bsd/kern/kern_acct.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  26 /*-
  27  * Copyright (c) 1982, 1986, 1989, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  * (c) UNIX System Laboratories, Inc.
  30  * All or some portions of this file are derived from material licensed
  31  * to the University of California by American Telephone and Telegraph
  32  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  33  * the permission of UNIX System Laboratories, Inc.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  *      @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
  64  */
  65 /* HISTORY
  66  * 08-May-95  Mac Gillon (mgillon) at NeXT
  67  *      Purged old history
  68  *      New version based on 4.4
  69  */
  70
  71
  72 #include <sys/param.h>
  73 #include <sys/proc.h>
  74 #include <sys/mount.h>
  75 #include <sys/vnode.h>
  76 #include <sys/file.h>
  77 #include <sys/syslog.h>
  78 #include <sys/kernel.h>
  79 #include <sys/namei.h>
  80 #include <sys/errno.h>
  81 #include <sys/acct.h>
  82 #include <sys/resourcevar.h>
  83 #include <sys/ioctl.h>
  84 #include <sys/tty.h>
  85
  86 /*
  87  * The routines implemented in this file are described in:
  88  *      Leffler, et al.: The Design and Implementation of the 4.3BSD
  89  *          UNIX Operating System (Addison Welley, 1989)
  90  * on pages 62-63.
  91  *
  92  * Arguably, to simplify accounting operations, this mechanism should
  93  * be replaced by one in which an accounting log file (similar to /dev/klog)
  94  * is read by a user process, etc.  However, that has its own problems.
  95  */
  96
  97 /*
  98  * Internal accounting functions.
  99  * The former's operation is described in Leffler, et al., and the latter
 100  * was provided by UCB with the 4.4BSD-Lite release
 101  */
 102 comp_t  encode_comp_t __P((u_long, u_long));
 103 void    acctwatch __P((void *));
 104 void    acctwatch_funnel __P((void *));
 105
 106 /*
 107  * Accounting vnode pointer, and saved vnode pointer.
 108  */
 109 struct  vnode *acctp;
 110 struct  vnode *savacctp;
 111
 112 /*
 113  * Values associated with enabling and disabling accounting
 114  */
 115 int     acctsuspend = 2;        /* stop accounting when < 2% free space left */
 116 int     acctresume = 4;         /* resume when free space risen to > 4% */
 117 int     acctchkfreq = 15;       /* frequency (in seconds) to check space */
 118
 119 /*
 120  * Accounting system call.  Written based on the specification and
 121  * previous implementation done by Mark Tinguely.
 122  */
 123 struct acct_args {
 124         char    *path;
 125 };
 126 acct(p, uap, retval)
 127         struct proc *p;
 128         struct acct_args *uap;
 129         int *retval;
 130 {
 131         struct nameidata nd;
 132         int error;
 133
 134         /* Make sure that the caller is root. */
 135         if (error = suser(p->p_ucred, &p->p_acflag))
 136                 return (error);
 137
 138         /*
 139          * If accounting is to be started to a file, open that file for
 140          * writing and make sure it's a 'normal'.
 141          */
 142         if (uap->path != NULL) {
 143                 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, p);
 144                 if (error = vn_open(&nd, FWRITE, 0))
 145                         return (error);
 146                 VOP_UNLOCK(nd.ni_vp, 0, p);
 147                 if (nd.ni_vp->v_type != VREG) {
 148                         vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
 149                         return (EACCES);
 150                 }
 151         }
 152
 153         /*
 154          * If accounting was previously enabled, kill the old space-watcher,
 155          * close the file, and (if no new file was specified, leave).
 156          */
 157         if (acctp != NULLVP || savacctp != NULLVP) {
 158                 untimeout(acctwatch_funnel, NULL);
 159                 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
 160                     p->p_ucred, p);
 161                 acctp = savacctp = NULLVP;
 162         }
 163         if (uap->path == NULL)
 164                 return (error);
 165
 166         /*
 167          * Save the new accounting file vnode, and schedule the new
 168          * free space watcher.
 169          */
 170         acctp = nd.ni_vp;
 171         acctwatch(NULL);
 172         return (error);
 173 }
 174
 175 /*
 176  * Write out process accounting information, on process exit.
 177  * Data to be written out is specified in Leffler, et al.
 178  * and are enumerated below.  (They're also noted in the system
 179  * "acct.h" header file.)
 180  */
 181 acct_process(p)
 182         struct proc *p;
 183 {
 184         struct acct acct;
 185         struct rusage *r;
 186         struct timeval ut, st, tmp;
 187         int s, t;
 188         struct vnode *vp;
 189
 190         /* If accounting isn't enabled, don't bother */
 191         vp = acctp;
 192         if (vp == NULLVP)
 193                 return (0);
 194
 195         /*
 196          * Get process accounting information.
