1 /*- 2 * Copyright (c) 1991, 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static const char copyright[] = 36 "@(#) Copyright (c) 1991, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 #if 0 42 static const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; 43 #endif 44 static const char rcsid[] = 45 "$FreeBSD$"; 46 #endif /* not lint */ 47 48 #include <sys/types.h> 49 #include <sys/msgbuf.h> 50 #include <sys/sysctl.h> 51 52 #include <err.h> 53 #include <fcntl.h> 54 #include <kvm.h> 55 #include <locale.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <unistd.h> 59 #include <vis.h> 60 #include <sys/syslog.h> 61 62 struct nlist nl[] = { 63 #define X_MSGBUF 0 64 { "_msgbufp" }, 65 { NULL }, 66 }; 67 68 void usage __P((void)); 69 70 #define KREAD(addr, var) \ 71 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) 72 73 int 74 main(argc, argv) 75 int argc; 76 char *argv[]; 77 { 78 int ch, newl, skip; 79 char *p, *ep; 80 struct msgbuf *bufp, cur; 81 char *bp, *memf, *nlistf; 82 kvm_t *kd; 83 char buf[5]; 84 int all = 0; 85 int pri; 86 size_t buflen; 87 int bufpos; 88 89 (void) setlocale(LC_CTYPE, ""); 90 memf = nlistf = NULL; 91 while ((ch = getopt(argc, argv, "aM:N:")) != -1) 92 switch(ch) { 93 case 'a': 94 all++; 95 break; 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 if (memf == NULL && nlistf == NULL) { 110 /* Running kernel. Use sysctl. */ 111 if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) 112 err(1, "sysctl kern.msgbuf"); 113 if ((bp = malloc(buflen)) == NULL) 114 errx(1, "malloc failed"); 115 if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) 116 err(1, "sysctl kern.msgbuf"); 117 /* We get a dewrapped buffer using sysctl. */ 118 bufpos = 0; 119 } else { 120 /* Read in kernel message buffer, do sanity checks. */ 121 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); 122 if (kd == NULL) 123 exit (1); 124 if (kvm_nlist(kd, nl) == -1) 125 errx(1, "kvm_nlist: %s", kvm_geterr(kd)); 126 if (nl[X_MSGBUF].n_type == 0) 127 errx(1, "%s: msgbufp not found", 128 nlistf ? nlistf : "namelist"); 129 if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) 130 errx(1, "kvm_read: %s", kvm_geterr(kd)); 131 if (cur.msg_magic != MSG_MAGIC) 132 errx(1, "kernel message buffer has different magic " 133 "number"); 134 bp = malloc(cur.msg_size); 135 if (!bp) 136 errx(1, "malloc failed"); 137 if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) != 138 cur.msg_size) 139 errx(1, "kvm_read: %s", kvm_geterr(kd)); 140 kvm_close(kd); 141 buflen = cur.msg_size; 142 bufpos = cur.msg_bufx; 143 if (bufpos >= buflen) 144 bufpos = 0; 145 } 146 147 /* 148 * The message buffer is circular. If the buffer has wrapped, the 149 * write pointer points to the oldest data. Otherwise, the write 150 * pointer points to \0's following the data. Read the entire 151 * buffer starting at the write pointer and ignore nulls so that 152 * we effectively start at the oldest data. 153 */ 154 p = bp + bufpos; 155 ep = (bufpos == 0 ? bp + buflen : p); 156 newl = skip = 0; 157 do { 158 if (p == bp + buflen) 159 p = bp; 160 ch = *p; 161 /* Skip "\n<.*>" syslog sequences. */ 162 if (skip) { 163 if (ch == '\n') { 164 skip = 0; 165 newl = 1; 166 } if (ch == '>') { 167 if (LOG_FAC(pri) == LOG_KERN || all) 168 newl = skip = 0; 169 } else if (ch >= '0' && ch <= '9') { 170 pri *= 10; 171 pri += ch - '0'; 172 } 173 continue; 174 } 175 if (newl && ch == '<') { 176 pri = 0; 177 skip = 1; 178 continue; 179 } 180 if (ch == '\0') 181 continue; 182 newl = ch == '\n'; 183 (void)vis(buf, ch, 0, 0); 184 if (buf[1] == 0) 185 (void)putchar(buf[0]); 186 else 187 (void)printf("%s", buf); 188 } while (++p != ep); 189 if (!newl) 190 (void)putchar('\n'); 191 exit(0); 192 } 193 194 void 195 usage() 196 { 197 (void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n"); 198 exit(1); 199 } 200