The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_acct.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * SPDX-License-Identifier: BSD-4-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1989, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  * (c) UNIX System Laboratories, Inc.
    7  * Copyright (c) 2005 Robert N. M. Watson
    8  * All rights reserved.
    9  *
   10  * All or some portions of this file are derived from material licensed
   11  * to the University of California by American Telephone and Telegraph
   12  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   13  * the permission of UNIX System Laboratories, Inc.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 3. 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  * Copyright (c) 1994 Christopher G. Demetriou
   40  *
   41  * Redistribution and use in source and binary forms, with or without
   42  * modification, are permitted provided that the following conditions
   43  * are met:
   44  * 1. Redistributions of source code must retain the above copyright
   45  *    notice, this list of conditions and the following disclaimer.
   46  * 2. Redistributions in binary form must reproduce the above copyright
   47  *    notice, this list of conditions and the following disclaimer in the
   48  *    documentation and/or other materials provided with the distribution.
   49  * 3. All advertising materials mentioning features or use of this software
   50  *    must display the following acknowledgement:
   51  *      This product includes software developed by the University of
   52  *      California, Berkeley and its contributors.
   53  * 4. Neither the name of the University nor the names of its contributors
   54  *    may be used to endorse or promote products derived from this software
   55  *    without specific prior written permission.
   56  *
   57  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   58  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   59  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   60  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   61  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   62  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   63  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   64  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   65  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   66  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   67  * SUCH DAMAGE.
   68  *
   69  *      @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
   70  */
   71 
   72 #include <sys/cdefs.h>
   73 __FBSDID("$FreeBSD$");
   74 
   75 #include <sys/param.h>
   76 #include <sys/systm.h>
   77 #include <sys/acct.h>
   78 #include <sys/fcntl.h>
   79 #include <sys/kernel.h>
   80 #include <sys/kthread.h>
   81 #include <sys/limits.h>
   82 #include <sys/lock.h>
   83 #include <sys/malloc.h>
   84 #include <sys/mount.h>
   85 #include <sys/mutex.h>
   86 #include <sys/namei.h>
   87 #include <sys/priv.h>
   88 #include <sys/proc.h>
   89 #include <sys/resourcevar.h>
   90 #include <sys/sched.h>
   91 #include <sys/sx.h>
   92 #include <sys/sysctl.h>
   93 #include <sys/syslog.h>
   94 #include <sys/sysproto.h>
   95 #include <sys/tty.h>
   96 #include <sys/vnode.h>
   97 
   98 #include <security/mac/mac_framework.h>
   99 
  100 _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_trailer) ==
  101     sizeof(struct acctv2) - offsetof(struct acctv2, ac_trailer), "trailer");
  102 _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_len2) ==
  103     sizeof(struct acctv2) - offsetof(struct acctv2, ac_len2), "len2");
  104 
  105 /*
  106  * The routines implemented in this file are described in:
  107  *      Leffler, et al.: The Design and Implementation of the 4.3BSD
  108  *          UNIX Operating System (Addison Welley, 1989)
  109  * on pages 62-63.
  110  * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction
  111  * compt_t representation described in the above reference was replaced
  112  * with that of IEEE-754 floats.
  113  *
  114  * Arguably, to simplify accounting operations, this mechanism should
  115  * be replaced by one in which an accounting log file (similar to /dev/klog)
  116  * is read by a user process, etc.  However, that has its own problems.
  117  */
  118 
  119 /* Floating point definitions from <float.h>. */
  120 #define FLT_MANT_DIG    24              /* p */
  121 #define FLT_MAX_EXP     128             /* emax */
  122 
  123 /*
  124  * Internal accounting functions.
  125  * The former's operation is described in Leffler, et al., and the latter
  126  * was provided by UCB with the 4.4BSD-Lite release
  127  */
  128 static uint32_t encode_timeval(struct timeval);
  129 static uint32_t encode_long(long);
  130 static void     acctwatch(void);
  131 static void     acct_thread(void *);
  132 static int      acct_disable(struct thread *, int);
  133 
  134 /*
  135  * Accounting vnode pointer, saved vnode pointer, and flags for each.
  136  * acct_sx protects against changes to the active vnode and credentials
  137  * while accounting records are being committed to disk.
