kern_acct.c revision 113624
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 * $FreeBSD: head/sys/kern/kern_acct.c 113624 2003-04-17 22:20:30Z jhb $ 41 */ 42 43#include "opt_mac.h" 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/lock.h> 48#include <sys/mutex.h> 49#include <sys/sysproto.h> 50#include <sys/proc.h> 51#include <sys/mac.h> 52#include <sys/mount.h> 53#include <sys/vnode.h> 54#include <sys/fcntl.h> 55#include <sys/syslog.h> 56#include <sys/kernel.h> 57#include <sys/sysent.h> 58#include <sys/sysctl.h> 59#include <sys/namei.h> 60#include <sys/acct.h> 61#include <sys/resourcevar.h> 62#include <sys/tty.h> 63 64/* 65 * The routines implemented in this file are described in: 66 * Leffler, et al.: The Design and Implementation of the 4.3BSD 67 * UNIX Operating System (Addison Welley, 1989) 68 * on pages 62-63. 69 * 70 * Arguably, to simplify accounting operations, this mechanism should 71 * be replaced by one in which an accounting log file (similar to /dev/klog) 72 * is read by a user process, etc. However, that has its own problems. 73 */ 74 75/* 76 * Internal accounting functions. 77 * The former's operation is described in Leffler, et al., and the latter 78 * was provided by UCB with the 4.4BSD-Lite release 79 */ 80static comp_t encode_comp_t(u_long, u_long); 81static void acctwatch(void *); 82 83/* 84 * Accounting callout used for periodic scheduling of acctwatch. 85 */ 86static struct callout acctwatch_callout; 87 88/* 89 * Accounting vnode pointer, saved vnode pointer, and flags for each. 90 */ 91static struct vnode *acctp; 92static struct ucred *acctcred; 93static int acctflags; 94static struct vnode *savacctp; 95static struct ucred *savacctcred; 96static int savacctflags; 97 98static struct mtx acct_mtx; 99MTX_SYSINIT(acct, &acct_mtx, "accounting", MTX_DEF); 100 101/* 102 * Values associated with enabling and disabling accounting 103 */ 104static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 105SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 106 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 107 108static int acctresume = 4; /* resume when free space risen to > 4% */ 109SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 110 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 111 112static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 113SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 114 &acctchkfreq, 0, "frequency for checking the free space"); 115 116/* 117 * Accounting system call. Written based on the specification and 118 * previous implementation done by Mark Tinguely. 119 * 120 * MPSAFE 121 */ 122int 123acct(td, uap) 124 struct thread *td; 125 struct acct_args /* { 126 char *path; 127 } */ *uap; 128{ 129 struct nameidata nd; 130 int error, flags; 131 132 /* Make sure that the caller is root. */ 133 error = suser(td); 134 if (error) 135 return (error); 136 137 mtx_lock(&Giant); 138 /* 139 * If accounting is to be started to a file, open that file for 140 * appending and make sure it's a 'normal'. 141 */ 142 if (uap->path != NULL) { 143 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td); 144 flags = FWRITE | O_APPEND; 145 error = vn_open(&nd, &flags, 0); 146 if (error) 147 goto done2; 148 NDFREE(&nd, NDF_ONLY_PNBUF); 149#ifdef MAC 150 error = mac_check_system_acct(td->td_ucred, nd.ni_vp); 151 if (error) { 152 vn_close(nd.ni_vp, flags, td->td_ucred, td); 153 goto done2; 154 } 155#endif 156 VOP_UNLOCK(nd.ni_vp, 0, td); 157 if (nd.ni_vp->v_type != VREG) { 158 vn_close(nd.ni_vp, flags, td->td_ucred, td); 159 error = EACCES; 160 goto done2; 161 } 162#ifdef MAC 163 } else { 164 error = mac_check_system_acct(td->td_ucred, NULL); 165 if (error) 166 goto done2; 167#endif 168 } 169 170 /* 171 * If accounting was previously enabled, kill the old space-watcher, 172 * close the file, and (if no new file was specified, leave). 173 */ 174 175 /* 176 * XXX arr: Should not hold lock over vnode operation. 177 */ 178 179 mtx_lock(&acct_mtx); 180 if (acctp != NULLVP || savacctp != NULLVP) { 181 callout_stop(&acctwatch_callout); 182 error = vn_close((acctp != NULLVP ? acctp : savacctp), 183 (acctp != NULLVP ? acctflags : savacctflags), 184 (acctcred != NOCRED ? acctcred : savacctcred), td); 185 acctp = savacctp = NULLVP; 186 crfree(acctcred != NOCRED ? acctcred : savacctcred); 187 acctcred = savacctcred = NOCRED; 188 } 189 if (uap->path == NULL) { 190 mtx_unlock(&acct_mtx); 191 goto done2; 192 } 193 194 /* 195 * Save the new accounting file vnode, and schedule the new 196 * free space watcher. 197 */ 198 acctp = nd.ni_vp; 199 acctcred = crhold(td->td_ucred); 200 acctflags = flags; 201 callout_init(&acctwatch_callout, 0); 202 mtx_unlock(&acct_mtx); 203 acctwatch(NULL); 204done2: 205 mtx_unlock(&Giant); 206 return (error); 207} 208 209/* 210 * Write out process accounting information, on process exit. 211 * Data to be written out is specified in Leffler, et al. 212 * and are enumerated below. (They're also noted in the system 213 * "acct.h" header file.) 214 */ 215 216int 217acct_process(td) 218 struct thread *td; 219{ 220 struct proc *p = td->td_proc; 221 struct acct acct; 222 struct rusage *r; 223 struct timeval ut, st, tmp; 224 int t, ret; 225 struct vnode *vp; 226 struct ucred *uc; 227 228 mtx_lock(&acct_mtx); 229 230 /* If accounting isn't enabled, don't bother */ 231 vp = acctp; 232 if (vp == NULLVP) { 233 mtx_unlock(&acct_mtx); 234 return (0); 235 } 236 237 /* 238 * Get process accounting information. 