1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * Copyright (c) 2005 Robert N. M. Watson 6 * All rights reserved. 7 * 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * Copyright (c) 1994 Christopher G. Demetriou 38 * 39 * Redistribution and use in source and binary forms, with or without 40 * modification, are permitted provided that the following conditions 41 * are met: 42 * 1. Redistributions of source code must retain the above copyright 43 * notice, this list of conditions and the following disclaimer. 44 * 2. Redistributions in binary form must reproduce the above copyright 45 * notice, this list of conditions and the following disclaimer in the 46 * documentation and/or other materials provided with the distribution. 47 * 3. All advertising materials mentioning features or use of this software 48 * must display the following acknowledgement: 49 * This product includes software developed by the University of 50 * California, Berkeley and its contributors. 51 * 4. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 68 */ 69 70 #include <sys/cdefs.h> 71 __FBSDID("$FreeBSD$"); 72 73 #include "opt_mac.h" 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/acct.h> 78 #include <sys/fcntl.h> 79 #include <sys/kernel.h> 80 #include <sys/kthread.h> 81 #include <sys/limits.h> 82 #include <sys/lock.h> 83 #include <sys/mount.h> 84 #include <sys/mutex.h> 85 #include <sys/namei.h> 86 #include <sys/priv.h> 87 #include <sys/proc.h> 88 #include <sys/resourcevar.h> 89 #include <sys/sched.h> 90 #include <sys/sx.h> 91 #include <sys/sysctl.h> 92 #include <sys/sysent.h> 93 #include <sys/syslog.h> 94 #include <sys/sysproto.h> 95 #include <sys/tty.h> 96 #include <sys/vnode.h> 97 98 #include <security/mac/mac_framework.h> 99 100 /* 101 * The routines implemented in this file are described in: 102 * Leffler, et al.: The Design and Implementation of the 4.3BSD 103 * UNIX Operating System (Addison Welley, 1989) 104 * on pages 62-63. 105 * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction 106 * compt_t representation described in the above reference was replaced 107 * with that of IEEE-754 floats. 108 * 109 * Arguably, to simplify accounting operations, this mechanism should 110 * be replaced by one in which an accounting log file (similar to /dev/klog) 111 * is read by a user process, etc. However, that has its own problems. 112 */ 113 114 /* Floating point definitions from <float.h>. */ 115 #define FLT_MANT_DIG 24 /* p */ 116 #define FLT_MAX_EXP 128 /* emax */ 117 118 /* 119 * Internal accounting functions. 120 * The former's operation is described in Leffler, et al., and the latter 121 * was provided by UCB with the 4.4BSD-Lite release 122 */ 123 static uint32_t encode_timeval(struct timeval); 124 static uint32_t encode_long(long); 125 static void acctwatch(void); 126 static void acct_thread(void *); 127 static int acct_disable(struct thread *); 128 129 /* 130 * Accounting vnode pointer, saved vnode pointer, and flags for each. 131 * acct_sx protects against changes to the active vnode and credentials 132 * while accounting records are being committed to disk. 133 */ 134 static int acct_configured; 135 static int acct_suspended; 136 static struct vnode *acct_vp; 137 static struct ucred *acct_cred; 138 static int acct_flags; 139 static struct sx acct_sx; 140 141 SX_SYSINIT(acct, &acct_sx, "acct_sx"); 142 143 /* 144 * State of the accounting kthread. 145 */ 146 static int acct_state; 147 148 #define ACCT_RUNNING 1 /* Accounting kthread is running. */ 149 #define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ 150 151 /* 152 * Values associated with enabling and disabling accounting 153 */ 154 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 155 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 156 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 157 158 static int acctresume = 4; /* resume when free space risen to > 4% */ 159 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 160 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 161 162 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 163 164 static int 165 sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) 166 { 167 int error, value; 168 169 /* Write out the old value. */ 170 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); 171 if (error || req->newptr == NULL) 172 return (error); 173 174 /* Read in and verify the new value. */ 175 error = SYSCTL_IN(req, &value, sizeof(int)); 176 if (error) 177 return (error); 178 if (value <= 0) 179 return (EINVAL); 180 acctchkfreq = value; 181 return (0); 182 } 183 SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW, 184 &acctchkfreq, 0, sysctl_acct_chkfreq, "I", 185 "frequency for checking the free space"); 186 187 SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, 188 "Accounting configured or not"); 189 190 SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, 191 "Accounting suspended or not"); 192 193 /* 194 * Accounting system call. Written based on the specification and previous 195 * implementation done by Mark Tinguely. 