bsd/kern/kern_acct.c

   1 /*
   2  * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*-
  30  * Copyright (c) 1982, 1986, 1989, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  * (c) UNIX System Laboratories, Inc.
  33  * All or some portions of this file are derived from material licensed
  34  * to the University of California by American Telephone and Telegraph
  35  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  36  * the permission of UNIX System Laboratories, Inc.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgement:
  48  *      This product includes software developed by the University of
  49  *      California, Berkeley and its contributors.
  50  * 4. Neither the name of the University nor the names of its contributors
  51  *    may be used to endorse or promote products derived from this software
  52  *    without specific prior written permission.
  53  *
  54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  64  * SUCH DAMAGE.
  65  *
  66  *      @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
  67  */
  68 /* HISTORY
  69  * 08-May-95  Mac Gillon (mgillon) at NeXT
  70  *      Purged old history
  71  *      New version based on 4.4
  72  */
  73 /*
  74  * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
  75  * support for mandatory and extensible security protections.  This notice
  76  * is included in support of clause 2.2 (b) of the Apple Public License,
  77  * Version 2.0.
  78  */
  79
  80
  81 #include <sys/param.h>
  82 #include <sys/proc_internal.h>
  83 #include <sys/kauth.h>
  84 #include <sys/mount_internal.h>
  85 #include <sys/vnode_internal.h>
  86 #include <sys/file_internal.h>
  87 #include <sys/syslog.h>
  88 #include <sys/kernel.h>
  89 #include <sys/namei.h>
  90 #include <sys/errno.h>
  91 #include <sys/acct.h>
  92 #include <sys/resourcevar.h>
  93 #include <sys/ioctl.h>
  94 #include <sys/tty.h>
  95 #include <sys/sysproto.h>
  96 #if CONFIG_MACF
  97 #include <security/mac_framework.h>
  98 #endif
  99
 100 /*
 101  * The routines implemented in this file are described in:
 102  *      Leffler, et al.: The Design and Implementation of the 4.3BSD
 103  *          UNIX Operating System (Addison Welley, 1989)
 104  * on pages 62-63.
 105  *
 106  * Arguably, to simplify accounting operations, this mechanism should
 107  * be replaced by one in which an accounting log file (similar to /dev/klog)
 108  * is read by a user process, etc.  However, that has its own problems.
 109  */
 110
 111 /*
 112  * Internal accounting functions.
 113  * The former's operation is described in Leffler, et al., and the latter
 114  * was provided by UCB with the 4.4BSD-Lite release
 115  */
 116 comp_t  encode_comp_t(uint32_t, uint32_t);
 117 void    acctwatch(void *);
 118 void    acct_init(void);
 119
 120 /*
 121  * Accounting vnode pointer, and suspended accounting vnode pointer.  States
 122  * are as follows:
 123  *
 124  *      acctp           suspend_acctp   state
 125  *      -------------   ------------    ------------------------------
 126  *      NULL            NULL            Accounting disabled
 127  *      !NULL           NULL            Accounting enabled
 128  *      NULL            !NULL           Accounting enabled, but suspended
 129  *      !NULL           !NULL           <not allowed>
 130  */
 131 struct  vnode *acctp;
 132 struct  vnode *suspend_acctp;
 133
 134 /*
 135  * Values associated with enabling and disabling accounting
 136  */
 137 int     acctsuspend = 2;        /* stop accounting when < 2% free space left */
 138 int     acctresume = 4;         /* resume when free space risen to > 4% */
 139 int     acctchkfreq = 15;       /* frequency (in seconds) to check space */
 140
 141
 142 static lck_grp_t       *acct_subsys_lck_grp;
 143 static lck_mtx_t       *acct_subsys_mutex;
 144
 145 #define ACCT_SUBSYS_LOCK() lck_mtx_lock(acct_subsys_mutex)
 146 #define ACCT_SUBSYS_UNLOCK() lck_mtx_unlock(acct_subsys_mutex)
 147
 148 void
 149 acct_init(void)
 150 {
 151         acct_subsys_lck_grp = lck_grp_alloc_init("acct", NULL);
 152         acct_subsys_mutex = lck_mtx_alloc_init(acct_subsys_lck_grp, NULL);
 153 }
 154
 155
 156 /*
 157  * Accounting system call.  Written based on the specification and
 158  * previous implementation done by Mark Tinguely.
 159  */
 160 int
 161 acct(proc_t p, struct acct_args *uap, __unused int *retval)
 162 {
 163         struct nameidata nd;
 164         int error;
 165         struct vfs_context *ctx;
 166
 167         ctx = vfs_context_current();
 168
 169         /* Make sure that the caller is root. */
 170         if ((error = suser(vfs_context_ucred(ctx), &p->p_acflag))) {
 171                 return error;
 172         }
 173
 174         /*
 175          * If accounting is to be started to a file, open that file for
 176          * writing and make sure it's a 'normal'.
