kern_acct.c revision 1.62.10.3
1 /* $NetBSD: kern_acct.c,v 1.62.10.3 2006/05/06 23:31:30 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 1.62.10.3 2006/05/06 23:31:30 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 #include <sys/kauth.h> 94 95 #include <sys/sa.h> 96 #include <sys/syscallargs.h> 97 98 /* 99 * The routines implemented in this file are described in: 100 * Leffler, et al.: The Design and Implementation of the 4.3BSD 101 * UNIX Operating System (Addison Welley, 1989) 102 * on pages 62-63. 103 * 104 * Arguably, to simplify accounting operations, this mechanism should 105 * be replaced by one in which an accounting log file (similar to /dev/klog) 106 * is read by a user process, etc. However, that has its own problems. 107 */ 108 109 /* 110 * Lock to serialize system calls and kernel threads. 111 */ 112 static struct lock acct_lock; 113 #define ACCT_LOCK() \ 114 do { \ 115 (void) lockmgr(&acct_lock, LK_EXCLUSIVE, NULL); \ 116 } while (/* CONSTCOND */0) 117 #define ACCT_UNLOCK() \ 118 do { \ 119 (void) lockmgr(&acct_lock, LK_RELEASE, NULL); \ 120 } while (/* CONSTCOND */0) 121 122 /* 123 * The global accounting state and related data. Gain the lock before 124 * accessing these variables. 125 */ 126 static enum { 127 ACCT_STOP, 128 ACCT_ACTIVE, 129 ACCT_SUSPENDED 130 } acct_state; /* The current accounting state. */ 131 static struct vnode *acct_vp; /* Accounting vnode pointer. */ 132 static kauth_cred_t acct_cred; /* Credential of accounting file 133 owner (i.e root). Used when 134 accounting file i/o. */ 135 static struct proc *acct_dkwatcher; /* Free disk space checker. */ 136 137 /* 138 * Values associated with enabling and disabling accounting 139 */ 140 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 141 int acctresume = 4; /* resume when free space risen to > 4% */ 142 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 143 144 /* 145 * Encode_comp_t converts from ticks in seconds and microseconds 146 * to ticks in 1/AHZ seconds. The encoding is described in 147 * Leffler, et al., on page 63. 148 */ 149 150 #define MANTSIZE 13 /* 13 bit mantissa. */ 151 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 152 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 153 154 static comp_t 155 encode_comp_t(u_long s, u_long us) 156 { 157 int exp, rnd; 158 159 exp = 0; 160 rnd = 0; 161 s *= AHZ; 162 s += us / (1000000 / AHZ); /* Maximize precision. */ 163 164 while (s > MAXFRACT) { 165 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 166 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 167 exp++; 168 } 169 170 /* If we need to round up, do it (and handle overflow correctly). */ 171 if (rnd && (++s > MAXFRACT)) { 172 s >>= EXPSIZE; 173 exp++; 174 } 175 176 /* Clean it up and polish it off. */ 177 exp <<= MANTSIZE; /* Shift the exponent into place */ 178 exp += s; /* and add on the mantissa. */ 179 return (exp); 180 } 181 182 static int 183 acct_chkfree(void) 184 { 185 int error; 186 struct statvfs sb; 187 int64_t bavail; 188 189 error = VFS_STATVFS(acct_vp->v_mount, &sb, NULL); 190 if (error != 0) 191 return (error); 192 193 bavail = sb.f_bfree - sb.f_bresvd; 194 195 switch (acct_state) { 196 case ACCT_SUSPENDED: 197 if (bavail > acctresume * sb.f_blocks / 100) { 198 acct_state = ACCT_ACTIVE; 199 log(LOG_NOTICE, "Accounting resumed\n"); 200 } 201 break; 202 case ACCT_ACTIVE: 203 if (bavail <= acctsuspend * sb.f_blocks / 100) { 204 acct_state = ACCT_SUSPENDED; 205 log(LOG_NOTICE, "Accounting suspended\n"); 206 } 207 break; 208 case ACCT_STOP: 209 break; 210 } 