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 * $FreeBSD$ 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/file.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/ioctl.h> 59 #include <sys/tty.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 static comp_t encode_comp_t __P((u_long, u_long)); 78 static void acctwatch __P((void *)); 79 80 /* 81 * Accounting vnode pointer, and saved vnode pointer. 82 */ 83 static struct vnode *acctp; 84 static struct vnode *savacctp; 85 86 /* 87 * Values associated with enabling and disabling accounting 88 */ 89 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 90 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 91 &acctsuspend, 0, ""); 92 93 static int acctresume = 4; /* resume when free space risen to > 4% */ 94 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 95 &acctresume, 0, ""); 96 97 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 98 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 99 &acctchkfreq, 0, ""); 100 101 /* 102 * Accounting system call. Written based on the specification and 103 * previous implementation done by Mark Tinguely. 104 */ 105 int 106 acct(a1, uap, a3) 107 struct proc *a1; 108 struct acct_args /* { 109 syscallarg(char *) path; 110 } */ *uap; 111 int *a3; 112 { 113 struct proc *p = curproc; /* XXX */ 114 struct nameidata nd; 115 int error; 116 117 /* Make sure that the caller is root. */ 118 error = suser(p->p_ucred, &p->p_acflag); 119 if (error) 120 return (error); 121 122 /* 123 * If accounting is to be started to a file, open that file for 124 * writing and make sure it's a 'normal'. 125 */ 126 if (SCARG(uap, path) != NULL) { 127 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 128 p); 129 error = vn_open(&nd, FWRITE, 0); 130 if (error) 131 return (error); 132 VOP_UNLOCK(nd.ni_vp, 0, p); 133 if (nd.ni_vp->v_type != VREG) { 134 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 135 return (EACCES); 136 } 137 } 138 139 /* 140 * If accounting was previously enabled, kill the old space-watcher, 141 * close the file, and (if no new file was specified, leave). 142 */ 143 if (acctp != NULLVP || savacctp != NULLVP) { 144 untimeout(acctwatch, NULL); 145 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE, 146 p->p_ucred, p); 147 acctp = savacctp = NULLVP; 148 } 149 if (SCARG(uap, path) == NULL) 150 return (error); 151 152 /* 153 * Save the new accounting file vnode, and schedule the new 154 * free space watcher. 155 */ 156 acctp = nd.ni_vp; 157 acctwatch(NULL); 158 return (error); 159 } 160 161 /* 162 * Write out process accounting information, on process exit. 163 * Data to be written out is specified in Leffler, et al. 164 * and are enumerated below. (They're also noted in the system 165 * "acct.h" header file.) 166 */ 167 168 int 169 acct_process(p) 170 struct proc *p; 171 { 172 struct acct acct; 173 struct rusage *r; 174 struct timeval ut, st, tmp; 175 int t; 176 struct vnode *vp; 177 178 /* If accounting isn't enabled, don't bother */ 179 vp = acctp; 180 if (vp == NULLVP) 181 return (0); 182 183 /* 184 * Get process accounting information. 185 */ 186 187 /* (1) The name of the command that ran */ 188 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 189 190 /* (2) The amount of user and system time that was used */ 191 calcru(p, &ut, &st, NULL); 192 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 193 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 194 195 /* (3) The elapsed time the commmand ran (and its starting time) */ 196 acct.ac_btime = p->p_stats->p_start.tv_sec; 197 microtime(&tmp); 198 timevalsub(&tmp, &p->p_stats->p_start); 199 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 200 201 /* (4) The average amount of memory used */ 202 r = &p->p_stats->p_ru; 203 tmp = ut; 204 timevaladd(&tmp, &st); 205 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 206 if (t) 207 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 208 else 209 acct.ac_mem = 0; 210 211 /* (5) The number of disk I/O operations done */ 212 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 213 214 /* (6) The UID and GID of the process */ 215 acct.ac_uid = p->p_cred->p_ruid; 216 acct.ac_gid = p->p_cred->p_rgid; 217 218 /* (7) The terminal from which the process was started */ 219 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 220 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 221 else 222 acct.ac_tty = NODEV; 223 224 /* (8) The boolean flags that tell how the process terminated, etc. */ 225 acct.ac_flag = p->p_acflag; 226 227 /* 228 * Now, just write the accounting information to the file. 229 */ 230 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 231 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 232 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 233 (int *)0, p)); 234 } 235 236 /* 237 * Encode_comp_t converts from ticks in seconds and microseconds 238 * to ticks in 1/AHZ seconds. The encoding is described in 239 * Leffler, et al., on page 63. 240 */ 241 242 #define MANTSIZE 13 /* 13 bit mantissa. */ 243 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 244 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 245 246 static comp_t 247 encode_comp_t(s, us) 248 u_long s, us; 249 { 250 int exp, rnd; 251 252 exp = 0; 253 rnd = 0; 254 s *= AHZ; 255 s += us / (1000000 / AHZ); /* Maximize precision. */ 256 257 while (s > MAXFRACT) { 258 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 259 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 260 exp++; 261 } 262 263 /* If we need to round up, do it (and handle overflow correctly). */ 264 if (rnd && (++s > MAXFRACT)) { 265 s >>= EXPSIZE; 266 exp++; 267 } 268 269 /* Clean it up and polish it off. */ 270 exp <<= MANTSIZE; /* Shift the exponent into place */ 271 exp += s; /* and add on the mantissa. */ 272 return (exp); 273 } 274 275 /* 276 * Periodically check the file system to see if accounting 277 * should be turned on or off. Beware the case where the vnode 278 * has been vgone()'d out from underneath us, e.g. when the file 279 * system containing the accounting file has been forcibly unmounted. 280 */ 281 /* ARGSUSED */ 282 static void 283 acctwatch(a) 284 void *a; 285 { 286 struct statfs sb; 287 288 if (savacctp != NULLVP) { 289 if (savacctp->v_type == VBAD) { 290 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 291 savacctp = NULLVP; 292 return; 293 } 294 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 295 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 296 acctp = savacctp; 297 savacctp = NULLVP; 298 log(LOG_NOTICE, "Accounting resumed\n"); 299 } 300 } else { 301 if (acctp == NULLVP) 302 return; 303 if (acctp->v_type == VBAD) { 304 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 305 acctp = NULLVP; 306 return; 307 } 308 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 309 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 310 savacctp = acctp; 311 acctp = NULLVP; 312 log(LOG_NOTICE, "Accounting suspended\n"); 313 } 314 } 315 timeout(acctwatch, NULL, acctchkfreq * hz); 316 } 317