196 */ 197 int 198 acct(struct thread *td, struct acct_args *uap) 199 { 200 struct nameidata nd; 201 int error, flags, vfslocked; 202 203 error = priv_check(td, PRIV_ACCT); 204 if (error) 205 return (error); 206 207 /* 208 * If accounting is to be started to a file, open that file for 209 * appending and make sure it's a 'normal'. 210 */ 211 if (uap->path != NULL) { 212 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE | AUDITVNODE1, 213 UIO_USERSPACE, uap->path, td); 214 flags = FWRITE | O_APPEND; 215 error = vn_open(&nd, &flags, 0, NULL); 216 if (error) 217 return (error); 218 vfslocked = NDHASGIANT(&nd); 219 NDFREE(&nd, NDF_ONLY_PNBUF); 220 #ifdef MAC 221 error = mac_system_check_acct(td->td_ucred, nd.ni_vp); 222 if (error) { 223 VOP_UNLOCK(nd.ni_vp, 0); 224 vn_close(nd.ni_vp, flags, td->td_ucred, td); 225 VFS_UNLOCK_GIANT(vfslocked); 226 return (error); 227 } 228 #endif 229 VOP_UNLOCK(nd.ni_vp, 0); 230 if (nd.ni_vp->v_type != VREG) { 231 vn_close(nd.ni_vp, flags, td->td_ucred, td); 232 VFS_UNLOCK_GIANT(vfslocked); 233 return (EACCES); 234 } 235 VFS_UNLOCK_GIANT(vfslocked); 236 #ifdef MAC 237 } else { 238 error = mac_system_check_acct(td->td_ucred, NULL); 239 if (error) 240 return (error); 241 #endif 242 } 243 244 /* 245 * Disallow concurrent access to the accounting vnode while we swap 246 * it out, in order to prevent access after close. 247 */ 248 sx_xlock(&acct_sx); 249 250 /* 251 * If accounting was previously enabled, kill the old space-watcher, 252 * close the file, and (if no new file was specified, leave). Reset 253 * the suspended state regardless of whether accounting remains 254 * enabled. 255 */ 256 acct_suspended = 0; 257 if (acct_vp != NULL) { 258 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 259 error = acct_disable(td); 260 VFS_UNLOCK_GIANT(vfslocked); 261 } 262 if (uap->path == NULL) { 263 if (acct_state & ACCT_RUNNING) { 264 acct_state |= ACCT_EXITREQ; 265 wakeup(&acct_state); 266 } 267 sx_xunlock(&acct_sx); 268 return (error); 269 } 270 271 /* 272 * Save the new accounting file vnode, and schedule the new 273 * free space watcher. 274 */ 275 acct_vp = nd.ni_vp; 276 acct_cred = crhold(td->td_ucred); 277 acct_flags = flags; 278 if (acct_state & ACCT_RUNNING) 279 acct_state &= ~ACCT_EXITREQ; 280 else { 281 /* 282 * Try to start up an accounting kthread. We may start more 283 * than one, but if so the extras will commit suicide as 284 * soon as they start up. 285 */ 286 error = kproc_create(acct_thread, NULL, NULL, 0, 0, 287 "accounting"); 288 if (error) { 289 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 290 (void) vn_close(acct_vp, acct_flags, acct_cred, td); 291 VFS_UNLOCK_GIANT(vfslocked); 292 crfree(acct_cred); 293 acct_configured = 0; 294 acct_vp = NULL; 295 acct_cred = NULL; 296 acct_flags = 0; 297 sx_xunlock(&acct_sx); 298 log(LOG_NOTICE, "Unable to start accounting thread\n"); 299 return (error); 300 } 301 } 302 acct_configured = 1; 303 sx_xunlock(&acct_sx); 304 log(LOG_NOTICE, "Accounting enabled\n"); 305 return (error); 306 } 307 308 /* 309 * Disable currently in-progress accounting by closing the vnode, dropping 310 * our reference to the credential, and clearing the vnode's flags. 311 */ 312 static int 313 acct_disable(struct thread *td) 314 { 315 int error; 316 317 sx_assert(&acct_sx, SX_XLOCKED); 318 error = vn_close(acct_vp, acct_flags, acct_cred, td); 319 crfree(acct_cred); 320 acct_configured = 0; 321 acct_vp = NULL; 322 acct_cred = NULL; 323 acct_flags = 0; 324 log(LOG_NOTICE, "Accounting disabled\n"); 325 return (error); 326 } 327 328 /* 329 * Write out process accounting information, on process exit. 330 * Data to be written out is specified in Leffler, et al. 331 * and are enumerated below. (They're also noted in the system 332 * "acct.h" header file.) 333 */ 334 int 335 acct_process(struct thread *td) 336 { 337 struct acctv2 acct; 338 struct timeval ut, st, tmp; 339 struct plimit *newlim, *oldlim; 340 struct proc *p; 341 struct rusage ru; 342 int t, ret, vfslocked; 343 344 /* 345 * Lockless check of accounting condition before doing the hard 346 * work. 347 */ 348 if (acct_vp == NULL || acct_suspended) 349 return (0); 350 351 sx_slock(&acct_sx); 352 353 /* 354 * If accounting isn't enabled, don't bother. Have to check again 355 * once we own the lock in case we raced with disabling of accounting 356 * by another thread. 