klibc - May 2008 - [PATCH] Fixes bug which strips every other digit in klibc-utils dmesg output

There is a bug in the way which klibc/usr/utils/dmesg.c tries to strip
the initial <[0-7]> from kernel messages.  The bug causes every other
numerical digit to be stripped from the output.  Fixed.

A bug report with lots of details has been filed for Debian and Ubuntu:
 * http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=483186
 * https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/235282

Signed-off-by: Anthony Fok <anthony.fok at thizgroup.com>
---
diff -Nur -x '*.orig' -x '*~' klibc-1.5.9/usr/utils/dmesg.c
klibc-1.5.9.new/usr/utils/dmesg.c
--- klibc-1.5.9/usr/utils/dmesg.c	2008-03-29 04:25:36.000000000 +0800
+++ klibc-1.5.9.new/usr/utils/dmesg.c	2008-05-27 07:07:36.000000000 +0800
@@ -50,20 +50,14 @@
 		exit(1);
 	}

-	while (buf[i] && i < len)
-		switch (buf[i]) {
-		case '<':
-			if (i == 0 || buf[i-1] == '\n')
-				i++;
-		case '0' ... '9':
-			if (i > 0 && buf[i-1] == '<')
-				i++;
-		case '>':
-			if (i > 0 && isdigit(buf[i-1]))
-				i++;
-		default:
-			putchar(buf[i++]);
-		}
+	while (buf[i] && i < len) {
+		if (i == 0 || buf[i-1] == '\n')
+			if (buf[i] == '<')
+				if (isdigit(buf[++i]))
+					if (buf[++i] == '>')
+						i++;
+		putchar(buf[i++]);
+	}

 	if (buf[i-1] != '\n')
 		putchar('\n');

On Wed, May 28, 2008 at 05:00:23AM +0800, Anthony Fok
wrote:
> There is a bug in the way which klibc/usr/utils/dmesg.c tries to strip
> the initial <[0-7]> from kernel messages.  The bug causes every other
> numerical digit to be stripped from the output.  Fixed.
> 
> A bug report with lots of details has been filed for Debian and Ubuntu:
>  * http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=483186
>  * https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/235282
> 
> Signed-off-by: Anthony Fok <anthony.fok at thizgroup.com>
> ---
> diff -Nur -x '*.orig' -x '*~' klibc-1.5.9/usr/utils/dmesg.c
> klibc-1.5.9.new/usr/utils/dmesg.c
> --- klibc-1.5.9/usr/utils/dmesg.c	2008-03-29 04:25:36.000000000 +0800
> +++ klibc-1.5.9.new/usr/utils/dmesg.c	2008-05-27 07:07:36.000000000 +0800
> @@ -50,20 +50,14 @@
>  		exit(1);
>  	}
> 
> -	while (buf[i] && i < len)
> -		switch (buf[i]) {
> -		case '<':
> -			if (i == 0 || buf[i-1] == '\n')
> -				i++;
> -		case '0' ... '9':
> -			if (i > 0 && buf[i-1] == '<')
> -				i++;
> -		case '>':
> -			if (i > 0 && isdigit(buf[i-1]))
> -				i++;
> -		default:
> -			putchar(buf[i++]);
> -		}
> +	while (buf[i] && i < len) {
> +		if (i == 0 || buf[i-1] == '\n')
> +			if (buf[i] == '<')
> +				if (isdigit(buf[++i]))
> +					if (buf[++i] == '>')
> +						i++;
> +		putchar(buf[i++]);
> +	}
> 
>  	if (buf[i-1] != '\n')
>  		putchar('\n');
nack on the coding style,
please don't remove the readable switch to an if spagetti code.

you are obfuscating the problem.

thanks

-- 
maks

[maks: removed you from the Cc: list because stro.at doesn't resolve at 
the moment... I know you're on the klibc list.]

maximilian attems wrote:
> 
> nack on the coding style,
> please don't remove the readable switch to an if spagetti code.
> 
> you are obfuscating the problem.
> 
Here is a more state-machine-like approach to the problem.  You may want 
to try it out.

	-hpa

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