subr_log.c

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    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, 1993
   28  *      The Regents of the University of California.  All rights reserved.
   29  *
   30  * Redistribution and use in source and binary forms, with or without
   31  * modification, are permitted provided that the following conditions
   32  * are met:
   33  * 1. Redistributions of source code must retain the above copyright
   34  *    notice, this list of conditions and the following disclaimer.
   35  * 2. Redistributions in binary form must reproduce the above copyright
   36  *    notice, this list of conditions and the following disclaimer in the
   37  *    documentation and/or other materials provided with the distribution.
   38  * 3. All advertising materials mentioning features or use of this software
   39  *    must display the following acknowledgement:
   40  *      This product includes software developed by the University of
   41  *      California, Berkeley and its contributors.
   42  * 4. Neither the name of the University nor the names of its contributors
   43  *    may be used to endorse or promote products derived from this software
   44  *    without specific prior written permission.
   45  *
   46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   56  * SUCH DAMAGE.
   57  *
   58  *      @(#)subr_log.c  8.3 (Berkeley) 2/14/95
   59  */
   60 
   61 /*
   62  * Error log buffer for kernel printf's.
   63  */
   64 
   65 #include <sys/param.h>
   66 #include <sys/systm.h>
   67 #include <sys/proc.h>
   68 #include <sys/vnode.h>
   69 #include <sys/ioctl.h>
   70 #include <sys/msgbuf.h>
   71 #include <sys/file.h>
   72 #include <sys/errno.h>
   73 #include <sys/select.h>
   74 #include <kern/thread.h>
   75 
   76 #define LOG_RDPRI       (PZERO + 1)
   77 
   78 #define LOG_NBIO        0x02
   79 #define LOG_ASYNC       0x04
   80 #define LOG_RDWAIT      0x08
   81 
   82 struct logsoftc {
   83         int     sc_state;               /* see above for possibilities */
   84         struct  selinfo sc_selp;        /* thread waiting for select */
   85         int     sc_pgid;                /* process/group for async I/O */
   86 } logsoftc;
   87 
   88 int     log_open;                       /* also used in log() */
   89 struct msgbuf temp_msgbuf;
   90 struct msgbuf *msgbufp;
   91 static int _logentrypend = 0;
   92 
   93 /*
   94  * Serialize log access.  Note that the log can be written at interrupt level,
   95  * so any log manipulations that can be done from, or affect, another processor
   96  * at interrupt level must be guarded with a spin lock.
   97  */
   98 decl_simple_lock_data(,log_lock);       /* stop races dead in their tracks */
   99 #define LOG_LOCK()      simple_lock(&log_lock)
  100 #define LOG_UNLOCK()    simple_unlock(&log_lock)
  101 #define LOG_LOCK_INIT() simple_lock_init(&log_lock)
  102 
  103 /*ARGSUSED*/
  104 logopen(dev, flags, mode, p)
  105         dev_t dev;
  106         int flags, mode;
  107         struct proc *p;
  108 {
  109         LOG_LOCK();
  110         if (log_open) {
  111                 LOG_UNLOCK();
  112                 return (EBUSY);
  113         }
  114         log_open = 1;
  115         logsoftc.sc_pgid = p->p_pid;            /* signal process only */
  116         /*
  117          * Potential race here with putchar() but since putchar should be
  118          * called by autoconf, msg_magic should be initialized by the time
  119          * we get here.
  120          */
  121         if (msgbufp->msg_magic != MSG_MAGIC) {
  122                 register int i;
  123 
  124                 msgbufp->msg_magic = MSG_MAGIC;
  125                 msgbufp->msg_bufx = msgbufp->msg_bufr = 0;
  126                 for (i=0; i < MSG_BSIZE; i++)
  127                         msgbufp->msg_bufc[i] = 0;
  128         }
  129         LOG_UNLOCK();
  130 
  131         return (0);
  132 }
  133 
  134 /*ARGSUSED*/
  135 int
  136 logclose(dev, flag)
  137         dev_t dev;
  138 {
  139         int oldpri;
  140         LOG_LOCK();
  141         log_open = 0;
  142         selwakeup(&logsoftc.sc_selp);
  143         oldpri = splhigh();
  144         selthreadclear(&logsoftc.sc_selp);
  145         splx(oldpri);
  146         LOG_UNLOCK();
  147         return (0);
  148 }
  149 
  150 /*ARGSUSED*/
  151 int
  152 logread(dev, uio, flag)
  153         dev_t dev;
  154         struct uio *uio;
  155         int flag;
  156 {
  157         register long l;
  158         register int s;
  159         int error = 0;
  160 
  161         s = splhigh();
  162         while (msgbufp->msg_bufr == msgbufp->msg_bufx) {
  163                 if (flag & IO_NDELAY) {
  164                         splx(s);
  165                         return (EWOULDBLOCK);
  166                 }
  167                 if (logsoftc.sc_state & LOG_NBIO) {
  168                         splx(s);
  169                         return (EWOULDBLOCK);
  170                 }
  171                 logsoftc.sc_state |= LOG_RDWAIT;
  172                 if (error = tsleep((caddr_t)msgbufp, LOG_RDPRI | PCATCH,
  173                                 "klog", 0)) {
  174                         splx(s);
