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 1.16 1997/09/02 20:05:36 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/acct.h> 56 #include <sys/resourcevar.h> 57 #include <sys/tty.h> 58 59 /* 60 * The routines implemented in this file are described in: 61 * Leffler, et al.: The Design and Implementation of the 4.3BSD 62 * UNIX Operating System (Addison Welley, 1989) 63 * on pages 62-63. 64 * 65 * Arguably, to simplify accounting operations, this mechanism should 66 * be replaced by one in which an accounting log file (similar to /dev/klog) 67 * is read by a user process, etc. However, that has its own problems. 68 */ 69 70 /* 71 * Internal accounting functions. 72 * The former's operation is described in Leffler, et al., and the latter 73 * was provided by UCB with the 4.4BSD-Lite release 74 */ 75 static comp_t encode_comp_t __P((u_long, u_long)); 76 static void acctwatch __P((void *)); 77 78 /* 79 * Accounting callout handle used for periodic scheduling of 80 * acctwatch. 81 */ 82 static struct callout_handle acctwatch_handle 83 = CALLOUT_HANDLE_INITIALIZER(&acctwatch_handle); 84 85 /* 86 * Accounting vnode pointer, and saved vnode pointer. 87 */ 88 static struct vnode *acctp; 89 static struct vnode *savacctp; 90 91 /* 92 * Values associated with enabling and disabling accounting 93 */ 94 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 95 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 96 &acctsuspend, 0, ""); 97 98 static int acctresume = 4; /* resume when free space risen to > 4% */ 99 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 100 &acctresume, 0, ""); 101 102 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 103 SYSCTL_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 */ 110 int 111 acct(a1, uap, a3) 112 struct proc *a1; 113 struct acct_args /* { 114 syscallarg(char *) path; 115 } */ *uap; 116 int *a3; 117 { 118 struct proc *p = curproc; /* XXX */ 119 struct nameidata nd; 120 int error; 121 122 /* Make sure that the caller is root. */ 123 error = suser(p->p_ucred, &p->p_acflag); 124 if (error) 125 return (error); 126 127 /* 128 * If accounting is to be started to a file, open that file for 129 * writing and make sure it's a 'normal'. 130 */ 131 if (SCARG(uap, path) != NULL) { 132 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 133 p); 134 error = vn_open(&nd, FWRITE, 0); 135 if (error) 136 return (error); 137 VOP_UNLOCK(nd.ni_vp, 0, p); 138 if (nd.ni_vp->v_type != VREG) { 139 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 140 return (EACCES); 141 } 142 } 143 144 /* 145 * If accounting was previously enabled, kill the old space-watcher, 146 * close the file, and (if no new file was specified, leave). 147 */ 148 if (acctp != NULLVP || savacctp != NULLVP) { 149 untimeout(acctwatch, NULL, acctwatch_handle); 150 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 151 p->p_ucred, p); 152 acctp = savacctp = NULLVP; 153 } 154 if (SCARG(uap, path) == NULL) 155 return (error); 156 157 /* 158 * Save the new accounting file vnode, and schedule the new 159 * free space watcher. 160 */ 161 acctp = nd.ni_vp; 162 acctwatch(NULL); 163 return (error); 164 } 165 166 /* 167 * Write out process accounting information, on process exit. 168 * Data to be written out is specified in Leffler, et al. 169 * and are enumerated below. (They're also noted in the system 170 * "acct.h" header file.) 171 */ 172 173 int 174 acct_process(p) 175 struct proc *p; 176 { 177 struct acct acct; 178 struct rusage *r; 179 struct timeval ut, st, tmp; 180 int t; 181 struct vnode *vp; 182 183 /* If accounting isn't enabled, don't bother */ 184 vp = acctp; 185 if (vp == NULLVP) 186 return (0); 187 188 /* 189 * Get process accounting information. 190 */ 191 192 /* (1) The name of the command that ran */ 193 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 194 195 /* (2) The amount of user and system time that was used */ 196 calcru(p, &ut, &st, NULL); 197 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 198 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 199 200 /* (3) The elapsed time the commmand ran (and its starting time) */ 201 acct.ac_btime = p->p_stats->p_start.tv_sec; 202 microtime(&tmp); 203 timevalsub(&tmp, &p->p_stats->p_start); 204 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 205 206 /* (4) The average amount of memory used */ 207 r = &p->p_stats->p_ru; 208 tmp = ut; 209 timevaladd(&tmp, &st); 210 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 211 if (t) 212 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 213 else 214 acct.ac_mem = 0; 215 216 /* (5) The number of disk I/O operations done */ 217 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 218 219 /* (6) The UID and GID of the process */ 220 acct.ac_uid = p->p_cred->p_ruid; 221 acct.ac_gid = p->p_cred->p_rgid; 222 223 /* (7) The terminal from which the process was started */ 224 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 225 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 226 else 227 acct.ac_tty = NODEV; 228 229 /* (8) The boolean flags that tell how the process terminated, etc. */ 230 acct.ac_flag = p->p_acflag; 231 232 /* 233 * Now, just write the accounting information to the file. 234 */ 235 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 236 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 237 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 238 (int *)0, p)); 239 } 240 241 /* 242 * Encode_comp_t converts from ticks in seconds and microseconds 243 * to ticks in 1/AHZ seconds. The encoding is described in 244 * Leffler, et al., on page 63. 245 */ 246 247 #define MANTSIZE 13 /* 13 bit mantissa. */ 248 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 249 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 250 251 static comp_t 252 encode_comp_t(s, us) 253 u_long s, us; 254 { 255 int exp, rnd; 256 257 exp = 0; 258 rnd = 0; 259 s *= AHZ; 260 s += us / (1000000 / AHZ); /* Maximize precision. */ 261 262 while (s > MAXFRACT) { 263 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 264 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 265 exp++; 266 } 267 268 /* If we need to round up, do it (and handle overflow correctly). */ 269 if (rnd && (++s > MAXFRACT)) { 270 s >>= EXPSIZE; 271 exp++; 272 } 273 274 /* Clean it up and polish it off. */ 275 exp <<= MANTSIZE; /* Shift the exponent into place */ 276 exp += s; /* and add on the mantissa. */ 277 return (exp); 278 } 279 280 /* 281 * Periodically check the file system to see if accounting 282 * should be turned on or off. Beware the case where the vnode 283 * has been vgone()'d out from underneath us, e.g. when the file 284 * system containing the accounting file has been forcibly unmounted. 285 */ 286 /* ARGSUSED */ 287 static void 288 acctwatch(a) 289 void *a; 290 { 291 struct statfs sb; 292 293 if (savacctp != NULLVP) { 294 if (savacctp->v_type == VBAD) { 295 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 296 savacctp = NULLVP; 297 return; 298 } 299 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 300 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 301 acctp = savacctp; 302 savacctp = NULLVP; 303 log(LOG_NOTICE, "Accounting resumed\n"); 304 } 305 } else { 306 if (acctp == NULLVP) 307 return; 308 if (acctp->v_type == VBAD) { 309 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 310 acctp = NULLVP; 311 return; 312 } 313 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 314 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 315 savacctp = acctp; 316 acctp = NULLVP; 317 log(LOG_NOTICE, "Accounting suspended\n"); 318 } 319 } 320 acctwatch_handle = timeout(acctwatch, NULL, acctchkfreq * hz); 321 } 322