239 */ 240 241 PROC_LOCK(p); 242 /* (1) The name of the command that ran */ 243 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 244 245 /* (2) The amount of user and system time that was used */ 246 mtx_lock_spin(&sched_lock); 247 calcru(p, &ut, &st, NULL); 248 mtx_unlock_spin(&sched_lock); 249 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 250 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 251 252 /* (3) The elapsed time the command ran (and its starting time) */ 253 acct.ac_btime = p->p_stats->p_start.tv_sec; 254 microtime(&tmp); 255 timevalsub(&tmp, &p->p_stats->p_start); 256 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 257 258 /* (4) The average amount of memory used */ 259 r = &p->p_stats->p_ru; 260 tmp = ut; 261 timevaladd(&tmp, &st); 262 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 263 if (t) 264 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 265 else 266 acct.ac_mem = 0; 267 268 /* (5) The number of disk I/O operations done */ 269 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 270 271 /* (6) The UID and GID of the process */ 272 acct.ac_uid = p->p_ucred->cr_ruid; 273 acct.ac_gid = p->p_ucred->cr_rgid; 274 275 /* (7) The terminal from which the process was started */ 276 SESS_LOCK(p->p_session); 277 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 278 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 279 else 280 acct.ac_tty = NOUDEV; 281 SESS_UNLOCK(p->p_session); 282 283 /* (8) The boolean flags that tell how the process terminated, etc. */ 284 acct.ac_flag = p->p_acflag; 285 PROC_UNLOCK(p); 286 287 /* 288 * Write the accounting information to the file. 289 */ 290 uc = crhold(acctcred); 291 vref(vp); 292 mtx_unlock(&acct_mtx); 293 294 /* 295 * Eliminate any file size rlimit. 296 */ 297 if (p->p_limit->p_refcnt > 1) { 298 p->p_limit->p_refcnt--; 299 p->p_limit = limcopy(p->p_limit); 300 } 301 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 302 303 VOP_LEASE(vp, td, uc, LEASE_WRITE); 304 ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 305 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED, 306 (int *)0, td); 307 vrele(vp); 308 crfree(uc); 309 return (ret); 310} 311 312/* 313 * Encode_comp_t converts from ticks in seconds and microseconds 314 * to ticks in 1/AHZ seconds. The encoding is described in 315 * Leffler, et al., on page 63. 316 */ 317 318#define MANTSIZE 13 /* 13 bit mantissa. */ 319#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 320#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 321 322static comp_t 323encode_comp_t(s, us) 324 u_long s, us; 325{ 326 int exp, rnd; 327 328 exp = 0; 329 rnd = 0; 330 s *= AHZ; 331 s += us / (1000000 / AHZ); /* Maximize precision. */ 332 333 while (s > MAXFRACT) { 334 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 335 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 336 exp++; 337 } 338 339 /* If we need to round up, do it (and handle overflow correctly). */ 340 if (rnd && (++s > MAXFRACT)) { 341 s >>= EXPSIZE; 342 exp++; 343 } 344 345 /* Clean it up and polish it off. */ 346 exp <<= MANTSIZE; /* Shift the exponent into place */ 347 exp += s; /* and add on the mantissa. */ 348 return (exp); 349} 350 351/* 352 * Periodically check the filesystem to see if accounting 353 * should be turned on or off. Beware the case where the vnode 354 * has been vgone()'d out from underneath us, e.g. when the file 355 * system containing the accounting file has been forcibly unmounted. 356 */ 357/* ARGSUSED */ 358static void 359acctwatch(a) 360 void *a; 361{ 362 struct statfs sb; 363 364 mtx_lock(&acct_mtx); 365 366 /* 367 * XXX arr: Need to fix the issue of holding acct_mtx over 368 * the below vnode operations. 369 */ 370 371 if (savacctp != NULLVP) { 372 if (savacctp->v_type == VBAD) { 373 (void) vn_close(savacctp, savacctflags, savacctcred, 374 NULL); 375 savacctp = NULLVP; 376 savacctcred = NOCRED; 377 mtx_unlock(&acct_mtx); 378 return; 379 } 380 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0); 381 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 382 acctp = savacctp; 383 acctcred = savacctcred; 384 acctflags = savacctflags; 385 savacctp = NULLVP; 386 savacctcred = NOCRED; 387 log(LOG_NOTICE, "Accounting resumed\n"); 388 } 389 } else { 390 if (acctp == NULLVP) { 391 mtx_unlock(&acct_mtx); 392 return; 393 } 394 if (acctp->v_type == VBAD) { 395 (void) vn_close(acctp, acctflags, acctcred, NULL); 396 acctp = NULLVP; 397 crfree(acctcred); 398 acctcred = NOCRED; 399 mtx_unlock(&acct_mtx); 400 return; 401 } 402 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0); 403 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 404 savacctp = acctp; 405 savacctflags = acctflags; 406 savacctcred = acctcred; 407 acctp = NULLVP; 408 acctcred = NOCRED; 409 log(LOG_NOTICE, "Accounting suspended\n"); 410 } 411 } 412 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL); 413 mtx_unlock(&acct_mtx); 414} 415