kern_acct.c revision 1.59
1 /* $NetBSD: kern_acct.c,v 1.59 2004/11/13 20:41:41 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_acct.c 8.8 (Berkeley) 5/14/95 37 */ 38 39 /*- 40 * Copyright (c) 1994 Christopher G. Demetriou 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the University of 53 * California, Berkeley and its contributors. 54 * 4. Neither the name of the University nor the names of its contributors 55 * may be used to endorse or promote products derived from this software 56 * without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 59 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 60 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 61 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 62 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 63 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 64 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 65 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 66 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 67 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 68 * SUCH DAMAGE. 69 * 70 * @(#)kern_acct.c 8.8 (Berkeley) 5/14/95 71 */ 72 73 #include <sys/cdefs.h> 74 __KERNEL_RCSID(0, "$NetBSD: kern_acct.c,v 1.59 2004/11/13 20:41:41 christos Exp $"); 75 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/proc.h> 79 #include <sys/mount.h> 80 #include <sys/vnode.h> 81 #include <sys/file.h> 82 #include <sys/syslog.h> 83 #include <sys/kernel.h> 84 #include <sys/kthread.h> 85 #include <sys/lock.h> 86 #include <sys/malloc.h> 87 #include <sys/namei.h> 88 #include <sys/errno.h> 89 #include <sys/acct.h> 90 #include <sys/resourcevar.h> 91 #include <sys/ioctl.h> 92 #include <sys/tty.h> 93 94 #include <sys/sa.h> 95 #include <sys/syscallargs.h> 96 97 /* 98 * The routines implemented in this file are described in: 99 * Leffler, et al.: The Design and Implementation of the 4.3BSD 100 * UNIX Operating System (Addison Welley, 1989) 101 * on pages 62-63. 102 * 103 * Arguably, to simplify accounting operations, this mechanism should 104 * be replaced by one in which an accounting log file (similar to /dev/klog) 105 * is read by a user process, etc. However, that has its own problems. 106 */ 107 108 /* 109 * The global accounting state and related data. Gain the lock before 110 * accessing these variables. 111 */ 112 enum { 113 ACCT_STOP, 114 ACCT_ACTIVE, 115 ACCT_SUSPENDED 116 } acct_state; /* The current accounting state. */ 117 struct vnode *acct_vp; /* Accounting vnode pointer. */ 118 struct ucred *acct_ucred; /* Credential of accounting file 119 owner (i.e root). Used when 120 accounting file i/o. */ 121 struct proc *acct_dkwatcher; /* Free disk space checker. */ 122 123 /* 124 * Lock to serialize system calls and kernel threads. 125 */ 126 struct lock acct_lock; 127 #define ACCT_LOCK() \ 128 do { \ 129 (void) lockmgr(&acct_lock, LK_EXCLUSIVE, NULL); \ 130 } while (/* CONSTCOND */0) 131 #define ACCT_UNLOCK() \ 132 do { \ 133 (void) lockmgr(&acct_lock, LK_RELEASE, NULL); \ 134 } while (/* CONSTCOND */0) 135 136 /* 137 * Internal accounting functions. 138 * The former's operation is described in Leffler, et al., and the latter 139 * was provided by UCB with the 4.4BSD-Lite release 140 */ 141 comp_t encode_comp_t(u_long, u_long); 142 void acctwatch(void *); 143 void acct_stop(void); 144 int acct_chkfree(void); 145 146 /* 147 * Values associated with enabling and disabling accounting 148 */ 149 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 150 int acctresume = 4; /* resume when free space risen to > 4% */ 151 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 152 153 void 154 acct_init() 155 { 156 157 acct_state = ACCT_STOP; 158 acct_vp = NULLVP; 159 acct_ucred = NULL; 160 lockinit(&acct_lock, PWAIT, "acctlk", 0, 0); 161 } 162 163 void 164 acct_stop() 165 { 166 int error; 167 168 if (acct_vp != NULLVP && acct_vp->v_type != VBAD) { 169 error = vn_close(acct_vp, FWRITE, acct_ucred, NULL); 170 #ifdef DIAGNOSTIC 171 if (error != 0) 172 printf("acct_stop: failed to close, errno = %d\n", 173 error); 174 #endif 175 acct_vp = NULLVP; 176 } 177 if (acct_ucred != NULL) { 178 crfree(acct_ucred); 179 acct_ucred = NULL; 180 } 181 acct_state = ACCT_STOP; 182 } 183 184 int 185 acct_chkfree() 186 { 187 int error; 188 struct statvfs sb; 189 int64_t bavail; 190 191 error = VFS_STATVFS(acct_vp->v_mount, &sb, NULL); 192 if (error != 0) 193 return (error); 194 195 bavail = sb.f_bfree - sb.f_bresvd; 196 197 switch (acct_state) { 198 case ACCT_SUSPENDED: 199 if (bavail > acctresume * sb.f_blocks / 100) { 200 acct_state = ACCT_ACTIVE; 201 log(LOG_NOTICE, "Accounting resumed\n"); 202 } 203 break; 204 case ACCT_ACTIVE: 205 if (bavail <= acctsuspend * sb.f_blocks / 100) { 206 acct_state = ACCT_SUSPENDED; 207 log(LOG_NOTICE, "Accounting suspended\n"); 208 } 209 break; 210 case ACCT_STOP: 211 break; 212 } 213 return (0); 214 } 215 216 /* 217 * Accounting system call. Written based on the specification and 218 * previous implementation done by Mark Tinguely. 219 */ 220 int 221 sys_acct(l, v, retval) 222 struct lwp *l; 223 void *v; 224 register_t *retval; 225 { 226 struct sys_acct_args /* { 227 syscallarg(const char *) path; 228 } */ *uap = v; 229 struct nameidata nd; 230 int error; 231 struct proc *p = l->l_proc; 232 233 /* Make sure that the caller is root. */ 234 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 235 return (error); 236 237 /* 238 * If accounting is to be started to a file, open that file for 239 * writing and make sure it's a 'normal'. 240 */ 241 if (SCARG(uap, path) != NULL) { 242 struct vattr va; 243 size_t pad; 244 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 245 p); 246 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) 247 return (error); 248 VOP_UNLOCK(nd.ni_vp, 0); 249 if (nd.ni_vp->v_type != VREG) { 250 error = EACCES; 251 goto bad; 252 } 253 if ((error = VOP_GETATTR(nd.ni_vp, &va, p->p_ucred, p)) != 0) 254 goto bad; 255 256 if ((pad = (va.va_size % sizeof(struct acct))) != 0) { 257 #ifdef DIAGNOSTIC 258 printf("Size of accounting file not a multiple of " 259 "%lu - incomplete record truncated\n", 260 (unsigned long)sizeof(struct acct)); 261 #endif 262 va.va_size -= pad; 263 if ((error = VOP_TRUNCATE(nd.ni_vp, va.va_size, 0, 264 p->p_ucred, p)) != 0) 265 goto bad; 266 } 267 } 268 269 ACCT_LOCK(); 270 271 /* 272 * If accounting was previously enabled, kill the old space-watcher, 273 * free credential for accounting file i/o, 274 * ... (and, if no new file was specified, leave). 275 */ 276 acct_stop(); 277 if (SCARG(uap, path) == NULL) 278 goto out; 279 280 /* 281 * Save the new accounting file vnode and credential, 282 * and schedule the new free space watcher. 283 */ 284 acct_state = ACCT_ACTIVE; 285 acct_vp = nd.ni_vp; 286 acct_ucred = p->p_ucred; 287 crhold(acct_ucred); 288 289 error = acct_chkfree(); /* Initial guess. */ 290 if (error != 0) { 291 acct_stop(); 292 goto out; 293 } 294 295 if (acct_dkwatcher == NULL) { 296 error = kthread_create1(acctwatch, NULL, &acct_dkwatcher, 297 "acctwatch"); 298 if (error != 0) 299 acct_stop(); 300 } 301 302 out: 303 ACCT_UNLOCK(); 304 return (error); 305 bad: 306 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 307 return error; 308 } 309 310 /* 311 * Write out process accounting information, on process exit. 312 * Data to be written out is specified in Leffler, et al. 313 * and are enumerated below. (They're also noted in the system 314 * "acct.h" header file.) 315 */ 316 int 317 acct_process(p) 318 struct proc *p; 319 { 320 struct acct acct; 321 struct rusage *r; 322 struct timeval ut, st, tmp; 323 int s, t, error = 0; 324 struct plimit *oplim = NULL; 325 326 ACCT_LOCK(); 327 328 /* If accounting isn't enabled, don't bother */ 329 if (acct_state != ACCT_ACTIVE) 330 goto out; 331 332 /* 333 * Raise the file limit so that accounting can't be stopped by 334 * the user. 335 * 336 * XXX We should think about the CPU limit, too. 337 */ 338 if (p->p_limit->p_refcnt > 1) { 339 oplim = p->p_limit; 340 p->p_limit = limcopy(p->p_limit); 341 } 342 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 343 344 /* 345 * Get process accounting information. 