Adding upstream version 2.33.1.upstream/2.33.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1547 insertions, 0 deletions

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
new file mode 100644
index 0000000..ba4e225
--- /dev/null
+++ b/sys-utils/dmesg.c
@@ -0,0 +1,1547 @@
+/*
+ * 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 <stdio.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <sys/klog.h>
+#include <sys/syslog.h>
+#include <sys/time.h>
+#include <sys/sysinfo.h>
+#include <ctype.h>
+#include <time.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "c.h"
+#include "colors.h"
+#include "nls.h"
+#include "strutils.h"
+#include "xalloc.h"
+#include "widechar.h"
+#include "all-io.h"
+#include "bitops.h"
+#include "closestream.h"
+#include "optutils.h"
+#include "timeutils.h"
+#include "monotonic.h"
+#include "mangle.h"
+#include "pager.h"
+
+/* Close the log.  Currently a NOP. */
+#define SYSLOG_ACTION_CLOSE          0
+/* Open the log. Currently a NOP. */
+#define SYSLOG_ACTION_OPEN           1
+/* Read from the log. */
+#define SYSLOG_ACTION_READ           2
+/* Read all messages remaining in the ring buffer. (allowed for non-root) */
+#define SYSLOG_ACTION_READ_ALL       3
+/* Read and clear all messages remaining in the ring buffer */
+#define SYSLOG_ACTION_READ_CLEAR     4
+/* Clear ring buffer. */
+#define SYSLOG_ACTION_CLEAR          5
+/* Disable printk's to console */
+#define SYSLOG_ACTION_CONSOLE_OFF    6
+/* Enable printk's to console */
+#define SYSLOG_ACTION_CONSOLE_ON     7
+/* Set level of messages printed to console */
+#define SYSLOG_ACTION_CONSOLE_LEVEL  8
+/* Return number of unread characters in the log buffer */
+#define SYSLOG_ACTION_SIZE_UNREAD    9
+/* Return size of the log buffer */
+#define SYSLOG_ACTION_SIZE_BUFFER   10
+
+/*
+ * Color scheme
+ */
+struct dmesg_color {
+	const char *scheme;	/* name used in termina-colors.d/dmesg.scheme */
+	const char *dflt;	/* default color ESC sequence */
+};
+
+enum {
+	DMESG_COLOR_SUBSYS,
+	DMESG_COLOR_TIME,
+	DMESG_COLOR_TIMEBREAK,
+	DMESG_COLOR_ALERT,
+	DMESG_COLOR_CRIT,
+	DMESG_COLOR_ERR,
+	DMESG_COLOR_WARN,
+	DMESG_COLOR_SEGFAULT
+};
+
+static const struct dmesg_color colors[] =
+{
+	[DMESG_COLOR_SUBSYS]    = { "subsys",	UL_COLOR_BROWN },
+	[DMESG_COLOR_TIME]	= { "time",     UL_COLOR_GREEN },
+	[DMESG_COLOR_TIMEBREAK]	= { "timebreak",UL_COLOR_GREEN UL_COLOR_BOLD },
+	[DMESG_COLOR_ALERT]	= { "alert",    UL_COLOR_REVERSE UL_COLOR_RED },
+	[DMESG_COLOR_CRIT]	= { "crit",     UL_COLOR_BOLD UL_COLOR_RED },
+	[DMESG_COLOR_ERR]       = { "err",      UL_COLOR_RED },
+	[DMESG_COLOR_WARN]	= { "warn",     UL_COLOR_BOLD },
+	[DMESG_COLOR_SEGFAULT]	= { "segfault", UL_COLOR_HALFBRIGHT UL_COLOR_RED }
+};
+
+#define dmesg_enable_color(_id) \
+		color_scheme_enable(colors[_id].scheme, colors[_id].dflt);
+
+/*
+ * 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") },
+	[LOG_ALERT]   = { "alert", N_("action must be taken immediately") },
+	[LOG_CRIT]    = { "crit",  N_("critical conditions") },
+	[LOG_ERR]     = { "err",   N_("error conditions") },
+	[LOG_WARNING] = { "warn",  N_("warning conditions") },
+	[LOG_NOTICE]  = { "notice",N_("normal but significant condition") },
+	[LOG_INFO]    = { "info",  N_("informational") },
+	[LOG_DEBUG]   = { "debug", N_("debug-level messages") }
+};
+
+/*
+ * sys/syslog.h uses (f << 3) for all facility codes.
+ * We want to use the codes as array indexes, so shift back...
+ *
+ * Note that libc LOG_FAC() macro returns the base codes, not the
+ * shifted code :-)
+ */
+#define FAC_BASE(f)	((f) >> 3)
+
+static const struct dmesg_name facility_names[] =
+{
+	[FAC_BASE(LOG_KERN)]     = { "kern",     N_("kernel messages") },
+	[FAC_BASE(LOG_USER)]     = { "user",     N_("random user-level messages") },
+	[FAC_BASE(LOG_MAIL)]     = { "mail",     N_("mail system") },
+	[FAC_BASE(LOG_DAEMON)]   = { "daemon",   N_("system daemons") },
+	[FAC_BASE(LOG_AUTH)]     = { "auth",     N_("security/authorization messages") },
+	[FAC_BASE(LOG_SYSLOG)]   = { "syslog",   N_("messages generated internally by syslogd") },
+	[FAC_BASE(LOG_LPR)]      = { "lpr",      N_("line printer subsystem") },
+	[FAC_BASE(LOG_NEWS)]     = { "news",     N_("network news subsystem") },
+	[FAC_BASE(LOG_UUCP)]     = { "uucp",     N_("UUCP subsystem") },
+	[FAC_BASE(LOG_CRON)]     = { "cron",     N_("clock daemon") },
+	[FAC_BASE(LOG_AUTHPRIV)] = { "authpriv", N_("security/authorization messages (private)") },
+	[FAC_BASE(LOG_FTP)]      = { "ftp",      N_("FTP daemon") },
+};
+
+/* supported methods to read message buffer
+ */
+enum {
+	DMESG_METHOD_KMSG,	/* read messages from /dev/kmsg (default) */
+	DMESG_METHOD_SYSLOG,	/* klogctl() buffer */
+	DMESG_METHOD_MMAP	/* mmap file with records (see --file) */
+};
+
+enum {
+	DMESG_TIMEFTM_NONE = 0,
+	DMESG_TIMEFTM_CTIME,		/* [ctime] */
+	DMESG_TIMEFTM_CTIME_DELTA,	/* [ctime <delta>] */
+	DMESG_TIMEFTM_DELTA,		/* [<delta>] */
+	DMESG_TIMEFTM_RELTIME,		/* [relative] */
+	DMESG_TIMEFTM_TIME,		/* [time] */
+	DMESG_TIMEFTM_TIME_DELTA,	/* [time <delta>] */
+	DMESG_TIMEFTM_ISO8601		/* 2013-06-13T22:11:00,123456+0100 */
+};
+#define is_timefmt(c, f) ((c)->time_fmt == (DMESG_TIMEFTM_ ##f))
+
+struct dmesg_control {
+	/* bit arrays -- see include/bitops.h */
+	char levels[ARRAY_SIZE(level_names) / NBBY + 1];
+	char facilities[ARRAY_SIZE(facility_names) / NBBY + 1];
+
+	struct timeval	lasttime;	/* last printed timestamp */
+	struct tm	lasttm;		/* last localtime */
+	struct timeval	boot_time;	/* system boot time */
+
+	int		action;		/* SYSLOG_ACTION_* */
+	int		method;		/* DMESG_METHOD_* */
+
+	size_t		bufsize;	/* size of syslog buffer */
+
+	int		kmsg;		/* /dev/kmsg file descriptor */
+	ssize_t		kmsg_first_read;/* initial read() return code */
+	char		kmsg_buf[BUFSIZ];/* buffer to read kmsg data */
+
+	/*
+	 * For the --file option we mmap whole file. The unnecessary (already
+	 * printed) pages are always unmapped. The result is that we have in
+	 * memory only the currently used page(s).