  175                         return (error);
  176                 }
  177         }
  178         splx(s);
  179         logsoftc.sc_state &= ~LOG_RDWAIT;
  180 
  181         while (uio->uio_resid > 0) {
  182                 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
  183                 if (l < 0)
  184                         l = MSG_BSIZE - msgbufp->msg_bufr;
  185                 l = min(l, uio->uio_resid);
  186                 if (l == 0)
  187                         break;
  188                 error = uiomove((caddr_t)&msgbufp->msg_bufc[msgbufp->msg_bufr],
  189                         (int)l, uio);
  190                 if (error)
  191                         break;
  192                 msgbufp->msg_bufr += l;
  193                 if (msgbufp->msg_bufr < 0 || msgbufp->msg_bufr >= MSG_BSIZE)
  194                         msgbufp->msg_bufr = 0;
  195         }
  196         return (error);
  197 }
  198 
  199 /*ARGSUSED*/
  200 int
  201 logselect(dev, rw, wql, p)
  202         dev_t dev;
  203         int rw;
  204         void * wql;
  205         struct proc *p;
  206 {
  207         int s = splhigh();
  208 
  209         switch (rw) {
  210 
  211         case FREAD:
  212                 if (msgbufp->msg_bufr != msgbufp->msg_bufx) {
  213                         splx(s);
  214                         return (1);
  215                 }
  216                 selrecord(p, &logsoftc.sc_selp, wql);
  217                 break;
  218         }
  219         splx(s);
  220         return (0);
  221 }
  222 
  223 void
  224 logwakeup()
  225 {
  226         struct proc *p;
  227         int pgid;
  228         boolean_t funnel_state;
  229 
  230         if (!log_open)
  231                 return;
  232         funnel_state = thread_funnel_set(kernel_flock, TRUE);
  233         selwakeup(&logsoftc.sc_selp);
  234         if (logsoftc.sc_state & LOG_ASYNC) {
  235                 LOG_LOCK();
  236                 pgid = logsoftc.sc_pgid;
  237                 LOG_UNLOCK();
  238                 if (pgid < 0)
  239                         gsignal(-pgid, SIGIO); 
  240                 else if (p = pfind(pgid))
  241                         psignal(p, SIGIO);
  242         }
  243         if (logsoftc.sc_state & LOG_RDWAIT) {
  244                 wakeup((caddr_t)msgbufp);
  245                 logsoftc.sc_state &= ~LOG_RDWAIT;
  246         }
  247         (void) thread_funnel_set(kernel_flock, funnel_state);
  248 }
  249 
  250 void
  251 klogwakeup()
  252 {
  253 
  254         if (_logentrypend) {
  255                 _logentrypend = 0;
  256                 logwakeup();
  257         }
  258 }
  259 
  260 /*ARGSUSED*/
  261 int
  262 logioctl(dev, com, data, flag)
  263         caddr_t data;
  264 {
  265         long l;
  266         int s;
  267 
  268         switch (com) {
  269 
  270         /* return number of characters immediately available */
  271         case FIONREAD:
  272                 s = splhigh();
  273                 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
  274                 splx(s);
  275                 if (l < 0)
  276                         l += MSG_BSIZE;
  277                 *(off_t *)data = l;
  278                 break;
  279 
  280         case FIONBIO:
  281                 if (*(int *)data)
  282                         logsoftc.sc_state |= LOG_NBIO;
  283                 else
  284                         logsoftc.sc_state &= ~LOG_NBIO;
  285                 break;
  286 
  287         case FIOASYNC:
  288                 if (*(int *)data)
  289                         logsoftc.sc_state |= LOG_ASYNC;
  290                 else
  291                         logsoftc.sc_state &= ~LOG_ASYNC;
  292                 break;
  293 
  294         case TIOCSPGRP:
  295                 LOG_LOCK();
  296                 logsoftc.sc_pgid = *(int *)data;
  297                 LOG_UNLOCK();
  298                 break;
  299 
  300         case TIOCGPGRP:
  301                 LOG_LOCK();
  302                 *(int *)data = logsoftc.sc_pgid;
  303                 LOG_UNLOCK();
  304                 break;
  305 
  306         default:
  307                 return (-1);
  308         }
  309         return (0);
  310 }
  311 
  312 void
  313 log_init()
  314 {
  315         msgbufp = &temp_msgbuf;
  316         LOG_LOCK_INIT();
  317 }
  318 
  319 void
  320 log_putc(char c)
  321 {
  322         register struct msgbuf *mbp;
  323 
  324         if (msgbufp == NULL)
  325                 msgbufp =&temp_msgbuf;
  326 
  327         mbp = msgbufp; 
  328         if (mbp-> msg_magic != MSG_MAGIC) { 
  329                 register int i;
  330 
  331                 mbp->msg_magic = MSG_MAGIC;
  332                 mbp->msg_bufx = mbp->msg_bufr = 0;
  333                 for (i=0; i < MSG_BSIZE; i++)
  334                         mbp->msg_bufc[i] = 0;
  335         }
  336         mbp->msg_bufc[mbp->msg_bufx++] = c;
  337         _logentrypend = 1;
  338         if (mbp->msg_bufx < 0 || mbp->msg_bufx >= MSG_BSIZE)
  339                 mbp->msg_bufx = 0;
  340 }
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FreeBSD/Linux Kernel Cross Reference sys/bsd/kern/subr_log.c

FreeBSD/Linux Kernel Cross Reference
sys/bsd/kern/subr_log.c
