kern_acct.c revision 82509
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 82509 2001-08-29 17:18:04Z rwatson $ 41 */ 42 43#include <sys/param.h> 44#include <sys/systm.h> 45#include <sys/lock.h> 46#include <sys/mutex.h> 47#include <sys/sysproto.h> 48#include <sys/proc.h> 49#include <sys/mount.h> 50#include <sys/vnode.h> 51#include <sys/fcntl.h> 52#include <sys/syslog.h> 53#include <sys/kernel.h> 54#include <sys/sysent.h> 55#include <sys/sysctl.h> 56#include <sys/namei.h> 57#include <sys/acct.h> 58#include <sys/resourcevar.h> 59#include <sys/tty.h> 60 61/* 62 * The routines implemented in this file are described in: 63 * Leffler, et al.: The Design and Implementation of the 4.3BSD 64 * UNIX Operating System (Addison Welley, 1989) 65 * on pages 62-63. 66 * 67 * Arguably, to simplify accounting operations, this mechanism should 68 * be replaced by one in which an accounting log file (similar to /dev/klog) 69 * is read by a user process, etc. However, that has its own problems. 70 */ 71 72/* 73 * Internal accounting functions. 74 * The former's operation is described in Leffler, et al., and the latter 75 * was provided by UCB with the 4.4BSD-Lite release 76 */ 77static comp_t encode_comp_t __P((u_long, u_long)); 78static void acctwatch __P((void *)); 79 80/* 81 * Accounting callout used for periodic scheduling of acctwatch. 82 */ 83static struct callout acctwatch_callout; 84 85/* 86 * Accounting vnode pointer, and saved vnode pointer. 87 */ 88static struct vnode *acctp; 89static struct vnode *savacctp; 90 91/* 92 * Values associated with enabling and disabling accounting 93 */ 94static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 95SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 96 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 97 98static int acctresume = 4; /* resume when free space risen to > 4% */ 99SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 100 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 101 102static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 103SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 104 &acctchkfreq, 0, "frequency for checking the free space"); 105 106/* 107 * Accounting system call. Written based on the specification and 108 * previous implementation done by Mark Tinguely. 109 */ 110int 111acct(a1, uap) 112 struct proc *a1; 113 struct acct_args /* { 114 syscallarg(char *) path; 115 } */ *uap; 116{ 117 struct proc *p = curproc; /* XXX */ 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 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 141 return (EACCES); 142 } 143 } 144 145 /* 146 * If accounting was previously enabled, kill the old space-watcher, 147 * close the file, and (if no new file was specified, leave). 148 */ 149 if (acctp != NULLVP || savacctp != NULLVP) { 150 callout_stop(&acctwatch_callout); 151 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 152 p->p_ucred, p); 153 acctp = savacctp = NULLVP; 154 } 155 if (SCARG(uap, path) == NULL) 156 return (error); 157 158 /* 159 * Save the new accounting file vnode, and schedule the new 160 * free space watcher. 161 */ 162 acctp = nd.ni_vp; 163 callout_init(&acctwatch_callout, 0); 164 acctwatch(NULL); 165 return (error); 166} 167 168/* 169 * Write out process accounting information, on process exit. 170 * Data to be written out is specified in Leffler, et al. 171 * and are enumerated below. (They're also noted in the system 172 * "acct.h" header file.) 173 */ 174 175int 176acct_process(p) 177 struct proc *p; 178{ 179 struct acct acct; 180 struct rusage *r; 181 struct timeval ut, st, tmp; 182 int t; 183 struct vnode *vp; 184 185 /* If accounting isn't enabled, don't bother */ 186 vp = acctp; 187 if (vp == NULLVP) 188 return (0); 189 190 /* 191 * Get process accounting information. 192 */ 193 194 /* (1) The name of the command that ran */ 195 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 196 197 /* (2) The amount of user and system time that was used */ 198 mtx_lock_spin(&sched_lock); 199 calcru(p, &ut, &st, NULL); 200 mtx_unlock_spin(&sched_lock); 201 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 202 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 203 204 /* (3) The elapsed time the commmand ran (and its starting time) */ 205 acct.ac_btime = p->p_stats->p_start.tv_sec; 206 microtime(&tmp); 207 timevalsub(&tmp, &p->p_stats->p_start); 208 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 209 210 /* (4) The average amount of memory used */ 211 r = &p->p_stats->p_ru; 212 tmp = ut; 213 timevaladd(&tmp, &st); 214 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 215 if (t) 216 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 217 else 218 acct.ac_mem = 0; 219 220 /* (5) The number of disk I/O operations done */ 221 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 222 223 /* (6) The UID and GID of the process */ 224 acct.ac_uid = p->p_ucred->cr_ruid; 225 acct.ac_gid = p->p_ucred->cr_rgid; 226 227 /* (7) The terminal from which the process was started */ 228 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 229 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 230 else 231 acct.ac_tty = NOUDEV; 232 233 /* (8) The boolean flags that tell how the process terminated, etc. */ 234 acct.ac_flag = p->p_acflag; 235 236 /* 237 * Eliminate any file size rlimit. 238 */ 239 if (p->p_limit->p_refcnt > 1 && 240 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 241 p->p_limit->p_refcnt--; 242 p->p_limit = limcopy(p->p_limit); 243 } 244 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 245 246 /* 247 * Write the accounting information to the file. 248 */ 249 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 250 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 251 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 252 (int *)0, p)); 253} 254 255/* 256 * Encode_comp_t converts from ticks in seconds and microseconds 257 * to ticks in 1/AHZ seconds. The encoding is described in 258 * Leffler, et al., on page 63. 259 */ 260 261#define MANTSIZE 13 /* 13 bit mantissa. */ 262#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 263#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 264 265static comp_t 266encode_comp_t(s, us) 267 u_long s, us; 268{ 269 int exp, rnd; 270 271 exp = 0; 272 rnd = 0; 273 s *= AHZ; 274 s += us / (1000000 / AHZ); /* Maximize precision. */ 275 276 while (s > MAXFRACT) { 277 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 278 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 279 exp++; 280 } 281 282 /* If we need to round up, do it (and handle overflow correctly). */ 283 if (rnd && (++s > MAXFRACT)) { 284 s >>= EXPSIZE; 285 exp++; 286 } 287 288 /* Clean it up and polish it off. */ 289 exp <<= MANTSIZE; /* Shift the exponent into place */ 290 exp += s; /* and add on the mantissa. */ 291 return (exp); 292} 293 294/* 295 * Periodically check the file system to see if accounting 296 * should be turned on or off. Beware the case where the vnode 297 * has been vgone()'d out from underneath us, e.g. when the file 298 * system containing the accounting file has been forcibly unmounted. 299 */ 300/* ARGSUSED */ 301static void 302acctwatch(a) 303 void *a; 304{ 305 struct statfs sb; 306 307 if (savacctp != NULLVP) { 308 if (savacctp->v_type == VBAD) { 309 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 310 savacctp = NULLVP; 311 return; 312 } 313 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 314 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 315 acctp = savacctp; 316 savacctp = NULLVP; 317 log(LOG_NOTICE, "Accounting resumed\n"); 318 } 319 } else { 320 if (acctp == NULLVP) 321 return; 322 if (acctp->v_type == VBAD) { 323 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 324 acctp = NULLVP; 325 return; 326 } 327 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 328 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 329 savacctp = acctp; 330 acctp = NULLVP; 331 log(LOG_NOTICE, "Accounting suspended\n"); 332 } 333 } 334 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL); 335} 336