+	 */
+	char		*filename;
+	char		*mmap_buff;
+	size_t		pagesize;
+	unsigned int	time_fmt;	/* time format */
+
+	unsigned int	follow:1,	/* wait for new messages */
+			raw:1,		/* raw mode */
+			fltr_lev:1,	/* filter out by levels[] */
+			fltr_fac:1,	/* filter out by facilities[] */
+			decode:1,	/* use "facility: level: " prefix */
+			pager:1,	/* pipe output into a pager */
+			color:1,	/* colorize messages */
+			force_prefix:1;	/* force timestamp and decode prefix
+					   on each line */
+	int		indent;		/* due to timestamps if newline */
+};
+
+struct dmesg_record {
+	const char	*mesg;
+	size_t		mesg_size;
+
+	int		level;
+	int		facility;
+	struct timeval  tv;
+
+	const char	*next;		/* buffer with next unparsed record */
+	size_t		next_size;	/* size of the next buffer */
+};
+
+#define INIT_DMESG_RECORD(_r)  do { \
+		(_r)->mesg = NULL; \
+		(_r)->mesg_size = 0; \
+		(_r)->facility = -1; \
+		(_r)->level = -1; \
+		(_r)->tv.tv_sec = 0; \
+		(_r)->tv.tv_usec = 0; \
+	} while (0)
+
+static int read_kmsg(struct dmesg_control *ctl);
+
+static int set_level_color(int log_level, const char *mesg, size_t mesgsz)
+{
+	int id = -1;
+
+	switch (log_level) {
+	case LOG_ALERT:
+		id = DMESG_COLOR_ALERT;
+		break;
+	case LOG_CRIT:
+		id = DMESG_COLOR_CRIT;
+		break;
+	case LOG_ERR:
+		id = DMESG_COLOR_ERR;
+		break;
+	case LOG_WARNING:
+		id = DMESG_COLOR_WARN;
+		break;
+	default:
+		break;
+	}
+
+	/* well, sometimes the messages contains important keywords, but in
+	 * non-warning/error messages
+	 */
+	if (id < 0 && memmem(mesg, mesgsz, "segfault at", 11))
+		id = DMESG_COLOR_SEGFAULT;
+
+	if (id >= 0)
+		dmesg_enable_color(id);
+
+	return id >= 0 ? 0 : -1;
+}
+
+static void __attribute__((__noreturn__)) usage(void)
+{
+	FILE *out = stdout;
+	size_t i;
+
+	fputs(USAGE_HEADER, out);
+	fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
+
+	fputs(USAGE_SEPARATOR, out);
+	fputs(_("Display or control the kernel ring buffer.\n"), out);
+
+	fputs(USAGE_OPTIONS, out);
+	fputs(_(" -C, --clear                 clear the kernel ring buffer\n"), out);
+	fputs(_(" -c, --read-clear            read and clear all messages\n"), out);
+	fputs(_(" -D, --console-off           disable printing messages to console\n"), out);
+	fputs(_(" -E, --console-on            enable printing messages to console\n"), out);
+	fputs(_(" -F, --file <file>           use the file instead of the kernel log buffer\n"), out);
+	fputs(_(" -f, --facility <list>       restrict output to defined facilities\n"), out);
+	fputs(_(" -H, --human                 human readable output\n"), out);
+	fputs(_(" -k, --kernel                display kernel messages\n"), out);
+	fputs(_(" -L, --color[=<when>]        colorize messages (auto, always or never)\n"), out);
+	fprintf(out,
+	        "                               %s\n", USAGE_COLORS_DEFAULT);
+	fputs(_(" -l, --level <list>          restrict output to defined levels\n"), out);
+	fputs(_(" -n, --console-level <level> set level of messages printed to console\n"), out);
+	fputs(_(" -P, --nopager               do not pipe output into a pager\n"), out);
+	fputs(_(" -p, --force-prefix          force timestamp output on each line of multi-line messages\n"), out);
+	fputs(_(" -r, --raw                   print the raw message buffer\n"), out);
+	fputs(_(" -S, --syslog                force to use syslog(2) rather than /dev/kmsg\n"), out);
+	fputs(_(" -s, --buffer-size <size>    buffer size to query the kernel ring buffer\n"), out);
+	fputs(_(" -u, --userspace             display userspace messages\n"), out);
+	fputs(_(" -w, --follow                wait for new messages\n"), out);
+	fputs(_(" -x, --decode                decode facility and level to readable string\n"), out);
+	fputs(_(" -d, --show-delta            show time delta between printed messages\n"), out);
+	fputs(_(" -e, --reltime               show local time and time delta in readable format\n"), out);
+	fputs(_(" -T, --ctime                 show human-readable timestamp (may be inaccurate!)\n"), out);
+	fputs(_(" -t, --notime                don't show any timestamp with messages\n"), out);
+	fputs(_("     --time-format <format>  show timestamp using the given format:\n"
+		"                               [delta|reltime|ctime|notime|iso]\n"
+		"Suspending/resume will make ctime and iso timestamps inaccurate.\n"), out);
+	fputs(USAGE_SEPARATOR, out);
+	printf(USAGE_HELP_OPTIONS(29));
+	fputs(_("\nSupported log facilities:\n"), out);
+	for (i = 0; i < ARRAY_SIZE(level_names); i++)
+		fprintf(out, " %7s - %s\n",
+			facility_names[i].name,
+			_(facility_names[i].help));
+
+	fputs(_("\nSupported log levels (priorities):\n"), out);
+	for (i = 0; i < ARRAY_SIZE(level_names); i++)
+		fprintf(out, " %7s - %s\n",
+			level_names[i].name,
+			_(level_names[i].help));
+
+	printf(USAGE_MAN_TAIL("dmesg(1)"));
+	exit(EXIT_SUCCESS);
+}
+
+/*
+ * LEVEL     ::= <number> | <name>
+ *  <number> ::= @len is set:  number in range <0..N>, where N < ARRAY_SIZE(level_names)
+ *           ::= @len not set: number in range <1..N>, where N <= ARRAY_SIZE(level_names)
+ *  <name>   ::= case-insensitive text
+ *
+ *  Note that @len argument is not set when parsing "-n <level>" command line
+ *  option. The console_level is interpreted as "log level less than the value".
