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0fc6e47b | 1 | /*- |
b890173a KB |
2 | * Copyright (c) 1991, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
0fc6e47b | 4 | * |
befa51e1 | 5 | * %sccs.include.redist.c% |
76797561 DF |
6 | */ |
7 | ||
8 | #ifndef lint | |
b890173a KB |
9 | static char copyright[] = |
10 | "@(#) Copyright (c) 1991, 1993\n\ | |
11 | The Regents of the University of California. All rights reserved.\n"; | |
0fc6e47b KB |
12 | #endif /* not lint */ |
13 | ||
14 | #ifndef lint | |
b890173a | 15 | static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) %G%"; |
0fc6e47b | 16 | #endif /* not lint */ |
76797561 | 17 | |
befa51e1 | 18 | #include <sys/cdefs.h> |
34a7981f | 19 | #include <sys/msgbuf.h> |
7c753ccc | 20 | |
1b207d8b | 21 | #include <fcntl.h> |
7c753ccc | 22 | #include <kvm.h> |
1b207d8b | 23 | #include <limits.h> |
a5d34734 KB |
24 | #include <nlist.h> |
25 | #include <stdio.h> | |
7c753ccc KB |
26 | #include <stdlib.h> |
27 | #include <time.h> | |
1b207d8b KB |
28 | #include <unistd.h> |
29 | #include <vis.h> | |
34a7981f | 30 | |
befa51e1 KB |
31 | struct nlist nl[] = { |
32 | #define X_MSGBUF 0 | |
b0f3bb00 | 33 | { "_msgbufp" }, |
befa51e1 | 34 | { NULL }, |
34a7981f BJ |
35 | }; |
36 | ||
1b207d8b | 37 | void usage __P((void)); |
befa51e1 | 38 | |
1b207d8b | 39 | #define KREAD(addr, var) \ |
c4fb1efb | 40 | kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) |
1b207d8b KB |
41 | |
42 | int | |
34a7981f | 43 | main(argc, argv) |
befa51e1 | 44 | int argc; |
1b207d8b | 45 | char *argv[]; |
34a7981f | 46 | { |
befa51e1 KB |
47 | register int ch, newl, skip; |
48 | register char *p, *ep; | |
b0f3bb00 | 49 | struct msgbuf *bufp, cur; |
ad07e3a9 | 50 | char *memf, *nlistf; |
1b207d8b | 51 | kvm_t *kd; |
2a9ae6db | 52 | char buf[5]; |
34a7981f | 53 | |
ad07e3a9 | 54 | memf = nlistf = NULL; |
befa51e1 KB |
55 | while ((ch = getopt(argc, argv, "M:N:")) != EOF) |
56 | switch(ch) { | |
57 | case 'M': | |
ad07e3a9 | 58 | memf = optarg; |
befa51e1 KB |
59 | break; |
60 | case 'N': | |
ad07e3a9 | 61 | nlistf = optarg; |
34a7981f | 62 | break; |
befa51e1 KB |
63 | case '?': |
64 | default: | |
65 | usage(); | |
34a7981f | 66 | } |
befa51e1 KB |
67 | argc -= optind; |
68 | argv += optind; | |
69 | ||
ad07e3a9 KB |
70 | /* |
71 | * Discard setgid privileges if not the running kernel so that bad | |
72 | * guys can't print interesting stuff from kernel memory. | |
73 | */ | |
74 | if (memf != NULL || nlistf != NULL) | |
75 | setgid(getgid()); | |
76 | ||
befa51e1 | 77 | /* Read in kernel message buffer, do sanity checks. */ |
2a9ae6db KB |
78 | if ((kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg")) == NULL) |
79 | exit (1); | |
1b207d8b | 80 | if (kvm_nlist(kd, nl) == -1) |
7c753ccc | 81 | errx(1, "kvm_nlist: %s", kvm_geterr(kd)); |
befa51e1 | 82 | if (nl[X_MSGBUF].n_type == 0) |
7c753ccc | 83 | errx(1, "%s: msgbufp not found", nlistf ? nlistf : "namelist"); |
1b207d8b | 84 | if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) |
7c753ccc | 85 | errx(1, "kvm_read: %s", kvm_geterr(kd)); |
1b207d8b | 86 | kvm_close(kd); |
befa51e1 | 87 | if (cur.msg_magic != MSG_MAGIC) |
7c753ccc | 88 | errx(1, "magic number incorrect"); |
befa51e1 KB |
89 | if (cur.msg_bufx >= MSG_BSIZE) |
90 | cur.msg_bufx = 0; | |
91 | ||
92 | /* | |
93 | * The message buffer is circular; start at the read pointer, and | |
94 | * go to the write pointer - 1. | |
95 | */ | |
96 | p = cur.msg_bufc + cur.msg_bufx; | |
97 | ep = cur.msg_bufc + cur.msg_bufx - 1; | |
98 | for (newl = skip = 0; p != ep; ++p) { | |
99 | if (p == cur.msg_bufc + MSG_BSIZE) | |
100 | p = cur.msg_bufc; | |
101 | ch = *p; | |
102 | /* Skip "\n<.*>" syslog sequences. */ | |
103 | if (skip) { | |
104 | if (ch == '>') | |
105 | newl = skip = 0; | |
106 | continue; | |
107 | } | |
108 | if (newl && ch == '<') { | |
109 | skip = 1; | |
110 | continue; | |
111 | } | |
112 | if (ch == '\0') | |
113 | continue; | |
1b207d8b | 114 | newl = ch == '\n'; |
7c753ccc | 115 | (void)vis(buf, ch, 0, 0); |
1b207d8b | 116 | if (buf[1] == 0) |
7c753ccc | 117 | (void)putchar(buf[0]); |
1b207d8b | 118 | else |
7c753ccc | 119 | (void)printf("%s", buf); |
befa51e1 KB |
120 | } |
121 | if (!newl) | |
122 | (void)putchar('\n'); | |
123 | exit(0); | |
34a7981f BJ |
124 | } |
125 | ||
befa51e1 KB |
126 | void |
127 | usage() | |
128 | { | |
129 | (void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n"); | |
130 | exit(1); | |
34a7981f | 131 | } |