kern_acct.c revision 116182
1/*- 2 * Copyright (c) 1994 Christopher G. Demetriou 3 * Copyright (c) 1982, 1986, 1989, 1993 4 * The Regents of the University of California. All rights reserved. 5 * (c) UNIX System Laboratories, Inc. 6 * All or some portions of this file are derived from material licensed 7 * to the University of California by American Telephone and Telegraph 8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 9 * the permission of UNIX System Laboratories, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 40 */ 41 42#include <sys/cdefs.h> 43__FBSDID("$FreeBSD: head/sys/kern/kern_acct.c 116182 2003-06-11 00:56:59Z obrien $"); 44 45#include "opt_mac.h" 46 47#include <sys/param.h> 48#include <sys/systm.h> 49#include <sys/lock.h> 50#include <sys/mutex.h> 51#include <sys/sysproto.h> 52#include <sys/proc.h> 53#include <sys/mac.h> 54#include <sys/mount.h> 55#include <sys/vnode.h> 56#include <sys/fcntl.h> 57#include <sys/syslog.h> 58#include <sys/kernel.h> 59#include <sys/sysent.h> 60#include <sys/sysctl.h> 61#include <sys/namei.h> 62#include <sys/acct.h> 63#include <sys/resourcevar.h> 64#include <sys/tty.h> 65 66/* 67 * The routines implemented in this file are described in: 68 * Leffler, et al.: The Design and Implementation of the 4.3BSD 69 * UNIX Operating System (Addison Welley, 1989) 70 * on pages 62-63. 71 * 72 * Arguably, to simplify accounting operations, this mechanism should 73 * be replaced by one in which an accounting log file (similar to /dev/klog) 74 * is read by a user process, etc. However, that has its own problems. 75 */ 76 77/* 78 * Internal accounting functions. 79 * The former's operation is described in Leffler, et al., and the latter 80 * was provided by UCB with the 4.4BSD-Lite release 81 */ 82static comp_t encode_comp_t(u_long, u_long); 83static void acctwatch(void *); 84 85/* 86 * Accounting callout used for periodic scheduling of acctwatch. 87 */ 88static struct callout acctwatch_callout; 89 90/* 91 * Accounting vnode pointer, saved vnode pointer, and flags for each. 92 */ 93static struct vnode *acctp; 94static struct ucred *acctcred; 95static int acctflags; 96static struct vnode *savacctp; 97static struct ucred *savacctcred; 98static int savacctflags; 99 100static struct mtx acct_mtx; 101MTX_SYSINIT(acct, &acct_mtx, "accounting", MTX_DEF); 102 103/* 104 * Values associated with enabling and disabling accounting 105 */ 106static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 107SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 108 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 109 110static int acctresume = 4; /* resume when free space risen to > 4% */ 111SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 112 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 113 114static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 115SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 116 &acctchkfreq, 0, "frequency for checking the free space"); 117 118/* 119 * Accounting system call. Written based on the specification and 120 * previous implementation done by Mark Tinguely. 121 * 122 * MPSAFE 123 */ 124int 125acct(td, uap) 126 struct thread *td; 127 struct acct_args /* { 128 char *path; 129 } */ *uap; 130{ 131 struct nameidata nd; 132 int error, flags; 133 134 /* Make sure that the caller is root. */ 135 error = suser(td); 136 if (error) 137 return (error); 138 139 mtx_lock(&Giant); 140 /* 141 * If accounting is to be started to a file, open that file for 142 * appending and make sure it's a 'normal'. 