346 */ 347 348 /* (1) The name of the command that ran */ 349 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); 350 351 /* (2) The amount of user and system time that was used */ 352 calcru(p, &ut, &st, NULL); 353 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 354 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 355 356 /* (3) The elapsed time the commmand ran (and its starting time) */ 357 acct.ac_btime = p->p_stats->p_start.tv_sec; 358 s = splclock(); 359 timersub(&time, &p->p_stats->p_start, &tmp); 360 splx(s); 361 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 362 363 /* (4) The average amount of memory used */ 364 r = &p->p_stats->p_ru; 365 timeradd(&ut, &st, &tmp); 366 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 367 if (t) 368 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 369 else 370 acct.ac_mem = 0; 371 372 /* (5) The number of disk I/O operations done */ 373 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 374 375 /* (6) The UID and GID of the process */ 376 acct.ac_uid = p->p_cred->p_ruid; 377 acct.ac_gid = p->p_cred->p_rgid; 378 379 /* (7) The terminal from which the process was started */ 380 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 381 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 382 else 383 acct.ac_tty = NODEV; 384 385 /* (8) The boolean flags that tell how the process terminated, etc. */ 386 acct.ac_flag = p->p_acflag; 387 388 /* 389 * Now, just write the accounting information to the file. 390 */ 391 VOP_LEASE(acct_vp, p, p->p_ucred, LEASE_WRITE); 392 error = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, 393 sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, 394 acct_ucred, NULL, NULL); 395 if (error != 0) 396 log(LOG_ERR, "Accounting: write failed %d\n", error); 397 398 if (oplim) { 399 limfree(p->p_limit); 400 p->p_limit = oplim; 401 } 402 403 out: 404 ACCT_UNLOCK(); 405 return (error); 406 } 407 408 /* 409 * Encode_comp_t converts from ticks in seconds and microseconds 410 * to ticks in 1/AHZ seconds. The encoding is described in 411 * Leffler, et al., on page 63. 412 */ 413 414 #define MANTSIZE 13 /* 13 bit mantissa. */ 415 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 416 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 417 418 comp_t 419 encode_comp_t(s, us) 420 u_long s, us; 421 { 422 int exp, rnd; 423 424 exp = 0; 425 rnd = 0; 426 s *= AHZ; 427 s += us / (1000000 / AHZ); /* Maximize precision. */ 428 429 while (s > MAXFRACT) { 430 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 431 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 432 exp++; 433 } 434 435 /* If we need to round up, do it (and handle overflow correctly). */ 436 if (rnd && (++s > MAXFRACT)) { 437 s >>= EXPSIZE; 438 exp++; 439 } 440 441 /* Clean it up and polish it off. */ 442 exp <<= MANTSIZE; /* Shift the exponent into place */ 443 exp += s; /* and add on the mantissa. */ 444 return (exp); 445 } 446 447 /* 448 * Periodically check the file system to see if accounting 449 * should be turned on or off. Beware the case where the vnode 450 * has been vgone()'d out from underneath us, e.g. when the file 451 * system containing the accounting file has been forcibly unmounted. 452 */ 453 void 454 acctwatch(arg) 455 void *arg; 456 { 457 int error; 458 459 log(LOG_NOTICE, "Accounting started\n"); 460 ACCT_LOCK(); 461 while (acct_state != ACCT_STOP) { 462 if (acct_vp->v_type == VBAD) { 463 log(LOG_NOTICE, "Accounting terminated\n"); 464 acct_stop(); 465 continue; 466 } 467 468 error = acct_chkfree(); 469 #ifdef DIAGNOSTIC 470 if (error != 0) 471 printf("acctwatch: failed to statvfs, error = %d\n", 472 error); 473 #endif 474 475 ACCT_UNLOCK(); 476 error = tsleep(acctwatch, PSWP, "actwat", acctchkfreq * hz); 477 ACCT_LOCK(); 478 #ifdef DIAGNOSTIC 479 if (error != 0 && error != EWOULDBLOCK) 480 printf("acctwatch: sleep error %d\n", error); 481 #endif 482 } 483 acct_dkwatcher = NULL; 484 ACCT_UNLOCK(); 485 486 kthread_exit(0); 487 } 488
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