 177          */
 178         if (uap->path != USER_ADDR_NULL) {
 179                 NDINIT(&nd, LOOKUP, OP_OPEN, NOFOLLOW, UIO_USERSPACE, uap->path, ctx);
 180                 if ((error = vn_open(&nd, FWRITE, 0))) {
 181                         return error;
 182                 }
 183 #if CONFIG_MACF
 184                 error = mac_system_check_acct(vfs_context_ucred(ctx), nd.ni_vp);
 185                 if (error) {
 186                         vnode_put(nd.ni_vp);
 187                         vn_close(nd.ni_vp, FWRITE, ctx);
 188                         return error;
 189                 }
 190 #endif
 191                 vnode_put(nd.ni_vp);
 192
 193                 if (nd.ni_vp->v_type != VREG) {
 194                         vn_close(nd.ni_vp, FWRITE, ctx);
 195                         return EACCES;
 196                 }
 197         }
 198 #if CONFIG_MACF
 199         else {
 200                 error = mac_system_check_acct(vfs_context_ucred(ctx), NULL);
 201                 if (error) {
 202                         return error;
 203                 }
 204         }
 205 #endif
 206
 207         /*
 208          * If accounting was previously enabled, kill the old space-watcher,
 209          * close the file, and (if no new file was specified, leave).
 210          */
 211         ACCT_SUBSYS_LOCK();
 212         if (acctp != NULLVP || suspend_acctp != NULLVP) {
 213                 untimeout(acctwatch, NULL);
 214                 error = vn_close((acctp != NULLVP ? acctp : suspend_acctp),
 215                     FWRITE, vfs_context_current());
 216
 217                 acctp = suspend_acctp = NULLVP;
 218         }
 219         if (uap->path == USER_ADDR_NULL) {
 220                 ACCT_SUBSYS_UNLOCK();
 221                 return error;
 222         }
 223
 224         /*
 225          * Save the new accounting file vnode, and schedule the new
 226          * free space watcher.
 227          */
 228         acctp = nd.ni_vp;
 229         ACCT_SUBSYS_UNLOCK();
 230
 231         acctwatch(NULL);
 232         return error;
 233 }
 234
 235 /*
 236  * Write out process accounting information, on process exit.
 237  * Data to be written out is specified in Leffler, et al.
 238  * and are enumerated below.  (They're also noted in the system
 239  * "acct.h" header file.)
 240  */
 241 int
 242 acct_process(proc_t p)
 243 {
 244         struct acct an_acct;
 245         struct rusage rup, *r;
 246         struct timeval ut, st, tmp;
 247         int t;
 248         int error;
 249         struct vnode *vp;
 250         kauth_cred_t safecred;
 251         struct session * sessp;
 252         struct  tty *tp;
 253
 254         /* If accounting isn't enabled, don't bother */
 255         ACCT_SUBSYS_LOCK();
 256         vp = acctp;
 257         if (vp == NULLVP) {
 258                 ACCT_SUBSYS_UNLOCK();
 259                 return 0;
 260         }
 261
 262         /*
 263          * Get process accounting information.
 264          */
 265
 266         /* (1) The name of the command that ran */
 267         bcopy(p->p_comm, an_acct.ac_comm, sizeof an_acct.ac_comm);
 268
 269         /* (2) The amount of user and system time that was used */
 270         calcru(p, &ut, &st, NULL);
 271         an_acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
 272         an_acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
 273
 274         /* (3) The elapsed time the commmand ran (and its starting time) */
 275         an_acct.ac_btime = p->p_start.tv_sec;
 276         microtime(&tmp);
 277         timevalsub(&tmp, &p->p_start);
 278         an_acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
 279
 280         /* (4) The average amount of memory used */
 281         proc_lock(p);
 282         rup = p->p_stats->p_ru;
 283         proc_unlock(p);
 284         r = &rup;
 285         tmp = ut;
 286         timevaladd(&tmp, &st);
 287         t = tmp.tv_sec * hz + tmp.tv_usec / tick;
 288         if (t) {
 289                 an_acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
 290         } else {
 291                 an_acct.ac_mem = 0;
 292         }
 293
 294         /* (5) The number of disk I/O operations done */
 295         an_acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
 296
 297         /* (6) The UID and GID of the process */
 298         safecred = kauth_cred_proc_ref(p);
 299
 300         an_acct.ac_uid = kauth_cred_getruid(safecred);
 301         an_acct.ac_gid = kauth_cred_getrgid(safecred);
 302
 303         /* (7) The terminal from which the process was started */
 304
 305         sessp = proc_session(p);
 306         if ((p->p_flag & P_CONTROLT) && (sessp != SESSION_NULL) && ((tp = SESSION_TP(sessp)) != TTY_NULL)) {
 307                 tty_lock(tp);
 308                 an_acct.ac_tty = tp->t_dev;
 309                 tty_unlock(tp);
 310         } else {
 311                 an_acct.ac_tty = NODEV;
 312         }
 313
 314         if (sessp != SESSION_NULL) {
 315                 session_rele(sessp);
 316         }
 317
 318         /* (8) The boolean flags that tell how the process terminated, etc. */
 319         an_acct.ac_flag = p->p_acflag;
 320
 321         /*
 322          * Now, just write the accounting information to the file.
