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/subr_log.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  * Copyright (c) 1982, 1986, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)subr_log.c  8.1 (Berkeley) 6/10/93
   30  */
   31 
   32 /*
   33  * Error log buffer for kernel printf's.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/5.4/sys/kern/subr_log.c 145335 2005-04-20 19:11:07Z cvs2svn $");
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/conf.h>
   42 #include <sys/proc.h>
   43 #include <sys/vnode.h>
   44 #include <sys/filio.h>
   45 #include <sys/ttycom.h>
   46 #include <sys/msgbuf.h>
   47 #include <sys/signalvar.h>
   48 #include <sys/kernel.h>
   49 #include <sys/poll.h>
   50 #include <sys/filedesc.h>
   51 #include <sys/sysctl.h>
   52 
   53 #define LOG_RDPRI       (PZERO + 1)
   54 
   55 #define LOG_ASYNC       0x04
   56 #define LOG_RDWAIT      0x08
   57 
   58 static  d_open_t        logopen;
   59 static  d_close_t       logclose;
   60 static  d_read_t        logread;
   61 static  d_ioctl_t       logioctl;
   62 static  d_poll_t        logpoll;
   63 
   64 static  void logtimeout(void *arg);
   65 
   66 #define CDEV_MAJOR 7
   67 static struct cdevsw log_cdevsw = {
   68         .d_version =    D_VERSION,
   69         .d_flags =      D_NEEDGIANT,
   70         .d_open =       logopen,
   71         .d_close =      logclose,
   72         .d_read =       logread,
   73         .d_ioctl =      logioctl,
   74         .d_poll =       logpoll,
   75         .d_name =       "log",
   76         .d_maj =        CDEV_MAJOR,
   77 };
   78 
   79 static struct logsoftc {
   80         int     sc_state;               /* see above for possibilities */
   81         struct  selinfo sc_selp;        /* process waiting on select call */
   82         struct  sigio *sc_sigio;        /* information for async I/O */
   83         struct  callout sc_callout;     /* callout to wakeup syslog  */
   84 } logsoftc;
   85 
   86 int     log_open;                       /* also used in log() */
   87 
   88 /* Times per second to check for a pending syslog wakeup. */
   89 static int      log_wakeups_per_second = 5;
   90 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
   91     &log_wakeups_per_second, 0, "");
   92 
   93 /*ARGSUSED*/
   94 static  int
   95 logopen(struct cdev *dev, int flags, int mode, struct thread *td)
   96 {
   97         if (log_open)
   98                 return (EBUSY);
   99         log_open = 1;
  100         callout_init(&logsoftc.sc_callout, 0);
  101         fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio);        /* signal process only */
  102         if (log_wakeups_per_second < 1) {
  103                 printf("syslog wakeup is less than one.  Adjusting to 1.\n");
  104                 log_wakeups_per_second = 1;
  105         }
  106         callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
  107             logtimeout, NULL);
  108         return (0);
  109 }
  110 
  111 /*ARGSUSED*/
  112 static  int
  113 logclose(struct cdev *dev, int flag, int mode, struct thread *td)
  114 {
  115 
  116         log_open = 0;
  117         callout_stop(&logsoftc.sc_callout);
  118         logsoftc.sc_state = 0;
  119         funsetown(&logsoftc.sc_sigio);
  120         return (0);
  121 }
  122 
  123 /*ARGSUSED*/
  124 static  int
  125 logread(struct cdev *dev, struct uio *uio, int flag)
  126 {
  127         char buf[128];
  128         struct msgbuf *mbp = msgbufp;
  129         int error = 0, l, s;
  130 
  131         s = splhigh();
  132         while (msgbuf_getcount(mbp) == 0) {
  133                 if (flag & IO_NDELAY) {
  134                         splx(s);
  135                         return (EWOULDBLOCK);
  136                 }
  137                 logsoftc.sc_state |= LOG_RDWAIT;
  138                 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) {
  139                         splx(s);
  140                         return (error);
  141                 }
  142         }
  143         splx(s);
  144         logsoftc.sc_state &= ~LOG_RDWAIT;
  145 
  146         while (uio->uio_resid > 0) {
  147                 l = imin(sizeof(buf), uio->uio_resid);
  148                 l = msgbuf_getbytes(mbp, buf, l);
  149                 if (l == 0)
  150                         break;
  151                 error = uiomove(buf, l, uio);
  152                 if (error)
  153                         break;
  154         }
  155         return (error);
  156 }
  157 
  158 /*ARGSUSED*/
  159 static  int
  160 logpoll(struct cdev *dev, int events, struct thread *td)
  161 {
  162         int s;
  163         int revents = 0;
  164 
  165         s = splhigh();
  166 
  167         if (events & (POLLIN | POLLRDNORM)) {
  168                 if (msgbuf_getcount(msgbufp) > 0)
  169                         revents |= events & (POLLIN | POLLRDNORM);
  170                 else
  171                         selrecord(td, &logsoftc.sc_selp);
  172         }
  173         splx(s);
  174         return (revents);
  175 }
  176 
  177 static void
  178 logtimeout(void *arg)
  179 {
  180 
  181         if (!log_open)
  182                 return;
  183         if (log_wakeups_per_second < 1) {
  184                 printf("syslog wakeup is less than one.  Adjusting to 1.\n");
  185                 log_wakeups_per_second = 1;
  186         }
  187         if (msgbuftrigger == 0) {
  188                 callout_reset(&logsoftc.sc_callout,
  189                     hz / log_wakeups_per_second, logtimeout, NULL);
  190                 return;
  191         }
  192         msgbuftrigger = 0;
  193         selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI);
  194         if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
  195                 pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
  196         if (logsoftc.sc_state & LOG_RDWAIT) {
  197                 wakeup(msgbufp);
  198                 logsoftc.sc_state &= ~LOG_RDWAIT;
  199         }
  200         callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
  201             logtimeout, NULL);
  202 }
  203 
  204 /*ARGSUSED*/
  205 static  int
  206 logioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td)
  207 {
  208 
  209         switch (com) {
  210 
  211         /* return number of characters immediately available */
  212         case FIONREAD:
  213                 *(int *)data = msgbuf_getcount(msgbufp);
  214                 break;
  215 
  216         case FIONBIO:
  217                 break;
  218 
  219         case FIOASYNC:
  220                 if (*(int *)data)
  221                         logsoftc.sc_state |= LOG_ASYNC;
  222                 else
  223                         logsoftc.sc_state &= ~LOG_ASYNC;
  224                 break;
  225 
  226         case FIOSETOWN:
  227                 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
  228 
  229         case FIOGETOWN:
  230                 *(int *)data = fgetown(&logsoftc.sc_sigio);
  231                 break;
  232 
  233         /* This is deprecated, FIOSETOWN should be used instead. */
  234         case TIOCSPGRP:
  235                 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
  236 
  237         /* This is deprecated, FIOGETOWN should be used instead */
  238         case TIOCGPGRP:
  239                 *(int *)data = -fgetown(&logsoftc.sc_sigio);
  240                 break;
  241 
  242         default:
  243                 return (ENOTTY);
  244         }
  245         return (0);
  246 }
  247 
  248 static void
  249 log_drvinit(void *unused)
  250 {
  251 
  252         make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
  253 }
  254 
  255 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)

Cache object: 350c35591527edff9c8cf55c9a6b5990


[ 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.