+ *
+ *  For example "dmesg -n 8" or "dmesg -n debug" enables debug console log
+ *  level by klogctl(SYSLOG_ACTION_CONSOLE_LEVEL, NULL, 8). The @str argument
+ *  has to be parsed to number in range <1..8>.
+ */
+static int parse_level(const char *str, size_t len)
+{
+	int offset = 0;
+
+	if (!str)
+		return -1;
+	if (!len) {
+		len = strlen(str);
+		offset = 1;
+	}
+	errno = 0;
+
+	if (isdigit(*str)) {
+		char *end = NULL;
+		long x = strtol(str, &end, 10) - offset;
+
+		if (!errno && end && end > str && (size_t) (end - str) == len &&
+		    x >= 0 && (size_t) x < ARRAY_SIZE(level_names))
+			return x + offset;
+	} else {
+		size_t i;
+
+		for (i = 0; i < ARRAY_SIZE(level_names); i++) {
+			const char *n = level_names[i].name;
+
+			if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
+				return i + offset;
+		}
+	}
+
+	if (errno)
+		err(EXIT_FAILURE, _("failed to parse level '%s'"), str);
+
+	errx(EXIT_FAILURE, _("unknown level '%s'"), str);
+	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)
+{
+	if (!str)
+		return -1;
+	if (!len)
+		len = strlen(str);
+	errno = 0;
+
+	if (isdigit(*str)) {
+		char *end = NULL;
+		long x = strtol(str, &end, 10);
+
+		if (!errno && end && end > str && (size_t) (end - str) == len &&
+		    x >= 0 && (size_t) x < ARRAY_SIZE(facility_names))
+			return x;
+	} else {
+		size_t i;
+
+		for (i = 0; i < ARRAY_SIZE(facility_names); i++) {
+			const char *n = facility_names[i].name;
+
+			if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
+				return i;
+		}
+	}
+
+	if (errno)
+		err(EXIT_FAILURE, _("failed to parse facility '%s'"), str);
+
+	errx(EXIT_FAILURE, _("unknown facility '%s'"), str);
+	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 '>' or ',' char.
+ */
+static const char *parse_faclev(const char *str, int *fac, int *lev)
+{
+	long num;
+	char *end = NULL;
+
+	if (!str)
+		return str;
+
+	errno = 0;
+	num = strtol(str, &end, 10);
+
+	if (!errno && end && end > str) {
+		*fac = LOG_FAC(num);
+		*lev = LOG_PRI(num);
+
+		if (*lev < 0 || (size_t) *lev > ARRAY_SIZE(level_names))
+			*lev = -1;
+		if (*fac < 0 || (size_t) *fac > ARRAY_SIZE(facility_names))
+			*fac = -1;
+		return end + 1;		/* skip '<' or ',' */
+	}
+
+	return str;
+}
+
+/*
+ * Parses timestamp from syslog message prefix, expected format:
+ *
+ *	seconds.microseconds]
+ *
+ * the ']' is the timestamp field terminator.
+ */
+static const char *parse_syslog_timestamp(const char *str0, struct timeval *tv)
+{
+	const char *str = str0;
+	char *end = NULL;
+
+	if (!str0)
+		return str0;
+
+	errno = 0;
+	tv->tv_sec = strtol(str, &end, 10);
+
+	if (!errno && end && *end == '.' && *(end + 1)) {
+		str = end + 1;
+		end = NULL;
+		tv->tv_usec = strtol(str, &end, 10);
+	}
+	if (errno || !end || end == str || *end != ']')
+		return str0;
+
+	return end + 1;	/* skip ']' */
+}
+
+/*
+ * Parses timestamp from /dev/kmsg, expected formats:
+ *
+ *	microseconds,
+ *	microseconds;
+ *
+ * the ',' is fields separators and ';' items terminator (for the last item)
+ */
+static const char *parse_kmsg_timestamp(const char *str0, struct timeval *tv)
+{
+	const char *str = str0;
+	char *end = NULL;
+	uint64_t usec;
+
+	if (!str0)
+		return str0;
+
+	errno = 0;
+	usec = strtoumax(str, &end, 10);
+
+	if (!errno && end && (*end == ';' || *end == ',')) {
+		tv->tv_usec = usec % 1000000;
+		tv->tv_sec = usec / 1000000;
+	} else
+		return str0;
+
+	return end + 1;	/* skip separator */
+}
+
+
+static double time_diff(struct timeval *a, struct timeval *b)
+{
+	return (a->tv_sec - b->tv_sec) + (a->tv_usec - b->tv_usec) / 1E6;
+}
+
+static int get_syslog_buffer_size(void)
+{
+	int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
+
+	return n > 0 ? n : 0;
+}
+
+/*
+ * Reads messages from regular file by mmap
+ */
+static ssize_t mmap_file_buffer(struct dmesg_control *ctl, char **buf)
+{
+	struct stat st;
+	int fd;
+
+	if (!ctl->filename)
+		return -1;
+
+	fd = open(ctl->filename, O_RDONLY);
+	if (fd < 0)
+		err(EXIT_FAILURE, _("cannot open %s"), ctl->filename);
+	if (fstat(fd, &st))
+		err(EXIT_FAILURE, _("stat of %s failed"), ctl->filename);
+
+	*buf = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+	if (*buf == MAP_FAILED)
+		err(EXIT_FAILURE, _("cannot mmap: %s"), ctl->filename);
+	ctl->mmap_buff = *buf;
+	ctl->pagesize = getpagesize();
+	close(fd);
+
+	return st.st_size;
+}
+
+/*
+ * Reads messages from kernel ring buffer by klogctl()
+ */
+static ssize_t read_syslog_buffer(struct dmesg_control *ctl, char **buf)
+{
+	size_t sz;
+	int rc = -1;
+
+	if (ctl->bufsize) {
+		sz = ctl->bufsize + 8;
+		*buf = xmalloc(sz * sizeof(char));
+		rc = klogctl(ctl->action, *buf, sz);
+	} else {
+		sz = 16392;
+		while (1) {
+			*buf = xmalloc(sz * sizeof(char));
+			rc = klogctl(SYSLOG_ACTION_READ_ALL, *buf, sz);
+			if (rc < 0)
+				break;
+			if ((size_t) rc != sz || sz > (1 << 28))
+				break;
+			free(*buf);
+			*buf = NULL;
+			sz *= 4;
+		}
+
+		if (rc > 0 && ctl->action == SYSLOG_ACTION_READ_CLEAR)
+			rc = klogctl(SYSLOG_ACTION_READ_CLEAR, *buf, sz);
+	}
+
+	return rc;
+}
+
+/*
+ * Top level function to read messages
