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Diffstat (limited to 'sbin/dmesg/dmesg.c')
| -rw-r--r-- | sbin/dmesg/dmesg.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/sbin/dmesg/dmesg.c b/sbin/dmesg/dmesg.c new file mode 100644 index 0000000..d789f5d --- /dev/null +++ b/sbin/dmesg/dmesg.c @@ -0,0 +1,157 @@ +/*- + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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. + */ + +#ifndef lint +static char copyright[] = +"@(#) Copyright (c) 1991, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; +#endif /* not lint */ + +#include <sys/cdefs.h> +#include <sys/msgbuf.h> + +#include <fcntl.h> +#include <kvm.h> +#include <limits.h> +#include <nlist.h> +#include <stdio.h> +#include <stdlib.h> +#include <time.h> +#include <unistd.h> +#include <vis.h> + +struct nlist nl[] = { +#define X_MSGBUF 0 + { "_msgbufp" }, + { NULL }, +}; + +void usage __P((void)); + +#define KREAD(addr, var) \ + kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) + +int +main(argc, argv) + int argc; + char *argv[]; +{ + register int ch, newl, skip; + register char *p, *ep; + struct msgbuf *bufp, cur; + char *memf, *nlistf; + kvm_t *kd; + char buf[5]; + + memf = nlistf = NULL; + while ((ch = getopt(argc, argv, "M:N:")) != EOF) + switch(ch) { + case 'M': + memf = optarg; + break; + case 'N': + nlistf = optarg; + break; + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + /* + * Discard setgid privileges if not the running kernel so that bad + * guys can't print interesting stuff from kernel memory. + */ + if (memf != NULL || nlistf != NULL) + setgid(getgid()); + + /* Read in kernel message buffer, do sanity checks. */ + if ((kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg")) == 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"); + if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) + errx(1, "kvm_read: %s", kvm_geterr(kd)); + kvm_close(kd); + if (cur.msg_magic != MSG_MAGIC) + errx(1, "magic number incorrect"); + if (cur.msg_bufx >= MSG_BSIZE) + cur.msg_bufx = 0; + + /* + * The message buffer is circular; start at the read pointer, and + * go to the write pointer - 1. + */ + p = cur.msg_bufc + cur.msg_bufx; + ep = cur.msg_bufc + cur.msg_bufx - 1; + for (newl = skip = 0; p != ep; ++p) { + if (p == cur.msg_bufc + MSG_BSIZE) + p = cur.msg_bufc; + ch = *p; + /* Skip "\n<.*>" syslog sequences. */ + if (skip) { + if (ch == '>') + newl = skip = 0; + continue; + } + if (newl && ch == '<') { + skip = 1; + continue; + } + if (ch == '\0') + continue; + newl = ch == '\n'; + (void)vis(buf, ch, 0, 0); + if (buf[1] == 0) + (void)putchar(buf[0]); + else + (void)printf("%s", buf); + } + if (!newl) + (void)putchar('\n'); + exit(0); +} + +void +usage() +{ + (void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n"); + exit(1); +} |
