dmesg: support colors customization

Signed-off-by: Karel Zak <kzak@redhat.com>

2 files changed, 81 insertions, 34 deletions

diff --git a/sys-utils/dmesg.1 b/sys-utils/dmesg.1
index 75af1ec53..c4c64dfe5 100644
--- a/sys-utils/dmesg.1
+++ b/sys-utils/dmesg.1
@@ -64,8 +64,8 @@ Display help text and exit.
 .IP "\fB\-k\fR, \fB\-\-kernel\fR"
 Print kernel messages.
 .IP "\fB\-L\fR, \fB\-\-color\fR[=\fIwhen\fR]"
-Colorize important messages.  The optional argument \fIwhen\fP can be \fBauto\fR,
-\fBnever\fR or \fBalways\fR.  If the \fIwhen\fR argument is omitted,
+Colorize important messages (enabled by default).  The optional argument \fIwhen\fP
+can be \fBauto\fR, \fBnever\fR or \fBalways\fR.  If the \fIwhen\fR argument is omitted,
 then it defaults to \fBauto\fR.
 .IP  "\fB\-l\fR, \fB\-\-level \fIlist\fR"
 Restrict output to the given (comma-separated)
@@ -178,23 +178,47 @@ format has the same issue as
 .BR ctime :
 the time may be inaccurate when a system is suspended and resumed.
 .SH COLORS
-Implicit coloring can be disabled as follows:
-.RS
+Implicit coloring can be disabled by an empty file \fI/etc/terminal-colors.d/dmesg.disable\fR.
 
-.br
-.BI "touch /etc/terminal-colors.d/dmesg.disable"
-.br
+See
+.BR terminal-colors.d (5)
+for more details about colorization configuration. The logical color names
+support by
+.B dmesg
+are:
+.TP
+.B subsys
+The message sub-system prefix (e.g. "ACPI:").
+.TP
+.B time
+The message timestamp.
+.TP
+.B alert
+The text of the message with the alert log priority.
+.TP
+.B crit
+The text of the message with the critical log priority.
+.TP
+.B err
+The text of the message with the error log priority.
+.TP
+.B warn
+The text of the message with the warning log priority.
+.TP
+.B segfault
+The text of the message that inform about segmentation fault.
 
-.RE
-For more details see
-.BR terminal-colors.d (5).
 .SH SEE ALSO
 .BR syslogd (8)
+.BR terminal-colors.d (5)
 .SH AUTHORS
 .MT kzak@redhat.com
 Karel Zak
 .ME
+
 .br
+.B dmesg
+was originally written by
 .MT tytso@athena.mit.edu
 Theodore Ts'o
 .ME
diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index 73b246e0b..147a3ff70 100644
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -61,16 +61,36 @@
 #define SYSLOG_ACTION_SIZE_BUFFER   10
 
 /*
- * Colors
+ * Color scheme
  */
-#define DMESG_COLOR_SUBSYS	UL_COLOR_BROWN
-#define DMESG_COLOR_TIME	UL_COLOR_GREEN
-#define DMESG_COLOR_RELTIME	UL_COLOR_BOLD_GREEN
-#define DMESG_COLOR_ALERT	UL_COLOR_REVERSE UL_COLOR_RED
-#define DMESG_COLOR_CRIT	UL_COLOR_BOLD_RED
-#define DMESG_COLOR_ERR		UL_COLOR_RED
-#define DMESG_COLOR_WARN	UL_COLOR_BOLD
-#define DMESG_COLOR_SEGFAULT	UL_COLOR_HALFBRIGHT UL_COLOR_RED
+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_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_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
@@ -202,19 +222,21 @@ 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:
-		color_enable(DMESG_COLOR_ALERT);
-		return 0;
+		id = DMESG_COLOR_ALERT;
+		break;
 	case LOG_CRIT:
-		color_enable(DMESG_COLOR_CRIT);
-		return 0;
+		id = DMESG_COLOR_CRIT;
+		break;
 	case LOG_ERR:
-		color_enable(DMESG_COLOR_ERR);
-		return 0;
+		id = DMESG_COLOR_ERR;
+		break;
 	case LOG_WARNING:
-		color_enable(DMESG_COLOR_WARN);
-		return 0;
+		id = DMESG_COLOR_WARN;
+		break;
 	default:
 		break;
 	}
@@ -222,12 +244,13 @@ static int set_level_color(int log_level, const char *mesg, size_t mesgsz)
 	/* well, sometimes the messges contains important keywords, but in
 	 * non-warning/error messages
 	 */
-	if (memmem(mesg, mesgsz, "segfault at", 11)) {
-		color_enable(DMESG_COLOR_SEGFAULT);
-		return 0;
-	}
+	if (id < 0 && memmem(mesg, mesgsz, "segfault at", 11))
+		id = DMESG_COLOR_SEGFAULT;
 
-	return 1;
+	if (id >= 0)
+		dmesg_enable_color(id);
+
+	return id >= 0 ? 0 : -1;
 }
 
 static void __attribute__((__noreturn__)) usage(FILE *out)
@@ -873,7 +896,7 @@ static void print_record(struct dmesg_control *ctl,
 				      level_names[rec->level].name);
 
 	if (ctl->color)
-		color_enable(DMESG_COLOR_TIME);
+		dmesg_enable_color(DMESG_COLOR_TIME);
 
 	switch (ctl->time_fmt) {
 		double delta;
@@ -932,7 +955,7 @@ mesg:
 		/* subsystem prefix */
 		const char *subsys = get_subsys_delimiter(mesg, mesg_size);
 		if (subsys) {
-			color_enable(DMESG_COLOR_SUBSYS);
+			dmesg_enable_color(DMESG_COLOR_SUBSYS);
 			safe_fwrite(mesg, subsys - mesg, stdout);
 			color_disable();