +SX_SYSINIT(acct, &acct_sx, "acct_sx"); + +/* + * State of the accounting kthread. + */ +static int acct_state; + +#define ACCT_RUNNING 1 /* Accounting kthread is running. */ +#define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ + +/* + * Values associated with enabling and disabling accounting + */ +static int acctsuspend = 2; /* stop accounting when < 2% free space left */ +SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, + &acctsuspend, 0, "percentage of free disk space below which accounting stops"); + +static int acctresume = 4; /* resume when free space risen to > 4% */ +SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, + &acctresume, 0, "percentage of free disk space above which accounting resumes"); + +static int acctchkfreq = 15; /* frequency (in seconds) to check space */ + +static int +sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) +{ + int error, value; + + /* Write out the old value. */ + error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); + if (error || req->newptr == NULL) + return (error); + + /* Read in and verify the new value. */ + error = SYSCTL_IN(req, &value, sizeof(int)); + if (error) + return (error); + if (value <= 0) + return (EINVAL); + acctchkfreq = value; + return (0); +} +SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW, + &acctchkfreq, 0, sysctl_acct_chkfreq, "I", + "frequency for checking the free space"); + +SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, + "Accounting configured or not"); + +SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, + "Accounting suspended or not"); + +/* + * Accounting system call. Written based on the specification and previous + * implementation done by Mark Tinguely. + */ +int +sys_acct(struct thread *td, struct acct_args *uap) +{ + struct nameidata nd; + int error, flags, replacing; + + error = priv_check(td, PRIV_ACCT); + if (error) + return (error); + + /* + * If accounting is to be started to a file, open that file for + * appending and make sure it's a 'normal'. + */ + if (uap->path != NULL) { + NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, + UIO_USERSPACE, uap->path, td); + flags = FWRITE | O_APPEND; + error = vn_open(&nd, &flags, 0, NULL); + if (error) + return (error); + NDFREE(&nd, NDF_ONLY_PNBUF); +#ifdef MAC + error = mac_system_check_acct(td->td_ucred, nd.ni_vp); + if (error) { + VOP_UNLOCK(nd.ni_vp, 0); + vn_close(nd.ni_vp, flags, td->td_ucred, td); + return (error); + } +#endif + VOP_UNLOCK(nd.ni_vp, 0); + if (nd.ni_vp->v_type != VREG) { + vn_close(nd.ni_vp, flags, td->td_ucred, td); + return (EACCES); + } +#ifdef MAC + } else { + error = mac_system_check_acct(td->td_ucred, NULL); + if (error) + return (error); +#endif + } + + /* + * Disallow concurrent access to the accounting vnode while we swap + * it out, in order to prevent access after close. + */ + sx_xlock(&acct_sx); + + /* + * Don't log spurious disable/enable messages if we are + * switching from one accounting file to another due to log + * rotation. + */ + replacing = (acct_vp != NULL && uap->path != NULL); + + /* + * If accounting was previously enabled, kill the old space-watcher, + * close the file, and (if no new file was specified, leave). Reset + * the suspended state regardless of whether accounting remains + * enabled. + */ + acct_suspended = 0; + if (acct_vp != NULL) + error = acct_disable(td, !replacing); + if (uap->path == NULL) { + if (acct_state & ACCT_RUNNING) { + acct_state |= ACCT_EXITREQ; + wakeup(&acct_state); + } + sx_xunlock(&acct_sx); + return (error); + } + + /* + * Save the new accounting file vnode, and schedule the new + * free space watcher. + */ + acct_vp = nd.ni_vp; + acct_cred = crhold(td->td_ucred); + acct_flags = flags; + if (acct_state & ACCT_RUNNING) + acct_state &= ~ACCT_EXITREQ; + else { + /* + * Try to start up an accounting kthread. We may start more + * than one, but if so the extras will commit suicide as + * soon as they start up. + */ + error = kproc_create(acct_thread, NULL, NULL, 0, 0, + "accounting"); + if (error) { + (void) vn_close(acct_vp, acct_flags, acct_cred, td); + crfree(acct_cred); + acct_configured = 0; + acct_vp = NULL; + acct_cred = NULL; + acct_flags = 0; + sx_xunlock(&acct_sx); + log(LOG_NOTICE, "Unable to start accounting thread\n"); + return (error); + } + } + acct_configured = 1; + sx_xunlock(&acct_sx); + if (!replacing) + log(LOG_NOTICE, "Accounting enabled\n"); + return (error); +} + +/* + * Disable currently in-progress accounting by closing the vnode, dropping + * our reference to the credential, and clearing the vnode's flags. + */ +static int +acct_disable(struct thread *td, int logging) +{ + int error; + + sx_assert(&acct_sx, SX_XLOCKED); + error = vn_close(acct_vp, acct_flags, acct_cred, td); + crfree(acct_cred); + acct_configured = 0; + acct_vp = NULL; + acct_cred = NULL; + acct_flags = 0; + if (logging) + log(LOG_NOTICE, "Accounting disabled\n"); + return (error); +} + +/* + * Write out process accounting information, on process exit. + * Data to be written out is specified in Leffler, et al. + * and are enumerated below. (They're also noted in the system + * "acct.h" header file.) + */ +int +acct_process(struct thread *td) +{ + struct acctv2 acct; + struct timeval ut, st, tmp; + struct plimit *newlim, *oldlim; + struct proc *p; + struct rusage ru; + int t, ret; + + /* + * Lockless check of accounting condition before doing the hard + * work. + */ + if (acct_vp == NULL || acct_suspended) + return (0); + + sx_slock(&acct_sx); + + /* + * If accounting isn't enabled, don't bother. Have to check again + * once we own the lock in case we raced with disabling of accounting + * by another thread. + */ + if (acct_vp == NULL || acct_suspended) { + sx_sunlock(&acct_sx); + return (0); + } + + p = td->td_proc; + + /* + * Get process accounting information. + */ + + sx_slock(&proctree_lock); + PROC_LOCK(p); + + /* (1) The terminal from which the process was started */ + if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) + acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp); + else + acct.ac_tty = NODEV; + sx_sunlock(&proctree_lock); + + /* (2) The name of the command that ran */ + bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); + + /* (3) The amount of user and system time that was used */ + rufetchcalc(p, &ru, &ut, &st); + acct.ac_utime = encode_timeval(ut); + acct.ac_stime = encode_timeval(st); + + /* (4) The elapsed time the command ran (and its starting time) */ + tmp = boottime; + timevaladd(&tmp, &p->p_stats->p_start); + acct.ac_btime = tmp.tv_sec; + microuptime(&tmp); + timevalsub(&tmp, &p->p_stats->p_start); + acct.ac_etime = encode_timeval(tmp); + + /* (5) The average amount of memory used */ + tmp = ut; + timevaladd(&tmp, &st); + /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ + t = tmp.tv_sec * hz + tmp.tv_usec / tick; + if (t) + acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + + + ru.ru_isrss) / t); + else + acct.ac_mem = 0; + + /* (6) The number of disk I/O operations done */ + acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); + + /* (7) The UID and GID of the process */ + acct.ac_uid = p->p_ucred->cr_ruid; + acct.ac_gid = p->p_ucred->cr_rgid; + + /* (8) The boolean flags that tell how the process terminated, etc. */ + acct.ac_flagx = p->p_acflag; + PROC_UNLOCK(p); + + /* Setup ancillary structure fields. */ + acct.ac_flagx |= ANVER; + acct.ac_zero = 0; + acct.ac_version = 2; + acct.ac_len = acct.ac_len2 = sizeof(acct); + + /* + * Eliminate any file size rlimit. + */ + newlim = lim_alloc(); + PROC_LOCK(p); + oldlim = p->p_limit; + lim_copy(newlim, oldlim); + newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; + p->p_limit = newlim; + PROC_UNLOCK(p); + lim_free(oldlim); + + /* + * Write the accounting information to the file. + */ + ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), + (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, + NULL, td); + sx_sunlock(&acct_sx); + return (ret); +} + +/* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ + +/* Convert timevals and longs into IEEE-754 bit patterns. */ + +/* Mantissa mask (MSB is implied, so subtract 1). */ +#define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) + +/* + * We calculate