- /*
- * 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);