kern_acct.c revision 71498
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 71498 2001-01-24 00:28:07Z jhb $ 41 */ 42 43#include <sys/param.h> 44#include <sys/systm.h> 45#include <sys/sysproto.h> 46#include <sys/proc.h> 47#include <sys/mount.h> 48#include <sys/vnode.h> 49#include <sys/fcntl.h> 50#include <sys/syslog.h> 51#include <sys/kernel.h> 52#include <sys/sysent.h> 53#include <sys/sysctl.h> 54#include <sys/namei.h> 55#include <sys/acct.h> 56#include <sys/resourcevar.h> 57#include <sys/tty.h> 58 59 60/* 61 * The routines implemented in this file are described in: 62 * Leffler, et al.: The Design and Implementation of the 4.3BSD 63 * UNIX Operating System (Addison Welley, 1989) 64 * on pages 62-63. 65 * 66 * Arguably, to simplify accounting operations, this mechanism should 67 * be replaced by one in which an accounting log file (similar to /dev/klog) 68 * is read by a user process, etc. However, that has its own problems. 69 */ 70 71/* 72 * Internal accounting functions. 73 * The former's operation is described in Leffler, et al., and the latter 74 * was provided by UCB with the 4.4BSD-Lite release 75 */ 76static comp_t encode_comp_t __P((u_long, u_long)); 77static void acctwatch __P((void *)); 78 79/* 80 * Accounting callout used for periodic scheduling of acctwatch. 81 */ 82static struct callout acctwatch_callout; 83 84/* 85 * Accounting vnode pointer, and saved vnode pointer. 86 */ 87static struct vnode *acctp; 88static struct vnode *savacctp; 89 90/* 91 * Values associated with enabling and disabling accounting 92 */ 93static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 94SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 95 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 96 97static int acctresume = 4; /* resume when free space risen to > 4% */ 98SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 99 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 100 101static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 102SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 103 &acctchkfreq, 0, "frequency for checking the free space"); 104 105/* 106 * Accounting system call. Written based on the specification and 107 * previous implementation done by Mark Tinguely. 108 */ 109int 110acct(a1, uap) 111 struct proc *a1; 112 struct acct_args /* { 113 syscallarg(char *) path; 114 } */ *uap; 115{ 116 struct proc *p = curproc; /* XXX */ 117 struct ucred *uc; 118 struct nameidata nd; 119 int error, flags; 120 121 /* Make sure that the caller is root. */ 122 error = suser(p); 123 if (error) 124 return (error); 125 126 /* 127 * If accounting is to be started to a file, open that file for 128 * writing and make sure it's a 'normal'. 129 */ 130 if (SCARG(uap, path) != NULL) { 131 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 132 p); 133 flags = FWRITE; 134 error = vn_open(&nd, &flags, 0); 135 if (error) 136 return (error); 137 NDFREE(&nd, NDF_ONLY_PNBUF); 138 VOP_UNLOCK(nd.ni_vp, 0, p); 139 if (nd.ni_vp->v_type != VREG) { 140 PROC_LOCK(p); 141 uc = p->p_ucred; 142 crhold(uc); 143 PROC_UNLOCK(p); 144 vn_close(nd.ni_vp, FWRITE, uc, p); 145 crfree(uc); 146 return (EACCES); 147 } 148 } 149 150 /* 151 * If accounting was previously enabled, kill the old space-watcher, 152 * close the file, and (if no new file was specified, leave). 153 */ 154 if (acctp != NULLVP || savacctp != NULLVP) { 155 callout_stop(&acctwatch_callout); 156 PROC_LOCK(p); 157 uc = p->p_ucred; 158 crhold(uc); 159 PROC_UNLOCK(p); 160 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 161 uc, p); 162 crfree(uc); 163 acctp = savacctp = NULLVP; 164 } 165 if (SCARG(uap, path) == NULL) 166 return (error); 167 168 /* 169 * Save the new accounting file vnode, and schedule the new 170 * free space watcher. 171 */ 172 acctp = nd.ni_vp; 173 callout_init(&acctwatch_callout, 0); 174 acctwatch(NULL); 175 return (error); 176} 177 178/* 179 * Write out process accounting information, on process exit. 180 * Data to be written out is specified in Leffler, et al. 181 * and are enumerated below. (They're also noted in the system 182 * "acct.h" header file.) 183 */ 184 185int 186acct_process(p) 187 struct proc *p; 188{ 189 struct acct acct; 190 struct ucred *uc; 191 struct rusage *r; 192 struct timeval ut, st, tmp; 193 int t, error; 194 struct vnode *vp; 195 196 /* If accounting isn't enabled, don't bother */ 197 vp = acctp; 198 if (vp == NULLVP) 199 return (0); 200 201 /* 202 * Get process accounting information. 