sys/kern/kern_acct.c

   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: src/sys/kern/kern_acct.c,v 1.23.2.1 2002/07/24 18:33:55 johan Exp $
  41  * $DragonFly: src/sys/kern/kern_acct.c,v 1.28 2008/05/08 01:26:00 dillon Exp $
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/sysproto.h>
  47 #include <sys/proc.h>
  48 #include <sys/priv.h>
  49 #include <sys/mount.h>
  50 #include <sys/vnode.h>
  51 #include <sys/fcntl.h>
  52 #include <sys/syslog.h>
  53 #include <sys/kernel.h>
  54 #include <sys/sysent.h>
  55 #include <sys/sysctl.h>
  56 #include <sys/nlookup.h>
  57 #include <sys/acct.h>
  58 #include <sys/resourcevar.h>
  59 #include <sys/tty.h>
  60
  61 #include <vm/vm_zone.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  * The former's operation is described in Leffler, et al., and the latter
  77  * was provided by UCB with the 4.4BSD-Lite release
  78  */
  79 static comp_t   encode_comp_t (u_long, u_long);
  80 static void     acctwatch (void *);
  81
  82 /*
  83  * Accounting callout handle used for periodic scheduling of
  84  * acctwatch.
  85  */
  86 static struct   callout acctwatch_handle;
  87
  88 /*
  89  * Accounting vnode pointer, and saved vnode pointer.
  90  */
  91 static struct   vnode *acctp;
  92 static struct   vnode *savacctp;
  93
  94 /*
  95  * Values associated with enabling and disabling accounting
  96  */
  97 static int acctsuspend = 2;     /* stop accounting when < 2% free space left */
  98 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
  99         &acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended");
 100
 101 static int acctresume = 4;      /* resume when free space risen to > 4% */
 102 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
 103         &acctresume, 0, "Minimum percentage of free disk space needed to resume accounting");
 104
 105 static int acctchkfreq = 15;    /* frequency (in seconds) to check space */
 106 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
 107         &acctchkfreq, 0, "Frequency (in seconds) of free disk space checking");
 108
 109 static void
 110 acct_init(void *arg __unused)
 111 {
 112         callout_init(&acctwatch_handle);
 113 }
 114 SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL);
 115
 116 /*
 117  * Accounting system call.  Written based on the specification and
 118  * previous implementation done by Mark Tinguely.
 119  *
 120  * acct(char *path)
 121  */
 122 int
 123 sys_acct(struct acct_args *uap)
 124 {
 125         struct thread *td = curthread;
 126         struct nlookupdata nd;
 127         struct vnode *vp;
 128         int error;
 129
 130         /* Make sure that the caller is root. */
 131         error = priv_check(td, PRIV_ROOT);
 132         if (error)
 133                 return (error);
 134
 135         /*
 136          * If accounting is to be started to a file, open that file for
 137          * appending and make sure it's a 'normal'.
 138          */
 139         if (uap->path != NULL) {
 140                 error = nlookup_init(&nd, uap->path, UIO_USERSPACE,
 141                                         NLC_LOCKVP);
 142                 if (error == 0)
 143                         error = vn_open(&nd, NULL, FWRITE | O_APPEND, 0);
 144                 if (error == 0 && nd.nl_open_vp->v_type != VREG)
 145                         error = EACCES;
 146                 if (error) {
 147                         nlookup_done(&nd);
 148                         return (error);
 149                 }
 150                 vp = nd.nl_open_vp;
 151                 nd.nl_open_vp = NULL;
 152                 nlookup_done(&nd);
 153
 154                 vn_unlock(vp);
 155         } else {
 156                 vp = NULL;
 157         }
 158
 159         /*
 160          * If accounting was previously enabled, kill the old space-watcher,
 161          * close the file.
 162          */
 163         if (acctp != NULLVP || savacctp != NULLVP) {
 164                 callout_stop(&acctwatch_handle);
 165                 error = vn_close((acctp != NULLVP ? acctp : savacctp),
 166                                 FWRITE | O_APPEND);
 167                 acctp = savacctp = NULLVP;
 168         }
 169
 170         /*
 171          * If no new file opened then leave.  We never did an nlookup so
 172          * don't try cleaning it up.
 173          */
 174         if (uap->path == NULL)
 175                 return (error);
 176
 177         /*
 178          * Save the new accounting file vnode, and schedule the new
 179          * free space watcher.
 180          */
 181         acctp = vp;
 182         acctwatch(NULL);
 183         return (error);
 184 }
 185
 186 /*
 187  * Write out process accounting information, on process exit.
 188  * Data to be written out is specified in Leffler, et al.
 189  * and are enumerated below.  (They're also noted in the system
 190  * "acct.h" header file.)