357 */ 358 if (acct_vp == NULL || acct_suspended) { 359 sx_sunlock(&acct_sx); 360 return (0); 361 } 362 363 p = td->td_proc; 364 365 /* 366 * Get process accounting information. 367 */ 368 369 PROC_LOCK(p); 370 /* (1) The name of the command that ran */ 371 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 372 373 /* (2) The amount of user and system time that was used */ 374 rufetchcalc(p, &ru, &ut, &st); 375 acct.ac_utime = encode_timeval(ut); 376 acct.ac_stime = encode_timeval(st); 377 378 /* (3) The elapsed time the command ran (and its starting time) */ 379 tmp = boottime; 380 timevaladd(&tmp, &p->p_stats->p_start); 381 acct.ac_btime = tmp.tv_sec; 382 microuptime(&tmp); 383 timevalsub(&tmp, &p->p_stats->p_start); 384 acct.ac_etime = encode_timeval(tmp); 385 386 /* (4) The average amount of memory used */ 387 tmp = ut; 388 timevaladd(&tmp, &st); 389 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ 390 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 391 if (t) 392 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + 393 + ru.ru_isrss) / t); 394 else 395 acct.ac_mem = 0; 396 397 /* (5) The number of disk I/O operations done */ 398 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); 399 400 /* (6) The UID and GID of the process */ 401 acct.ac_uid = p->p_ucred->cr_ruid; 402 acct.ac_gid = p->p_ucred->cr_rgid; 403 404 /* (7) The terminal from which the process was started */ 405 SESS_LOCK(p->p_session); 406 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 407 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 408 else 409 acct.ac_tty = NODEV; 410 SESS_UNLOCK(p->p_session); 411 412 /* (8) The boolean flags that tell how the process terminated, etc. */ 413 acct.ac_flagx = p->p_acflag; 414 PROC_UNLOCK(p); 415 416 /* Setup ancillary structure fields. */ 417 acct.ac_flagx |= ANVER; 418 acct.ac_zero = 0; 419 acct.ac_version = 2; 420 acct.ac_len = acct.ac_len2 = sizeof(acct); 421 422 /* 423 * Eliminate any file size rlimit. 424 */ 425 newlim = lim_alloc(); 426 PROC_LOCK(p); 427 oldlim = p->p_limit; 428 lim_copy(newlim, oldlim); 429 newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 430 p->p_limit = newlim; 431 PROC_UNLOCK(p); 432 lim_free(oldlim); 433 434 /* 435 * Write the accounting information to the file. 436 */ 437 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 438 VOP_LEASE(acct_vp, td, acct_cred, LEASE_WRITE); 439 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), 440 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, 441 (int *)0, td); 442 VFS_UNLOCK_GIANT(vfslocked); 443 sx_sunlock(&acct_sx); 444 return (ret); 445 } 446 447 /* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ 448 449 /* Convert timevals and longs into IEEE-754 bit patterns. */ 450 451 /* Mantissa mask (MSB is implied, so subtract 1). */ 452 #define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) 453 454 /* 455 * We calculate integer values to a precision of approximately 456 * 28 bits. 457 * This is high-enough precision to fill the 24 float bits 458 * and low-enough to avoid overflowing the 32 int bits. 459 */ 460 #define CALC_BITS 28 461 462 /* log_2(1000000). */ 463 #define LOG2_1M 20 464 465 /* 466 * Convert the elements of a timeval into a 32-bit word holding 467 * the bits of a IEEE-754 float. 468 * The float value represents the timeval's value in microsecond units. 469 */ 470 static uint32_t 471 encode_timeval(struct timeval tv) 472 { 473 int log2_s; 474 int val, exp; /* Unnormalized value and exponent */ 475 int norm_exp; /* Normalized exponent */ 476 int shift; 477 478 /* 479 * First calculate value and exponent to about CALC_BITS precision. 480 * Note that the following conditionals have been ordered so that 481 * the most common cases appear first. 