211 return (0); 212 } 213 214 static void 215 acct_stop(void) 216 { 217 int error; 218 219 if (acct_vp != NULLVP && acct_vp->v_type != VBAD) { 220 error = vn_close(acct_vp, FWRITE, acct_cred, NULL); 221 #ifdef DIAGNOSTIC 222 if (error != 0) 223 printf("acct_stop: failed to close, errno = %d\n", 224 error); 225 #endif 226 acct_vp = NULLVP; 227 } 228 if (acct_cred != NULL) { 229 kauth_cred_free(acct_cred); 230 acct_cred = NULL; 231 } 232 acct_state = ACCT_STOP; 233 } 234 235 /* 236 * Periodically check the file system to see if accounting 237 * should be turned on or off. Beware the case where the vnode 238 * has been vgone()'d out from underneath us, e.g. when the file 239 * system containing the accounting file has been forcibly unmounted. 240 */ 241 static void 242 acctwatch(void *arg) 243 { 244 int error; 245 246 log(LOG_NOTICE, "Accounting started\n"); 247 ACCT_LOCK(); 248 while (acct_state != ACCT_STOP) { 249 if (acct_vp->v_type == VBAD) { 250 log(LOG_NOTICE, "Accounting terminated\n"); 251 acct_stop(); 252 continue; 253 } 254 255 error = acct_chkfree(); 256 #ifdef DIAGNOSTIC 257 if (error != 0) 258 printf("acctwatch: failed to statvfs, error = %d\n", 259 error); 260 #endif 261 262 ACCT_UNLOCK(); 263 error = tsleep(acctwatch, PSWP, "actwat", acctchkfreq * hz); 264 ACCT_LOCK(); 265 #ifdef DIAGNOSTIC 266 if (error != 0 && error != EWOULDBLOCK) 267 printf("acctwatch: sleep error %d\n", error); 268 #endif 269 } 270 acct_dkwatcher = NULL; 271 ACCT_UNLOCK(); 272 273 kthread_exit(0); 274 } 275 276 void 277 acct_init(void) 278 { 279 280 acct_state = ACCT_STOP; 281 acct_vp = NULLVP; 282 acct_cred = NULL; 283 lockinit(&acct_lock, PWAIT, "acctlk", 0, 0); 284 } 285 286 /* 287 * Accounting system call. Written based on the specification and 288 * previous implementation done by Mark Tinguely. 289 */ 290 int 291 sys_acct(struct lwp *l, void *v, register_t *retval) 292 { 293 struct sys_acct_args /* { 294 syscallarg(const char *) path; 295 } */ *uap = v; 296 struct nameidata nd; 297 int error; 298 struct proc *p = l->l_proc; 299 300 /* Make sure that the caller is root. */ 301 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, 302 &p->p_acflag)) != 0) 303 return (error); 304 305 /* 306 * If accounting is to be started to a file, open that file for 307 * writing and make sure it's a 'normal'. 308 */ 309 if (SCARG(uap, path) != NULL) { 310 struct vattr va; 311 size_t pad; 312 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 313 l); 314 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) 315 return (error); 316 if (nd.ni_vp->v_type != VREG) { 317 VOP_UNLOCK(nd.ni_vp, 0); 318 error = EACCES; 319 goto bad; 320 } 321 if ((error = VOP_GETATTR(nd.ni_vp, &va, p->p_cred, l)) != 0) { 322 VOP_UNLOCK(nd.ni_vp, 0); 323 goto bad; 324 } 325 326 if ((pad = (va.va_size % sizeof(struct acct))) != 0) { 327 u_quad_t size = va.va_size - pad; 328 #ifdef DIAGNOSTIC 329 printf("Size of accounting file not a multiple of " 330 "%lu - incomplete record truncated\n", 331 (unsigned long)sizeof(struct acct)); 332 #endif 333 VATTR_NULL(&va); 334 va.va_size = size; 335 error = VOP_SETATTR(nd.ni_vp, &va, p->p_cred, l); 336 if (error != 0) { 337 VOP_UNLOCK(nd.ni_vp, 0); 338 goto bad; 339 } 340 } 341 VOP_UNLOCK(nd.ni_vp, 0); 342 } 343 344 ACCT_LOCK(); 345 346 /* 347 * If accounting was previously enabled, kill the old space-watcher, 348 * free credential for accounting file i/o, 349 * ... (and, if no new file was specified, leave). 350 */ 351 acct_stop(); 352 if (SCARG(uap, path) == NULL) 353 goto out; 354 355 /* 356 * Save the new accounting file vnode and credential, 357 * and schedule the new free space watcher. 