+ */
+static ssize_t read_buffer(struct dmesg_control *ctl, char **buf)
+{
+	ssize_t n = -1;
+
+	switch (ctl->method) {
+	case DMESG_METHOD_MMAP:
+		n = mmap_file_buffer(ctl, buf);
+		break;
+	case DMESG_METHOD_SYSLOG:
+		if (!ctl->bufsize)
+			ctl->bufsize = get_syslog_buffer_size();
+
+		n = read_syslog_buffer(ctl, buf);
+		break;
+	case DMESG_METHOD_KMSG:
+		/*
+		 * Since kernel 3.5.0
+		 */
+		n = read_kmsg(ctl);
+		if (n == 0 && ctl->action == SYSLOG_ACTION_READ_CLEAR)
+			n = klogctl(SYSLOG_ACTION_CLEAR, NULL, 0);
+		break;
+	default:
+		abort();	/* impossible method -> drop core */
+	}
+
+	return n;
+}
+
+static int fwrite_hex(const char *buf, size_t size, FILE *out)
+{
+	size_t i;
+
+	for (i = 0; i < size; i++) {
+		int rc = fprintf(out, "\\x%02hhx", buf[i]);
+		if (rc < 0)
+			return rc;
+	}
+	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, int indent, FILE *out)
+{
+	size_t i;
+#ifdef HAVE_WIDECHAR
+	mbstate_t s;
+	memset(&s, 0, sizeof (s));
+#endif
+	for (i = 0; i < size; i++) {
+		const char *p = buf + i;
+		int rc, hex = 0;
+		size_t len;
+
+#ifdef HAVE_WIDECHAR
+		wchar_t wc;
+		len = mbrtowc(&wc, p, size - i, &s);
+
+		if (len == 0)				/* L'\0' */
+			return;
+
+		if (len == (size_t)-1 || len == (size_t)-2) {		/* invalid sequence */
+			memset(&s, 0, sizeof (s));
+			len = hex = 1;
+		} else if (len > 1 && !iswprint(wc)) {	/* non-printable multibyte */
+			hex = 1;
+		}
+		i += len - 1;
+#else
+		len = 1;
+		if (!isprint((unsigned char) *p) &&
+		    !isspace((unsigned char) *p))        /* non-printable */
+			hex = 1;
+#endif
+		if (hex)
+			rc = fwrite_hex(p, len, out);
+		else if (*p == '\n' && *(p + 1) && indent) {
+		        rc = fwrite(p, 1, len, out) != len;
+			if (fprintf(out, "%*s", indent, "") != indent)
+				rc |= 1;
+		}
+		else
+			rc = fwrite(p, 1, len, out) != len;
+		if (rc != 0) {
+			if (errno != EPIPE)
+				err(EXIT_FAILURE, _("write failed"));
+			exit(EXIT_SUCCESS);
+		}
+	}
+}
+
+static const char *skip_item(const char *begin, const char *end, const char *sep)
+{
+	while (begin < end) {
+		int c = *begin++;
+
+		if (c == '\0' || strchr(sep, c))
+			break;
+	}
+
+	return begin;
+}
+
+/*
+ * Parses one record from syslog(2) buffer
+ */
+static int get_next_syslog_record(struct dmesg_control *ctl,
+				  struct dmesg_record *rec)
+{
+	size_t i;
+	const char *begin = NULL;
+
+	if (ctl->method != DMESG_METHOD_MMAP &&
+	    ctl->method != DMESG_METHOD_SYSLOG)
+		return -1;
+
+	if (!rec->next || !rec->next_size)
+		return 1;
+
+	INIT_DMESG_RECORD(rec);
+
+	/*
+	 * Unmap already printed file data from memory
+	 */
+	if (ctl->mmap_buff && (size_t) (rec->next - ctl->mmap_buff) > ctl->pagesize) {
+		void *x = ctl->mmap_buff;
+
+		ctl->mmap_buff += ctl->pagesize;
+		munmap(x, ctl->pagesize);
+	}
+
+	for (i = 0; i < rec->next_size; i++) {
+		const char *p = rec->next + i;
+		const char *end = NULL;
+
+		if (!begin)
+			begin = p;
+		if (i + 1 == rec->next_size) {
+			end = p + 1;
+			i++;
+		} else if (*p == '\n' && *(p + 1) == '<')
+			end = p;
+
+		if (begin && !*begin)
+			begin = NULL;	/* zero(s) at the end of the buffer? */
+		if (!begin || !end)
+			continue;
+		if (end <= begin)
+			continue;	/* error or empty line? */
+
+		if (*begin == '<') {
+			if (ctl->fltr_lev || ctl->fltr_fac || ctl->decode || ctl->color)
+				begin = parse_faclev(begin + 1, &rec->facility,
+						     &rec->level);
+			else
+				begin = skip_item(begin, end, ">");
+		}
+
+		if (*begin == '[' && (*(begin + 1) == ' ' ||
+				      isdigit(*(begin + 1)))) {
+
+			if (!is_timefmt(ctl, NONE))
+				begin = parse_syslog_timestamp(begin + 1, &rec->tv);
+			else
+				begin = skip_item(begin, end, "]");
+
+			if (begin < end && *begin == ' ')
+				begin++;
+		}
+
+		rec->mesg = begin;
+		rec->mesg_size = end - begin;
+
+		/* Don't count \n from the last message to the message size */
+		if (*end != '\n' && *(end - 1) == '\n')
+			rec->mesg_size--;
+
+		rec->next_size -= end - rec->next;
+		rec->next = rec->next_size > 0 ? end + 1 : NULL;
+		if (rec->next_size > 0)
+			rec->next_size--;
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static int accept_record(struct dmesg_control *ctl, struct dmesg_record *rec)
+{
+	if (ctl->fltr_lev && (rec->facility < 0 ||
+			      !isset(ctl->levels, rec->level)))
+		return 0;
+
+	if (ctl->fltr_fac && (rec->facility < 0 ||
+			      !isset(ctl->facilities, rec->facility)))
+		return 0;
+
+	return 1;
+}
+
+static void raw_print(struct dmesg_control *ctl, const char *buf, size_t size)
+{
+	int lastc = '\n';
+
+	if (!ctl->mmap_buff) {
+		/*
+		 * Print whole ring buffer
+		 */
+		safe_fwrite(buf, size, 0, stdout);
+		lastc = buf[size - 1];
+	} else {
+		/*
+		 * Print file in small chunks to save memory
+		 */
+		while (size) {
+			size_t sz = size > ctl->pagesize ? ctl->pagesize : size;
+			char *x = ctl->mmap_buff;
+
+			safe_fwrite(x, sz, 0, stdout);
+			lastc = x[sz - 1];
+			size -= sz;
+			ctl->mmap_buff += sz;
+			munmap(x, sz);
+		}
+	}
+
+	if (lastc != '\n')
+		putchar('\n');
+}
+
+static struct tm *record_localtime(struct dmesg_control *ctl,
