kern_acct.c revision 1.66.4.8
1 /* $NetBSD: kern_acct.c,v 1.66.4.8 2007/01/28 01:34:18 ad 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 1.66.4.8 2007/01/28 01:34:18 ad 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/malloc.h> 86 #include <sys/namei.h> 87 #include <sys/errno.h> 88 #include <sys/acct.h> 89 #include <sys/resourcevar.h> 90 #include <sys/ioctl.h> 91 #include <sys/tty.h> 92 #include <sys/kauth.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 * Mutex to serialize system calls and kernel threads. 110 */ 111 kmutex_t acct_mutex; 112 113 /* 114 * The global accounting state and related data. Gain the mutex before 115 * accessing these variables. 116 */ 117 static enum { 118 ACCT_STOP, 119 ACCT_ACTIVE, 120 ACCT_SUSPENDED 121 } acct_state; /* The current accounting state. */ 122 static struct vnode *acct_vp; /* Accounting vnode pointer. */ 123 static kauth_cred_t acct_cred; /* Credential of accounting file 124 owner (i.e root). Used when 125 accounting file i/o. */ 126 static struct proc *acct_dkwatcher; /* Free disk space checker. */ 127 128 /* 129 * Values associated with enabling and disabling accounting 130 */ 131 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 132 int acctresume = 4; /* resume when free space risen to > 4% */ 133 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 134 135 /* 136 * Encode_comp_t converts from ticks in seconds and microseconds 137 * to ticks in 1/AHZ seconds. The encoding is described in 138 * Leffler, et al., on page 63. 139 */ 140 141 #define MANTSIZE 13 /* 13 bit mantissa. */ 142 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 143 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 144 145 static comp_t 146 encode_comp_t(u_long s, u_long us) 147 { 148 int exp, rnd; 149 150 exp = 0; 151 rnd = 0; 152 s *= AHZ; 153 s += us / (1000000 / AHZ); /* Maximize precision. */ 154 155 while (s > MAXFRACT) { 156 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 157 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 158 exp++; 159 } 160 161 /* If we need to round up, do it (and handle overflow correctly). */ 162 if (rnd && (++s > MAXFRACT)) { 163 s >>= EXPSIZE; 164 exp++; 165 } 166 167 /* Clean it up and polish it off. */ 168 exp <<= MANTSIZE; /* Shift the exponent into place */ 169 exp += s; /* and add on the mantissa. */ 170 return (exp); 171 } 172 173 static int 174 acct_chkfree(void) 175 { 176 int error; 177 struct statvfs *sb; 178 int64_t bavail; 179 180 sb = malloc(sizeof(*sb), M_TEMP, M_WAITOK); 181 error = VFS_STATVFS(acct_vp->v_mount, sb, NULL); 182 if (error != 0) 183 return (error); 184 185 bavail = sb->f_bfree - sb->f_bresvd; 186 187 switch (acct_state) { 188 case ACCT_SUSPENDED: 189 if (bavail > acctresume * sb->f_blocks / 100) { 190 acct_state = ACCT_ACTIVE; 191 log(LOG_NOTICE, "Accounting resumed\n"); 192 } 193 break; 194 case ACCT_ACTIVE: 195 if (bavail <= acctsuspend * sb->f_blocks / 100) { 196 acct_state = ACCT_SUSPENDED; 197 log(LOG_NOTICE, "Accounting suspended\n"); 198 } 199 break; 200 case ACCT_STOP: 201 break; 202 } 203 free(sb, M_TEMP); 204 return (0); 205 } 206 207 static void 208 acct_stop(void) 209 { 210 int error; 211 212 if (acct_vp != NULLVP && acct_vp->v_type != VBAD) { 213 error = vn_close(acct_vp, FWRITE, acct_cred, NULL); 214 #ifdef DIAGNOSTIC 215 if (error != 0) 216 printf("acct_stop: failed to close, errno = %d\n", 217 error); 218 #endif 219 acct_vp = NULLVP; 220 } 221 if (acct_cred != NULL) { 222 kauth_cred_free(acct_cred); 223 acct_cred = NULL; 224 } 225 acct_state = ACCT_STOP; 226 } 227 228 /* 229 * Periodically check the file system to see if accounting 230 * should be turned on or off. Beware the case where the vnode 231 * has been vgone()'d out from underneath us, e.g. when the file 232 * system containing the accounting file has been forcibly unmounted. 