  138  */
  139 static int               acct_configured;
  140 static int               acct_suspended;
  141 static struct vnode     *acct_vp;
  142 static struct ucred     *acct_cred;
  143 static int               acct_flags;
  144 static struct sx         acct_sx;
  145 
  146 SX_SYSINIT(acct, &acct_sx, "acct_sx");
  147 
  148 /*
  149  * State of the accounting kthread.
  150  */
  151 static int               acct_state;
  152 
  153 #define ACCT_RUNNING    1       /* Accounting kthread is running. */
  154 #define ACCT_EXITREQ    2       /* Accounting kthread should exit. */
  155 
  156 /*
  157  * Values associated with enabling and disabling accounting
  158  */
  159 static int acctsuspend = 2;     /* stop accounting when < 2% free space left */
  160 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
  161         &acctsuspend, 0, "percentage of free disk space below which accounting stops");
  162 
  163 static int acctresume = 4;      /* resume when free space risen to > 4% */
  164 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
  165         &acctresume, 0, "percentage of free disk space above which accounting resumes");
  166 
  167 static int acctchkfreq = 15;    /* frequency (in seconds) to check space */
  168 
  169 static int
  170 sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS)
  171 {
  172         int error, value;
  173 
  174         /* Write out the old value. */
  175         error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int));
  176         if (error || req->newptr == NULL)
  177                 return (error);
  178 
  179         /* Read in and verify the new value. */
  180         error = SYSCTL_IN(req, &value, sizeof(int));
  181         if (error)
  182                 return (error);
  183         if (value <= 0)
  184                 return (EINVAL);
  185         acctchkfreq = value;
  186         return (0);
  187 }
  188 SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq,
  189     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &acctchkfreq, 0,
  190     sysctl_acct_chkfreq, "I",
  191     "frequency for checking the free space");
  192 
  193 SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0,
  194         "Accounting configured or not");
  195 
  196 SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0,
  197         "Accounting suspended or not");
  198 
  199 /*
  200  * Accounting system call.  Written based on the specification and previous
  201  * implementation done by Mark Tinguely.
  202  */
  203 int
  204 sys_acct(struct thread *td, struct acct_args *uap)
  205 {
  206         struct nameidata nd;
  207         int error, flags, replacing;
  208 
  209         error = priv_check(td, PRIV_ACCT);
  210         if (error)
  211                 return (error);
  212 
  213         /*
  214          * If accounting is to be started to a file, open that file for
  215          * appending and make sure it's a 'normal'.
  216          */
  217         if (uap->path != NULL) {
  218                 NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, UIO_USERSPACE,
  219                     uap->path);
  220                 flags = FWRITE | O_APPEND;
  221                 error = vn_open(&nd, &flags, 0, NULL);
  222                 if (error)
  223                         return (error);
  224                 NDFREE_PNBUF(&nd);
  225 #ifdef MAC
  226                 error = mac_system_check_acct(td->td_ucred, nd.ni_vp);
  227                 if (error) {
  228                         VOP_UNLOCK(nd.ni_vp);
  229                         vn_close(nd.ni_vp, flags, td->td_ucred, td);
  230                         return (error);
  231                 }
  232 #endif
  233                 VOP_UNLOCK(nd.ni_vp);
  234                 if (nd.ni_vp->v_type != VREG) {
  235                         vn_close(nd.ni_vp, flags, td->td_ucred, td);
  236                         return (EACCES);
  237                 }
  238 #ifdef MAC
  239         } else {
  240                 error = mac_system_check_acct(td->td_ucred, NULL);
  241                 if (error)
  242                         return (error);
  243 #endif
  244         }
  245 
  246         /*
  247          * Disallow concurrent access to the accounting vnode while we swap
  248          * it out, in order to prevent access after close.
  249          */
  250         sx_xlock(&acct_sx);
  251 
  252         /*
  253          * Don't log spurious disable/enable messages if we are
  254          * switching from one accounting file to another due to log
  255          * rotation.
  256          */
  257         replacing = (acct_vp != NULL && uap->path != NULL);
  258 
  259         /*
  260          * If accounting was previously enabled, kill the old space-watcher,
  261          * close the file, and (if no new file was specified, leave).  Reset
  262          * the suspended state regardless of whether accounting remains
  263          * enabled.