+				   struct dmesg_record *rec,
+				   struct tm *tm)
+{
+	time_t t = ctl->boot_time.tv_sec + rec->tv.tv_sec;
+	return localtime_r(&t, tm);
+}
+
+static char *record_ctime(struct dmesg_control *ctl,
+			  struct dmesg_record *rec,
+			  char *buf, size_t bufsiz)
+{
+	struct tm tm;
+
+	record_localtime(ctl, rec, &tm);
+
+	if (strftime(buf, bufsiz, "%a %b %e %H:%M:%S %Y", &tm) == 0)
+		*buf = '\0';
+	return buf;
+}
+
+static char *short_ctime(struct tm *tm, char *buf, size_t bufsiz)
+{
+	if (strftime(buf, bufsiz, "%b%e %H:%M", tm) == 0)
+		*buf = '\0';
+	return buf;
+}
+
+static char *iso_8601_time(struct dmesg_control *ctl, struct dmesg_record *rec,
+			   char *buf, size_t bufsz)
+{
+	struct timeval tv = {
+		.tv_sec = ctl->boot_time.tv_sec + rec->tv.tv_sec,
+		.tv_usec = rec->tv.tv_usec
+	};
+
+	if (strtimeval_iso(&tv,	ISO_TIMESTAMP_COMMA_T, buf, bufsz) != 0)
+		return NULL;
+
+	return buf;
+}
+
+static double record_count_delta(struct dmesg_control *ctl,
+				 struct dmesg_record *rec)
+{
+	double delta = 0;
+
+	if (timerisset(&ctl->lasttime))
+		delta = time_diff(&rec->tv, &ctl->lasttime);
+
+	ctl->lasttime = rec->tv;
+	return delta;
+}
+
+static const char *get_subsys_delimiter(const char *mesg, size_t mesg_size)
+{
+	const char *p = mesg;
+	size_t sz = mesg_size;
+
+	while (sz > 0) {
+		const char *d = strnchr(p, sz, ':');
+		if (!d)
+			return NULL;
+		sz -= d - p + 1;
+		if (sz) {
+			if (isblank(*(d + 1)))
+				return d;
+			p = d + 1;
+		}
+	}
+	return NULL;
+}
+
+static void print_record(struct dmesg_control *ctl,
+			 struct dmesg_record *rec)
+{
+	char buf[128];
+	char fpbuf[32] = "\0";
+	char tsbuf[64] = "\0";
+	size_t mesg_size = rec->mesg_size;
+	int timebreak = 0;
+	char *mesg_copy = NULL;
+	const char *line = NULL;
+
+	if (!accept_record(ctl, rec))
+		return;
+
+	if (!rec->mesg_size) {
+		putchar('\n');
+		return;
+	}
+
+	/*
+	 * Compose syslog(2) compatible raw output -- used for /dev/kmsg for
+	 * backward compatibility with syslog(2) buffers only
+	 */
+	if (ctl->raw) {
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf),
+				       "<%d>[%5ld.%06ld] ",
+				       LOG_MAKEPRI(rec->facility, rec->level),
+				       (long) rec->tv.tv_sec,
+				       (long) rec->tv.tv_usec);
+		goto full_output;
+	}
+
+	/* Store decode information (facility & priority level) in a buffer */
+	if (ctl->decode &&
+	    (rec->level > -1) && (rec->level < (int) ARRAY_SIZE(level_names)) &&
+	    (rec->facility > -1) &&
+	    (rec->facility < (int) ARRAY_SIZE(facility_names)))
+		snprintf(fpbuf, sizeof(fpbuf), "%-6s:%-6s: ",
+			 facility_names[rec->facility].name,
+			 level_names[rec->level].name);
+
+	/* Store the timestamp in a buffer */
+	switch (ctl->time_fmt) {
+		double delta;
+		struct tm cur;
+	case DMESG_TIMEFTM_NONE:
+		ctl->indent = 0;
+		break;
+	case DMESG_TIMEFTM_CTIME:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[%s] ",
+				      record_ctime(ctl, rec, buf, sizeof(buf)));
+		break;
+	case DMESG_TIMEFTM_CTIME_DELTA:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[%s <%12.06f>] ",
+				      record_ctime(ctl, rec, buf, sizeof(buf)),
+				      record_count_delta(ctl, rec));
+		break;
+	case DMESG_TIMEFTM_DELTA:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[<%12.06f>] ",
+				      record_count_delta(ctl, rec));
+		break;
+	case DMESG_TIMEFTM_RELTIME:
+		record_localtime(ctl, rec, &cur);
+		delta = record_count_delta(ctl, rec);
+		if (cur.tm_min != ctl->lasttm.tm_min ||
+		    cur.tm_hour != ctl->lasttm.tm_hour ||
+		    cur.tm_yday != ctl->lasttm.tm_yday) {
+			timebreak = 1;
+			ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[%s] ",
+					      short_ctime(&cur, buf,
+							  sizeof(buf)));
+		} else {
+			if (delta < 10)
+				ctl->indent = snprintf(tsbuf, sizeof(tsbuf),
+						"[  %+8.06f] ",  delta);
+			else
+				ctl->indent = snprintf(tsbuf, sizeof(tsbuf),
+						"[ %+9.06f] ", delta);
+		}
+		ctl->lasttm = cur;
+		break;
+	case DMESG_TIMEFTM_TIME:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[%5ld.%06ld] ",
+				      (long)rec->tv.tv_sec,
+				      (long)rec->tv.tv_usec);
+		break;
+	case DMESG_TIMEFTM_TIME_DELTA:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "[%5ld.%06ld <%12.06f>] ",
+				      (long)rec->tv.tv_sec,
+				      (long)rec->tv.tv_usec,
+				      record_count_delta(ctl, rec));
+		break;
+	case DMESG_TIMEFTM_ISO8601:
+		ctl->indent = snprintf(tsbuf, sizeof(tsbuf), "%s ",
+				      iso_8601_time(ctl, rec, buf,
+						    sizeof(buf)));
+		break;
+	default:
+		abort();
+	}
+
+	ctl->indent += strlen(fpbuf);
+
+full_output:
+	/* Output the decode information */
+	if (*fpbuf)
+		fputs(fpbuf, stdout);
+
+	/* Output the timestamp buffer */
+	if (*tsbuf) {
+		/* Colorize the timestamp */
+		if (ctl->color)
+			dmesg_enable_color(timebreak ? DMESG_COLOR_TIMEBREAK :
+						       DMESG_COLOR_TIME);
+		if (ctl->time_fmt != DMESG_TIMEFTM_RELTIME) {
+			fputs(tsbuf, stdout);
+		} else {
+			/*
+			 * For relative timestamping, the first line's
+			 * timestamp is the offset and all other lines will
+			 * report an offset of 0.000000.
