dmesg colorized output

From 1a89c8497525030c8710c3936aa8d558976f0502 Mon Sep 17 00:00:00 2001

sys-utils/dmesg.c +1 -0

index 4c85f9f..fc384d7 100644
@@ -23,6 +23,7 @@
 #include <fcntl.h>
 
 #include "c.h"
+#include "colors.h"
 #include "nls.h"
 #include "strutils.h"
 #include "xalloc.h"

sys-utils/dmesg.c +3 -1

 /* Close the log.  Currently a NOP. */
 #define SYSLOG_ACTION_CLOSE          0
 /* Open the log. Currently a NOP. */

@@ -147,7 +153,8 @@ struct dmesg_control {
 			notime:1,	/* don't print timestamp */
 			delta:1,	/* show time deltas */
 			reltime:1,	/* show human readable relative times */
-			ctime:1;	/* show human readable time */
+			ctime:1,	/* show human readable time */
+			color:1;	/* colorize error and panic messages */
 };
 
 struct dmesg_record {

@@ -193,6 +200,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 		" -f, --facility <list>       restrict output to defined facilities\n"
 		" -h, --help                  display this help and exit\n"
 		" -k, --kernel                display kernel messages\n"
+		" -L, --color                 colorize error and panic messages\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"

sys-utils/dmesg.c +8 -1

 	safe_fwrite(rec->mesg, rec->mesg_size, stdout);
 
+  if (ctl->color)
+    rst_clr(stdout);
+
 	if (*(rec->mesg + rec->mesg_size - 1) != '\n')
 		putchar('\n');
 }

@@ -1046,6 +1062,7 @@ int main(int argc, char *argv[])
 	static const struct option longopts[] = {
 		{ "buffer-size",   required_argument, NULL, 's' },
 		{ "clear",         no_argument,	      NULL, 'C' },
+		{ "color",         no_argument,	      NULL, 'L' },
 		{ "console-level", required_argument, NULL, 'n' },
 		{ "console-off",   no_argument,       NULL, 'D' },
 		{ "console-on",    no_argument,       NULL, 'E' },

@@ -1080,7 +1097,7 @@ int main(int argc, char *argv[])
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "CcDdEeF:f:hkl:n:rSs:TtuVwx",
+	while ((c = getopt_long(argc, argv, "CcDdEeF:f:hkLl:n:rSs:TtuVwx",
 				longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);

@@ -1123,6 +1140,9 @@ int main(int argc, char *argv[])
 			ctl.fltr_fac = 1;
 			setbit(ctl.facilities, FAC_BASE(LOG_KERN));
 			break;
+		case 'L':
+			ctl.color = 1;
+			break;
 		case 'l':
 			ctl.fltr_lev= 1;
 			if (string_to_bitarray(optarg,

Quoted 1 line · Ondrej Oprala

new file mode 100644

include/colors.h

Quoted 4 lines

index 0000000..90b62a7

include/colors.h new file +0 -0

@@ -0,0 +1,19 @@

Please, see another files in include/.

#ifndef UTIL_LINUX_COLOR_H
#define UTIL_LINUX_COLOR_H

include/colors.h line 10

Quoted 10 lines

include/colors.h new file +10 -0

+/*
+ * Copyright (C) 2012 Ondrej Oprala <[email protected]>
+ *
+ * This file may be distributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#define CLR_RST "\033[0m"

   #define UL_COLOR_RESET

to keep it readable. It would be also nice to have macros for individual colors (UL_COLOR_{RED,YELLOW,BLUE,...} and extra modes like bold.

(It's also possible to set background colors, but I guess that foreground colors are enough for our utils.)

lib/colors.c line 10

Quoted 13 lines

lib/colors.c new file +10 -0

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2012 Ondrej Oprala <[email protected]>
+ *
+ * This file may be distributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+#include "colors.h"
+
+void set_clr(const char *clr_scheme, FILE *out)

color_enable()

Is it necessary to care about "out"? Maybe we can assume that the output is stdout.

lib/colors.c line 14

Quoted 4 lines

lib/colors.c new file +4 -0

+{
+	if (isatty(fileno(out)))
+		fprintf(out, clr_scheme);
+}

if I good remember than isatty() is internally implemented by any ioctl(). It would be probably better to have something like:

   int colors_init();

where we check all necessary terminal features and initialize a global variable, so in color_enable/disable() we will check the variable only.

lib/colors.c line 16

Quoted 1 line

lib/colors.c new file +1 -0

+void rst_clr(FILE *out)

color_disable()

Maybe for the functions names we should also use ul_ prefix to avoid collisions (for example ncurses library also uses pretty generic names for color functions).

lib/colors.c line 20

Quoted 4 lines

lib/colors.c new file +4 -0

+{
+	if (isatty(fileno(out)))
+		fprintf(out, CLR_RST);
+}

Please, use fputs() rather than fprintf().