482 */ 483 if (tv.tv_sec == 0) { 484 if (tv.tv_usec == 0) 485 return (0); 486 exp = 0; 487 val = tv.tv_usec; 488 } else { 489 /* 490 * Calculate the value to a precision of approximately 491 * CALC_BITS. 492 */ 493 log2_s = fls(tv.tv_sec) - 1; 494 if (log2_s + LOG2_1M < CALC_BITS) { 495 exp = 0; 496 val = 1000000 * tv.tv_sec + tv.tv_usec; 497 } else { 498 exp = log2_s + LOG2_1M - CALC_BITS; 499 val = (unsigned int)(((u_int64_t)1000000 * tv.tv_sec + 500 tv.tv_usec) >> exp); 501 } 502 } 503 /* Now normalize and pack the value into an IEEE-754 float. */ 504 norm_exp = fls(val) - 1; 505 shift = FLT_MANT_DIG - norm_exp - 1; 506 #ifdef ACCT_DEBUG 507 printf("val=%d exp=%d shift=%d log2(val)=%d\n", 508 val, exp, shift, norm_exp); 509 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 510 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 511 #endif 512 return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | 513 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 514 } 515 516 /* 517 * Convert a non-negative long value into the bit pattern of 518 * an IEEE-754 float value. 519 */ 520 static uint32_t 521 encode_long(long val) 522 { 523 int norm_exp; /* Normalized exponent */ 524 int shift; 525 526 if (val == 0) 527 return (0); 528 if (val < 0) { 529 log(LOG_NOTICE, 530 "encode_long: negative value %ld in accounting record\n", 531 val); 532 val = LONG_MAX; 533 } 534 norm_exp = fls(val) - 1; 535 shift = FLT_MANT_DIG - norm_exp - 1; 536 #ifdef ACCT_DEBUG 537 printf("val=%d shift=%d log2(val)=%d\n", 538 val, shift, norm_exp); 539 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 540 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 541 #endif 542 return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | 543 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 544 } 545 546 /* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ 547 548 /* 549 * Periodically check the filesystem to see if accounting 550 * should be turned on or off. Beware the case where the vnode 551 * has been vgone()'d out from underneath us, e.g. when the file 552 * system containing the accounting file has been forcibly unmounted. 553 */ 554 /* ARGSUSED */ 555 static void 556 acctwatch(void) 557 { 558 struct statfs sb; 559 int vfslocked; 560 561 sx_assert(&acct_sx, SX_XLOCKED); 562 563 /* 564 * If accounting was disabled before our kthread was scheduled, 565 * then acct_vp might be NULL. If so, just ask our kthread to 566 * exit and return. 567 */ 568 if (acct_vp == NULL) { 569 acct_state |= ACCT_EXITREQ; 570 return; 571 } 572 573 /* 574 * If our vnode is no longer valid, tear it down and signal the 575 * accounting thread to die. 576 */ 577 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 578 if (acct_vp->v_type == VBAD) { 579 (void) acct_disable(NULL); 580 VFS_UNLOCK_GIANT(vfslocked); 581 acct_state |= ACCT_EXITREQ; 582 return; 583 } 584 585 /* 586 * Stopping here is better than continuing, maybe it will be VBAD 587 * next time around. 588 */ 589 if (VFS_STATFS(acct_vp->v_mount, &sb, curthread) < 0) { 590 VFS_UNLOCK_GIANT(vfslocked); 591 return; 592 } 593 VFS_UNLOCK_GIANT(vfslocked); 594 if (acct_suspended) { 595 if (sb.f_bavail > (int64_t)(acctresume * sb.f_blocks / 596 100)) { 597 acct_suspended = 0; 598 log(LOG_NOTICE, "Accounting resumed\n"); 599 } 600 } else { 601 if (sb.f_bavail <= (int64_t)(acctsuspend * sb.f_blocks / 602 100)) { 603 acct_suspended = 1; 604 log(LOG_NOTICE, "Accounting suspended\n"); 605 } 606 } 607 } 608 609 /* 610 * The main loop for the dedicated kernel thread that periodically calls 611 * acctwatch(). 612 */ 613 static void 614 acct_thread(void *dummy) 615 { 616 u_char pri; 617 618 /* This is a low-priority kernel thread. */ 619 pri = PRI_MAX_KERN; 620 thread_lock(curthread); 621 sched_prio(curthread, pri); 622 thread_unlock(curthread); 623 624 /* If another accounting kthread is already running, just die. */ 625 sx_xlock(&acct_sx); 626 if (acct_state & ACCT_RUNNING) { 627 sx_xunlock(&acct_sx); 628 kproc_exit(0); 629 } 630 acct_state |= ACCT_RUNNING; 631 632 /* Loop until we are asked to exit. */ 633 while (!(acct_state & ACCT_EXITREQ)) { 634 635 /* Perform our periodic checks. */ 636 acctwatch(); 637 638 /* 639 * We check this flag again before sleeping since the 640 * acctwatch() might have shut down accounting and asked us 641 * to exit. 642 */ 643 if (!(acct_state & ACCT_EXITREQ)) { 644 sx_sleep(&acct_state, &acct_sx, 0, "-", 645 acctchkfreq * hz); 646 } 647 } 648 649 /* 650 * Acknowledge the exit request and shutdown. We clear both the 651 * exit request and running flags. 652 */ 653 acct_state = 0; 654 sx_xunlock(&acct_sx); 655 kproc_exit(0); 656 } 657