kern_acct.c revision 48726
1254562Scy/*- 2254562Scy * Copyright (c) 1994 Christopher G. Demetriou 3254562Scy * Copyright (c) 1982, 1986, 1989, 1993 4254562Scy * The Regents of the University of California. All rights reserved. 5254562Scy * (c) UNIX System Laboratories, Inc. 6254562Scy * All or some portions of this file are derived from material licensed 7254562Scy * to the University of California by American Telephone and Telegraph 8254562Scy * Co. or Unix System Laboratories, Inc. and are reproduced herein with 9254562Scy * the permission of UNIX System Laboratories, Inc. 10254562Scy * 11254562Scy * Redistribution and use in source and binary forms, with or without 12254562Scy * modification, are permitted provided that the following conditions 13254562Scy * are met: 14254562Scy * 1. Redistributions of source code must retain the above copyright 15254562Scy * notice, this list of conditions and the following disclaimer. 16254562Scy * 2. Redistributions in binary form must reproduce the above copyright 17254562Scy * notice, this list of conditions and the following disclaimer in the 18254562Scy * documentation and/or other materials provided with the distribution. 19254562Scy * 3. All advertising materials mentioning features or use of this software 20254562Scy * must display the following acknowledgement: 21254562Scy * This product includes software developed by the University of 22254562Scy * California, Berkeley and its contributors. 23254562Scy * 4. Neither the name of the University nor the names of its contributors 24254562Scy * may be used to endorse or promote products derived from this software 25254562Scy * without specific prior written permission. 26254562Scy * 27254562Scy * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28254562Scy * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29254562Scy * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30254562Scy * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31254562Scy * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32254562Scy * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33254562Scy * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34254562Scy * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35254562Scy * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36254562Scy * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37254562Scy * SUCH DAMAGE. 38254562Scy * 39254562Scy * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 40254562Scy * $Id: kern_acct.c,v 1.20 1999/04/27 11:15:53 phk Exp $ 41254562Scy */ 42254562Scy 43254562Scy#include <sys/param.h> 44254562Scy#include <sys/systm.h> 45254562Scy#include <sys/sysproto.h> 46254562Scy#include <sys/proc.h> 47254562Scy#include <sys/mount.h> 48254562Scy#include <sys/vnode.h> 49254562Scy#include <sys/fcntl.h> 50254562Scy#include <sys/syslog.h> 51254562Scy#include <sys/kernel.h> 52254562Scy#include <sys/sysent.h> 53254562Scy#include <sys/sysctl.h> 54254562Scy#include <sys/namei.h> 55254562Scy#include <sys/acct.h> 56254562Scy#include <sys/resourcevar.h> 57254562Scy#include <sys/tty.h> 58254562Scy 59254562Scy/* 60254562Scy * The routines implemented in this file are described in: 61254562Scy * Leffler, et al.: The Design and Implementation of the 4.3BSD 62254562Scy * UNIX Operating System (Addison Welley, 1989) 63254562Scy * on pages 62-63. 64254562Scy * 65254562Scy * Arguably, to simplify accounting operations, this mechanism should 66254562Scy * be replaced by one in which an accounting log file (similar to /dev/klog) 67254562Scy * is read by a user process, etc. However, that has its own problems. 68254562Scy */ 69254562Scy 70254562Scy/* 71254562Scy * Internal accounting functions. 72254562Scy * The former's operation is described in Leffler, et al., and the latter 73254562Scy * was provided by UCB with the 4.4BSD-Lite release 74254562Scy */ 75254562Scystatic comp_t encode_comp_t __P((u_long, u_long)); 76254562Scystatic void acctwatch __P((void *)); 77254562Scy 78254562Scy/* 79254562Scy * Accounting callout handle used for periodic scheduling of 80254562Scy * acctwatch. 81254562Scy */ 82254562Scystatic struct callout_handle acctwatch_handle 83254562Scy = CALLOUT_HANDLE_INITIALIZER(&acctwatch_handle); 84254562Scy 85254562Scy/* 86254562Scy * Accounting vnode pointer, and saved vnode pointer. 87254562Scy */ 88254562Scystatic struct vnode *acctp; 89254562Scystatic struct vnode *savacctp; 90254562Scy 91254562Scy/* 92254562Scy * Values associated with enabling and disabling accounting 93254562Scy */ 94254562Scystatic int acctsuspend = 2; /* stop accounting when < 2% free space left */ 95254562ScySYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 96 &acctsuspend, 0, ""); 97 98static int acctresume = 4; /* resume when free space risen to > 4% */ 99SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 100 &acctresume, 0, ""); 101 102static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 103SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 104 &acctchkfreq, 0, ""); 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; 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 error = vn_open(&nd, FWRITE, 0); 134 if (error) 135 return (error); 136 VOP_UNLOCK(nd.ni_vp, 0, p); 137 if (nd.ni_vp->v_type != VREG) { 138 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 139 return (EACCES); 140 } 141 } 142 143 /* 144 * If accounting was previously enabled, kill the old space-watcher, 145 * close the file, and (if no new file was specified, leave). 