| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | *
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| 4 | * dmesg - display/control kernel ring buffer.
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| 5 | *
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| 6 | * Copyright 2006 Rob Landley <rob@landley.net>
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| 7 | * Copyright 2006 Bernhard Reutner-Fischer <rep.nop@aon.at>
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| 8 | *
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| 9 | * Licensed under GPLv2, see file LICENSE in this source tree.
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| 10 | */
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| 11 |
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| 12 | //usage:#define dmesg_trivial_usage
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| 13 | //usage: "[-c] [-n LEVEL] [-s SIZE]"
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| 14 | //usage:#define dmesg_full_usage "\n\n"
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| 15 | //usage: "Print or control the kernel ring buffer\n"
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| 16 | //usage: "\n -c Clear ring buffer after printing"
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| 17 | //usage: "\n -n LEVEL Set console logging level"
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| 18 | //usage: "\n -s SIZE Buffer size"
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| 19 | //usage: "\n -r Print raw message buffer"
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| 20 |
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| 21 | #include <sys/klog.h>
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| 22 | #include "libbb.h"
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| 23 |
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| 24 | int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 25 | int dmesg_main(int argc UNUSED_PARAM, char **argv)
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| 26 | {
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| 27 | int len, level;
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| 28 | char *buf;
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| 29 | unsigned opts;
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| 30 | enum {
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| 31 | OPT_c = 1 << 0,
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| 32 | OPT_s = 1 << 1,
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| 33 | OPT_n = 1 << 2,
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| 34 | OPT_r = 1 << 3
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| 35 | };
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| 36 |
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| 37 | opt_complementary = "s+:n+"; /* numeric */
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| 38 | opts = getopt32(argv, "cs:n:r", &len, &level);
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| 39 | if (opts & OPT_n) {
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| 40 | if (klogctl(8, NULL, (long) level))
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| 41 | bb_perror_msg_and_die("klogctl");
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| 42 | return EXIT_SUCCESS;
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| 43 | }
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| 44 |
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| 45 | if (!(opts & OPT_s))
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| 46 | len = klogctl(10, NULL, 0); /* read ring buffer size */
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| 47 | if (len < 16*1024)
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| 48 | len = 16*1024;
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| 49 | if (len > 16*1024*1024)
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| 50 | len = 16*1024*1024;
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| 51 |
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| 52 | buf = xmalloc(len);
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| 53 | len = klogctl(3 + (opts & OPT_c), buf, len); /* read ring buffer */
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| 54 | if (len < 0)
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| 55 | bb_perror_msg_and_die("klogctl");
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| 56 | if (len == 0)
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| 57 | return EXIT_SUCCESS;
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| 58 |
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| 59 |
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| 60 | if (ENABLE_FEATURE_DMESG_PRETTY && !(opts & OPT_r)) {
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| 61 | int last = '\n';
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| 62 | int in = 0;
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| 63 |
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| 64 | /* Skip <[0-9]+> at the start of lines */
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| 65 | while (1) {
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| 66 | if (last == '\n' && buf[in] == '<') {
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| 67 | while (buf[in++] != '>' && in < len)
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| 68 | ;
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| 69 | } else {
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| 70 | last = buf[in++];
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| 71 | putchar(last);
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| 72 | }
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| 73 | if (in >= len)
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| 74 | break;
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| 75 | }
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| 76 | /* Make sure we end with a newline */
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| 77 | if (last != '\n')
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| 78 | bb_putchar('\n');
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| 79 | } else {
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| 80 | full_write(STDOUT_FILENO, buf, len);
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| 81 | if (buf[len-1] != '\n')
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| 82 | bb_putchar('\n');
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| 83 | }
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| 84 |
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| 85 | if (ENABLE_FEATURE_CLEAN_UP) free(buf);
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| 86 |
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| 87 | return EXIT_SUCCESS;
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| 88 | }
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