.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
.\" May be distributed under the GNU General Public License
-.TH DMESG 1 "Jun 2011"
+.TH DMESG 1 "Jul 2011"
.SH NAME
dmesg \- print or control the kernel ring buffer
.SH SYNOPSIS
.IP "\fB\-e, \-\-console-on\fP"
Enable printing messages to the console.
.IP "\fB\-f, \-\-facility \fIlist\fP"
-Restrict output to defined (comma separated) list of facilities. For exmaple
+Restrict output to defined (comma separated) list of facilities. For example
.sp
dmesg --facility=daemon
.sp
-will print messages from system daemons only.
-.IP "\fB\-x, \-\-decode\fP"
-Decode facility and level (priority) number to human readable prefixes.
+will print messages from system daemons only. For all supported facilities see
+.B dmesg \-\-help
+output.
.IP "\fB\-h, \-\-help\fP"
Print a help text and exit.
.IP "\fB\-l, \-\-level \fIlist\fP"
-Restrict output to defined (comma separated) list of levels. For exmaple
+Restrict output to defined (comma separated) list of levels. For example
.sp
dmesg --level=err,warn
.sp
-will print error and warning messages only.
-.IP "\fB\-x, \-\-decode\fP"
-Decode facility and level (priority) number to human readable prefixes.
+will print error and warning messages only. For all supported levels see
+.B dmesg \-\-help
+output.
.IP "\fB\-n, \-\-console-level \fIlevel\fP
Set the
.I level
then this option can be used to view the entire buffer.
.IP "\fB\-V, \-\-version\fP"
Output version information and exit.
+.IP "\fB\-x, \-\-decode\fP"
+Decode facility and level (priority) number to human readable prefixes.
.SH SEE ALSO
.BR syslogd (8)
-.\" .SH AUTHOR
-.\" Theodore Ts'o (tytso@athena.mit.edu)
+.SH AUTHORS
+.nf
+Karel Zak <kzak@redhat.com>
+Theodore Ts'o <tytso@athena.mit.edu>
+.fi
.SH AVAILABILITY
The dmesg command is part of the util-linux package and is available from
ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
-/* 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@pld.ORG.PL>
- * - added Native Language Support
+/*
+ * dmesg.c -- Print out the contents of the kernel ring buffer
*
+ * Copyright (C) 1993 Theodore Ts'o <tytso@athena.mit.edu>
+ * Copyright (C) 2011 Karel Zak <kzak@redhat.com>
+ *
+ * This program comes with ABSOLUTELY NO WARRANTY.
*/
-
#include <linux/unistd.h>
#include <stdio.h>
#include <getopt.h>
/* Return size of the log buffer */
#define SYSLOG_ACTION_SIZE_BUFFER 10
-#ifndef LOG_PRIMASK
-#define LOG_PRIMASK 0x07 /* mask to extract priority part (internal) */
- /* extract priority */
-#define LOG_PRI(p) ((p) & LOG_PRIMASK)
-#endif
-
-#ifndef LOG_FACMASK
-#define LOG_FACMASK 0x03f8 /* mask to extract facility part */
- /* facility of pri */
-#define LOG_FAC(p) (((p) & LOG_FACMASK) >> 3)
-#endif
-
/*
- * Priority names, based on sys/syslog.h
+ * Priority and facility names
*/
struct dmesg_name {
const char *name;
const char *help;
};
+/*
+ * Priority names -- based on sys/syslog.h
+ */
static const struct dmesg_name level_names[] =
{
[LOG_EMERG] = { "emerg", N_("system is unusable") },
" -d, --console-off disable printing messages to console\n"
" -e, --console-on enable printing messages to console\n"
" -f, --facility=LIST restrict output to defined facilities\n"
- " -x, --decode decode facility and level to readable string\n"
" -h, --help display this help and exit\n"
" -l, --level=LIST restrict output to defined levels\n"
" -n, --console-level=LEVEL set level of messages printed to console\n"
" -r, --raw print the raw message buffer\n"
" -s, --buffer-size=SIZE buffer size to query the kernel ring buffer\n"
- " -V, --version output version information and exit\n\n"));
+ " -V, --version output version information and exit\n\n"
+ " -x, --decode decode facility and level to readable string\n"));
fprintf(out, _("Supported log facilities:\n"));
for (i = 0; i < ARRAY_SIZE(level_names); i++) {
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
+/*
+ * LEVEL ::= <number> | <name>
+ * <number> ::= number in range <0..N>, where N < ARRAY_SIZE(level_names)
+ * <name> ::= case-insensitive text
+ */
static int parse_level(const char *str, size_t len)
{
int i;
return -1;
}
+/*
+ * FACILITY ::= <number> | <name>
+ * <number> ::= number in range <0..N>, where N < ARRAY_SIZE(facility_names)
+ * <name> ::= case-insensitive text
+ */
static int parse_facility(const char *str, size_t len)
{
int i;
return -1;
}
+/*
+ * Parses numerical prefix used for all messages in kernel ring buffer.