+			 */
+			if (!line)
+				fputs(tsbuf, stdout);
+			else
+				printf("[  +0.000000] ");
+		}
+		if (ctl->color)
+			color_disable();
+	}
+
+	/*
+	 * A kernel message may contain several lines of output, separated
+	 * by '\n'.  If the timestamp and decode outputs are forced then each
+	 * line of the message must be displayed with that information.
+	 */
+	if (ctl->force_prefix) {
+		if (!line) {
+			mesg_copy = xstrdup(rec->mesg);
+			line = strtok(mesg_copy, "\n");
+			mesg_size = strlen(line);
+		}
+	} else {
+		line = rec->mesg;
+		mesg_size = rec->mesg_size;
+	}
+
+	/* Colorize kernel message output */
+	if (ctl->color) {
+		/* Subsystem prefix */
+		const char *subsys = get_subsys_delimiter(line, mesg_size);
+		int has_color = 0;
+
+		if (subsys) {
+			dmesg_enable_color(DMESG_COLOR_SUBSYS);
+			safe_fwrite(line, subsys - line, ctl->indent, stdout);
+			color_disable();
+
+			mesg_size -= subsys - line;
+			line = subsys;
+		}
+		/* Error, alert .. etc. colors */
+		has_color = set_level_color(rec->level, line, mesg_size) == 0;
+		safe_fwrite(line, mesg_size, ctl->indent, stdout);
+		if (has_color)
+			color_disable();
+	} else
+		safe_fwrite(line, mesg_size, ctl->indent, stdout);
+
+	/* Get the next line */
+	if (ctl->force_prefix) {
+		line = strtok(NULL, "\n");
+		if (line && *line) {
+			putchar('\n');
+			mesg_size = strlen(line);
+			goto full_output;
+		}
+		free(mesg_copy);
+	}
+
+	putchar('\n');
+}
+
+/*
+ * Prints the 'buf' kernel ring buffer; the messages are filtered out according
+ * to 'levels' and 'facilities' bitarrays.
+ */
+static void print_buffer(struct dmesg_control *ctl,
+			const char *buf, size_t size)
+{
+	struct dmesg_record rec = { .next = buf, .next_size = size };
+
+	if (ctl->raw) {
+		raw_print(ctl, buf, size);
+		return;
+	}
+
+	while (get_next_syslog_record(ctl, &rec) == 0)
+		print_record(ctl, &rec);
+}
+
+static ssize_t read_kmsg_one(struct dmesg_control *ctl)
+{
+	ssize_t size;
+
+	/* kmsg returns EPIPE if record was modified while reading */
+	do {
+		size = read(ctl->kmsg, ctl->kmsg_buf,
+			    sizeof(ctl->kmsg_buf) - 1);
+	} while (size < 0 && errno == EPIPE);
+
+	return size;
+}
+
+static int init_kmsg(struct dmesg_control *ctl)
+{
+	int mode = O_RDONLY;
+
+	if (!ctl->follow)
+		mode |= O_NONBLOCK;
+	else
+		setlinebuf(stdout);
+
+	ctl->kmsg = open("/dev/kmsg", mode);
+	if (ctl->kmsg < 0)
+		return -1;
+
+	/*
+	 * Seek after the last record available at the time
+	 * the last SYSLOG_ACTION_CLEAR was issued.
+	 *
+	 * ... otherwise SYSLOG_ACTION_CLEAR will have no effect for kmsg.
+	 */
+	lseek(ctl->kmsg, 0, SEEK_DATA);
+
+	/*
+	 * Old kernels (<3.5) allow to successfully open /dev/kmsg for
+	 * read-only, but read() returns -EINVAL :-(((
+	 *
+	 * Let's try to read the first record. The record is later processed in
+	 * read_kmsg().
+	 */
+	ctl->kmsg_first_read = read_kmsg_one(ctl);
+	if (ctl->kmsg_first_read < 0) {
+		close(ctl->kmsg);
+		ctl->kmsg = -1;
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * /dev/kmsg record format:
+ *
+ *     faclev,seqnum,timestamp[optional, ...];message\n
+ *      TAGNAME=value
+ *      ...
+ *
+ * - fields are separated by ','
+ * - last field is terminated by ';'
+ *
+ */
+#define LAST_KMSG_FIELD(s)	(!s || !*s || *(s - 1) == ';')
+
+static int parse_kmsg_record(struct dmesg_control *ctl,
+			     struct dmesg_record *rec,
+			     char *buf,
+			     size_t sz)
+{
+	const char *p = buf, *end;
+
+	if (sz == 0 || !buf || !*buf)
+		return -1;
+
+	end = buf + (sz - 1);
+	INIT_DMESG_RECORD(rec);
+
+	while (p < end && isspace(*p))
+		p++;
+
+	/* A) priority and facility */
+	if (ctl->fltr_lev || ctl->fltr_fac || ctl->decode ||
+	    ctl->raw || ctl->color)
+		p = parse_faclev(p, &rec->facility, &rec->level);
+	else
+		p = skip_item(p, end, ",");
+	if (LAST_KMSG_FIELD(p))
+		goto mesg;
+
+	/* B) sequence number */
+	p = skip_item(p, end, ",;");
+	if (LAST_KMSG_FIELD(p))
+		goto mesg;
+
+	/* C) timestamp */
+	if (is_timefmt(ctl, NONE))
+		p = skip_item(p, end, ",;");
+	else
+		p = parse_kmsg_timestamp(p, &rec->tv);
+	if (LAST_KMSG_FIELD(p))
+		goto mesg;
+
+	/* D) optional fields (ignore) */
+	p = skip_item(p, end, ";");
+
+mesg:
+	/* E) message text */
+	rec->mesg = p;
+	p = skip_item(p, end, "\n");
+	if (!p)
+		return -1;
+
+	/* The message text is terminated by \n, but it's possible that the
+	 * message contains another stuff behind this linebreak; in this case
+	 * the previous skip_item() returns pointer to the stuff behind \n.