143 */ 144 if (uap->path != NULL) { 145 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td); 146 flags = FWRITE | O_APPEND; 147 error = vn_open(&nd, &flags, 0); 148 if (error) 149 goto done2; 150 NDFREE(&nd, NDF_ONLY_PNBUF); 151#ifdef MAC 152 error = mac_check_system_acct(td->td_ucred, nd.ni_vp); 153 if (error) { 154 vn_close(nd.ni_vp, flags, td->td_ucred, td); 155 goto done2; 156 } 157#endif 158 VOP_UNLOCK(nd.ni_vp, 0, td); 159 if (nd.ni_vp->v_type != VREG) { 160 vn_close(nd.ni_vp, flags, td->td_ucred, td); 161 error = EACCES; 162 goto done2; 163 } 164#ifdef MAC 165 } else { 166 error = mac_check_system_acct(td->td_ucred, NULL); 167 if (error) 168 goto done2; 169#endif 170 } 171 172 /* 173 * If accounting was previously enabled, kill the old space-watcher, 174 * close the file, and (if no new file was specified, leave). 175 */ 176 177 /* 178 * XXX arr: Should not hold lock over vnode operation. 179 */ 180 181 mtx_lock(&acct_mtx); 182 if (acctp != NULLVP || savacctp != NULLVP) { 183 callout_stop(&acctwatch_callout); 184 error = vn_close((acctp != NULLVP ? acctp : savacctp), 185 (acctp != NULLVP ? acctflags : savacctflags), 186 (acctcred != NOCRED ? acctcred : savacctcred), td); 187 acctp = savacctp = NULLVP; 188 crfree(acctcred != NOCRED ? acctcred : savacctcred); 189 acctcred = savacctcred = NOCRED; 190 } 191 if (uap->path == NULL) { 192 mtx_unlock(&acct_mtx); 193 goto done2; 194 } 195 196 /* 197 * Save the new accounting file vnode, and schedule the new 198 * free space watcher. 199 */ 200 acctp = nd.ni_vp; 201 acctcred = crhold(td->td_ucred); 202 acctflags = flags; 203 callout_init(&acctwatch_callout, 0); 204 mtx_unlock(&acct_mtx); 205 acctwatch(NULL); 206done2: 207 mtx_unlock(&Giant); 208 return (error); 209} 210 211/* 212 * Write out process accounting information, on process exit. 213 * Data to be written out is specified in Leffler, et al. 214 * and are enumerated below. (They're also noted in the system 215 * "acct.h" header file.) 216 */ 217 218int 219acct_process(td) 220 struct thread *td; 221{ 222 struct proc *p = td->td_proc; 223 struct acct acct; 224 struct rusage *r; 225 struct timeval ut, st, tmp; 226 int t, ret; 227 struct vnode *vp; 228 struct ucred *uc; 229 230 mtx_lock(&acct_mtx); 231 232 /* If accounting isn't enabled, don't bother */ 233 vp = acctp; 234 if (vp == NULLVP) { 235 mtx_unlock(&acct_mtx); 236 return (0); 237 } 238 239 /* 240 * Get process accounting information. 241 */ 242 243 PROC_LOCK(p); 244 /* (1) The name of the command that ran */ 245 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 246 247 /* (2) The amount of user and system time that was used */ 248 mtx_lock_spin(&sched_lock); 249 calcru(p, &ut, &st, NULL); 250 mtx_unlock_spin(&sched_lock); 251 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 252 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 253 254 /* (3) The elapsed time the command ran (and its starting time) */ 255 tmp = boottime; 256 timevaladd(&tmp, &p->p_stats->p_start); 257 acct.ac_btime = tmp.tv_sec; 258 microuptime(&tmp); 259 timevalsub(&tmp, &p->p_stats->p_start); 260 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 261 262 /* (4) The average amount of memory used */ 263 r = &p->p_stats->p_ru; 264 tmp = ut; 265 timevaladd(&tmp, &st); 266 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 267 if (t) 268 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 269 else 270 acct.ac_mem = 0; 271 272 /* (5) The number of disk I/O operations done */ 273 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 274 275 /* (6) The UID and GID of the process */ 276 acct.ac_uid = p->p_ucred->cr_ruid; 277 acct.ac_gid = p->p_ucred->cr_rgid; 278 279 /* (7) The terminal from which the process was started */ 280 SESS_LOCK(p->p_session); 281 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 282 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 283 else 284 acct.ac_tty = NOUDEV; 285 SESS_UNLOCK(p->p_session); 286 287 /* (8) The boolean flags that tell how the process terminated, etc. */ 288 acct.ac_flag = p->p_acflag; 289 PROC_UNLOCK(p); 290 291 /* 292 * Write the accounting information to the file. 293 */ 294 uc = crhold(acctcred); 295 vref(vp); 296 mtx_unlock(&acct_mtx); 297 298 /* 299 * Eliminate any file size rlimit. 