233 */ 234 static void 235 acctwatch(void *arg) 236 { 237 int error; 238 239 log(LOG_NOTICE, "Accounting started\n"); 240 mutex_enter(&acct_mutex); 241 while (acct_state != ACCT_STOP) { 242 if (acct_vp->v_type == VBAD) { 243 log(LOG_NOTICE, "Accounting terminated\n"); 244 acct_stop(); 245 continue; 246 } 247 248 error = acct_chkfree(); 249 #ifdef DIAGNOSTIC 250 if (error != 0) 251 printf("acctwatch: failed to statvfs, error = %d\n", 252 error); 253 #endif 254 error = kpause("actwat", FALSE, acctchkfreq * hz, &acct_mutex); 255 #ifdef DIAGNOSTIC 256 if (error != 0 && error != EWOULDBLOCK) 257 printf("acctwatch: sleep error %d\n", error); 258 #endif 259 } 260 acct_dkwatcher = NULL; 261 mutex_exit(&acct_mutex); 262 263 kthread_exit(0); 264 } 265 266 void 267 acct_init(void) 268 { 269 270 acct_state = ACCT_STOP; 271 acct_vp = NULLVP; 272 acct_cred = NULL; 273 mutex_init(&acct_mutex, MUTEX_DEFAULT, IPL_NONE); 274 } 275 276 /* 277 * Accounting system call. Written based on the specification and 278 * previous implementation done by Mark Tinguely. 279 */ 280 int 281 sys_acct(struct lwp *l, void *v, register_t *retval) 282 { 283 struct sys_acct_args /* { 284 syscallarg(const char *) path; 285 } */ *uap = v; 286 struct nameidata nd; 287 int error; 288 289 /* Make sure that the caller is root. */ 290 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_ACCOUNTING, 291 0, NULL, NULL, NULL))) 292 return (error); 293 294 /* 295 * If accounting is to be started to a file, open that file for 296 * writing and make sure it's a 'normal'. 297 */ 298 if (SCARG(uap, path) != NULL) { 299 struct vattr va; 300 size_t pad; 301 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 302 l); 303 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) 304 return (error); 305 if (nd.ni_vp->v_type != VREG) { 306 VOP_UNLOCK(nd.ni_vp, 0); 307 error = EACCES; 308 goto bad; 309 } 310 if ((error = VOP_GETATTR(nd.ni_vp, &va, l->l_cred, l)) != 0) { 311 VOP_UNLOCK(nd.ni_vp, 0); 312 goto bad; 313 } 314 315 if ((pad = (va.va_size % sizeof(struct acct))) != 0) { 316 u_quad_t size = va.va_size - pad; 317 #ifdef DIAGNOSTIC 318 printf("Size of accounting file not a multiple of " 319 "%lu - incomplete record truncated\n", 320 (unsigned long)sizeof(struct acct)); 321 #endif 322 VATTR_NULL(&va); 323 va.va_size = size; 324 error = VOP_SETATTR(nd.ni_vp, &va, l->l_cred, l); 325 if (error != 0) { 326 VOP_UNLOCK(nd.ni_vp, 0); 327 goto bad; 328 } 329 } 330 VOP_UNLOCK(nd.ni_vp, 0); 331 } 332 333 mutex_enter(&acct_mutex); 334 335 /* 336 * If accounting was previously enabled, kill the old space-watcher, 337 * free credential for accounting file i/o, 338 * ... (and, if no new file was specified, leave). 339 */ 340 acct_stop(); 341 if (SCARG(uap, path) == NULL) 342 goto out; 343 344 /* 345 * Save the new accounting file vnode and credential, 346 * and schedule the new free space watcher. 