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0fc6e47b | 1 | /*- |
befa51e1 | 2 | * Copyright (c) 1991 The Regents of the University of California. |
0fc6e47b KB |
3 | * All rights reserved. |
4 | * | |
befa51e1 | 5 | * %sccs.include.redist.c% |
76797561 DF |
6 | */ |
7 | ||
8 | #ifndef lint | |
0fc6e47b | 9 | char copyright[] = |
befa51e1 | 10 | "@(#) Copyright (c) 1991 The Regents of the University of California.\n\ |
0fc6e47b KB |
11 | All rights reserved.\n"; |
12 | #endif /* not lint */ | |
13 | ||
14 | #ifndef lint | |
c4fb1efb | 15 | static char sccsid[] = "@(#)dmesg.c 5.14 (Berkeley) %G%"; |
0fc6e47b | 16 | #endif /* not lint */ |
76797561 | 17 | |
befa51e1 | 18 | #include <sys/cdefs.h> |
34a7981f | 19 | #include <sys/msgbuf.h> |
1b207d8b KB |
20 | #include <fcntl.h> |
21 | #include <limits.h> | |
befa51e1 | 22 | #include <time.h> |
a5d34734 | 23 | #include <nlist.h> |
befa51e1 KB |
24 | #include <kvm.h> |
25 | #include <stdlib.h> | |
a5d34734 | 26 | #include <stdio.h> |
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27 | #include <unistd.h> |
28 | #include <vis.h> | |
34a7981f | 29 | |
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30 | struct nlist nl[] = { |
31 | #define X_MSGBUF 0 | |
b0f3bb00 | 32 | { "_msgbufp" }, |
befa51e1 | 33 | { NULL }, |
34a7981f BJ |
34 | }; |
35 | ||
befa51e1 | 36 | void err __P((const char *, ...)); |
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) |
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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; |
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51 | kvm_t *kd; |
52 | char buf[_POSIX2_LINE_MAX]; | |
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 | } |
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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. */ |
1b207d8b KB |
78 | buf[0] = 0; |
79 | kd = kvm_open(nlistf, memf, NULL, O_RDONLY, buf); | |
80 | if (kd == NULL) | |
81 | err("kvm_open: %s", buf); | |
82 | if (kvm_nlist(kd, nl) == -1) | |
83 | err("kvm_nlist: %s", kvm_geterr(kd)); | |
befa51e1 | 84 | if (nl[X_MSGBUF].n_type == 0) |
24c3fce5 | 85 | err("%s: msgbufp not found", nlistf ? nlistf : "namelist"); |
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86 | if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) |
87 | err("kvm_read: %s", kvm_geterr(kd)); | |
88 | kvm_close(kd); | |
befa51e1 KB |
89 | if (cur.msg_magic != MSG_MAGIC) |
90 | err("magic number incorrect"); | |
91 | if (cur.msg_bufx >= MSG_BSIZE) | |
92 | cur.msg_bufx = 0; | |
93 | ||
94 | /* | |
95 | * The message buffer is circular; start at the read pointer, and | |
96 | * go to the write pointer - 1. | |
97 | */ | |
98 | p = cur.msg_bufc + cur.msg_bufx; | |
99 | ep = cur.msg_bufc + cur.msg_bufx - 1; | |
100 | for (newl = skip = 0; p != ep; ++p) { | |
101 | if (p == cur.msg_bufc + MSG_BSIZE) | |
102 | p = cur.msg_bufc; | |
103 | ch = *p; | |
104 | /* Skip "\n<.*>" syslog sequences. */ | |
105 | if (skip) { | |
106 | if (ch == '>') | |
107 | newl = skip = 0; | |
108 | continue; | |
109 | } | |
110 | if (newl && ch == '<') { | |
111 | skip = 1; | |
112 | continue; | |
113 | } | |
114 | if (ch == '\0') | |
115 | continue; | |
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116 | newl = ch == '\n'; |
117 | (void) vis(buf, ch, 0, 0); | |
118 | if (buf[1] == 0) | |
119 | (void) putchar(buf[0]); | |
120 | else | |
121 | (void) fputs(buf, stdout); | |
befa51e1 KB |
122 | } |
123 | if (!newl) | |
124 | (void)putchar('\n'); | |
125 | exit(0); | |
34a7981f BJ |
126 | } |
127 | ||
befa51e1 KB |
128 | #if __STDC__ |
129 | #include <stdarg.h> | |
130 | #else | |
131 | #include <varargs.h> | |
132 | #endif | |
133 | ||
134 | void | |
135 | #if __STDC__ | |
136 | err(const char *fmt, ...) | |
137 | #else | |
138 | err(fmt, va_alist) | |
139 | char *fmt; | |
140 | va_dcl | |
141 | #endif | |
34a7981f | 142 | { |
befa51e1 KB |
143 | va_list ap; |
144 | #if __STDC__ | |
145 | va_start(ap, fmt); | |
146 | #else | |
147 | va_start(ap); | |
148 | #endif | |
149 | (void)fprintf(stderr, "dmesg: "); | |
150 | (void)vfprintf(stderr, fmt, ap); | |
151 | va_end(ap); | |
152 | (void)fprintf(stderr, "\n"); | |
153 | exit(1); | |
154 | /* NOTREACHED */ | |
155 | } | |
34a7981f | 156 | |
befa51e1 KB |
157 | void |
158 | usage() | |
159 | { | |
160 | (void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n"); | |
161 | exit(1); | |
34a7981f | 162 | } |