create a document for mdev so people dont have to rtfs

[oweals/busybox.git] / util-linux / dmesg.c

diff --git a/util-linux/dmesg.c b/util-linux/dmesg.c
index b6c990d99f733e865823bd7b4e6775942dd3f4bd..0bbc306fca3f312588529f74f97bc2d29f651e58 100644 (file)
--- a/util-linux/dmesg.c
+++ b/util-linux/dmesg.c
@@ -1,132 +1,54 @@
 /* vi: set sw=4 ts=4: */
-/* dmesg.c -- Print out the contents of the kernel ring buffer
- * Created: Sat Oct  9 16:19:47 1993
- * Revised: Thu Oct 28 21:52:17 1993 by faith@cs.unc.edu
- * Copyright 1993 Theodore Ts'o (tytso@athena.mit.edu)
- * This program comes with ABSOLUTELY NO WARRANTY.
- * Modifications by Rick Sladkey (jrs@world.std.com)
- * Larger buffersize 3 June 1998 by Nicolai Langfeldt, based on a patch
- * by Peeter Joot.  This was also suggested by John Hudson.
- * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
- * - added Native Language Support
+/*
  *
- * from util-linux -- adapted for busybox by 
- * Erik Andersen <andersee@debian.org>. I ripped out Native Language 
- * Support, replaced getopt, added some gotos for redundant stuff.
+ * dmesg - display/control kernel ring buffer.
+ *
+ * Copyright 2006 Rob Landley <rob@landley.net>
+ * Copyright 2006 Bernhard Fischer <rep.nop@aon.at>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
 
-#include "internal.h"
-#include <stdio.h>
-#include <stdlib.h>
-
-#if __GNU_LIBRARY__ < 5
-
-#ifndef __alpha__
-# define __NR_klogctl __NR_syslog
-#include <sys/syscall.h>
-static inline _syscall3(int, klogctl, int, type, char *, b, int, len);
-#else                                                  /* __alpha__ */
-#define klogctl syslog
-#endif
+#include "busybox.h"
+#include <unistd.h>
+#include <sys/klog.h>
 
-#else
-# include <sys/klog.h>
-#endif
-
-static const char dmesg_usage[] = "dmesg [-c] [-n LEVEL] [-s SIZE]\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-       "\nPrints or controls the kernel ring buffer\n\n"
-       "Options:\n"
-       "\t-c\t\tClears the ring buffer's contents after printing\n"
-       "\t-n LEVEL\tSets console logging level\n"
-       "\t-s SIZE\t\tUse a buffer of size SIZE\n"
-#endif
-       ;
-
-int dmesg_main(int argc, char **argv)
+int dmesg_main(int argc, char *argv[]);
+int dmesg_main(int argc, char *argv[])
 {
-       char *buf;
-       int bufsize = 8196;
-       int i;
-       int n;
-       int level = 0;
-       int lastc;
-       int cmd = 3;
-       int stopDoingThat;
-
-       argc--;
-       argv++;
-
-       /* Parse any options */
-       while (argc && **argv == '-') {
-               stopDoingThat = FALSE;
-               while (stopDoingThat == FALSE && *++(*argv)) {
-                       switch (**argv) {
-                       case 'c':
-                               cmd = 4;
-                               break;
-                       case 'n':
-                               cmd = 8;
-                               if (--argc == 0)
-                                       goto end;
-                               level = atoi(*(++argv));
-                               if (--argc > 0)
-                                       ++argv;
-                               stopDoingThat = TRUE;
-                               break;
-                       case 's':
-                               if (--argc == 0)
-                                       goto end;
-                               bufsize = atoi(*(++argv));
-                               if (--argc > 0)
-                                       ++argv;
-                               stopDoingThat = TRUE;
-                               break;
-                       default:
-                               goto end;
+       char *size, *level;
+       int flags = getopt32(argc, argv, "cs:n:", &size, &level);
+
+       if (flags & 4) {
+               if (klogctl(8, NULL, xatoul_range(level, 0, 10)))
+                       bb_perror_msg_and_die("klogctl");
+       } else {
+               int len;
+               char *buf;
+
+               len = (flags & 2) ? xatoul_range(size, 2, INT_MAX) : 16384;
+               buf = xmalloc(len);
+               if (0 > (len = klogctl(3 + (flags & 1), buf, len)))
+                       bb_perror_msg_and_die("klogctl");
+
+               // Skip <#> at the start of lines, and make sure we end with a newline.
+
+               if (ENABLE_FEATURE_DMESG_PRETTY) {
+                       int last = '\n';
+                       int in;
+
+                       for (in = 0; in<len;) {
+                               if (last == '\n' && buf[in] == '<') in += 3;
+                               else putchar(last = buf[in++]);
                        }
+                       if (last != '\n') putchar('\n');
+               } else {
+                       write(1,buf,len);
+                       if (len && buf[len-1]!='\n') putchar('\n');
                }
-       }
-
-       if (argc > 1) {
-               goto end;
-       }
-
-       if (cmd == 8) {
-               n = klogctl(cmd, NULL, level);
-               if (n < 0) {
-                       goto klogctl_error;
-               }
-               exit(TRUE);
-       }
 
-       if (bufsize < 4096)
-               bufsize = 4096;
-       buf = (char *) xmalloc(bufsize);
-       n = klogctl(cmd, buf, bufsize);
-       if (n < 0) {
-               goto klogctl_error;
+               if (ENABLE_FEATURE_CLEAN_UP) free(buf);
        }
 
-       lastc = '\n';
-       for (i = 0; i < n; i++) {
-               if ((i == 0 || buf[i - 1] == '\n') && buf[i] == '<') {
-                       i++;
-                       while (buf[i] >= '0' && buf[i] <= '9')
-                               i++;
-                       if (buf[i] == '>')
-                               i++;
-               }
-               lastc = buf[i];
-               putchar(lastc);
-       }
-       if (lastc != '\n')
-               putchar('\n');
-       exit(TRUE);
-  end:
-       usage(dmesg_usage);
-       exit(FALSE);
-  klogctl_error:
-       perror("klogctl");
-       return(FALSE);
+       return 0;
 }