+	 * Let's normalize all these situations and make sure we always point to
+	 * the \n.
+	 *
+	 * Note that the next unhexmangle_to_buffer() will replace \n by \0.
+	 */
+	if (*p && *p != '\n')
+		p--;
+
+	/*
+	 * Kernel escapes non-printable characters, unfortunately kernel
+	 * definition of "non-printable" is too strict. On UTF8 console we can
+	 * print many chars, so let's decode from kernel.
+	 */
+	rec->mesg_size = unhexmangle_to_buffer(rec->mesg,
+				(char *) rec->mesg, p - rec->mesg + 1);
+
+	rec->mesg_size--;	/* don't count \0 */
+
+	/* F) message tags (ignore) */
+
+	return 0;
+}
+
+/*
+ * Note that each read() call for /dev/kmsg returns always one record. It means
+ * that we don't have to read whole message buffer before the records parsing.
+ *
+ * So this function does not compose one huge buffer (like read_syslog_buffer())
+ * and print_buffer() is unnecessary. All is done in this function.
+ *
+ * Returns 0 on success, -1 on error.
+ */
+static int read_kmsg(struct dmesg_control *ctl)
+{
+	struct dmesg_record rec;
+	ssize_t sz;
+
+	if (ctl->method != DMESG_METHOD_KMSG || ctl->kmsg < 0)
+		return -1;
+
+	/*
+	 * The very first read() call is done in kmsg_init() where we test
+	 * /dev/kmsg usability. The return code from the initial read() is
+	 * stored in ctl->kmsg_first_read;
+	 */
+	sz = ctl->kmsg_first_read;
+
+	while (sz > 0) {
+		*(ctl->kmsg_buf + sz) = '\0';	/* for debug messages */
+
+		if (parse_kmsg_record(ctl, &rec,
+				      ctl->kmsg_buf, (size_t) sz) == 0)
+			print_record(ctl, &rec);
+
+		sz = read_kmsg_one(ctl);
+	}
+
+	return 0;
+}
+
+static int which_time_format(const char *s)
+{
+	if (!strcmp(s, "notime"))
+		return DMESG_TIMEFTM_NONE;
+	if (!strcmp(s, "ctime"))
+		return DMESG_TIMEFTM_CTIME;
+	if (!strcmp(s, "delta"))
+		return DMESG_TIMEFTM_DELTA;
+	if (!strcmp(s, "reltime"))
+		return DMESG_TIMEFTM_RELTIME;
+	if (!strcmp(s, "iso"))
+		return DMESG_TIMEFTM_ISO8601;
+	errx(EXIT_FAILURE, _("unknown time format: %s"), s);
+}
+
+#ifdef TEST_DMESG
+static inline int dmesg_get_boot_time(struct timeval *tv)
+{
+	char *str = getenv("DMESG_TEST_BOOTIME");
+	uintmax_t sec, usec;
+
+	if (str && sscanf(str, "%ju.%ju", &sec, &usec) == 2) {
+		tv->tv_sec = sec;
+		tv->tv_usec = usec;
+		return tv->tv_sec >= 0 && tv->tv_usec >= 0 ? 0 : -EINVAL;
+	}
+
+	return get_boot_time(tv);
+}
+#else
+# define dmesg_get_boot_time	get_boot_time
+#endif
+
+int main(int argc, char *argv[])
+{
+	char *buf = NULL;
+	int  c, nopager = 0;
+	int  console_level = 0;
+	int  klog_rc = 0;
+	int  delta = 0;
+	ssize_t n;
+	static struct dmesg_control ctl = {
+		.filename = NULL,
+		.action = SYSLOG_ACTION_READ_ALL,
+		.method = DMESG_METHOD_KMSG,
+		.kmsg = -1,
+		.time_fmt = DMESG_TIMEFTM_TIME,
+		.indent = 0,
+	};
+	int colormode = UL_COLORMODE_UNDEF;
+	enum {
+		OPT_TIME_FORMAT = CHAR_MAX + 1,
+	};
+
+	static const struct option longopts[] = {
+		{ "buffer-size",   required_argument, NULL, 's' },
+		{ "clear",         no_argument,	      NULL, 'C' },
+		{ "color",         optional_argument, NULL, 'L' },
+		{ "console-level", required_argument, NULL, 'n' },
+		{ "console-off",   no_argument,       NULL, 'D' },
+		{ "console-on",    no_argument,       NULL, 'E' },
+		{ "decode",        no_argument,	      NULL, 'x' },
+		{ "file",          required_argument, NULL, 'F' },
+		{ "facility",      required_argument, NULL, 'f' },
+		{ "follow",        no_argument,       NULL, 'w' },
+		{ "human",         no_argument,       NULL, 'H' },
+		{ "help",          no_argument,	      NULL, 'h' },
+		{ "kernel",        no_argument,       NULL, 'k' },
+		{ "level",         required_argument, NULL, 'l' },
+		{ "syslog",        no_argument,       NULL, 'S' },
+		{ "raw",           no_argument,       NULL, 'r' },
+		{ "read-clear",    no_argument,	      NULL, 'c' },
+		{ "reltime",       no_argument,       NULL, 'e' },
+		{ "show-delta",    no_argument,	      NULL, 'd' },
+		{ "ctime",         no_argument,       NULL, 'T' },
+		{ "notime",        no_argument,       NULL, 't' },
+		{ "nopager",       no_argument,       NULL, 'P' },
+		{ "userspace",     no_argument,       NULL, 'u' },
+		{ "version",       no_argument,	      NULL, 'V' },
+		{ "time-format",   required_argument, NULL, OPT_TIME_FORMAT },
+		{ "force-prefix",  no_argument,       NULL, 'p' },
+		{ NULL,	           0, NULL, 0 }
+	};
+
+	static const ul_excl_t excl[] = {	/* rows and cols in ASCII order */
+		{ 'C','D','E','c','n','r' },	/* clear,off,on,read-clear,level,raw*/
+		{ 'H','r' },			/* human, raw */
+		{ 'L','r' },			/* color, raw */
+		{ 'S','w' },			/* syslog,follow */
+		{ 'T','r' },			/* ctime, raw */
+		{ 'd','r' },			/* delta, raw */