146 */ 147 if (acctp != NULLVP || savacctp != NULLVP) { 148 untimeout(acctwatch, NULL, acctwatch_handle); 149 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 150 p->p_ucred, p); 151 acctp = savacctp = NULLVP; 152 } 153 if (SCARG(uap, path) == NULL) 154 return (error); 155 156 /* 157 * Save the new accounting file vnode, and schedule the new 158 * free space watcher. 159 */ 160 acctp = nd.ni_vp; 161 acctwatch(NULL); 162 return (error); 163} 164 165/* 166 * Write out process accounting information, on process exit. 167 * Data to be written out is specified in Leffler, et al. 168 * and are enumerated below. (They're also noted in the system 169 * "acct.h" header file.) 170 */ 171 172int 173acct_process(p) 174 struct proc *p; 175{ 176 struct acct acct; 177 struct rusage *r; 178 struct timeval ut, st, tmp; 179 int t; 180 struct vnode *vp; 181 182 /* If accounting isn't enabled, don't bother */ 183 vp = acctp; 184 if (vp == NULLVP) 185 return (0); 186 187 /* 188 * Get process accounting information. 189 */ 190 191 /* (1) The name of the command that ran */ 192 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 193 194 /* (2) The amount of user and system time that was used */ 195 calcru(p, &ut, &st, NULL); 196 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 197 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 198 199 /* (3) The elapsed time the commmand ran (and its starting time) */ 200 acct.ac_btime = p->p_stats->p_start.tv_sec; 201 microtime(&tmp); 202 timevalsub(&tmp, &p->p_stats->p_start); 203 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 204 205 /* (4) The average amount of memory used */ 206 r = &p->p_stats->p_ru; 207 tmp = ut; 208 timevaladd(&tmp, &st); 209 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 210 if (t) 211 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 212 else 213 acct.ac_mem = 0; 214 215 /* (5) The number of disk I/O operations done */ 216 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 217 218 /* (6) The UID and GID of the process */ 219 acct.ac_uid = p->p_cred->p_ruid; 220 acct.ac_gid = p->p_cred->p_rgid; 221 222 /* (7) The terminal from which the process was started */ 223 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 224 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 225 else 226 acct.ac_tty = NOUDEV; 227 228 /* (8) The boolean flags that tell how the process terminated, etc. */ 229 acct.ac_flag = p->p_acflag; 230 231 /* 232 * Eliminate any file size rlimit. 233 */ 234 if (p->p_limit->p_refcnt > 1 && 235 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 236 p->p_limit->p_refcnt--; 237 p->p_limit = limcopy(p->p_limit); 238 } 239 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 240 241 /* 242 * Write the accounting information to the file. 243 */ 244 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 245 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 246 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 247 (int *)0, p)); 248} 249 250/* 251 * Encode_comp_t converts from ticks in seconds and microseconds 252 * to ticks in 1/AHZ seconds. The encoding is described in 253 * Leffler, et al., on page 63. 254 */ 255 256#define MANTSIZE 13 /* 13 bit mantissa. */ 257#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 258#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 259 260static comp_t 261encode_comp_t(s, us) 262 u_long s, us; 263{ 264 int exp, rnd; 265 266 exp = 0; 267 rnd = 0; 268 s *= AHZ; 269 s += us / (1000000 / AHZ); /* Maximize precision. */ 270 271 while (s > MAXFRACT) { 272 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 273 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 274 exp++; 275 } 276 277 /* If we need to round up, do it (and handle overflow correctly). */ 278 if (rnd && (++s > MAXFRACT)) { 279 s >>= EXPSIZE; 280 exp++; 281 } 282 283 /* Clean it up and polish it off. */ 284 exp <<= MANTSIZE; /* Shift the exponent into place */ 285 exp += s; /* and add on the mantissa. */ 286 return (exp); 287} 288 289/* 290 * Periodically check the file system to see if accounting 291 * should be turned on or off. Beware the case where the vnode 292 * has been vgone()'d out from underneath us, e.g. when the file 293 * system containing the accounting file has been forcibly unmounted. 294 */ 295/* ARGSUSED */ 296static void 297acctwatch(a) 298 void *a; 299{ 300 struct statfs sb; 301 302 if (savacctp != NULLVP) { 303 if (savacctp->v_type == VBAD) { 304 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 305 savacctp = NULLVP; 306 return; 307 } 308 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 309 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 310 acctp = savacctp; 311 savacctp = NULLVP; 312 log(LOG_NOTICE, "Accounting resumed\n"); 313 } 314 } else { 315 if (acctp == NULLVP) 316 return; 317 if (acctp->v_type == VBAD) { 318 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 319 acctp = NULLVP; 320 return; 321 } 322 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 323 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 324 savacctp = acctp; 325 acctp = NULLVP; 326 log(LOG_NOTICE, "Accounting suspended\n"); 327 } 328 } 329 acctwatch_handle = timeout(acctwatch, NULL, acctchkfreq * hz); 330} 331