integer values to a precision of approximately + * 28 bits. + * This is high-enough precision to fill the 24 float bits + * and low-enough to avoid overflowing the 32 int bits. + */ +#define CALC_BITS 28 + +/* log_2(1000000). */ +#define LOG2_1M 20 + +/* + * Convert the elements of a timeval into a 32-bit word holding + * the bits of a IEEE-754 float. + * The float value represents the timeval's value in microsecond units. + */ +static uint32_t +encode_timeval(struct timeval tv) +{ + int log2_s; + int val, exp; /* Unnormalized value and exponent */ + int norm_exp; /* Normalized exponent */ + int shift; + + /* + * First calculate value and exponent to about CALC_BITS precision. + * Note that the following conditionals have been ordered so that + * the most common cases appear first. + */ + if (tv.tv_sec == 0) { + if (tv.tv_usec == 0) + return (0); + exp = 0; + val = tv.tv_usec; + } else { + /* + * Calculate the value to a precision of approximately + * CALC_BITS. + */ + log2_s = fls(tv.tv_sec) - 1; + if (log2_s + LOG2_1M < CALC_BITS) { + exp = 0; + val = 1000000 * tv.tv_sec + tv.tv_usec; + } else { + exp = log2_s + LOG2_1M - CALC_BITS; + val = (unsigned int)(((uint64_t)1000000 * tv.tv_sec + + tv.tv_usec) >> exp); + } + } + /* Now normalize and pack the value into an IEEE-754 float. */ + norm_exp = fls(val) - 1; + shift = FLT_MANT_DIG - norm_exp - 1; +#ifdef ACCT_DEBUG + printf("val=%d exp=%d shift=%d log2(val)=%d\n", + val, exp, shift, norm_exp); + printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, + ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); +#endif + return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | + ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); +} + +/* + * Convert a non-negative long value into the bit pattern of + * an IEEE-754 float value. + */ +static uint32_t +encode_long(long val) +{ + int norm_exp; /* Normalized exponent */ + int shift; + + if (val == 0) + return (0); + if (val < 0) { + log(LOG_NOTICE, + "encode_long: negative value %ld in accounting record\n", + val); + val = LONG_MAX; + } + norm_exp = fls(val) - 1; + shift = FLT_MANT_DIG - norm_exp - 1; +#ifdef ACCT_DEBUG + printf("val=%d shift=%d log2(val)=%d\n", + val, shift, norm_exp); + printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, + ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); +#endif + return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | + ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); +} + +/* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ + +/* + * Periodically check the filesystem to see if accounting + * should be turned on or off. Beware the case where the vnode + * has been vgone()'d out from underneath us, e.g. when the file + * system containing the accounting file has been forcibly unmounted. + */ +/* ARGSUSED */ +static void +acctwatch(void) +{ + struct statfs sb; + + sx_assert(&acct_sx, SX_XLOCKED); + + /* + * If accounting was disabled before our kthread was scheduled, + * then acct_vp might be NULL. If so, just ask our kthread to + * exit and return. + */ + if (acct_vp == NULL) { + acct_state |= ACCT_EXITREQ; + return; + } + + /* + * If our vnode is no longer valid, tear it down and signal the + * accounting thread to die. + */ + if (acct_vp->v_type == VBAD) { + (void) acct_disable(NULL, 1); + acct_state |= ACCT_EXITREQ; + return; + } + + /* + * Stopping here is better than continuing, maybe it will be VBAD + * next time around. + */ + if (VFS_STATFS(acct_vp->v_mount, &sb) < 0) + return; + 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; + thread_lock(curthread); + sched_prio(curthread, pri); + thread_unlock(curthread); + + /* If another accounting kthread is already running, just die. */ + sx_xlock(&acct_sx); + if (acct_state & ACCT_RUNNING) { + sx_xunlock(&acct_sx); + kproc_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_sleep(&acct_state, &acct_sx, 0, "-", + acctchkfreq * hz); + } + } + + /* + * Acknowledge the exit request and shutdown. We clear both the + * exit request and running flags. + */ + acct_state = 0; + sx_xunlock(&acct_sx); + kproc_exit(0); +} |