203 */ 204 205 /* (1) The name of the command that ran */ 206 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 207 208 /* (2) The amount of user and system time that was used */ 209 mtx_enter(&sched_lock, MTX_SPIN); 210 calcru(p, &ut, &st, NULL); 211 mtx_exit(&sched_lock, MTX_SPIN); 212 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 213 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 214 215 /* (3) The elapsed time the commmand ran (and its starting time) */ 216 acct.ac_btime = p->p_stats->p_start.tv_sec; 217 microtime(&tmp); 218 timevalsub(&tmp, &p->p_stats->p_start); 219 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 220 221 /* (4) The average amount of memory used */ 222 r = &p->p_stats->p_ru; 223 tmp = ut; 224 timevaladd(&tmp, &st); 225 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 226 if (t) 227 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 228 else 229 acct.ac_mem = 0; 230 231 /* (5) The number of disk I/O operations done */ 232 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 233 234 PROC_LOCK(p); 235 /* (6) The UID and GID of the process */ 236 acct.ac_uid = p->p_cred->p_ruid; 237 acct.ac_gid = p->p_cred->p_rgid; 238 239 /* (7) The terminal from which the process was started */ 240 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 241 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 242 else 243 acct.ac_tty = NOUDEV; 244 245 /* (8) The boolean flags that tell how the process terminated, etc. */ 246 acct.ac_flag = p->p_acflag; 247 248 /* 249 * Eliminate any file size rlimit. 250 */ 251 mtx_assert(&Giant, MA_OWNED); 252 if (p->p_limit->p_refcnt > 1 && 253 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 254 p->p_limit->p_refcnt--; 255 p->p_limit = limcopy(p->p_limit); 256 } 257 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 258 259 /* 260 * Write the accounting information to the file. 261 */ 262 uc = p->p_ucred; 263 crhold(uc); 264 PROC_UNLOCK(p); 265 VOP_LEASE(vp, p, uc, LEASE_WRITE); 266 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 267 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, (int *)0, p); 268 crfree(uc); 269 return (error); 270} 271 272/* 273 * Encode_comp_t converts from ticks in seconds and microseconds 274 * to ticks in 1/AHZ seconds. The encoding is described in 275 * Leffler, et al., on page 63. 276 */ 277 278#define MANTSIZE 13 /* 13 bit mantissa. */ 279#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 280#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 281 282static comp_t 283encode_comp_t(s, us) 284 u_long s, us; 285{ 286 int exp, rnd; 287 288 exp = 0; 289 rnd = 0; 290 s *= AHZ; 291 s += us / (1000000 / AHZ); /* Maximize precision. */ 292 293 while (s > MAXFRACT) { 294 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 295 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 296 exp++; 297 } 298 299 /* If we need to round up, do it (and handle overflow correctly). */ 300 if (rnd && (++s > MAXFRACT)) { 301 s >>= EXPSIZE; 302 exp++; 303 } 304 305 /* Clean it up and polish it off. */ 306 exp <<= MANTSIZE; /* Shift the exponent into place */ 307 exp += s; /* and add on the mantissa. */ 308 return (exp); 309} 310 311/* 312 * Periodically check the file system to see if accounting 313 * should be turned on or off. Beware the case where the vnode 314 * has been vgone()'d out from underneath us, e.g. when the file 315 * system containing the accounting file has been forcibly unmounted. 316 */ 317/* ARGSUSED */ 318static void 319acctwatch(a) 320 void *a; 321{ 322 struct statfs sb; 323 324 if (savacctp != NULLVP) { 325 if (savacctp->v_type == VBAD) { 326 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 327 savacctp = NULLVP; 328 return; 329 } 330 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 331 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 332 acctp = savacctp; 333 savacctp = NULLVP; 334 log(LOG_NOTICE, "Accounting resumed\n"); 335 } 336 } else { 337 if (acctp == NULLVP) 338 return; 339 if (acctp->v_type == VBAD) { 340 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 341 acctp = NULLVP; 342 return; 343 } 344 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 345 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 346 savacctp = acctp; 347 acctp = NULLVP; 348 log(LOG_NOTICE, "Accounting suspended\n"); 349 } 350 } 351 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL); 352} 353