+ *
+ * Priorities/facilities are encoded into a single 32-bit quantity, where the
+ * bottom 3 bits are the priority (0-7) and the top 28 bits are the facility
+ * (0-big number).
+ *
+ * Note that the number has to end with '>' char.
+ */
static const char *parse_faclev(const char *str, int *fac, int *lev)
{
long num;
return str;
}
+/*
+ * LIST ::= <item> [, <item>]
+ *
+ * The <item> is translated to 'id' by name2id() function and the 'id' is used
+ * as a possition in the 'ary' bit array. It means that the 'id' has to be in
+ * range <0..N> where N < sizeof(ary) * NBBY.
+ */
static int list_to_bitarray(const char *list,
int (*name2id)(const char *name, size_t namesz),
char *ary)
return n > 0 ? n : 0;
}
+/*
+ * Reads messages from kernel ring buffer
+ */
static int read_buffer(char **buf, size_t bufsize, int clear)
{
size_t sz;
return 0;
}
+/*
+ * Prints to 'out' and non-printable chars are replaced with \x<hex> sequences.
+ */
static void safe_fwrite(const char *buf, size_t size, FILE *out)
{
int i;
}
}
+/*
+ * Prints the 'buf' kernel ring buffer; the messages are filtered out according
+ * to 'levels' and 'facilities' bitarrays.
+ */
static void print_buffer(const char *buf, size_t size, int flags,
char *levels, char *facilities)
{
char facilities[ARRAY_SIZE(facility_names) / NBBY + 1] = { 0 };
static const struct option longopts[] = {
- { "clear", no_argument, NULL, 'C' },
- { "read-clear", no_argument, NULL, 'c' },
- { "raw", no_argument, NULL, 'r' },
{ "buffer-size", required_argument, NULL, 's' },
- { "decode", no_argument, NULL, 'x' },
+ { "clear", no_argument, NULL, 'C' },
{ "console-level", required_argument, NULL, 'n' },
- { "level", required_argument, NULL, 'l' },
{ "console-off", no_argument, NULL, 'd' },
{ "console-on", no_argument, NULL, 'e' },
+ { "decode", no_argument, NULL, 'x' },
{ "facility", required_argument, NULL, 'f' },
- { "version", no_argument, NULL, 'V' },
{ "help", no_argument, NULL, 'h' },
+ { "level", required_argument, NULL, 'l' },
+ { "raw", no_argument, NULL, 'r' },
+ { "read-clear", no_argument, NULL, 'c' },
+ { "version", no_argument, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
- while ((c = getopt_long(argc, argv, "Ccdehl:rn:s:Vxf:", longopts, NULL)) != -1) {
+ while ((c = getopt_long(argc, argv, "Ccdef:hl:n:rs:Vx", longopts, NULL)) != -1) {
if (cmd != -1 && strchr("Ccnde", c))
errx(EXIT_FAILURE, "%s %s",
flags |= DMESG_FL_FACILITY;
list_to_bitarray(optarg, parse_facility, facilities);
break;
- case 'n':
- cmd = SYSLOG_ACTION_CONSOLE_LEVEL;
- console_level = parse_level(optarg, 0);
+ case 'h':
+ usage(stdout);
break;
case 'l':
flags |= DMESG_FL_LEVEL;
list_to_bitarray(optarg, parse_level, levels);
break;
+ case 'n':
+ cmd = SYSLOG_ACTION_CONSOLE_LEVEL;
+ console_level = parse_level(optarg, 0);
+ break;
case 'r':
flags |= DMESG_FL_RAW;
break;
- case 'x':
- flags |= DMESG_FL_DECODE;
- break;
case 's':
bufsize = strtol_or_err(optarg,
_("failed to parse buffer size"));
printf(_("%s from %s\n"), program_invocation_short_name,
PACKAGE_STRING);
return EXIT_SUCCESS;
- case 'h':
- usage(stdout);
+ case 'x':
+ flags |= DMESG_FL_DECODE;
break;
case '?':
default:
projects / thirdparty / util-linux.git / commitdiff