 197          */
 198
 199         /* (1) The name of the command that ran */
 200         bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
 201
 202         /* (2) The amount of user and system time that was used */
 203         calcru(p, &ut, &st, NULL);
 204         acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
 205         acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
 206
 207         /* (3) The elapsed time the commmand ran (and its starting time) */
 208         acct.ac_btime = p->p_stats->p_start.tv_sec;
 209         s = splclock();
 210         tmp = time;
 211         splx(s);
 212         timevalsub(&tmp, &p->p_stats->p_start);
 213         acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
 214
 215         /* (4) The average amount of memory used */
 216         r = &p->p_stats->p_ru;
 217         tmp = ut;
 218         timevaladd(&tmp, &st);
 219         t = tmp.tv_sec * hz + tmp.tv_usec / tick;
 220         if (t)
 221                 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
 222         else
 223                 acct.ac_mem = 0;
 224
 225         /* (5) The number of disk I/O operations done */
 226         acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
 227
 228         /* (6) The UID and GID of the process */
 229         acct.ac_uid = p->p_cred->p_ruid;
 230         acct.ac_gid = p->p_cred->p_rgid;
 231
 232         /* (7) The terminal from which the process was started */
 233         if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
 234                 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
 235         else
 236                 acct.ac_tty = NODEV;
 237
 238         /* (8) The boolean flags that tell how the process terminated, etc. */
 239         acct.ac_flag = p->p_acflag;
 240
 241         /*
 242          * Now, just write the accounting information to the file.
 243          */
 244         VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
 245         return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
 246             (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
 247             (int *)0, p));
 248 }
 249
 250 /*
 251  * Encode_comp_t converts from ticks in seconds and microseconds
 252  * to ticks in 1/AHZ seconds.  The encoding is described in
 253  * Leffler, et al., on page 63.
 254  */
 255
 256 #define MANTSIZE        13                      /* 13 bit mantissa. */
 257 #define EXPSIZE         3                       /* Base 8 (3 bit) exponent. */
 258 #define MAXFRACT        ((1 << MANTSIZE) - 1)   /* Maximum fractional value. */
 259
 260 comp_t
 261 encode_comp_t(s, us)
 262         u_long s, us;
 263 {
 264         int exp, rnd;
 265
 266         exp = 0;
 267         rnd = 0;
 268         s *= AHZ;
 269         s += us / (1000000 / AHZ);      /* Maximize precision. */
 270
 271         while (s > MAXFRACT) {
 272         rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
 273                 s >>= EXPSIZE;          /* Base 8 exponent == 3 bit shift. */
 274                 exp++;
 275         }
 276
 277         /* If we need to round up, do it (and handle overflow correctly). */
 278         if (rnd && (++s > MAXFRACT)) {
 279                 s >>= EXPSIZE;
 280                 exp++;
 281         }
 282
 283         /* Clean it up and polish it off. */
 284         exp <<= MANTSIZE;               /* Shift the exponent into place */
 285         exp += s;                       /* and add on the mantissa. */
 286         return (exp);
 287 }
 288
 289 void
 290 acctwatch_funnel(a)
 291         void *a;
 292 {
 293         thread_funnel_set(kernel_flock, TRUE);
 294         acctwatch(a);
 295         thread_funnel_set(kernel_flock, FALSE);
 296 }
 297
 298
 299 /*
 300  * Periodically check the file system to see if accounting
 301  * should be turned on or off.  Beware the case where the vnode
 302  * has been vgone()'d out from underneath us, e.g. when the file
 303  * system containing the accounting file has been forcibly unmounted.
 304  */
 305 /* ARGSUSED */
 306 void
 307 acctwatch(a)
 308         void *a;
 309 {
 310         struct statfs sb;
 311
 312         if (savacctp != NULLVP) {
 313                 if (savacctp->v_type == VBAD) {
 314                         (void) vn_close(savacctp, FWRITE, NOCRED, NULL);
 315                         savacctp = NULLVP;
 316                         return;
 317                 }
 318                 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0);
 319                 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
 320                         acctp = savacctp;
 321                         savacctp = NULLVP;
 322                         log(LOG_NOTICE, "Accounting resumed\n");
 323                 }
 324         } else if (acctp != NULLVP) {
 325                 if (acctp->v_type == VBAD) {
 326                         (void) vn_close(acctp, FWRITE, NOCRED, NULL);
 327                         acctp = NULLVP;
 328                         return;
 329                 }
 330                 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0);
 331                 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
 332                         savacctp = acctp;
 333                         acctp = NULLVP;
 334                         log(LOG_NOTICE, "Accounting suspended\n");
 335                 }
 336         } else {
 337                 return;
 338         }
 339
 340         timeout(acctwatch_funnel, NULL, acctchkfreq * hz);
 341 }