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 #if 0 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1991, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #ifndef lint 42 static const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; 43 #endif /* not lint */ 44 #endif 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 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 <nlist.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <unistd.h> 60 #include <vis.h> 61 #include <sys/syslog.h> 62 63 struct nlist nl[] = { 64 #define X_MSGBUF 0 65 { "_msgbufp" }, 66 { NULL }, 67 }; 68 69 void usage(void) __dead2; 70 71 #define KREAD(addr, var) \ 72 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) 73 74 int 75 main(int argc, char *argv[]) 76 { 77 int ch, newl, skip; 78 char *p, *ep; 79 struct msgbuf *bufp, cur; 80 char *bp, *memf, *nlistf; 81 kvm_t *kd; 82 char buf[5]; 83 int all = 0; 84 int pri; 85 size_t buflen, bufpos; 86 87 (void) setlocale(LC_CTYPE, ""); 88 memf = nlistf = NULL; 89 while ((ch = getopt(argc, argv, "aM:N:")) != -1) 90 switch(ch) { 91 case 'a': 92 all++; 93 break; 94 case 'M': 95 memf = optarg; 96 break; 97 case 'N': 98 nlistf = optarg; 99 break; 100 case '?': 101 default: 102 usage(); 103 } 104 argc -= optind; 105 argv += optind; 106 107 if (memf == NULL && nlistf == NULL) { 108 /* Running kernel. Use sysctl. */ 109 if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) 110 err(1, "sysctl kern.msgbuf"); 111 if ((bp = malloc(buflen)) == NULL) 112 errx(1, "malloc failed"); 113 if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) 114 err(1, "sysctl kern.msgbuf"); 115 /* We get a dewrapped buffer using sysctl. */ 116 bufpos = 0; 117 } else { 118 /* Read in kernel message buffer, do sanity checks. */ 119 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); 120 if (kd == NULL) 121 exit (1); 122 if (kvm_nlist(kd, nl) == -1) 123 errx(1, "kvm_nlist: %s", kvm_geterr(kd)); 124 if (nl[X_MSGBUF].n_type == 0) 125 errx(1, "%s: msgbufp not found", 126 nlistf ? nlistf : "namelist"); 127 if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) 128 errx(1, "kvm_read: %s", kvm_geterr(kd)); 129 if (cur.msg_magic != MSG_MAGIC) 130 errx(1, "kernel message buffer has different magic " 131 "number"); 132 bp = malloc(cur.msg_size); 133 if (!bp) 134 errx(1, "malloc failed"); 135 if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) != 136 cur.msg_size) 137 errx(1, "kvm_read: %s", kvm_geterr(kd)); 138 kvm_close(kd); 139 buflen = cur.msg_size; 140 bufpos = MSGBUF_SEQ_TO_POS(&cur, cur.msg_wseq); 141 } 142 143 /* 144 * The message buffer is circular. If the buffer has wrapped, the 145 * write pointer points to the oldest data. Otherwise, the write 146 * pointer points to \0's following the data. Read the entire 147 * buffer starting at the write pointer and ignore nulls so that 148 * we effectively start at the oldest data. 149 */ 150 p = bp + bufpos; 151 ep = (bufpos == 0 ? bp + buflen : p); 152 newl = skip = 0; 153 do { 154 if (p == bp + buflen) 155 p = bp; 156 ch = *p; 157 /* Skip "\n<.*>" syslog sequences. */ 158 if (skip) { 159 if (ch == '\n') { 160 skip = 0; 161 newl = 1; 162 } if (ch == '>') { 163 if (LOG_FAC(pri) == LOG_KERN || all) 164 newl = skip = 0; 165 } else if (ch >= '0' && ch <= '9') { 166 pri *= 10; 167 pri += ch - '0'; 168 } 169 continue; 170 } 171 if (newl && ch == '<') { 172 pri = 0; 173 skip = 1; 174 continue; 175 } 176 if (ch == '\0') 177 continue; 178 newl = ch == '\n'; 179 (void)vis(buf, ch, 0, 0); 180 if (buf[1] == 0) 181 (void)putchar(buf[0]); 182 else 183 (void)printf("%s", buf); 184 } while (++p != ep); 185 if (!newl) 186 (void)putchar('\n'); 187 exit(0); 188 } 189 190 void 191 usage(void) 192 { 193 (void)fprintf(stderr, "usage: dmesg [-a] [-M core] [-N system]\n"); 194 exit(1); 195 } 196