  264          */
  265         acct_suspended = 0;
  266         if (acct_vp != NULL)
  267                 error = acct_disable(td, !replacing);
  268         if (uap->path == NULL) {
  269                 if (acct_state & ACCT_RUNNING) {
  270                         acct_state |= ACCT_EXITREQ;
  271                         wakeup(&acct_state);
  272                 }
  273                 sx_xunlock(&acct_sx);
  274                 return (error);
  275         }
  276 
  277         /*
  278          * Save the new accounting file vnode, and schedule the new
  279          * free space watcher.
  280          */
  281         acct_vp = nd.ni_vp;
  282         acct_cred = crhold(td->td_ucred);
  283         acct_flags = flags;
  284         if (acct_state & ACCT_RUNNING)
  285                 acct_state &= ~ACCT_EXITREQ;
  286         else {
  287                 /*
  288                  * Try to start up an accounting kthread.  We may start more
  289                  * than one, but if so the extras will commit suicide as
  290                  * soon as they start up.
  291                  */
  292                 error = kproc_create(acct_thread, NULL, NULL, 0, 0,
  293                     "accounting");
  294                 if (error) {
  295                         (void) acct_disable(td, 0);
  296                         sx_xunlock(&acct_sx);
  297                         log(LOG_NOTICE, "Unable to start accounting thread\n");
  298                         return (error);
  299                 }
  300         }
  301         acct_configured = 1;
  302         sx_xunlock(&acct_sx);
  303         if (!replacing)
  304                 log(LOG_NOTICE, "Accounting enabled\n");
  305         return (error);
  306 }
  307 
  308 /*
  309  * Disable currently in-progress accounting by closing the vnode, dropping
  310  * our reference to the credential, and clearing the vnode's flags.
  311  */
  312 static int
  313 acct_disable(struct thread *td, int logging)
  314 {
  315         int error;
  316 
  317         sx_assert(&acct_sx, SX_XLOCKED);
  318         error = vn_close(acct_vp, acct_flags, acct_cred, td);
  319         crfree(acct_cred);
  320         acct_configured = 0;
  321         acct_vp = NULL;
  322         acct_cred = NULL;
  323         acct_flags = 0;
  324         if (logging)
  325                 log(LOG_NOTICE, "Accounting disabled\n");
  326         return (error);
  327 }
  328 
  329 /*
  330  * Write out process accounting information, on process exit.
  331  * Data to be written out is specified in Leffler, et al.
  332  * and are enumerated below.  (They're also noted in the system
  333  * "acct.h" header file.)
  334  */
  335 int
  336 acct_process(struct thread *td)
  337 {
  338         struct acctv3 acct;
  339         struct timeval ut, st, tmp;
  340         struct proc *p;
  341         struct rusage ru;
  342         int t, ret;
  343 
  344         /*
  345          * Lockless check of accounting condition before doing the hard
  346          * work.
  347          */
  348         if (acct_vp == NULL || acct_suspended)
  349                 return (0);
  350 
  351         memset(&acct, 0, sizeof(acct));
  352 
  353         sx_slock(&acct_sx);
  354 
  355         /*
  356          * If accounting isn't enabled, don't bother.  Have to check again
  357          * once we own the lock in case we raced with disabling of accounting
  358          * by another thread.
  359          */
  360         if (acct_vp == NULL || acct_suspended) {
  361                 sx_sunlock(&acct_sx);
  362                 return (0);
  363         }
  364 
  365         p = td->td_proc;
  366         td->td_pflags2 |= TDP2_ACCT;
  367 
  368         /*
  369          * Get process accounting information.
