kern_acct.c revision 1.47.12.1
1 /* $NetBSD: kern_acct.c,v 1.47.12.1 2000/11/20 18:08:57 bouyer Exp $ */ 2 3 /*- 4 * Copyright (c) 1994 Christopher G. Demetriou 5 * Copyright (c) 1982, 1986, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)kern_acct.c 8.8 (Berkeley) 5/14/95 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/mount.h> 48 #include <sys/vnode.h> 49 #include <sys/file.h> 50 #include <sys/syslog.h> 51 #include <sys/kernel.h> 52 #include <sys/kthread.h> 53 #include <sys/lock.h> 54 #include <sys/malloc.h> 55 #include <sys/namei.h> 56 #include <sys/errno.h> 57 #include <sys/acct.h> 58 #include <sys/resourcevar.h> 59 #include <sys/ioctl.h> 60 #include <sys/tty.h> 61 62 #include <sys/syscallargs.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 * The global accounting state and related data. Gain the lock before 77 * accessing these variables. 78 */ 79 enum { 80 ACCT_STOP, 81 ACCT_ACTIVE, 82 ACCT_SUSPENDED 83 } acct_state; /* The current accounting state. */ 84 struct vnode *acct_vp; /* Accounting vnode pointer. */ 85 struct ucred *acct_ucred; /* Credential of accounting file 86 owner (i.e root). Used when 87 accounting file i/o. */ 88 struct proc *acct_dkwatcher; /* Free disk space checker. */ 89 90 /* 91 * Lock to serialize system calls and kernel threads. 92 */ 93 struct lock acct_lock; 94 #define ACCT_LOCK() \ 95 do { \ 96 (void) lockmgr(&acct_lock, LK_EXCLUSIVE, NULL); \ 97 } while (/* CONSTCOND */0) 98 #define ACCT_UNLOCK() \ 99 do { \ 100 (void) lockmgr(&acct_lock, LK_RELEASE, NULL); \ 101 } while (/* CONSTCOND */0) 102 103 /* 104 * Internal accounting functions. 105 * The former's operation is described in Leffler, et al., and the latter 106 * was provided by UCB with the 4.4BSD-Lite release 107 */ 108 comp_t encode_comp_t __P((u_long, u_long)); 109 void acctwatch __P((void *)); 110 void acct_stop __P((void)); 111 int acct_chkfree __P((void)); 112 113 /* 114 * Values associated with enabling and disabling accounting 115 */ 116 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 117 int acctresume = 4; /* resume when free space risen to > 4% */ 118 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 119 120 void 121 acct_init() 122 { 123 124 acct_state = ACCT_STOP; 125 acct_vp = NULLVP; 126 acct_ucred = NULL; 127 lockinit(&acct_lock, PWAIT, "acctlk", 0, 0); 128 } 129 130 void 131 acct_stop() 132 { 133 int error; 134 135 if (acct_vp != NULLVP && acct_vp->v_type != VBAD) { 136 error = vn_close(acct_vp, FWRITE, acct_ucred, NULL); 137 #ifdef DIAGNOSTIC 138 if (error != 0) 139 printf("acct_stop: failed to close, errno = %d\n", 140 error); 141 #endif 142 acct_vp = NULLVP; 143 } 144 if (acct_ucred != NULL) { 145 crfree(acct_ucred); 146 acct_ucred = NULL; 147 } 148 acct_state = ACCT_STOP; 149 } 150 151 int 152 acct_chkfree() 153 { 154 int error; 155 struct statfs sb; 156 157 error = VFS_STATFS(acct_vp->v_mount, &sb, NULL); 158 if (error != 0) 159 return (error); 160 161 switch (acct_state) { 162 case ACCT_SUSPENDED: 163 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 164 acct_state = ACCT_ACTIVE; 165 log(LOG_NOTICE, "Accounting resumed\n"); 166 } 167 break; 168 case ACCT_ACTIVE: 169 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 170 acct_state = ACCT_SUSPENDED; 171 log(LOG_NOTICE, "Accounting suspended\n"); 172 } 173 break; 174 case ACCT_STOP: 175 break; 176 } 177 return (0); 178 } 179 180 /* 181 * Accounting system call. Written based on the specification and 182 * previous implementation done by Mark Tinguely. 183 */ 184 int 185 sys_acct(p, v, retval) 186 struct proc *p; 187 void *v; 188 register_t *retval; 189 { 190 struct sys_acct_args /* { 191 syscallarg(const char *) path; 192 } */ *uap = v; 193 struct nameidata nd; 194 int error; 195 196 /* Make sure that the caller is root. */ 197 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 198 return (error); 199 200 /* 201 * If accounting is to be started to a file, open that file for 202 * writing and make sure it's a 'normal'. 203 */ 204 if (SCARG(uap, path) != NULL) { 205 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 206 p); 207 if ((error = vn_open(&nd, FWRITE, 0)) != 0) 208 return (error); 209 VOP_UNLOCK(nd.ni_vp, 0); 210 if (nd.ni_vp->v_type != VREG) { 211 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 212 return (EACCES); 213 } 214 } 215 216 ACCT_LOCK(); 217 218 /* 219 * If accounting was previously enabled, kill the old space-watcher, 220 * free credential for accounting file i/o, 221 * ... (and, if no new file was specified, leave). 222 */ 223 acct_stop(); 224 if (SCARG(uap, path) == NULL) 225 goto out; 226 227 /* 228 * Save the new accounting file vnode and credential, 229 * and schedule the new free space watcher. 