+		{ 'e','r' },			/* reltime, raw */
+		{ 'r','x' },			/* raw, decode */
+		{ 'r','t' },			/* notime, raw */
+		{ 0 }
+	};
+	int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+	atexit(close_stdout);
+
+	while ((c = getopt_long(argc, argv, "CcDdEeF:f:HhkL::l:n:iPprSs:TtuVwx",
+				longopts, NULL)) != -1) {
+
+		err_exclusive_options(c, longopts, excl, excl_st);
+
+		switch (c) {
+		case 'C':
+			ctl.action = SYSLOG_ACTION_CLEAR;
+			break;
+		case 'c':
+			ctl.action = SYSLOG_ACTION_READ_CLEAR;
+			break;
+		case 'D':
+			ctl.action = SYSLOG_ACTION_CONSOLE_OFF;
+			break;
+		case 'd':
+			delta = 1;
+			break;
+		case 'E':
+			ctl.action = SYSLOG_ACTION_CONSOLE_ON;
+			break;
+		case 'e':
+			ctl.time_fmt = DMESG_TIMEFTM_RELTIME;
+			break;
+		case 'F':
+			ctl.filename = optarg;
+			ctl.method = DMESG_METHOD_MMAP;
+			break;
+		case 'f':
+			ctl.fltr_fac = 1;
+			if (string_to_bitarray(optarg,
+					     ctl.facilities, parse_facility) < 0)
+				return EXIT_FAILURE;
+			break;
+		case 'H':
+			ctl.time_fmt = DMESG_TIMEFTM_RELTIME;
+			colormode = UL_COLORMODE_AUTO;
+			ctl.pager = 1;
+			break;
+		case 'h':
+			usage();
+			break;
+		case 'k':
+			ctl.fltr_fac = 1;
+			setbit(ctl.facilities, FAC_BASE(LOG_KERN));
+			break;
+		case 'L':
+			colormode = UL_COLORMODE_AUTO;
+			if (optarg)
+				colormode = colormode_or_err(optarg,
+						_("unsupported color mode"));
+			break;
+		case 'l':
+			ctl.fltr_lev= 1;
+			if (string_to_bitarray(optarg,
+					     ctl.levels, parse_level) < 0)
+				return EXIT_FAILURE;
+			break;
+		case 'n':
+			ctl.action = SYSLOG_ACTION_CONSOLE_LEVEL;
+			console_level = parse_level(optarg, 0);
+			break;
+		case 'P':
+			nopager = 1;
+			break;
+		case 'p':
+			ctl.force_prefix = 1;
+			break;
+		case 'r':
+			ctl.raw = 1;
+			break;
+		case 'S':
+			ctl.method = DMESG_METHOD_SYSLOG;
+			break;
+		case 's':
+			ctl.bufsize = strtou32_or_err(optarg,
+					_("invalid buffer size argument"));
+			if (ctl.bufsize < 4096)
+				ctl.bufsize = 4096;
+			break;
+		case 'T':
+			ctl.time_fmt = DMESG_TIMEFTM_CTIME;
+			break;
+		case 't':
+			ctl.time_fmt = DMESG_TIMEFTM_NONE;
+			break;
+		case 'u':
+			ctl.fltr_fac = 1;
+			for (n = 1; (size_t) n < ARRAY_SIZE(facility_names); n++)
+				setbit(ctl.facilities, n);
+			break;
+		case 'V':
+			printf(UTIL_LINUX_VERSION);
+			return EXIT_SUCCESS;
+		case 'w':
+			ctl.follow = 1;
+			break;
+		case 'x':
+			ctl.decode = 1;
+			break;
+		case OPT_TIME_FORMAT:
+			ctl.time_fmt = which_time_format(optarg);
+			break;
+		default:
+			errtryhelp(EXIT_FAILURE);
+		}
+	}
+
+	if (argc != optind) {
+		warnx(_("bad usage"));
+		errtryhelp(EXIT_FAILURE);
+	}
+
+	if ((is_timefmt(&ctl, RELTIME) ||
+	     is_timefmt(&ctl, CTIME)   ||
+	     is_timefmt(&ctl, ISO8601))
+	    && dmesg_get_boot_time(&ctl.boot_time) != 0)
+		ctl.time_fmt = DMESG_TIMEFTM_NONE;
+
+	if (delta)
+		switch (ctl.time_fmt) {
+		case DMESG_TIMEFTM_CTIME:
+			ctl.time_fmt = DMESG_TIMEFTM_CTIME_DELTA;
+			break;
+		case DMESG_TIMEFTM_TIME:
+			ctl.time_fmt = DMESG_TIMEFTM_TIME_DELTA;
+			break;
+		case DMESG_TIMEFTM_ISO8601:
+			warnx(_("--show-delta is ignored when used together with iso8601 time format"));
+			break;
+		default:
+			ctl.time_fmt = DMESG_TIMEFTM_DELTA;
+		}
+
+
+	ctl.color = colors_init(colormode, "dmesg") ? 1 : 0;
+	if (ctl.follow)
+		nopager = 1;
+	ctl.pager = nopager ? 0 : ctl.pager;
+	if (ctl.pager)
+		pager_redirect();
+
+	switch (ctl.action) {
+	case SYSLOG_ACTION_READ_ALL:
+	case SYSLOG_ACTION_READ_CLEAR:
+		if (ctl.method == DMESG_METHOD_KMSG && init_kmsg(&ctl) != 0)
+			ctl.method = DMESG_METHOD_SYSLOG;
+
+		if (ctl.raw
+		    && ctl.method != DMESG_METHOD_KMSG
+		    && (ctl.fltr_lev || ctl.fltr_fac))
+			    errx(EXIT_FAILURE, _("--raw can be used together with --level or "
+				 "--facility only when reading messages from /dev/kmsg"));
+
+		/* only kmsg supports multi-line messages */
+		if (ctl.force_prefix && ctl.method != DMESG_METHOD_KMSG)
+			ctl.force_prefix = 0;
+
+		if (ctl.pager)
+			pager_redirect();
+		n = read_buffer(&ctl, &buf);
+		if (n > 0)
+			print_buffer(&ctl, buf, n);
+		if (!ctl.mmap_buff)
+			free(buf);
+		if (n < 0)
+			err(EXIT_FAILURE, _("read kernel buffer failed"));
+		if (ctl.kmsg >= 0)
+			close(ctl.kmsg);
+		break;
+	case SYSLOG_ACTION_CLEAR:
+	case SYSLOG_ACTION_CONSOLE_OFF:
+	case SYSLOG_ACTION_CONSOLE_ON:
+		klog_rc = klogctl(ctl.action, NULL, 0);
+		break;
+	case SYSLOG_ACTION_CONSOLE_LEVEL:
+		klog_rc = klogctl(ctl.action, NULL, console_level);
+		break;
+	default:
+		errx(EXIT_FAILURE, _("unsupported command"));
+		break;
+	}
+
+
+	if (klog_rc)
+		err(EXIT_FAILURE, _("klogctl failed"));
+
+	return EXIT_SUCCESS;
+}