1 /* $NetBSD: kern_acct.c,v 1.47 1998/08/04 04:03:11 perry 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 8.8 (Berkeley) 5/14/95 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 sys_acct(p, v, retval) 99 struct proc *p; 100 void *v; 101 register_t *retval; 102 { 103 struct sys_acct_args /* { 104 syscallarg(const char *) path; 105 } */ *uap = v; 106 struct nameidata nd; 107 int error; 108 109 /* Make sure that the caller is root. */ 110 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 111 return (error); 112 113 /* 114 * If accounting is to be started to a file, open that file for 115 * writing and make sure it's a 'normal'. 116 */ 117 if (SCARG(uap, path) != NULL) { 118 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 119 p); 120 if ((error = vn_open(&nd, FWRITE, 0)) != 0) 121 return (error); 122 VOP_UNLOCK(nd.ni_vp, 0); 123 if (nd.ni_vp->v_type != VREG) { 124 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 125 return (EACCES); 126 } 127 } 128 129 /* 130 * If accounting was previously enabled, kill the old space-watcher, 131 * close the file, and (if no new file was specified, leave). 132 */ 133 if (acctp != NULLVP || savacctp != NULLVP) { 134 untimeout(acctwatch, NULL); 135 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 136 p->p_ucred, p); 137 acctp = savacctp = NULLVP; 138 } 139 if (SCARG(uap, path) == NULL) 140 return (error); 141 142 /* 143 * Save the new accounting file vnode, and schedule the new 144 * free space watcher. 145 */ 146 acctp = nd.ni_vp; 147 acctwatch(NULL); 148 return (error); 149 } 150 151 /* 152 * Write out process accounting information, on process exit. 153 * Data to be written out is specified in Leffler, et al. 154 * and are enumerated below. (They're also noted in the system 155 * "acct.h" header file.) 156 */ 157 int 158 acct_process(p) 159 struct proc *p; 160 { 161 struct acct acct; 162 struct rusage *r; 163 struct timeval ut, st, tmp; 164 int s, t; 165 struct vnode *vp; 166 167 /* If accounting isn't enabled, don't bother */ 168 vp = acctp; 169 if (vp == NULLVP) 170 return (0); 171 172 /* 173 * Get process accounting information. 174 */ 175 176 /* (1) The name of the command that ran */ 177 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); 178 179 /* (2) The amount of user and system time that was used */ 180 calcru(p, &ut, &st, NULL); 181 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 182 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 183 184 /* (3) The elapsed time the commmand ran (and its starting time) */ 185 acct.ac_btime = p->p_stats->p_start.tv_sec; 186 s = splclock(); 187 timersub(&time, &p->p_stats->p_start, &tmp); 188 splx(s); 189 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 190 191 /* (4) The average amount of memory used */ 192 r = &p->p_stats->p_ru; 193 timeradd(&ut, &st, &tmp); 194 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 195 if (t) 196 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 197 else 198 acct.ac_mem = 0; 199 200 /* (5) The number of disk I/O operations done */ 201 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 202 203 /* (6) The UID and GID of the process */ 204 acct.ac_uid = p->p_cred->p_ruid; 205 acct.ac_gid = p->p_cred->p_rgid; 206 207 /* (7) The terminal from which the process was started */ 208 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 209 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 210 else 211 acct.ac_tty = NODEV; 212 213 /* (8) The boolean flags that tell how the process terminated, etc. */ 214 acct.ac_flag = p->p_acflag; 215 216 /* 217 * Now, just write the accounting information to the file. 218 */ 219 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 220 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof(acct), 221 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 222 NULL, p)); 223 } 224 225 /* 226 * Encode_comp_t converts from ticks in seconds and microseconds 227 * to ticks in 1/AHZ seconds. The encoding is described in 228 * Leffler, et al., on page 63. 229 */ 230 231 #define MANTSIZE 13 /* 13 bit mantissa. */ 232 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 233 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 234 235 comp_t 236 encode_comp_t(s, us) 237 u_long s, us; 238 { 239 int exp, rnd; 240 241 exp = 0; 242 rnd = 0; 243 s *= AHZ; 244 s += us / (1000000 / AHZ); /* Maximize precision. */ 245 246 while (s > MAXFRACT) { 247 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 248 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 249 exp++; 250 } 251 252 /* If we need to round up, do it (and handle overflow correctly). */ 253 if (rnd && (++s > MAXFRACT)) { 254 s >>= EXPSIZE; 255 exp++; 256 } 257 258 /* Clean it up and polish it off. */ 259 exp <<= MANTSIZE; /* Shift the exponent into place */ 260 exp += s; /* and add on the mantissa. */ 261 return (exp); 262 } 263 264 /* 265 * Periodically check the file system to see if accounting 266 * should be turned on or off. Beware the case where the vnode 267 * has been vgone()'d out from underneath us, e.g. when the file 268 * system containing the accounting file has been forcibly unmounted. 269 */ 270 /* ARGSUSED */ 271 void 272 acctwatch(a) 273 void *a; 274 { 275 struct statfs sb; 276 277 if (savacctp != NULLVP) { 278 if (savacctp->v_type == VBAD) { 279 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 280 savacctp = NULLVP; 281 return; 282 } 283 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 284 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 285 acctp = savacctp; 286 savacctp = NULLVP; 287 log(LOG_NOTICE, "Accounting resumed\n"); 288 } 289 } else if (acctp != NULLVP) { 290 if (acctp->v_type == VBAD) { 291 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 292 acctp = NULLVP; 293 return; 294 } 295 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 296 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 297 savacctp = acctp; 298 acctp = NULLVP; 299 log(LOG_NOTICE, "Accounting suspended\n"); 300 } 301 } else 302 return; 303 timeout(acctwatch, NULL, acctchkfreq * hz); 304 } 305