Quoted 16 lines

sys-utils/dmesg.c +1 -0

index 4c85f9f..fc384d7 100644
@@ -23,6 +23,7 @@
 #include <fcntl.h>
 
 #include "c.h"
+#include "colors.h"
 #include "nls.h"
 #include "strutils.h"
 #include "xalloc.h"

@@ -33,6 +34,11 @@
 #include "optutils.h"
 #include "mangle.h"
 

sys-utils/dmesg.c line 38

Quoted 2 lines

sys-utils/dmesg.c +2 -0

+#define K_PANIC 1
+#define K_ERR 3

really no, already defined by LOG_* macros in <sys/syslog.h>, see also level_names[] array in dmesg.c.

sys-utils/dmesg.c line 40

Quoted 2 lines

sys-utils/dmesg.c +2 -0

+#define CLR_PANIC "\033[31m" //Red
+#define CLR_ERR "\033[1;31m" //Bright Red

#define DMESG_COLOR_ALERT UL_COLOR_RED
#define DMESG_COLOR_ERR UL_COLOR_BRIGHT_RED

Quoted 22 lines

sys-utils/dmesg.c +3 -1

 /* Close the log.  Currently a NOP. */
 #define SYSLOG_ACTION_CLOSE          0
 /* Open the log. Currently a NOP. */

@@ -147,7 +153,8 @@ struct dmesg_control {
 			notime:1,	/* don't print timestamp */
 			delta:1,	/* show time deltas */
 			reltime:1,	/* show human readable relative times */
-			ctime:1;	/* show human readable time */
+			ctime:1,	/* show human readable time */
+			color:1;	/* colorize error and panic messages */
 };
 
 struct dmesg_record {

@@ -193,6 +200,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 		" -f, --facility <list>       restrict output to defined facilities\n"
 		" -h, --help                  display this help and exit\n"
 		" -k, --kernel                display kernel messages\n"
+		" -L, --color                 colorize error and panic messages\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"

sys-utils/dmesg.c static void print_record(struct dmesg_control *ctl, · line 853

Quoted 7 lines

sys-utils/dmesg.c +4 -0

@@ -839,8 +847,16 @@ static void print_record(struct dmesg_control *ctl,
 		printf("[%5d.%06d] ", (int) rec->tv.tv_sec, (int) rec->tv.tv_usec);
 
 mesg:
+  //Change the output color for panic and error messages
+  if (ctl->color)
+    set_clr(rec->level == K_PANIC ? CLR_PANIC :
+        rec->level == K_ERR ? CLR_ERR : CLR_RST, stdout);

keep it elegant:

    if (ctl->color)
        set_level_color(rec->level);

:-)

Quoted 36 lines

sys-utils/dmesg.c +8 -1

 	safe_fwrite(rec->mesg, rec->mesg_size, stdout);
 
+  if (ctl->color)
+    rst_clr(stdout);
+
 	if (*(rec->mesg + rec->mesg_size - 1) != '\n')
 		putchar('\n');
 }

@@ -1046,6 +1062,7 @@ int main(int argc, char *argv[])
 	static const struct option longopts[] = {
 		{ "buffer-size",   required_argument, NULL, 's' },
 		{ "clear",         no_argument,	      NULL, 'C' },
+		{ "color",         no_argument,	      NULL, 'L' },
 		{ "console-level", required_argument, NULL, 'n' },
 		{ "console-off",   no_argument,       NULL, 'D' },
 		{ "console-on",    no_argument,       NULL, 'E' },

@@ -1080,7 +1097,7 @@ int main(int argc, char *argv[])
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "CcDdEeF:f:hkl:n:rSs:TtuVwx",
+	while ((c = getopt_long(argc, argv, "CcDdEeF:f:hkLl:n:rSs:TtuVwx",
 				longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);

@@ -1123,6 +1140,9 @@ int main(int argc, char *argv[])
 			ctl.fltr_fac = 1;
 			setbit(ctl.facilities, FAC_BASE(LOG_KERN));
 			break;
+		case 'L':
+			ctl.color = 1;
+			break;
 		case 'l':
 			ctl.fltr_lev= 1;
 			if (string_to_bitarray(optarg,

sys-utils/dmesg.c int main(int argc, char *argv[]) · line 1205

Quoted 8 lines

sys-utils/dmesg.c +2 -2

@@ -1180,9 +1200,9 @@ int main(int argc, char *argv[])
 		usage(stderr);
 
 	if (ctl.raw && (ctl.fltr_lev || ctl.fltr_fac || ctl.delta ||
-			ctl.notime || ctl.ctime || ctl.decode))
+			ctl.notime || ctl.ctime || ctl.decode || ctl.color))
 		errx(EXIT_FAILURE, _("--raw can't be used together with level, "
-		     "facility, decode, delta, ctime or notime options"));
+		     "facility, decode, delta, ctime, notime or color options"));

   if (ctl.color && ul_color_init() != 0)
     ctl.color = 0;

Thanks!

Karel

Quoted 2 lines · Karel Zak

Quoted 1 line · Ondrej Oprala

new file mode 100644

Hehe I actually started doing this last night.

I'm wondering if we actually need a new lib file for colors. I mean AFAICT, dmesg is the only place we want to use it and I don't see that

changing any time soon - Unix hackers don't like colors, we live oh so boring lives :)

Quoted 8 lines · Davidlohr Bueso

Quoted 2 lines · Karel Zak

Quoted 1 line · Ondrej Oprala

new file mode 100644

Hehe I actually started doing this last night.

I'm wondering if we actually need a new lib file for colors. I mean AFAICT, dmesg is the only place we want to use it and I don't see that

What about fdisk where we have many dialogs, warnings, hints? :-) It's not about colors only, but also about bold, etc.

The another possibility is namei(1) where we can provide output compatible with ls(1), or cal(1), etc.

Quoted 2 lines

changing any time soon - Unix hackers don't like colors, we live oh so boring lives :)

All this should be optional. I guess than many people use aliases with colors

$ alias | grep color
alias egrep='egrep --color=tty'
alias fgrep='fgrep --color=tty'
alias grep='grep --color=tty'
alias l.='ls -d .* --color=auto'
alias ll='ls -l --color=auto'
alias ls='ls --color=auto'