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 1.14 1997/03/23 03:36:17 bde 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/fcntl.h> 50 #include <sys/syslog.h> 51 #include <sys/kernel.h> 52 #include <sys/sysent.h> 53 #include <sys/sysctl.h> 54 #include <sys/namei.h> 55 #include <sys/errno.h> 56 #include <sys/acct.h> 57 #include <sys/resourcevar.h> 58 #include <sys/tty.h> 59 60 /* 61 * The routines implemented in this file are described in: 62 * Leffler, et al.: The Design and Implementation of the 4.3BSD 63 * UNIX Operating System (Addison Welley, 1989) 64 * on pages 62-63. 65 * 66 * Arguably, to simplify accounting operations, this mechanism should 67 * be replaced by one in which an accounting log file (similar to /dev/klog) 68 * is read by a user process, etc. However, that has its own problems. 69 */ 70 71 /* 72 * Internal accounting functions. 73 * The former's operation is described in Leffler, et al., and the latter 74 * was provided by UCB with the 4.4BSD-Lite release 75 */ 76 static comp_t encode_comp_t __P((u_long, u_long)); 77 static void acctwatch __P((void *)); 78 79 /* 80 * Accounting vnode pointer, and saved vnode pointer. 81 */ 82 static struct vnode *acctp; 83 static struct vnode *savacctp; 84 85 /* 86 * Values associated with enabling and disabling accounting 87 */ 88 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 89 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 90 &acctsuspend, 0, ""); 91 92 static int acctresume = 4; /* resume when free space risen to > 4% */ 93 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 94 &acctresume, 0, ""); 95 96 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 97 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 98 &acctchkfreq, 0, ""); 99 100 /* 101 * Accounting system call. Written based on the specification and 102 * previous implementation done by Mark Tinguely. 103 */ 104 int 105 acct(a1, uap, a3) 106 struct proc *a1; 107 struct acct_args /* { 108 syscallarg(char *) path; 109 } */ *uap; 110 int *a3; 111 { 112 struct proc *p = curproc; /* XXX */ 113 struct nameidata nd; 114 int error; 115 116 /* Make sure that the caller is root. */ 117 error = suser(p->p_ucred, &p->p_acflag); 118 if (error) 119 return (error); 120 121 /* 122 * If accounting is to be started to a file, open that file for 123 * writing and make sure it's a 'normal'. 124 */ 125 if (SCARG(uap, path) != NULL) { 126 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 127 p); 128 error = vn_open(&nd, FWRITE, 0); 129 if (error) 130 return (error); 131 VOP_UNLOCK(nd.ni_vp, 0, p); 132 if (nd.ni_vp->v_type != VREG) { 133 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 134 return (EACCES); 135 } 136 } 137 138 /* 139 * If accounting was previously enabled, kill the old space-watcher, 140 * close the file, and (if no new file was specified, leave). 141 */ 142 if (acctp != NULLVP || savacctp != NULLVP) { 143 untimeout(acctwatch, NULL); 144 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 145 p->p_ucred, p); 146 acctp = savacctp = NULLVP; 147 } 148 if (SCARG(uap, path) == NULL) 149 return (error); 150 151 /* 152 * Save the new accounting file vnode, and schedule the new 153 * free space watcher. 154 */ 155 acctp = nd.ni_vp; 156 acctwatch(NULL); 157 return (error); 158 } 159 160 /* 161 * Write out process accounting information, on process exit. 162 * Data to be written out is specified in Leffler, et al. 163 * and are enumerated below. (They're also noted in the system 164 * "acct.h" header file.) 165 */ 166 167 int 168 acct_process(p) 169 struct proc *p; 170 { 171 struct acct acct; 172 struct rusage *r; 173 struct timeval ut, st, tmp; 174 int t; 175 struct vnode *vp; 176 177 /* If accounting isn't enabled, don't bother */ 178 vp = acctp; 179 if (vp == NULLVP) 180 return (0); 181 182 /* 183 * Get process accounting information. 184 */ 185 186 /* (1) The name of the command that ran */ 187 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 188 189 /* (2) The amount of user and system time that was used */ 190 calcru(p, &ut, &st, NULL); 191 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 192 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 193 194 /* (3) The elapsed time the commmand ran (and its starting time) */ 195 acct.ac_btime = p->p_stats->p_start.tv_sec; 196 microtime(&tmp); 197 timevalsub(&tmp, &p->p_stats->p_start); 198 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 199 200 /* (4) The average amount of memory used */ 201 r = &p->p_stats->p_ru; 202 tmp = ut; 203 timevaladd(&tmp, &st); 204 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 205 if (t) 206 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 207 else 208 acct.ac_mem = 0; 209 210 /* (5) The number of disk I/O operations done */ 211 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 212 213 /* (6) The UID and GID of the process */ 214 acct.ac_uid = p->p_cred->p_ruid; 215 acct.ac_gid = p->p_cred->p_rgid; 216 217 /* (7) The terminal from which the process was started */ 218 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 219 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 220 else 221 acct.ac_tty = NODEV; 222 223 /* (8) The boolean flags that tell how the process terminated, etc. */ 224 acct.ac_flag = p->p_acflag; 225 226 /* 227 * Now, just write the accounting information to the file. 228 */ 229 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 230 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 231 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 232 (int *)0, p)); 233 } 234 235 /* 236 * Encode_comp_t converts from ticks in seconds and microseconds 237 * to ticks in 1/AHZ seconds. The encoding is described in 238 * Leffler, et al., on page 63. 239 */ 240 241 #define MANTSIZE 13 /* 13 bit mantissa. */ 242 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 243 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 244 245 static comp_t 246 encode_comp_t(s, us) 247 u_long s, us; 248 { 249 int exp, rnd; 250 251 exp = 0; 252 rnd = 0; 253 s *= AHZ; 254 s += us / (1000000 / AHZ); /* Maximize precision. */ 255 256 while (s > MAXFRACT) { 257 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 258 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 259 exp++; 260 } 261 262 /* If we need to round up, do it (and handle overflow correctly). */ 263 if (rnd && (++s > MAXFRACT)) { 264 s >>= EXPSIZE; 265 exp++; 266 } 267 268 /* Clean it up and polish it off. */ 269 exp <<= MANTSIZE; /* Shift the exponent into place */ 270 exp += s; /* and add on the mantissa. */ 271 return (exp); 272 } 273 274 /* 275 * Periodically check the file system to see if accounting 276 * should be turned on or off. Beware the case where the vnode 277 * has been vgone()'d out from underneath us, e.g. when the file 278 * system containing the accounting file has been forcibly unmounted. 279 */ 280 /* ARGSUSED */ 281 static void 282 acctwatch(a) 283 void *a; 284 { 285 struct statfs sb; 286 287 if (savacctp != NULLVP) { 288 if (savacctp->v_type == VBAD) { 289 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 290 savacctp = NULLVP; 291 return; 292 } 293 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 294 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 295 acctp = savacctp; 296 savacctp = NULLVP; 297 log(LOG_NOTICE, "Accounting resumed\n"); 298 } 299 } else { 300 if (acctp == NULLVP) 301 return; 302 if (acctp->v_type == VBAD) { 303 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 304 acctp = NULLVP; 305 return; 306 } 307 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 308 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 309 savacctp = acctp; 310 acctp = NULLVP; 311 log(LOG_NOTICE, "Accounting suspended\n"); 312 } 313 } 314 timeout(acctwatch, NULL, acctchkfreq * hz); 315 } 316