| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * |
| 4 | * dmesg - display/control kernel ring buffer. |
| 5 | * |
| 6 | * Copyright 2006 Rob Landley <rob@landley.net> |
| 7 | * Copyright 2006 Bernhard Reutner-Fischer <rep.nop@aon.at> |
| 8 | * |
| 9 | * Licensed under GPLv2, see file LICENSE in this source tree. |
| 10 | */ |
| 11 | |
| 12 | //usage:#define dmesg_trivial_usage |
| 13 | //usage: "[-c] [-n LEVEL] [-s SIZE]" |
| 14 | //usage:#define dmesg_full_usage "\n\n" |
| 15 | //usage: "Print or control the kernel ring buffer\n" |
| 16 | //usage: "\n -c Clear ring buffer after printing" |
| 17 | //usage: "\n -n LEVEL Set console logging level" |
| 18 | //usage: "\n -s SIZE Buffer size" |
| 19 | |
| 20 | #include <sys/klog.h> |
| 21 | #include "libbb.h" |
| 22 | |
| 23 | int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 24 | int dmesg_main(int argc UNUSED_PARAM, char **argv) |
| 25 | { |
| 26 | int len, level; |
| 27 | char *buf; |
| 28 | unsigned opts; |
| 29 | enum { |
| 30 | OPT_c = 1 << 0, |
| 31 | OPT_s = 1 << 1, |
| 32 | OPT_n = 1 << 2 |
| 33 | }; |
| 34 | |
| 35 | opt_complementary = "s+:n+"; /* numeric */ |
| 36 | opts = getopt32(argv, "cs:n:", &len, &level); |
| 37 | if (opts & OPT_n) { |
| 38 | if (klogctl(8, NULL, (long) level)) |
| 39 | bb_perror_msg_and_die("klogctl"); |
| 40 | return EXIT_SUCCESS; |
| 41 | } |
| 42 | |
| 43 | if (!(opts & OPT_s)) |
| 44 | len = klogctl(10, NULL, 0); /* read ring buffer size */ |
| 45 | if (len < 16*1024) |
| 46 | len = 16*1024; |
| 47 | if (len > 16*1024*1024) |
| 48 | len = 16*1024*1024; |
| 49 | |
| 50 | buf = xmalloc(len); |
| 51 | len = klogctl(3 + (opts & OPT_c), buf, len); /* read ring buffer */ |
| 52 | if (len < 0) |
| 53 | bb_perror_msg_and_die("klogctl"); |
| 54 | if (len == 0) |
| 55 | return EXIT_SUCCESS; |
| 56 | |
| 57 | |
| 58 | if (ENABLE_FEATURE_DMESG_PRETTY) { |
| 59 | int last = '\n'; |
| 60 | int in = 0; |
| 61 | |
| 62 | /* Skip <[0-9]+> at the start of lines */ |
| 63 | while (1) { |
| 64 | if (last == '\n' && buf[in] == '<') { |
| 65 | while (buf[in++] != '>' && in < len) |
| 66 | ; |
| 67 | } else { |
| 68 | last = buf[in++]; |
| 69 | putchar(last); |
| 70 | } |
| 71 | if (in >= len) |
| 72 | break; |
| 73 | } |
| 74 | /* Make sure we end with a newline */ |
| 75 | if (last != '\n') |
| 76 | bb_putchar('\n'); |
| 77 | } else { |
| 78 | full_write(STDOUT_FILENO, buf, len); |
| 79 | if (buf[len-1] != '\n') |
| 80 | bb_putchar('\n'); |
| 81 | } |
| 82 | |
| 83 | if (ENABLE_FEATURE_CLEAN_UP) free(buf); |
| 84 | |
| 85 | return EXIT_SUCCESS; |
| 86 | } |