 323          */
 324         if ((error = vnode_getwithref(vp)) == 0) {
 325                 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&an_acct, sizeof(an_acct),
 326                     (off_t)0, UIO_SYSSPACE, IO_APPEND | IO_UNIT, safecred,
 327                     (int *)0, p);
 328                 vnode_put(vp);
 329         }
 330
 331         kauth_cred_unref(&safecred);
 332         ACCT_SUBSYS_UNLOCK();
 333
 334         return error;
 335 }
 336
 337 /*
 338  * Encode_comp_t converts from ticks in seconds and microseconds
 339  * to ticks in 1/AHZ seconds.  The encoding is described in
 340  * Leffler, et al., on page 63.
 341  */
 342
 343 #define MANTSIZE        13                      /* 13 bit mantissa. */
 344 #define EXPSIZE         3                       /* Base 8 (3 bit) exponent. */
 345 #define MAXFRACT        ((1 << MANTSIZE) - 1)   /* Maximum fractional value. */
 346
 347 comp_t
 348 encode_comp_t(uint32_t s, uint32_t us)
 349 {
 350         int exp, rnd;
 351
 352         exp = 0;
 353         rnd = 0;
 354         s *= AHZ;
 355         s += us / (1000000 / AHZ);      /* Maximize precision. */
 356
 357         while (s > MAXFRACT) {
 358                 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
 359                 s >>= EXPSIZE;          /* Base 8 exponent == 3 bit shift. */
 360                 exp++;
 361         }
 362
 363         /* If we need to round up, do it (and handle overflow correctly). */
 364         if (rnd && (++s > MAXFRACT)) {
 365                 s >>= EXPSIZE;
 366                 exp++;
 367         }
 368
 369         /* Clean it up and polish it off. */
 370         exp <<= MANTSIZE;               /* Shift the exponent into place */
 371         exp += s;                       /* and add on the mantissa. */
 372         return exp;
 373 }
 374
 375 /*
 376  * Periodically check the file system to see if accounting
 377  * should be turned on or off.  Beware the case where the vnode
 378  * has been vgone()'d out from underneath us, e.g. when the file
 379  * system containing the accounting file has been forcibly unmounted.
 380  */
 381 /* ARGSUSED */
 382 void
 383 acctwatch(__unused void *a)
 384 {
 385         vfs_context_t ctx = vfs_context_current();
 386         struct vfs_attr va;
 387
 388         VFSATTR_INIT(&va);
 389         VFSATTR_WANTED(&va, f_blocks);
 390         VFSATTR_WANTED(&va, f_bavail);
 391
 392         ACCT_SUBSYS_LOCK();
 393         if (suspend_acctp != NULLVP) {
 394                 /*
 395                  * Resuming accounting when accounting is suspended, and the
 396                  * filesystem containing the suspended accounting file goes
 397                  * below a low watermark
 398                  */
 399                 if (suspend_acctp->v_type == VBAD) {
 400                         (void) vn_close(suspend_acctp, FWRITE, vfs_context_kernel());
 401                         suspend_acctp = NULLVP;
 402                         ACCT_SUBSYS_UNLOCK();
 403                         return;
 404                 }
 405                 (void)vfs_getattr(suspend_acctp->v_mount, &va, ctx);
 406                 if (va.f_bavail > acctresume * va.f_blocks / 100) {
 407                         acctp = suspend_acctp;
 408                         suspend_acctp = NULLVP;
 409                         log(LOG_NOTICE, "Accounting resumed\n");
 410                 }
 411         } else if (acctp != NULLVP) {
 412                 /*
 413                  * Suspending accounting when accounting is currently active,
 414                  * and the filesystem containing the active accounting file
 415                  * goes over a high watermark
 416                  */
 417                 if (acctp->v_type == VBAD) {
 418                         (void) vn_close(acctp, FWRITE, vfs_context_kernel());
 419                         acctp = NULLVP;
 420                         ACCT_SUBSYS_UNLOCK();
 421                         return;
 422                 }
 423                 (void)vfs_getattr(acctp->v_mount, &va, ctx);
 424                 if (va.f_bavail <= acctsuspend * va.f_blocks / 100) {
 425                         suspend_acctp = acctp;
 426                         acctp = NULLVP;
 427                         log(LOG_NOTICE, "Accounting suspended\n");
 428                 }
 429         } else {
 430                 ACCT_SUBSYS_UNLOCK();
 431                 return;
 432         }
 433         ACCT_SUBSYS_UNLOCK();
 434
 435         timeout(acctwatch, NULL, acctchkfreq * hz);
 436 }