dmesg.tproj/dmesg.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*-
  25  * Copyright (c) 1991, 1993
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 #include <sys/cdefs.h>
  58 #include <sys/msgbuf.h>
  59
  60 #include <fcntl.h>
  61 #include <kvm.h>
  62 #include <limits.h>
  63 #include <nlist.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <time.h>
  67 #include <unistd.h>
  68 #include <vis.h>
  69
  70 struct nlist nl[] = {
  71 #define X_MSGBUF        0
  72         { "_msgbufp" },
  73         { NULL },
  74 };
  75
  76 void usage __P((void));
  77
  78 #define KREAD(addr, var) \
  79         kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var)
  80
  81 int
  82 main(argc, argv)
  83         int argc;
  84         char *argv[];
  85 {
  86         register int ch, newl, skip;
  87         register char *p, *ep;
  88         struct msgbuf *bufp, cur;
  89         char *memf, *nlistf;
  90         kvm_t *kd;
  91         char buf[5];
  92
  93         memf = nlistf = NULL;
  94         while ((ch = getopt(argc, argv, "M:N:")) != EOF)
  95                 switch(ch) {
  96                 case 'M':
  97                         memf = optarg;
  98                         break;
  99                 case 'N':
 100                         nlistf = optarg;
 101                         break;
 102                 case '?':
 103                 default:
 104                         usage();
 105                 }
 106         argc -= optind;
 107         argv += optind;
 108
 109         /*
 110          * Discard setgid privileges if not the running kernel so that bad
 111          * guys can't print interesting stuff from kernel memory.
 112          */
 113         if (memf != NULL || nlistf != NULL)
 114                 setgid(getgid());
 115
 116         /* Read in kernel message buffer, do sanity checks. */
 117         if ((kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg")) == NULL)
 118                 exit (1);
 119         if (kvm_nlist(kd, nl) == -1)
 120                 errx(1, "kvm_nlist: %s", kvm_geterr(kd));
 121         if (nl[X_MSGBUF].n_type == 0)
 122                 errx(1, "%s: msgbufp not found", nlistf ? nlistf : "namelist");
 123         if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur))
 124                 errx(1, "kvm_read: %s", kvm_geterr(kd));
 125         kvm_close(kd);
 126         if (cur.msg_magic != MSG_MAGIC)
 127                 errx(1, "magic number incorrect");
 128         if (cur.msg_bufx >= MSG_BSIZE)
 129                 cur.msg_bufx = 0;
 130
 131         /*
 132          * The message buffer is circular; start at the read pointer, and
 133          * go to the write pointer - 1.
 134          */
 135         p = cur.msg_bufc + cur.msg_bufx;
 136         ep = cur.msg_bufc + cur.msg_bufx - 1;
 137         for (newl = skip = 0; p != ep; ++p) {
 138                 if (p == cur.msg_bufc + MSG_BSIZE)
 139                         p = cur.msg_bufc;
 140                 ch = *p;
 141                 /* Skip "\n<.*>" syslog sequences. */
 142                 if (skip) {
 143                         if (ch == '>')
 144                                 newl = skip = 0;
 145                         continue;
 146                 }
 147                 if (newl && ch == '<') {
 148                         skip = 1;
 149                         continue;
 150                 }
 151                 if (ch == '\0')
 152                         continue;
 153                 newl = ch == '\n';
 154                 (void)vis(buf, ch, 0, 0);
 155                 if (buf[1] == 0)
 156                         (void)putchar(buf[0]);
 157                 else
 158                         (void)printf("%s", buf);
 159         }
 160         if (!newl)
 161                 (void)putchar('\n');
 162         exit(0);
 163 }
 164
 165 void
 166 usage()
 167 {
 168         (void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n");
 169         exit(1);
 170 }