300 */ 301 if (p->p_limit->p_refcnt > 1) { 302 p->p_limit->p_refcnt--; 303 p->p_limit = limcopy(p->p_limit); 304 } 305 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 306 307 VOP_LEASE(vp, td, uc, LEASE_WRITE); 308 ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 309 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED, 310 (int *)0, td); 311 vrele(vp); 312 crfree(uc); 313 return (ret); 314} 315 316/* 317 * Encode_comp_t converts from ticks in seconds and microseconds 318 * to ticks in 1/AHZ seconds. The encoding is described in 319 * Leffler, et al., on page 63. 320 */ 321 322#define MANTSIZE 13 /* 13 bit mantissa. */ 323#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 324#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 325 326static comp_t 327encode_comp_t(s, us) 328 u_long s, us; 329{ 330 int exp, rnd; 331 332 exp = 0; 333 rnd = 0; 334 s *= AHZ; 335 s += us / (1000000 / AHZ); /* Maximize precision. */ 336 337 while (s > MAXFRACT) { 338 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 339 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 340 exp++; 341 } 342 343 /* If we need to round up, do it (and handle overflow correctly). */ 344 if (rnd && (++s > MAXFRACT)) { 345 s >>= EXPSIZE; 346 exp++; 347 } 348 349 /* Clean it up and polish it off. */ 350 exp <<= MANTSIZE; /* Shift the exponent into place */ 351 exp += s; /* and add on the mantissa. */ 352 return (exp); 353} 354 355/* 356 * Periodically check the filesystem to see if accounting 357 * should be turned on or off. Beware the case where the vnode 358 * has been vgone()'d out from underneath us, e.g. when the file 359 * system containing the accounting file has been forcibly unmounted. 360 */ 361/* ARGSUSED */ 362static void 363acctwatch(a) 364 void *a; 365{ 366 struct statfs sb; 367 368 mtx_lock(&acct_mtx); 369 370 /* 371 * XXX arr: Need to fix the issue of holding acct_mtx over 372 * the below vnode operations. 373 */ 374 375 if (savacctp != NULLVP) { 376 if (savacctp->v_type == VBAD) { 377 (void) vn_close(savacctp, savacctflags, savacctcred, 378 NULL); 379 savacctp = NULLVP; 380 savacctcred = NOCRED; 381 mtx_unlock(&acct_mtx); 382 return; 383 } 384 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0); 385 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 386 acctp = savacctp; 387 acctcred = savacctcred; 388 acctflags = savacctflags; 389 savacctp = NULLVP; 390 savacctcred = NOCRED; 391 log(LOG_NOTICE, "Accounting resumed\n"); 392 } 393 } else { 394 if (acctp == NULLVP) { 395 mtx_unlock(&acct_mtx); 396 return; 397 } 398 if (acctp->v_type == VBAD) { 399 (void) vn_close(acctp, acctflags, acctcred, NULL); 400 acctp = NULLVP; 401 crfree(acctcred); 402 acctcred = NOCRED; 403 mtx_unlock(&acct_mtx); 404 return; 405 } 406 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0); 407 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 408 savacctp = acctp; 409 savacctflags = acctflags; 410 savacctcred = acctcred; 411 acctp = NULLVP; 412 acctcred = NOCRED; 413 log(LOG_NOTICE, "Accounting suspended\n"); 414 } 415 } 416 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL); 417 mtx_unlock(&acct_mtx); 418} 419