  370          */
  371 
  372         sx_slock(&proctree_lock);
  373         PROC_LOCK(p);
  374 
  375         /* (1) The terminal from which the process was started */
  376         if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
  377                 acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp);
  378         else
  379                 acct.ac_tty = NODEV;
  380         sx_sunlock(&proctree_lock);
  381 
  382         /* (2) The name of the command that ran */
  383         bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
  384 
  385         /* (3) The amount of user and system time that was used */
  386         rufetchcalc(p, &ru, &ut, &st);
  387         acct.ac_utime = encode_timeval(ut);
  388         acct.ac_stime = encode_timeval(st);
  389 
  390         /* (4) The elapsed time the command ran (and its starting time) */
  391         getboottime(&tmp);
  392         timevaladd(&tmp, &p->p_stats->p_start);
  393         acct.ac_btime = tmp.tv_sec;
  394         microuptime(&tmp);
  395         timevalsub(&tmp, &p->p_stats->p_start);
  396         acct.ac_etime = encode_timeval(tmp);
  397 
  398         /* (5) The average amount of memory used */
  399         tmp = ut;
  400         timevaladd(&tmp, &st);
  401         /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */
  402         t = tmp.tv_sec * hz + tmp.tv_usec / tick;
  403         if (t)
  404                 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss +
  405                     + ru.ru_isrss) / t);
  406         else
  407                 acct.ac_mem = 0;
  408 
  409         /* (6) The number of disk I/O operations done */
  410         acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock);
  411 
  412         /* (7) The UID and GID of the process */
  413         acct.ac_uid = p->p_ucred->cr_ruid;
  414         acct.ac_gid = p->p_ucred->cr_rgid;
  415 
  416         /* (8) The boolean flags that tell how the process terminated, etc. */
  417         acct.ac_flagx = p->p_acflag;
  418 
  419         PROC_UNLOCK(p);
  420 
  421         /* Setup ancillary structure fields. */
  422         acct.ac_flagx |= ANVER;
  423         acct.ac_zero = 0;
  424         acct.ac_version = 3;
  425         acct.ac_len = acct.ac_len2 = sizeof(acct);
  426 
  427         /*
  428          * Write the accounting information to the file.
  429          */
  430         ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct),
  431             (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED,
  432             NULL, td);
  433         sx_sunlock(&acct_sx);
  434         td->td_pflags2 &= ~TDP2_ACCT;
  435         return (ret);
  436 }
  437 
  438 /* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */
  439 
  440 /* Convert timevals and longs into IEEE-754 bit patterns. */
  441 
  442 /* Mantissa mask (MSB is implied, so subtract 1). */
  443 #define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1)
  444 
  445 /*
  446  * We calculate integer values to a precision of approximately
  447  * 28 bits.
  448  * This is high-enough precision to fill the 24 float bits
  449  * and low-enough to avoid overflowing the 32 int bits.
  450  */
  451 #define CALC_BITS 28
  452 
  453 /* log_2(1000000). */
  454 #define LOG2_1M 20
  455 
  456 /*
  457  * Convert the elements of a timeval into a 32-bit word holding
  458  * the bits of a IEEE-754 float.
  459  * The float value represents the timeval's value in microsecond units.
  460  */
  461 static uint32_t
  462 encode_timeval(struct timeval tv)
  463 {
  464         int log2_s;
  465         int val, exp;   /* Unnormalized value and exponent */
  466         int norm_exp;   /* Normalized exponent */
  467         int shift;
  468 
  469         /*
  470          * First calculate value and exponent to about CALC_BITS precision.
  471          * Note that the following conditionals have been ordered so that
  472          * the most common cases appear first.
  473          */
  474         if (tv.tv_sec == 0) {
  475                 if (tv.tv_usec == 0)
  476                         return (0);
  477                 exp = 0;
  478                 val = tv.tv_usec;
  479         } else {
  480                 /*
  481                  * Calculate the value to a precision of approximately
  482                  * CALC_BITS.
  483                  */
  484                 log2_s = fls(tv.tv_sec) - 1;
  485                 if (log2_s + LOG2_1M < CALC_BITS) {
  486                         exp = 0;
  487                         val = 1000000 * tv.tv_sec + tv.tv_usec;
  488                 } else {
  489                         exp = log2_s + LOG2_1M - CALC_BITS;
  490                         val = (unsigned int)(((uint64_t)1000000 * tv.tv_sec +
  491                             tv.tv_usec) >> exp);
  492                 }
  493         }
  494         /* Now normalize and pack the value into an IEEE-754 float. */
  495         norm_exp = fls(val) - 1;
  496         shift = FLT_MANT_DIG - norm_exp - 1;
  497 #ifdef ACCT_DEBUG
  498         printf("val=%d exp=%d shift=%d log2(val)=%d\n",
  499             val, exp, shift, norm_exp);
  500         printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp,
  501             ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK));
  502 #endif
  503         return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) |
  504             ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK));
  505 }
  506 
  507 /*
  508  * Convert a non-negative long value into the bit pattern of
  509  * an IEEE-754 float value.
