1 /* $NetBSD: kern_acct.c,v 1.32 1994/07/04 20:43:06 mycroft 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 8.1 (Berkeley) 6/14/93 42 */ 43 44 #include <sys/param.h> 45 #include <sys/proc.h> 46 #include <sys/mount.h> 47 #include <sys/vnode.h> 48 #include <sys/file.h> 49 #include <sys/syslog.h> 50 #include <sys/kernel.h> 51 #include <sys/namei.h> 52 #include <sys/errno.h> 53 #include <sys/acct.h> 54 #include <sys/resourcevar.h> 55 #include <sys/ioctl.h> 56 #include <sys/tty.h> 57 58 /* 59 * The routines implemented in this file are described in: 60 * Leffler, et al.: The Design and Implementation of the 4.3BSD 61 * UNIX Operating System (Addison Welley, 1989) 62 * on pages 62-63. 63 * 64 * Arguably, to simplify accounting operations, this mechanism should 65 * be replaced by one in which an accounting log file (similar to /dev/klog) 66 * is read by a user process, etc. However, that has its own problems. 67 */ 68 69 /* 70 * Internal accounting functions. 71 * The former's operation is described in Leffler, et al., and the latter 72 * was provided by UCB with the 4.4BSD-Lite release 73 */ 74 comp_t encode_comp_t __P((u_long, u_long)); 75 void acctwatch __P((void *)); 76 77 /* 78 * Accounting vnode pointer, and saved vnode pointer. 79 */ 80 struct vnode *acctp; 81 struct vnode *savacctp; 82 83 /* 84 * Values associated with enabling and disabling accounting 85 */ 86 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 87 int acctresume = 4; /* resume when free space risen to > 4% */ 88 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 89 90 /* 91 * Accounting system call. Written based on the specification and 92 * previous implementation done by Mark Tinguely. 93 */ 94 struct acct_args { 95 char *path; 96 }; 97 acct(p, uap, retval) 98 struct proc *p; 99 struct acct_args *uap; 100 int *retval; 101 { 102 struct nameidata nd; 103 int error; 104 105 /* Make sure that the caller is root. */ 106 if (error = suser(p->p_ucred, &p->p_acflag)) 107 return (error); 108 109 /* 110 * If accounting is to be started to a file, open that file for 111 * writing and make sure it's a 'normal'. 112 */ 113 if (uap->path != NULL) { 114 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, p); 115 if (error = vn_open(&nd, FWRITE, 0)) 116 return (error); 117 VOP_UNLOCK(nd.ni_vp); 118 if (nd.ni_vp->v_type != VREG) { 119 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 120 return (EACCES); 121 } 122 } 123 124 /* 125 * If accounting was previously enabled, kill the old space-watcher, 126 * close the file, and (if no new file was specified, leave). 127 */ 128 if (acctp != NULLVP || savacctp != NULLVP) { 129 untimeout(acctwatch, NULL); 130 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 131 p->p_ucred, p); 132 acctp = savacctp = NULLVP; 133 } 134 if (uap->path == NULL) 135 return (error); 136 137 /* 138 * Save the new accounting file vnode, and schedule the new 139 * free space watcher. 140 */ 141 acctp = nd.ni_vp; 142 acctwatch(NULL); 143 return (error); 144 } 145 146 /* 147 * Write out process accounting information, on process exit. 148 * Data to be written out is specified in Leffler, et al. 149 * and are enumerated below. (They're also noted in the system 150 * "acct.h" header file.) 151 */ 152 acct_process(p) 153 struct proc *p; 154 { 155 struct acct acct; 156 struct rusage *r; 157 struct timeval ut, st, tmp; 158 int s, t; 159 struct vnode *vp; 160 161 /* If accounting isn't enabled, don't bother */ 162 vp = acctp; 163 if (vp == NULLVP) 164 return (0); 165 166 /* 167 * Get process accounting information. 168 */ 169 170 /* (1) The name of the command that ran */ 171 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 172 173 /* (2) The amount of user and system time that was used */ 174 calcru(p, &ut, &st, NULL); 175 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 176 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 177 178 /* (3) The elapsed time the commmand ran (and its starting time) */ 179 acct.ac_btime = p->p_stats->p_start.tv_sec; 180 s = splclock(); 181 tmp = time; 182 splx(s); 183 timevalsub(&tmp, &p->p_stats->p_start); 184 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 185 186 /* (4) The average amount of memory used */ 187 r = &p->p_stats->p_ru; 188 tmp = ut; 189 timevaladd(&tmp, &st); 190 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 191 if (t) 192 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 193 else 194 acct.ac_mem = 0; 195 196 /* (5) The number of disk I/O operations done */ 197 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 198 199 /* (6) The UID and GID of the process */ 200 acct.ac_uid = p->p_cred->p_ruid; 201 acct.ac_gid = p->p_cred->p_rgid; 202 203 /* (7) The terminal from which the process was started */ 204 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 205 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 206 else 207 acct.ac_tty = NODEV; 208 209 /* (8) The boolean flags that tell how the process terminated, etc. */ 210 acct.ac_flag = p->p_acflag; 211 212 /* 213 * Now, just write the accounting information to the file. 214 */ 215 LEASE_CHECK(vp, p, p->p_ucred, LEASE_WRITE); 216 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 217 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 218 (int *)0, p)); 219 } 220 221 /* 222 * Encode_comp_t converts from ticks in seconds and microseconds 223 * to ticks in 1/AHZ seconds. The encoding is described in 224 * Leffler, et al., on page 63. 225 */ 226 227 #define MANTSIZE 13 /* 13 bit mantissa. */ 228 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 229 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 230 231 comp_t 232 encode_comp_t(s, us) 233 u_long s, us; 234 { 235 int exp, rnd; 236 237 exp = 0; 238 rnd = 0; 239 s *= AHZ; 240 s += us / (1000000 / AHZ); /* Maximize precision. */ 241 242 while (s > MAXFRACT) { 243 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 244 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 245 exp++; 246 } 247 248 /* If we need to round up, do it (and handle overflow correctly). */ 249 if (rnd && (++s > MAXFRACT)) { 250 s >>= EXPSIZE; 251 exp++; 252 } 253 254 /* Clean it up and polish it off. */ 255 exp <<= MANTSIZE; /* Shift the exponent into place */ 256 exp += s; /* and add on the mantissa. */ 257 return (exp); 258 } 259 260 /* 261 * Periodically check the file system to see if accounting 262 * should be turned on or off. Beware the case where the vnode 263 * has been vgone()'d out from underneath us, e.g. when the file 264 * system containing the accounting file has been forcibly unmounted. 265 */ 266 /* ARGSUSED */ 267 void 268 acctwatch(a) 269 void *a; 270 { 271 struct statfs sb; 272 273 if (savacctp != NULLVP) { 274 if (savacctp->v_type == VBAD) { 275 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 276 savacctp = NULLVP; 277 return; 278 } 279 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 280 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 281 acctp = savacctp; 282 savacctp = NULLVP; 283 log(LOG_NOTICE, "Accounting resumed\n"); 284 } 285 } else if (acctp != NULLVP) { 286 if (acctp->v_type == VBAD) { 287 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 288 acctp = NULLVP; 289 return; 290 } 291 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 292 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 293 savacctp = acctp; 294 acctp = NULLVP; 295 log(LOG_NOTICE, "Accounting suspended\n"); 296 } 297 } else 298 return; 299 timeout(acctwatch, NULL, acctchkfreq * hz); 300 } 301