dmesg: rework color feature, compat. with more

when used with less or more, the colors were not in
the same buffer, resulting blocs of colors.

Also, reset color numbers to the 16 ANSI ones.

Reduce the diff with busybox to be able to send the patch.
This is the first full busybox aosp feature with the new build system

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>

Change-Id: Ia0239a0bea02da01cae15736150dfee4fe66dcdb

4 files changed, 47 insertions, 28 deletions

diff --git a/busybox-full.config b/busybox-full.config
index 27221c6..95664c4 100644
--- a/busybox-full.config
+++ b/busybox-full.config
@@ -538,6 +538,7 @@ CONFIG_BLKID=y
 CONFIG_FEATURE_BLKID_TYPE=y
 CONFIG_DMESG=y
 # CONFIG_FEATURE_DMESG_PRETTY is not set
+CONFIG_FEATURE_DMESG_COLOR=y
 # CONFIG_FBSET is not set
 # CONFIG_FEATURE_FBSET_FANCY is not set
 # CONFIG_FEATURE_FBSET_READMODE is not set
diff --git a/busybox-minimal.config b/busybox-minimal.config
index fe852c2..ad8574f 100644
--- a/busybox-minimal.config
+++ b/busybox-minimal.config
@@ -538,6 +538,7 @@ CONFIG_BLKID=y
 CONFIG_FEATURE_BLKID_TYPE=y
 CONFIG_DMESG=y
 # CONFIG_FEATURE_DMESG_PRETTY is not set
+CONFIG_FEATURE_DMESG_COLOR=y
 # CONFIG_FBSET is not set
 # CONFIG_FEATURE_FBSET_FANCY is not set
 # CONFIG_FEATURE_FBSET_READMODE is not set
diff --git a/util-linux/Config.src b/util-linux/Config.src
index 8c5343b..9af923e 100644
--- a/util-linux/Config.src
+++ b/util-linux/Config.src
@@ -81,6 +81,14 @@ config FEATURE_DMESG_PRETTY
 	    <6>BIOS-provided physical RAM map:
 	    <6> BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
 
+config FEATURE_DMESG_COLOR
+	bool "Colored dmesg output"
+	default y
+	depends on DMESG
+	help
+	  Allow to show errors and warnings in different colors
+	  dmesg -C
+
 config FBSET
 	bool "fbset"
 	default y
diff --git a/util-linux/dmesg.c b/util-linux/dmesg.c
index 84173ce..ba52036 100644
--- a/util-linux/dmesg.c
+++ b/util-linux/dmesg.c
@@ -10,23 +10,37 @@
  */
 
 //usage:#define dmesg_trivial_usage
-//usage:       "[-c] [-n LEVEL] [-r] [-s SIZE] [-C]"
+//usage:       "[-c] [-n LEVEL] [-s SIZE]"
+//usage:	IF_FEATURE_DMESG_PRETTY(" [-r]")
+//usage:	IF_FEATURE_DMESG_COLOR(" [-C]")
 //usage:#define dmesg_full_usage "\n\n"
 //usage:       "Print or control the kernel ring buffer\n"
 //usage:     "\n	-c		Clear ring buffer after printing"
 //usage:     "\n	-n LEVEL	Set console logging level"
-//usage:     "\n	-r		Show level prefix"
 //usage:     "\n	-s SIZE		Buffer size"
-//usage:     "\n	-C		Colored output"
+//usage:	IF_FEATURE_DMESG_PRETTY(
+//usage:     "\n	-r		Show level prefix")
+//usage:	IF_FEATURE_DMESG_COLOR(
+//usage:     "\n	-C		Colored output")
 
 #include <sys/klog.h>
 #include "libbb.h"
 
+#if ENABLE_FEATURE_DMESG_COLOR
 #define COLOR_DEFAULT 0
-#define COLOR_WHITE   231
-#define COLOR_YELLOW  226
-#define COLOR_ORANGE  166
-#define COLOR_RED     196
+#define COLOR_WHITE   97
+#define COLOR_YELLOW  93
+#define COLOR_ORANGE  33
+#define COLOR_RED     91
+
+static void set_color(int color)
+{
+	printf("%c[%dm", 0x1B, color);
+}
+
+#else
+#define set_color(c) {}
+#endif
 
 int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int dmesg_main(int argc UNUSED_PARAM, char **argv)
@@ -34,12 +48,14 @@ int dmesg_main(int argc UNUSED_PARAM, char **argv)
 	int len, level;
 	char *buf;
 	unsigned opts;
+	int color = 0;
 	enum {
 		OPT_c = 1 << 0,
 		OPT_s = 1 << 1,
 		OPT_n = 1 << 2,
 		OPT_r = 1 << 3,
-		OPT_C = 1 << 4
+		OPT_C = 1 << 4,
+		OPT_end
 	};
 
 	opt_complementary = "s+:n+"; /* numeric */
@@ -67,14 +83,15 @@ int dmesg_main(int argc UNUSED_PARAM, char **argv)
 
 	if ((ENABLE_FEATURE_DMESG_PRETTY || (opts & OPT_C)) && !(opts & OPT_r)) {
 		int last = '\n';
-		int in = 0, l, color;
-		char pfx[16], *lvl;
+		int in = 0;
 
 		/* Skip <[0-9]+> at the start of lines */
 		while (1) {
 			if (last == '\n' && buf[in] == '<') {
+
+#if ENABLE_FEATURE_DMESG_COLOR
 				if (opts & OPT_C) {
-					lvl = buf + in + 1;
+					char *lvl = buf + in + 1;
 					sscanf(lvl, "%d", &level);
 
 					switch (level) {
@@ -84,18 +101,14 @@ int dmesg_main(int argc UNUSED_PARAM, char **argv)
 					case 4: color = COLOR_ORANGE; break;
 					case 5: color = COLOR_YELLOW; break;
 					case 7: color = COLOR_WHITE;  break;
-					case 6: // common dmesg info
-					default: color = COLOR_DEFAULT;
+					case 6: /* common dmesg info */
+					default:
+						color = COLOR_DEFAULT;
 					}
 
-					if (color != COLOR_DEFAULT)
-						l = sprintf(pfx, "%c[%d;%d;%dm",
-							0x1B, 38, 5, color);
-					else
-						l = sprintf(pfx, "%c[%dm", 0x1B, 0);
-
-					full_write(STDOUT_FILENO, pfx, l);
+					set_color(color);
 				}
+#endif
 				while (buf[in++] != '>' && in < len)
 					;
 			} else {
@@ -105,17 +118,9 @@ int dmesg_main(int argc UNUSED_PARAM, char **argv)
 			if (in >= len)
 				break;
 		}
-
-		if (opts & OPT_C) {
-			/* Reset default terminal color */
-			l = sprintf(pfx, "%c[%dm", 0x1B, 0);
-			full_write(STDOUT_FILENO, pfx, l);
-		}
-
 		/* Make sure we end with a newline */
 		if (last != '\n')
 			bb_putchar('\n');
-
 	} else {
 		full_write(STDOUT_FILENO, buf, len);
 		if (buf[len-1] != '\n')
@@ -124,5 +129,9 @@ int dmesg_main(int argc UNUSED_PARAM, char **argv)
 
 	if (ENABLE_FEATURE_CLEAN_UP) free(buf);
 
+	/* Reset default terminal color */
+	if (color)
+		set_color(0);
+
 	return EXIT_SUCCESS;
 }