347 */ 348 acct_state = ACCT_ACTIVE; 349 acct_vp = nd.ni_vp; 350 acct_cred = l->l_cred; 351 kauth_cred_hold(acct_cred); 352 353 error = acct_chkfree(); /* Initial guess. */ 354 if (error != 0) { 355 acct_stop(); 356 goto out; 357 } 358 359 if (acct_dkwatcher == NULL) { 360 error = kthread_create1(acctwatch, NULL, &acct_dkwatcher, 361 "acctwatch"); 362 if (error != 0) 363 acct_stop(); 364 } 365 366 out: 367 mutex_exit(&acct_mutex); 368 return (error); 369 bad: 370 vn_close(nd.ni_vp, FWRITE, l->l_cred, l); 371 return error; 372 } 373 374 /* 375 * Write out process accounting information, on process exit. 376 * Data to be written out is specified in Leffler, et al. 377 * and are enumerated below. (They're also noted in the system 378 * "acct.h" header file.) 379 */ 380 int 381 acct_process(struct lwp *l) 382 { 383 struct acct acct; 384 struct timeval ut, st, tmp; 385 struct rusage *r; 386 int t, error = 0; 387 struct plimit *oplim = NULL; 388 struct proc *p = l->l_proc; 389 390 mutex_enter(&acct_mutex); 391 392 /* If accounting isn't enabled, don't bother */ 393 if (acct_state != ACCT_ACTIVE) 394 goto out; 395 396 /* 397 * Raise the file limit so that accounting can't be stopped by 398 * the user. 399 * 400 * XXX We should think about the CPU limit, too. 401 */ 402 if (p->p_limit->p_refcnt > 1) { 403 oplim = p->p_limit; 404 p->p_limit = limcopy(p->p_limit); 405 } 406 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 407 408 /* 409 * Get process accounting information. 410 */ 411 412 /* (1) The name of the command that ran */ 413 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); 414 415 /* (2) The amount of user and system time that was used */ 416 mutex_enter(&p->p_smutex); 417 calcru(p, &ut, &st, NULL, NULL); 418 mutex_exit(&p->p_smutex); 419 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 420 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 421 422 /* (3) The elapsed time the commmand ran (and its starting time) */ 423 acct.ac_btime = p->p_stats->p_start.tv_sec; 424 getmicrotime(&tmp); 425 timersub(&tmp, &p->p_stats->p_start, &tmp); 426 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 427 428 /* (4) The average amount of memory used */ 429 r = &p->p_stats->p_ru; 430 timeradd(&ut, &st, &tmp); 431 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 432 if (t) 433 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 434 else 435 acct.ac_mem = 0; 436 437 /* (5) The number of disk I/O operations done */ 438 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 439 440 /* (6) The UID and GID of the process */ 441 acct.ac_uid = kauth_cred_getuid(l->l_cred); 442 acct.ac_gid = kauth_cred_getgid(l->l_cred); 443 444 /* (7) The terminal from which the process was started */ 445 rw_enter(&proclist_lock, RW_READER); 446 if ((p->p_lflag & PL_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 447 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 448 else 449 acct.ac_tty = NODEV; 450 rw_exit(&proclist_lock); 451 452 /* (8) The boolean flags that tell how the process terminated, etc. */ 453 acct.ac_flag = p->p_acflag; 454 455 /* 456 * Now, just write the accounting information to the file. 457 */ 458 VOP_LEASE(acct_vp, l, l->l_cred, LEASE_WRITE); 459 error = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, 460 sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, 461 acct_cred, NULL, NULL); 462 if (error != 0) 463 log(LOG_ERR, "Accounting: write failed %d\n", error); 464 465 if (oplim) { 466 limfree(p->p_limit); 467 p->p_limit = oplim; 468 } 469 470 out: 471 mutex_exit(&acct_mutex); 472 return (error); 473 } 474
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