kern_acct.c revision 12221
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 * $Id: kern_acct.c,v 1.8 1995/10/29 15:30:56 phk Exp $ 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/file.h> 50#include <sys/syslog.h> 51#include <sys/kernel.h> 52#include <sys/namei.h> 53#include <sys/errno.h> 54#include <sys/acct.h> 55#include <sys/resourcevar.h> 56#include <sys/ioctl.h> 57#include <sys/tty.h> 58 59/* 60 * The routines implemented in this file are described in: 61 * Leffler, et al.: The Design and Implementation of the 4.3BSD 62 * UNIX Operating System (Addison Welley, 1989) 63 * on pages 62-63. 64 * 65 * Arguably, to simplify accounting operations, this mechanism should 66 * be replaced by one in which an accounting log file (similar to /dev/klog) 67 * is read by a user process, etc. However, that has its own problems. 68 */ 69 70/* 71 * Internal accounting functions. 72 * The former's operation is described in Leffler, et al., and the latter 73 * was provided by UCB with the 4.4BSD-Lite release 74 */ 75comp_t encode_comp_t __P((u_long, u_long)); 76void acctwatch __P((void *)); 77 78/* 79 * Accounting vnode pointer, and saved vnode pointer. 80 */ 81struct vnode *acctp; 82struct vnode *savacctp; 83 84/* 85 * Values associated with enabling and disabling accounting 86 */ 87int acctsuspend = 2; /* stop accounting when < 2% free space left */ 88int acctresume = 4; /* resume when free space risen to > 4% */ 89int acctchkfreq = 15; /* frequency (in seconds) to check space */ 90 91/* 92 * Accounting system call. Written based on the specification and 93 * previous implementation done by Mark Tinguely. 94 */ 95#ifndef _SYS_SYSPROTO_H_ 96struct acct_args { 97 char *path; 98}; 99 100#endif 101int 102acct(p, uap, retval) 103 struct proc *p; 104 struct acct_args *uap; 105 int *retval; 106{ 107 struct nameidata nd; 108 int error; 109 110 /* Make sure that the caller is root. */ 111 error = suser(p->p_ucred, &p->p_acflag); 112 if (error) 113 return (error); 114 115 /* 116 * If accounting is to be started to a file, open that file for 117 * writing and make sure it's a 'normal'. 118 */ 119 if (uap->path != NULL) { 120 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, p); 121 error = vn_open(&nd, FWRITE, 0); 122 if (error) 123 return (error); 124 VOP_UNLOCK(nd.ni_vp); 125 if (nd.ni_vp->v_type != VREG) { 126 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 127 return (EACCES); 128 } 129 } 130 131 /* 132 * If accounting was previously enabled, kill the old space-watcher, 133 * close the file, and (if no new file was specified, leave). 134 */ 135 if (acctp != NULLVP || savacctp != NULLVP) { 136 untimeout(acctwatch, NULL); 137 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 138 p->p_ucred, p); 139 acctp = savacctp = NULLVP; 140 } 141 if (uap->path == NULL) 142 return (error); 143 144 /* 145 * Save the new accounting file vnode, and schedule the new 146 * free space watcher. 147 */ 148 acctp = nd.ni_vp; 149 acctwatch(NULL); 150 return (error); 151} 152 153/* 154 * Write out process accounting information, on process exit. 155 * Data to be written out is specified in Leffler, et al. 156 * and are enumerated below. (They're also noted in the system 157 * "acct.h" header file.) 158 */ 159 160int 161acct_process(p) 162 struct proc *p; 163{ 164 struct acct acct; 165 struct rusage *r; 166 struct timeval ut, st, tmp; 167 int t; 168 struct vnode *vp; 169 170 /* If accounting isn't enabled, don't bother */ 171 vp = acctp; 172 if (vp == NULLVP) 173 return (0); 174 175 /* 176 * Get process accounting information. 177 */ 178 179 /* (1) The name of the command that ran */ 180 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 181 182 /* (2) The amount of user and system time that was used */ 183 calcru(p, &ut, &st, NULL); 184 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 185 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 186 187 /* (3) The elapsed time the commmand ran (and its starting time) */ 188 acct.ac_btime = p->p_stats->p_start.tv_sec; 189 microtime(&tmp); 190 timevalsub(&tmp, &p->p_stats->p_start); 191 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 192 193 /* (4) The average amount of memory used */ 194 r = &p->p_stats->p_ru; 195 tmp = ut; 196 timevaladd(&tmp, &st); 197 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 198 if (t) 199 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 200 else 201 acct.ac_mem = 0; 202 203 /* (5) The number of disk I/O operations done */ 204 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 205 206 /* (6) The UID and GID of the process */ 207 acct.ac_uid = p->p_cred->p_ruid; 208 acct.ac_gid = p->p_cred->p_rgid; 209 210 /* (7) The terminal from which the process was started */ 211 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 212 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 213 else 214 acct.ac_tty = NODEV; 215 216 /* (8) The boolean flags that tell how the process terminated, etc. */ 217 acct.ac_flag = p->p_acflag; 218 219 /* 220 * Now, just write the accounting information to the file. 221 */ 222 LEASE_CHECK(vp, p, p->p_ucred, LEASE_WRITE); 223 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 224 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 225 (int *)0, p)); 226} 227 228/* 229 * Encode_comp_t converts from ticks in seconds and microseconds 230 * to ticks in 1/AHZ seconds. The encoding is described in 231 * Leffler, et al., on page 63. 232 */ 233 234#define MANTSIZE 13 /* 13 bit mantissa. */ 235#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 236#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 237 238comp_t 239encode_comp_t(s, us) 240 u_long s, us; 241{ 242 int exp, rnd; 243 244 exp = 0; 245 rnd = 0; 246 s *= AHZ; 247 s += us / (1000000 / AHZ); /* Maximize precision. */ 248 249 while (s > MAXFRACT) { 250 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 251 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 252 exp++; 253 } 254 255 /* If we need to round up, do it (and handle overflow correctly). */ 256 if (rnd && (++s > MAXFRACT)) { 257 s >>= EXPSIZE; 258 exp++; 259 } 260 261 /* Clean it up and polish it off. */ 262 exp <<= MANTSIZE; /* Shift the exponent into place */ 263 exp += s; /* and add on the mantissa. */ 264 return (exp); 265} 266 267/* 268 * Periodically check the file system to see if accounting 269 * should be turned on or off. Beware the case where the vnode 270 * has been vgone()'d out from underneath us, e.g. when the file 271 * system containing the accounting file has been forcibly unmounted. 272 */ 273/* ARGSUSED */ 274void 275acctwatch(a) 276 void *a; 277{ 278 struct statfs sb; 279 280 if (savacctp != NULLVP) { 281 if (savacctp->v_type == VBAD) { 282 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 283 savacctp = NULLVP; 284 return; 285 } 286 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 287 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 288 acctp = savacctp; 289 savacctp = NULLVP; 290 log(LOG_NOTICE, "Accounting resumed\n"); 291 } 292 } else if (acctp != NULLVP) { 293 if (acctp->v_type == VBAD) { 294 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 295 acctp = NULLVP; 296 return; 297 } 298 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 299 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 300 savacctp = acctp; 301 acctp = NULLVP; 302 log(LOG_NOTICE, "Accounting suspended\n"); 303 } 304 } else 305 return; 306 timeout(acctwatch, NULL, acctchkfreq * hz); 307} 308