358 */ 359 acct_state = ACCT_ACTIVE; 360 acct_vp = nd.ni_vp; 361 acct_cred = p->p_cred; 362 kauth_cred_hold(acct_cred); 363 364 error = acct_chkfree(); /* Initial guess. */ 365 if (error != 0) { 366 acct_stop(); 367 goto out; 368 } 369 370 if (acct_dkwatcher == NULL) { 371 error = kthread_create1(acctwatch, NULL, &acct_dkwatcher, 372 "acctwatch"); 373 if (error != 0) 374 acct_stop(); 375 } 376 377 out: 378 ACCT_UNLOCK(); 379 return (error); 380 bad: 381 vn_close(nd.ni_vp, FWRITE, p->p_cred, l); 382 return error; 383 } 384 385 /* 386 * Write out process accounting information, on process exit. 387 * Data to be written out is specified in Leffler, et al. 388 * and are enumerated below. (They're also noted in the system 389 * "acct.h" header file.) 390 */ 391 int 392 acct_process(struct lwp *l) 393 { 394 struct acct acct; 395 struct rusage *r; 396 struct timeval ut, st, tmp; 397 int s, t, error = 0; 398 struct plimit *oplim = NULL; 399 struct proc *p = l->l_proc; 400 401 ACCT_LOCK(); 402 403 /* If accounting isn't enabled, don't bother */ 404 if (acct_state != ACCT_ACTIVE) 405 goto out; 406 407 /* 408 * Raise the file limit so that accounting can't be stopped by 409 * the user. 410 * 411 * XXX We should think about the CPU limit, too. 412 */ 413 if (p->p_limit->p_refcnt > 1) { 414 oplim = p->p_limit; 415 p->p_limit = limcopy(p->p_limit); 416 } 417 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 418 419 /* 420 * Get process accounting information. 421 */ 422 423 /* (1) The name of the command that ran */ 424 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); 425 426 /* (2) The amount of user and system time that was used */ 427 calcru(p, &ut, &st, NULL); 428 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 429 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 430 431 /* (3) The elapsed time the commmand ran (and its starting time) */ 432 acct.ac_btime = p->p_stats->p_start.tv_sec; 433 s = splclock(); 434 timersub(&time, &p->p_stats->p_start, &tmp); 435 splx(s); 436 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 437 438 /* (4) The average amount of memory used */ 439 r = &p->p_stats->p_ru; 440 timeradd(&ut, &st, &tmp); 441 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 442 if (t) 443 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 444 else 445 acct.ac_mem = 0; 446 447 /* (5) The number of disk I/O operations done */ 448 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 449 450 /* (6) The UID and GID of the process */ 451 acct.ac_uid = kauth_cred_getuid(p->p_cred); 452 acct.ac_gid = kauth_cred_getgid(p->p_cred); 453 454 /* (7) The terminal from which the process was started */ 455 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 456 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 457 else 458 acct.ac_tty = NODEV; 459 460 /* (8) The boolean flags that tell how the process terminated, etc. */ 461 acct.ac_flag = p->p_acflag; 462 463 /* 464 * Now, just write the accounting information to the file. 465 */ 466 VOP_LEASE(acct_vp, l, p->p_cred, LEASE_WRITE); 467 error = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, 468 sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, 469 acct_cred, NULL, NULL); 470 if (error != 0) 471 log(LOG_ERR, "Accounting: write failed %d\n", error); 472 473 if (oplim) { 474 limfree(p->p_limit); 475 p->p_limit = oplim; 476 } 477 478 out: 479 ACCT_UNLOCK(); 480 return (error); 481 } 482
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