/*- * SPDX-License-Identifier: BSD-4-Clause * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * 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. */ #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/malloc.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/syslog.h> #include <sys/sysproto.h> #include <sys/tty.h> #include <sys/vnode.h> #include <security/mac/mac_framework.h> _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_trailer) == sizeof(struct acctv2) - offsetof(struct acctv2, ac_trailer), "trailer"); _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_len2) == sizeof(struct acctv2) - offsetof(struct acctv2, ac_len2), "len2"); /* * 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 | CTLFLAG_MPSAFE, &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); flags = FWRITE | O_APPEND; error = vn_open(&nd, &flags, 0, NULL); if (error) return (error); NDFREE_PNBUF(&nd); #ifdef MAC error = mac_system_check_acct(td->td_ucred, nd.ni_vp); if (error) { VOP_UNLOCK(nd.ni_vp); vn_close(nd.ni_vp, flags, td->td_ucred, td); return (error); } #endif VOP_UNLOCK(nd.ni_vp); 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) acct_disable(td, 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 acctv3 acct; struct timeval ut, st, tmp; 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); memset(&acct, 0, sizeof(acct)); 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; td->td_pflags2 |= TDP2_ACCT; /* * 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) */ getboottime(&tmp); 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 = 3; acct.ac_len = acct.ac_len2 = sizeof(acct); /* * 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); td->td_pflags2 &= ~TDP2_ACCT; 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 *sp; 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. */ sp = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK); if (VFS_STATFS(acct_vp->v_mount, sp) < 0) { free(sp, M_STATFS); return; } if (acct_suspended) { if (sp->f_bavail > (int64_t)(acctresume * sp->f_blocks / 100)) { acct_suspended = 0; log(LOG_NOTICE, "Accounting resumed\n"); } } else { if (sp->f_bavail <= (int64_t)(acctsuspend * sp->f_blocks / 100)) { acct_suspended = 1; log(LOG_NOTICE, "Accounting suspended\n"); } } free(sp, M_STATFS); } /* * 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); }