230 */ 231 acct_state = ACCT_ACTIVE; 232 acct_vp = nd.ni_vp; 233 acct_ucred = p->p_ucred; 234 crhold(acct_ucred); 235 236 error = acct_chkfree(); /* Initial guess. */ 237 if (error != 0) { 238 acct_stop(); 239 goto out; 240 } 241 242 if (acct_dkwatcher == NULL) { 243 error = kthread_create1(acctwatch, NULL, &acct_dkwatcher, 244 "acctwatch"); 245 if (error != 0) 246 acct_stop(); 247 } 248 249 out: 250 ACCT_UNLOCK(); 251 return (error); 252 } 253 254 /* 255 * Write out process accounting information, on process exit. 256 * Data to be written out is specified in Leffler, et al. 257 * and are enumerated below. (They're also noted in the system 258 * "acct.h" header file.) 259 */ 260 int 261 acct_process(p) 262 struct proc *p; 263 { 264 struct acct acct; 265 struct rusage *r; 266 struct timeval ut, st, tmp; 267 int s, t, error = 0; 268 struct plimit *oplim = NULL; 269 270 ACCT_LOCK(); 271 272 /* If accounting isn't enabled, don't bother */ 273 if (acct_state != ACCT_ACTIVE) 274 goto out; 275 276 /* 277 * Raise the file limit so that accounting can't be stopped by 278 * the user. 279 * 280 * XXX We should think about the CPU limit, too. 281 */ 282 if (p->p_limit->p_refcnt > 1) { 283 oplim = p->p_limit; 284 p->p_limit = limcopy(p->p_limit); 285 } 286 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 287 288 /* 289 * Get process accounting information. 290 */ 291 292 /* (1) The name of the command that ran */ 293 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); 294 295 /* (2) The amount of user and system time that was used */ 296 calcru(p, &ut, &st, NULL); 297 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 298 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 299 300 /* (3) The elapsed time the commmand ran (and its starting time) */ 301 acct.ac_btime = p->p_stats->p_start.tv_sec; 302 s = splclock(); 303 timersub(&time, &p->p_stats->p_start, &tmp); 304 splx(s); 305 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 306 307 /* (4) The average amount of memory used */ 308 r = &p->p_stats->p_ru; 309 timeradd(&ut, &st, &tmp); 310 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 311 if (t) 312 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 313 else 314 acct.ac_mem = 0; 315 316 /* (5) The number of disk I/O operations done */ 317 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 318 319 /* (6) The UID and GID of the process */ 320 acct.ac_uid = p->p_cred->p_ruid; 321 acct.ac_gid = p->p_cred->p_rgid; 322 323 /* (7) The terminal from which the process was started */ 324 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 325 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 326 else 327 acct.ac_tty = NODEV; 328 329 /* (8) The boolean flags that tell how the process terminated, etc. */ 330 acct.ac_flag = p->p_acflag; 331 332 /* 333 * Now, just write the accounting information to the file. 334 */ 335 VOP_LEASE(acct_vp, p, p->p_ucred, LEASE_WRITE); 336 error = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, 337 sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, 338 acct_ucred, NULL, p); 339 if (error != 0) 340 log(LOG_ERR, "Accounting: write failed %d\n", error); 341 342 if (oplim) { 343 limfree(p->p_limit); 344 p->p_limit = oplim; 345 } 346 347 out: 348 ACCT_UNLOCK(); 349 return (error); 350 } 351 352 /* 353 * Encode_comp_t converts from ticks in seconds and microseconds 354 * to ticks in 1/AHZ seconds. The encoding is described in 355 * Leffler, et al., on page 63. 356 */ 357 358 #define MANTSIZE 13 /* 13 bit mantissa. */ 359 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 360 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 361 362 comp_t 363 encode_comp_t(s, us) 364 u_long s, us; 365 { 366 int exp, rnd; 367 368 exp = 0; 369 rnd = 0; 370 s *= AHZ; 371 s += us / (1000000 / AHZ); /* Maximize precision. */ 372 373 while (s > MAXFRACT) { 374 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 375 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 376 exp++; 377 } 378 379 /* If we need to round up, do it (and handle overflow correctly). */ 380 if (rnd && (++s > MAXFRACT)) { 381 s >>= EXPSIZE; 382 exp++; 383 } 384 385 /* Clean it up and polish it off. */ 386 exp <<= MANTSIZE; /* Shift the exponent into place */ 387 exp += s; /* and add on the mantissa. */ 388 return (exp); 389 } 390 391 /* 392 * Periodically check the file system to see if accounting 393 * should be turned on or off. Beware the case where the vnode 394 * has been vgone()'d out from underneath us, e.g. when the file 395 * system containing the accounting file has been forcibly unmounted. 396 */ 397 void 398 acctwatch(arg) 399 void *arg; 400 { 401 int error; 402 403 log(LOG_NOTICE, "Accounting started\n"); 404 ACCT_LOCK(); 405 while (acct_state != ACCT_STOP) { 406 if (acct_vp->v_type == VBAD) { 407 log(LOG_NOTICE, "Accounting terminated\n"); 408 acct_stop(); 409 continue; 410 } 411 412 error = acct_chkfree(); 413 #ifdef DIAGNOSTIC 414 if (error != 0) 415 printf("acctwatch: failed to statfs, error = %d\n", 416 error); 417 #endif 418 419 ACCT_UNLOCK(); 420 error = tsleep(acctwatch, PSWP, "actwat", acctchkfreq * hz); 421 ACCT_LOCK(); 422 #ifdef DIAGNOSTIC 423 if (error != 0 && error != EWOULDBLOCK) 424 printf("acctwatch: sleep error %d\n", error); 425 #endif 426 } 427 acct_dkwatcher = NULL; 428 ACCT_UNLOCK(); 429 430 kthread_exit(0); 431 } 432
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