 191  */
 192
 193 int
 194 acct_process(struct proc *p)
 195 {
 196         struct acct acct;
 197         struct rusage *r;
 198         struct rusage ru;
 199         struct timeval tmp;
 200         struct rlimit rlim;
 201         int t;
 202         struct vnode *vp;
 203
 204         /* If accounting isn't enabled, don't bother */
 205         vp = acctp;
 206         if (vp == NULLVP)
 207                 return (0);
 208
 209         /*
 210          * Get process accounting information.
 211          */
 212
 213         /* (1) The name of the command that ran */
 214         bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
 215
 216         /* (2) The amount of user and system time that was used */
 217         calcru_proc(p, &ru);
 218         acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec);
 219         acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec);
 220
 221         /* (3) The elapsed time the commmand ran (and its starting time) */
 222         acct.ac_btime = p->p_start.tv_sec;
 223         microtime(&tmp);
 224         timevalsub(&tmp, &p->p_start);
 225         acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
 226
 227         /* (4) The average amount of memory used */
 228         r = &p->p_ru;
 229         tmp = ru.ru_utime;;
 230         timevaladd(&tmp, &ru.ru_stime);
 231         t = tmp.tv_sec * hz + tmp.tv_usec / tick;
 232         if (t)
 233                 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
 234         else
 235                 acct.ac_mem = 0;
 236
 237         /* (5) The number of disk I/O operations done */
 238         acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
 239
 240         /* (6) The UID and GID of the process */
 241         acct.ac_uid = p->p_ucred->cr_ruid;
 242         acct.ac_gid = p->p_ucred->cr_rgid;
 243
 244         /* (7) The terminal from which the process was started */
 245         if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
 246                 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
 247         else
 248                 acct.ac_tty = NOUDEV;
 249
 250         /* (8) The boolean flags that tell how the process terminated, etc. */
 251         acct.ac_flag = p->p_acflag;
 252
 253         /*
 254          * Eliminate any file size rlimit.
 255          */
 256         rlim.rlim_cur = RLIM_INFINITY;
 257         rlim.rlim_max = RLIM_INFINITY;
 258         plimit_modify(p, RLIMIT_FSIZE, &rlim);
 259
 260         /*
 261          * Write the accounting information to the file.
 262          */
 263         return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
 264             (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
 265             (int *)0));
 266 }
 267
 268 /*
 269  * Encode_comp_t converts from ticks in seconds and microseconds
 270  * to ticks in 1/AHZ seconds.  The encoding is described in
 271  * Leffler, et al., on page 63.
 272  */
 273
 274 #define MANTSIZE        13                      /* 13 bit mantissa. */
 275 #define EXPSIZE         3                       /* Base 8 (3 bit) exponent. */
 276 #define MAXFRACT        ((1 << MANTSIZE) - 1)   /* Maximum fractional value. */
 277
 278 static comp_t
 279 encode_comp_t(u_long s, u_long us)
 280 {
 281         int exp, rnd;
 282
 283         exp = 0;
 284         rnd = 0;
 285         s *= AHZ;
 286         s += us / (1000000 / AHZ);      /* Maximize precision. */
 287
 288         while (s > MAXFRACT) {
 289         rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
 290                 s >>= EXPSIZE;          /* Base 8 exponent == 3 bit shift. */
 291                 exp++;
 292         }
 293
 294         /* If we need to round up, do it (and handle overflow correctly). */
 295         if (rnd && (++s > MAXFRACT)) {
 296                 s >>= EXPSIZE;
 297                 exp++;
 298         }
 299
 300         /* Clean it up and polish it off. */
 301         exp <<= MANTSIZE;               /* Shift the exponent into place */
 302         exp += s;                       /* and add on the mantissa. */
 303         return (exp);
 304 }
 305
 306 /*
 307  * Periodically check the file system to see if accounting
 308  * should be turned on or off.  Beware the case where the vnode
 309  * has been vgone()'d out from underneath us, e.g. when the file
 310  * system containing the accounting file has been forcibly unmounted.
 311  */
 312 /* ARGSUSED */
 313 static void
 314 acctwatch(void *a)
 315 {
 316         struct statfs sb;
 317
 318         if (savacctp != NULLVP) {
 319                 if (savacctp->v_type == VBAD) {
 320                         (void) vn_close(savacctp, FWRITE | O_APPEND);
 321                         savacctp = NULLVP;
 322                         return;
 323                 }
 324                 (void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred);
 325                 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
 326                         acctp = savacctp;
 327                         savacctp = NULLVP;
 328                         log(LOG_NOTICE, "Accounting resumed\n");
 329                 }
 330         } else {
 331                 if (acctp == NULLVP)
 332                         return;
 333                 if (acctp->v_type == VBAD) {
 334                         (void) vn_close(acctp, FWRITE | O_APPEND);
 335                         acctp = NULLVP;
 336                         return;
 337                 }
 338                 (void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred);
 339                 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
 340                         savacctp = acctp;
 341                         acctp = NULLVP;
 342                         log(LOG_NOTICE, "Accounting suspended\n");
 343                 }
 344         }
 345         callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL);
 346 }