1 /* $NetBSD: kern_acct.c,v 1.39 1995/03/21 13:33:46 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/systm.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 #include <sys/syscallargs.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 */ 77 comp_t encode_comp_t __P((u_long, u_long)); 78 void acctwatch __P((void *)); 79 80 /* 81 * Accounting vnode pointer, and saved vnode pointer. 82 */ 83 struct vnode *acctp; 84 struct vnode *savacctp; 85 86 /* 87 * Values associated with enabling and disabling accounting 88 */ 89 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 90 int acctresume = 4; /* resume when free space risen to > 4% */ 91 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 92 93 /* 94 * Accounting system call. Written based on the specification and 95 * previous implementation done by Mark Tinguely. 96 */ 97 int 98 acct(p, uap, retval) 99 struct proc *p; 100 struct acct_args /* { 101 syscallarg(char *) path; 102 } */ *uap; 103 register_t *retval; 104 { 105 struct nameidata nd; 106 int error; 107 108 /* Make sure that the caller is root. */ 109 if (error = suser(p->p_ucred, &p->p_acflag)) 110 return (error); 111 112 /* 113 * If accounting is to be started to a file, open that file for 114 * writing and make sure it's a 'normal'. 115 */ 116 if (SCARG(uap, path) != NULL) { 117 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 118 p); 119 if (error = vn_open(&nd, FWRITE, 0)) 120 return (error); 121 VOP_UNLOCK(nd.ni_vp); 122 if (nd.ni_vp->v_type != VREG) { 123 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 124 return (EACCES); 125 } 126 } 127 128 /* 129 * If accounting was previously enabled, kill the old space-watcher, 130 * close the file, and (if no new file was specified, leave). 131 */ 132 if (acctp != NULLVP || savacctp != NULLVP) { 133 untimeout(acctwatch, NULL); 134 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 135 p->p_ucred, p); 136 acctp = savacctp = NULLVP; 137 } 138 if (SCARG(uap, path) == NULL) 139 return (error); 140 141 /* 142 * Save the new accounting file vnode, and schedule the new 143 * free space watcher. 144 */ 145 acctp = nd.ni_vp; 146 acctwatch(NULL); 147 return (error); 148 } 149 150 /* 151 * Write out process accounting information, on process exit. 152 * Data to be written out is specified in Leffler, et al. 153 * and are enumerated below. (They're also noted in the system 154 * "acct.h" header file.) 155 */ 156 int 157 acct_process(p) 158 struct proc *p; 159 { 160 struct acct acct; 161 struct rusage *r; 162 struct timeval ut, st, tmp; 163 int s, t; 164 struct vnode *vp; 165 166 /* If accounting isn't enabled, don't bother */ 167 vp = acctp; 168 if (vp == NULLVP) 169 return (0); 170 171 /* 172 * Get process accounting information. 173 */ 174 175 /* (1) The name of the command that ran */ 176 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 177 178 /* (2) The amount of user and system time that was used */ 179 calcru(p, &ut, &st, NULL); 180 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 181 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 182 183 /* (3) The elapsed time the commmand ran (and its starting time) */ 184 acct.ac_btime = p->p_stats->p_start.tv_sec; 185 s = splclock(); 186 timersub(&time, &p->p_stats->p_start, &tmp); 187 splx(s); 188 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 189 190 /* (4) The average amount of memory used */ 191 r = &p->p_stats->p_ru; 192 timeradd(&ut, &st, &tmp); 193 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 194 if (t) 195 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 196 else 197 acct.ac_mem = 0; 198 199 /* (5) The number of disk I/O operations done */ 200 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 201 202 /* (6) The UID and GID of the process */ 203 acct.ac_uid = p->p_cred->p_ruid; 204 acct.ac_gid = p->p_cred->p_rgid; 205 206 /* (7) The terminal from which the process was started */ 207 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 208 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 209 else 210 acct.ac_tty = NODEV; 211 212 /* (8) The boolean flags that tell how the process terminated, etc. */ 213 acct.ac_flag = p->p_acflag; 214 215 /* 216 * Now, just write the accounting information to the file. 217 */ 218 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 219 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 220 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 221 (int *)0, p)); 222 } 223 224 /* 225 * Encode_comp_t converts from ticks in seconds and microseconds 226 * to ticks in 1/AHZ seconds. The encoding is described in 227 * Leffler, et al., on page 63. 228 */ 229 230 #define MANTSIZE 13 /* 13 bit mantissa. */ 231 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 232 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 233 234 comp_t 235 encode_comp_t(s, us) 236 u_long s, us; 237 { 238 int exp, rnd; 239 240 exp = 0; 241 rnd = 0; 242 s *= AHZ; 243 s += us / (1000000 / AHZ); /* Maximize precision. */ 244 245 while (s > MAXFRACT) { 246 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 247 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 248 exp++; 249 } 250 251 /* If we need to round up, do it (and handle overflow correctly). */ 252 if (rnd && (++s > MAXFRACT)) { 253 s >>= EXPSIZE; 254 exp++; 255 } 256 257 /* Clean it up and polish it off. */ 258 exp <<= MANTSIZE; /* Shift the exponent into place */ 259 exp += s; /* and add on the mantissa. */ 260 return (exp); 261 } 262 263 /* 264 * Periodically check the file system to see if accounting 265 * should be turned on or off. Beware the case where the vnode 266 * has been vgone()'d out from underneath us, e.g. when the file 267 * system containing the accounting file has been forcibly unmounted. 268 */ 269 /* ARGSUSED */ 270 void 271 acctwatch(a) 272 void *a; 273 { 274 struct statfs sb; 275 276 if (savacctp != NULLVP) { 277 if (savacctp->v_type == VBAD) { 278 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 279 savacctp = NULLVP; 280 return; 281 } 282 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 283 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 284 acctp = savacctp; 285 savacctp = NULLVP; 286 log(LOG_NOTICE, "Accounting resumed\n"); 287 } 288 } else if (acctp != NULLVP) { 289 if (acctp->v_type == VBAD) { 290 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 291 acctp = NULLVP; 292 return; 293 } 294 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 295 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 296 savacctp = acctp; 297 acctp = NULLVP; 298 log(LOG_NOTICE, "Accounting suspended\n"); 299 } 300 } else 301 return; 302 timeout(acctwatch, NULL, acctchkfreq * hz); 303 } 304