  510  */
  511 static uint32_t
  512 encode_long(long val)
  513 {
  514         int norm_exp;   /* Normalized exponent */
  515         int shift;
  516 
  517         if (val == 0)
  518                 return (0);
  519         if (val < 0) {
  520                 log(LOG_NOTICE,
  521                     "encode_long: negative value %ld in accounting record\n",
  522                     val);
  523                 val = LONG_MAX;
  524         }
  525         norm_exp = fls(val) - 1;
  526         shift = FLT_MANT_DIG - norm_exp - 1;
  527 #ifdef ACCT_DEBUG
  528         printf("val=%d shift=%d log2(val)=%d\n",
  529             val, shift, norm_exp);
  530         printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp,
  531             ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK));
  532 #endif
  533         return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) |
  534             ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK));
  535 }
  536 
  537 /* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */
  538 
  539 /*
  540  * Periodically check the filesystem to see if accounting
  541  * should be turned on or off.  Beware the case where the vnode
  542  * has been vgone()'d out from underneath us, e.g. when the file
  543  * system containing the accounting file has been forcibly unmounted.
  544  */
  545 /* ARGSUSED */
  546 static void
  547 acctwatch(void)
  548 {
  549         struct statfs *sp;
  550 
  551         sx_assert(&acct_sx, SX_XLOCKED);
  552 
  553         /*
  554          * If accounting was disabled before our kthread was scheduled,
  555          * then acct_vp might be NULL.  If so, just ask our kthread to
  556          * exit and return.
  557          */
  558         if (acct_vp == NULL) {
  559                 acct_state |= ACCT_EXITREQ;
  560                 return;
  561         }
  562 
  563         /*
  564          * If our vnode is no longer valid, tear it down and signal the
  565          * accounting thread to die.
  566          */
  567         if (acct_vp->v_type == VBAD) {
  568                 (void) acct_disable(NULL, 1);
  569                 acct_state |= ACCT_EXITREQ;
  570                 return;
  571         }
  572 
  573         /*
  574          * Stopping here is better than continuing, maybe it will be VBAD
  575          * next time around.
  576          */
  577         sp = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
  578         if (VFS_STATFS(acct_vp->v_mount, sp) < 0) {
  579                 free(sp, M_STATFS);
  580                 return;
  581         }
  582         if (acct_suspended) {
  583                 if (sp->f_bavail > (int64_t)(acctresume * sp->f_blocks /
  584                     100)) {
  585                         acct_suspended = 0;
  586                         log(LOG_NOTICE, "Accounting resumed\n");
  587                 }
  588         } else {
  589                 if (sp->f_bavail <= (int64_t)(acctsuspend * sp->f_blocks /
  590                     100)) {
  591                         acct_suspended = 1;
  592                         log(LOG_NOTICE, "Accounting suspended\n");
  593                 }
  594         }
  595         free(sp, M_STATFS);
  596 }
  597 
  598 /*
  599  * The main loop for the dedicated kernel thread that periodically calls
  600  * acctwatch().
  601  */
  602 static void
  603 acct_thread(void *dummy)
  604 {
  605         u_char pri;
  606 
  607         /* This is a low-priority kernel thread. */
  608         pri = PRI_MAX_KERN;
  609         thread_lock(curthread);
  610         sched_prio(curthread, pri);
  611         thread_unlock(curthread);
  612 
  613         /* If another accounting kthread is already running, just die. */
  614         sx_xlock(&acct_sx);
  615         if (acct_state & ACCT_RUNNING) {
  616                 sx_xunlock(&acct_sx);
  617                 kproc_exit(0);
  618         }
  619         acct_state |= ACCT_RUNNING;
  620 
  621         /* Loop until we are asked to exit. */
  622         while (!(acct_state & ACCT_EXITREQ)) {
  623                 /* Perform our periodic checks. */
  624                 acctwatch();
  625 
  626                 /*
  627                  * We check this flag again before sleeping since the
  628                  * acctwatch() might have shut down accounting and asked us
  629                  * to exit.
  630                  */
  631                 if (!(acct_state & ACCT_EXITREQ)) {
  632                         sx_sleep(&acct_state, &acct_sx, 0, "-",
  633                             acctchkfreq * hz);
  634                 }
  635         }
  636 
  637         /*
  638          * Acknowledge the exit request and shutdown.  We clear both the
  639          * exit request and running flags.
  640          */
  641         acct_state = 0;
  642         sx_xunlock(&acct_sx);
  643         kproc_exit(0);
  644 }

Cache object: 9550ca9097e93fa51ef4dc19f736359c


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.