[PATCH] dmesg colorized output

Ondrej Oprala
2012-10-10T07:44:09Z

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Hi, this patch should implement the dmesg entry in your TODO list.
I've also created a tiny colors module, which should be enough for
simple output coloring for other programs in the future.
Cheers,
Ondrej.

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>From 1a89c8497525030c8710c3936aa8d558976f0502 Mon Sep 17 00:00:00 2001
From: Ondrej Oprala <ooprala@redhat.com>
Date: Tue, 9 Oct 2012 12:32:55 +0200
Subject: [PATCH] dmesg: Add a --color option to colorize error and panic
messages

---
include/colors.h | 19 +++++++++++++++++++
lib/Makemodule.am | 1 +
lib/colors.c | 20 ++++++++++++++++++++
sys-utils/dmesg.c | 28 ++++++++++++++++++++++++----
4 files changed, 64 insertions(+), 4 deletions(-)
create mode 100644 include/colors.h
create mode 100644 lib/colors.c

diff --git a/include/colors.h b/include/colors.h
new file mode 100644
index 0000000..90b62a7
--- /dev/null
+++ b/include/colors.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2012 Ondrej Oprala <ooprala@redhat.com>
+ *
+ * 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"
+
+/*
+ * Set output colors according to CLR_SCHEME, which should
+ * be in ANSI color code format
+ */
+extern void set_clr(const char *clr_scheme, FILE *out);
+
+/* Reset to default */
+extern void rst_clr(FILE *out);
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 33a3eb8..3c89fb8 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -5,6 +5,7 @@ libcommon_la_SOURCES = \
lib/at.c \
lib/blkdev.c \
lib/canonicalize.c \
+ lib/colors.c \
lib/cpuset.c \
lib/crc32.c \
lib/env.c \
diff --git a/lib/colors.c b/lib/colors.c
new file mode 100644
index 0000000..0e03f98
--- /dev/null
+++ b/lib/colors.c
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2012 Ondrej Oprala <ooprala@redhat.com>
+ *
+ * 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)
+{
+ if (isatty(fileno(out)))
+ fprintf(out, clr_scheme);
+}
+
+void rst_clr(FILE *out)
+{
+ if (isatty(fileno(out)))
+ fprintf(out, CLR_RST);
+}
diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index 4c85f9f..fc384d7 100644
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -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"

+#define K_PANIC 1
+#define K_ERR 3
+#define CLR_PANIC "\033[31m" //Red
+#define CLR_ERR "\033[1;31m" //Bright Red
+
/* 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 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 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"
@@ -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);
+
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,
@@ -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.notime && (ctl.ctime || ctl.reltime))
errx(EXIT_FAILURE, _("--notime can't be used together with --ctime or --reltime"));
--
1.7.11.4