LXR busybox/util-linux/dmesg.c

   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 tarball for details.
  10 */
  11
  12#include <sys/klog.h>
  13#include "libbb.h"
  14
  15int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  16int dmesg_main(int argc UNUSED_PARAM, char **argv)
  17{
  18        int len;
  19        char *buf;
  20        char *size, *level;
  21        unsigned flags = getopt32(argv, "cs:n:", &size, &level);
  22        enum {
  23                OPT_c = 1<<0,
  24                OPT_s = 1<<1,
  25                OPT_n = 1<<2
  26        };
  27
  28        if (flags & OPT_n) {
  29                if (klogctl(8, NULL, xatoul_range(level, 0, 10)))
  30                        bb_perror_msg_and_die("klogctl");
  31                return EXIT_SUCCESS;
  32        }
  33
  34        len = (flags & OPT_s) ? xatoul_range(size, 2, INT_MAX) : 16384;
  35        buf = xmalloc(len);
  36        len = klogctl(3 + (flags & OPT_c), buf, len);
  37        if (len < 0)
  38                bb_perror_msg_and_die("klogctl");
  39        if (len == 0)
  40                return EXIT_SUCCESS;
  41
  42        /* Skip <#> at the start of lines, and make sure we end with a newline. */
  43
  44        if (ENABLE_FEATURE_DMESG_PRETTY) {
  45                int last = '\n';
  46                int in = 0;
  47
  48                do {
  49                        if (last == '\n' && buf[in] == '<')
  50                                in += 3;
  51                        else {
  52                                last = buf[in++];
  53                                bb_putchar(last);
  54                        }
  55                } while (in < len);
  56                if (last != '\n')
  57                        bb_putchar('\n');
  58        } else {
  59                full_write(STDOUT_FILENO, buf, len);
  60                if (buf[len-1] != '\n')
  61                        bb_putchar('\n');
  62        }
  63
  64        if (ENABLE_FEATURE_CLEAN_UP) free(buf);
  65
  66        return EXIT_SUCCESS;
  67}
  68