/*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved. * @(#)dmesg.c 8.1 (Berkeley) 6/5/93 * $FreeBSD: src/sbin/dmesg/dmesg.c,v 1.11.2.3 2001/08/08 22:32:15 obrien Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include static struct nlist nl[] = { #define X_MSGBUF 0 { "_msgbufp", 0, 0, 0, 0 }, { NULL, 0, 0, 0, 0 }, }; static void dumpbuf(char *bp, size_t bufpos, size_t buflen, int *newl, int *skip, int *pri); static void usage(void) __dead2; #define KREAD(addr, var) \ kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) #define INCRBUFSIZE 65536 static int all_opt; int main(int argc, char **argv) { int newl, skip; struct msgbuf *bufp, cur; char *bp, *memf, *nlistf; kvm_t *kd; int ch; int clear = 0; int pri = 0; int tailmode = 0; int kno; size_t buflen, bufpos; struct stat st; setlocale(LC_CTYPE, ""); memf = nlistf = NULL; while ((ch = getopt(argc, argv, "acfM:N:n:")) != -1) { switch(ch) { case 'a': all_opt++; break; case 'c': clear = 1; break; case 'f': ++tailmode; break; case 'M': memf = optarg; break; case 'N': nlistf = optarg; break; case 'n': kno = strtol(optarg, NULL, 0); asprintf(&memf, "vmcore.%d", kno); asprintf(&nlistf, "kern.%d", kno); if (stat(memf, &st) || stat(nlistf, &st)) { free(memf); free(nlistf); asprintf(&memf, "/var/crash/vmcore.%d", kno); asprintf(&nlistf, "/var/crash/kern.%d", kno); } break; case '?': default: usage(); } } argc -= optind; argv += optind; newl = 1; skip = 0; pri = 0; if (memf == NULL && nlistf == NULL && tailmode == 0) { /* Running kernel. Use sysctl. */ buflen = 0; if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) err(1, "sysctl kern.msgbuf"); if (buflen == 0) /* can happen if msgbuf was cleared */ buflen = 1; if ((bp = malloc(buflen)) == NULL) errx(1, "malloc failed"); if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) err(1, "sysctl kern.msgbuf"); /* We get a dewrapped buffer using sysctl. */ bufpos = 0; dumpbuf(bp, bufpos, buflen, &newl, &skip, &pri); } else { u_int rindex; u_int xindex; u_int ri; u_int xi; u_int n; /* Read in kernel message buffer, do sanity checks. */ kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); if (kd == NULL) exit (1); if (kvm_nlist(kd, nl) == -1) errx(1, "kvm_nlist: %s", kvm_geterr(kd)); if (nl[X_MSGBUF].n_type == 0) errx(1, "%s: msgbufp not found", nlistf ? nlistf : "namelist"); bp = malloc(INCRBUFSIZE); if (!bp) errx(1, "malloc failed"); if (KREAD(nl[X_MSGBUF].n_value, bufp)) errx(1, "kvm_read: %s", kvm_geterr(kd)); if (KREAD((long)bufp, cur)) errx(1, "kvm_read: %s", kvm_geterr(kd)); if (cur.msg_magic != MSG_MAGIC && cur.msg_magic != MSG_OMAGIC) errx(1, "kernel message buffer has different magic " "number"); /* * NOTE: current algorithm is compatible with both old and * new msgbuf structures. The new structure doesn't * modulo the indexes (so we do), and adds a separate * log index which we don't access here. */ rindex = cur.msg_bufr; for (;;) { /* * Calculate index for dump and do sanity clipping. */ xindex = cur.msg_bufx; n = xindex - rindex; if (n > cur.msg_size - 1024) { rindex = xindex - cur.msg_size + 2048; n = xindex - rindex; } ri = rindex % cur.msg_size; xi = xindex % cur.msg_size; if (ri < xi) buflen = xi - ri; else buflen = cur.msg_size - ri; if (buflen > n) buflen = n; if (buflen > INCRBUFSIZE) buflen = INCRBUFSIZE; if (kvm_read(kd, (long)cur.msg_ptr + ri, bp, buflen) != (ssize_t)buflen) { errx(1, "kvm_read: %s", kvm_geterr(kd)); } if (buflen) dumpbuf(bp, 0, buflen, &newl, &skip, &pri); ri = (ri + buflen) % cur.msg_size; n = n - buflen; rindex += buflen; if ((int)n <= 0) { if (tailmode == 0) break; fflush(stdout); if (tailmode == 1) sleep(1); } if (KREAD((long)bufp, cur)) errx(1, "kvm_read: %s", kvm_geterr(kd)); } kvm_close(kd); } if (!newl) putchar('\n'); if (clear) { if (sysctlbyname("kern.msgbuf_clear", NULL, NULL, &clear, sizeof(int)) != 0) { err(1, "sysctl kern.msgbuf_clear"); } } return(0); } static void dumpbuf(char *bp, size_t bufpos, size_t buflen, int *newl, int *skip, int *pri) { int ch; char *p, *ep; char buf[5]; /* * The message buffer is circular. If the buffer has wrapped, the * write pointer points to the oldest data. Otherwise, the write * pointer points to \0's following the data. Read the entire * buffer starting at the write pointer and ignore nulls so that * we effectively start at the oldest data. */ p = bp + bufpos; ep = (bufpos == 0 ? bp + buflen : p); do { if (p == bp + buflen) p = bp; ch = *p; /* Skip "\n<.*>" syslog sequences. */ if (*skip) { if (ch == '\n') { *skip = 0; *newl = 1; } if (ch == '>') { if (LOG_FAC(*pri) == LOG_KERN) *newl = *skip = 0; } else if (ch >= '0' && ch <= '9') { *pri *= 10; *pri += ch - '0'; } continue; } if (*newl && ch == '<' && all_opt == 0) { *pri = 0; *skip = 1; continue; } if (ch == '\0') continue; *newl = (ch == '\n'); vis(buf, ch, VIS_NOSLASH, 0); if (buf[1] == 0) putchar(buf[0]); else printf("%s", buf); } while (++p != ep); } static void usage(void) { fprintf(stderr, "usage: dmesg [-ac] [-M core] [-N system]\n"); exit(1); }