1 /* $OpenBSD: kern_acct.c,v 1.10 2001/11/02 21:42:15 art Exp $ */ 2 /* $NetBSD: kern_acct.c,v 1.42 1996/02/04 02:15:12 christos Exp $ */ 3 4 /*- 5 * Copyright (c) 1994 Christopher G. Demetriou 6 * Copyright (c) 1982, 1986, 1989, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/proc.h> 48 #include <sys/mount.h> 49 #include <sys/vnode.h> 50 #include <sys/file.h> 51 #include <sys/syslog.h> 52 #include <sys/kernel.h> 53 #include <sys/namei.h> 54 #include <sys/errno.h> 55 #include <sys/acct.h> 56 #include <sys/resourcevar.h> 57 #include <sys/ioctl.h> 58 #include <sys/tty.h> 59 #include <sys/kthread.h> 60 61 #include <sys/syscallargs.h> 62 63 /* 64 * The routines implemented in this file are described in: 65 * Leffler, et al.: The Design and Implementation of the 4.3BSD 66 * UNIX Operating System (Addison Welley, 1989) 67 * on pages 62-63. 68 * 69 * Arguably, to simplify accounting operations, this mechanism should 70 * be replaced by one in which an accounting log file (similar to /dev/klog) 71 * is read by a user process, etc. However, that has its own problems. 72 */ 73 74 /* 75 * Internal accounting functions. 76 */ 77 comp_t encode_comp_t(u_long, u_long); 78 int acct_start(void); 79 void acct_thread(void *); 80 81 /* 82 * Accounting vnode pointer, and saved vnode pointer. 83 */ 84 struct vnode *acctp; 85 struct vnode *savacctp; 86 87 /* 88 * Values associated with enabling and disabling accounting 89 */ 90 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 91 int acctresume = 4; /* resume when free space risen to > 4% */ 92 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 93 94 struct proc *acct_proc; 95 96 /* 97 * Accounting system call. Written based on the specification and 98 * previous implementation done by Mark Tinguely. 99 */ 100 int 101 sys_acct(p, v, retval) 102 struct proc *p; 103 void *v; 104 register_t *retval; 105 { 106 struct sys_acct_args /* { 107 syscallarg(char *) path; 108 } */ *uap = v; 109 struct nameidata nd; 110 int error; 111 112 /* Make sure that the caller is root. */ 113 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 114 return (error); 115 116 /* 117 * If accounting is to be started to a file, open that file for 118 * writing and make sure it's a 'normal'. 119 */ 120 if (SCARG(uap, path) != NULL) { 121 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 122 p); 123 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) 124 return (error); 125 VOP_UNLOCK(nd.ni_vp, 0, p); 126 if (nd.ni_vp->v_type != VREG) { 127 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 128 return (EACCES); 129 } 130 } 131 132 /* 133 * If accounting was previously enabled, kill the old space-watcher, 134 * close the file, and (if no new file was specified, leave). 135 */ 136 if (acctp != NULL || savacctp != NULL) { 137 wakeup(&acct_proc); 138 error = vn_close((acctp != NULL ? acctp : savacctp), FWRITE, 139 p->p_ucred, p); 140 acctp = savacctp = NULL; 141 } 142 if (SCARG(uap, path) == NULL) 143 return (0); 144 145 /* 146 * Save the new accounting file vnode, and schedule the new 147 * free space watcher. 148 */ 149 acctp = nd.ni_vp; 150 if ((error = acct_start()) != 0) { 151 acctp = NULL; 152 (void)vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 153 return (error); 154 } 155 return (0); 156 } 157 158 /* 159 * Write out process accounting information, on process exit. 160 * Data to be written out is specified in Leffler, et al. 161 * and are enumerated below. (They're also noted in the system 162 * "acct.h" header file.) 163 */ 164 int 165 acct_process(struct proc *p) 166 { 167 struct acct acct; 168 struct rusage *r; 169 struct timeval ut, st, tmp; 170 int s, t; 171 struct vnode *vp; 172 struct plimit *oplim = NULL; 173 int error; 174 175 /* If accounting isn't enabled, don't bother */ 176 vp = acctp; 177 if (vp == NULL) 178 return (0); 179 180 /* 181 * Raise the file limit so that accounting can't be stopped by the 182 * user. (XXX - we should think about the cpu limit too). 183 */ 184 if (p->p_limit->p_refcnt > 1) { 185 oplim = p->p_limit; 186 p->p_limit = limcopy(p->p_limit); 187 } 188 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 189 190 /* 191 * Get process accounting information. 192 */ 193 194 /* (1) The name of the command that ran */ 195 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 196 197 /* (2) The amount of user and system time that was used */ 198 calcru(p, &ut, &st, NULL); 199 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 200 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 201 202 /* (3) The elapsed time the commmand ran (and its starting time) */ 203 acct.ac_btime = p->p_stats->p_start.tv_sec; 204 s = splclock(); 205 timersub(&time, &p->p_stats->p_start, &tmp); 206 splx(s); 207 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 208 209 /* (4) The average amount of memory used */ 210 r = &p->p_stats->p_ru; 211 timeradd(&ut, &st, &tmp); 212 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 213 if (t) 214 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 215 else 216 acct.ac_mem = 0; 217 218 /* (5) The number of disk I/O operations done */ 219 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 220 221 /* (6) The UID and GID of the process */ 222 acct.ac_uid = p->p_cred->p_ruid; 223 acct.ac_gid = p->p_cred->p_rgid; 224 225 /* (7) The terminal from which the process was started */ 226 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 227 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 228 else 229 acct.ac_tty = NODEV; 230 231 /* (8) The boolean flags that tell how the process terminated, etc. */ 232 acct.ac_flag = p->p_acflag; 233 234 /* 235 * Now, just write the accounting information to the file. 236 */ 237 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 238 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 239 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, NULL, p); 240 241 if (oplim) { 242 limfree(p->p_limit); 243 p->p_limit = oplim; 244 } 245 246 return error; 247 } 248 249 /* 250 * Encode_comp_t converts from ticks in seconds and microseconds 251 * to ticks in 1/AHZ seconds. The encoding is described in 252 * Leffler, et al., on page 63. 253 */ 254 255 #define MANTSIZE 13 /* 13 bit mantissa. */ 256 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 257 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 258 259 comp_t 260 encode_comp_t(u_long s, u_long us) 261 { 262 int exp, rnd; 263 264 exp = 0; 265 rnd = 0; 266 s *= AHZ; 267 s += us / (1000000 / AHZ); /* Maximize precision. */ 268 269 while (s > MAXFRACT) { 270 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 271 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 272 exp++; 273 } 274 275 /* If we need to round up, do it (and handle overflow correctly). */ 276 if (rnd && (++s > MAXFRACT)) { 277 s >>= EXPSIZE; 278 exp++; 279 } 280 281 /* Clean it up and polish it off. */ 282 exp <<= MANTSIZE; /* Shift the exponent into place */ 283 exp += s; /* and add on the mantissa. */ 284 return (exp); 285 } 286 287 int 288 acct_start(void) 289 { 290 /* Already running. */ 291 if (acct_proc != NULL) 292 return (0); 293 294 return (kthread_create(acct_thread, NULL, &acct_proc, "acct")); 295 } 296 297 /* 298 * Periodically check the file system to see if accounting 299 * should be turned on or off. Beware the case where the vnode 300 * has been vgone()'d out from underneath us, e.g. when the file 301 * system containing the accounting file has been forcibly unmounted. 302 */ 303 /* ARGSUSED */ 304 void 305 acct_thread(void *arg) 306 { 307 struct statfs sb; 308 309 for (;;) { 310 if (savacctp != NULL) { 311 if (savacctp->v_type == VBAD) { 312 (void) vn_close(savacctp, FWRITE, NOCRED, NULL); 313 savacctp = NULL; 314 return; 315 } 316 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 317 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 318 acctp = savacctp; 319 savacctp = NULL; 320 log(LOG_NOTICE, "Accounting resumed\n"); 321 } 322 } else if (acctp != NULL) { 323 if (acctp->v_type == VBAD) { 324 (void) vn_close(acctp, FWRITE, NOCRED, NULL); 325 acctp = NULL; 326 return; 327 } 328 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 329 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 330 savacctp = acctp; 331 acctp = NULL; 332 log(LOG_NOTICE, "Accounting suspended\n"); 333 } 334 } else { 335 acct_proc = NULL; 336 kthread_exit(0); 337 } 338 tsleep(&acct_proc, PPAUSE, "acct", acctchkfreq *hz); 339 } 340 } 341