[PATCH e2fsprogs] print "mostly-printable" xattr strings in debugfs

[PATCH e2fsprogs] print "mostly-printable" xattr strings in debugfs

[Eric Sandeen]

Taking a cue from getfattr... if a string is "mostly"
printable characters, go ahead & print as a string,
and escape what's left over.

so we get:

Extended attributes stored in inode body: 
  selinux = "system_u:object_r:root_t:s0\000" (28)

instead of:

Extended attributes stored in inode body: 
  selinux = "73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f 72 3a 72 6f 6f 74 5f 74 3a 73 30 00 " (28)

(selinux includes the trailing null in "len" so it
never prints as a string today)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---
 
Index: e2fsprogs-1.40.5/debugfs/debugfs.c
===================================================================
--- e2fsprogs-1.40.5.orig/debugfs/debugfs.c
+++ e2fsprogs-1.40.5/debugfs/debugfs.c
@@ -434,19 +434,21 @@ static int list_blocks_proc(ext2_filsys 
 
 static void dump_xattr_string(FILE *out, const char *str, int len)
 {
-	int printable = 1;
+	int printable = 0;
 	int i;
 	
-	/* check is string printable? */
+	/* check: is string "printable enough?" */
 	for (i = 0; i < len; i++)
-		if (!isprint(str[i])) {
-			printable = 0;
-			break;
-		}
+		if (isprint(str[i]))
+			printable++;
+
+	if (printable <= len*7/8)
+		printable = 0;
 
 	for (i = 0; i < len; i++)
 		if (printable)
-			fprintf(out, "%c", (unsigned char)str[i]);
+			fprintf(out, isprint(str[i]) ? "%c" : "\\%03o",
+				(unsigned char)str[i]);
 		else
 			fprintf(out, "%02x ", (unsigned char)str[i]);
 }

Re: [PATCH e2fsprogs] print "mostly-printable" xattr strings in debugfs

[Eric Sandeen]

Eric Sandeen wrote:
> Taking a cue from getfattr... if a string is "mostly"
> printable characters, go ahead & print as a string,
> and escape what's left over.

Ted, ping on this?  Since we use selinux a lot, it'd be nice to have
something readable in debugfs output.

If there's anything you don't like about the patch I'll be happy to fix
it up.

Thanks,
-Eric

> so we get:
> 
> Extended attributes stored in inode body: 
>   selinux = "system_u:object_r:root_t:s0\000" (28)
> 
> instead of:
> 
> Extended attributes stored in inode body: 
>   selinux = "73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f 72 3a 72 6f 6f 74 5f 74 3a 73 30 00 " (28)
> 
> (selinux includes the trailing null in "len" so it
> never prints as a string today)
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>  
> Index: e2fsprogs-1.40.5/debugfs/debugfs.c
> ===================================================================
> --- e2fsprogs-1.40.5.orig/debugfs/debugfs.c
> +++ e2fsprogs-1.40.5/debugfs/debugfs.c
> @@ -434,19 +434,21 @@ static int list_blocks_proc(ext2_filsys 
>  
>  static void dump_xattr_string(FILE *out, const char *str, int len)
>  {
> -	int printable = 1;
> +	int printable = 0;
>  	int i;
>  	
> -	/* check is string printable? */
> +	/* check: is string "printable enough?" */
>  	for (i = 0; i < len; i++)
> -		if (!isprint(str[i])) {
> -			printable = 0;
> -			break;
> -		}
> +		if (isprint(str[i]))
> +			printable++;
> +
> +	if (printable <= len*7/8)
> +		printable = 0;
>  
>  	for (i = 0; i < len; i++)
>  		if (printable)
> -			fprintf(out, "%c", (unsigned char)str[i]);
> +			fprintf(out, isprint(str[i]) ? "%c" : "\\%03o",
> +				(unsigned char)str[i]);
>  		else
>  			fprintf(out, "%02x ", (unsigned char)str[i]);
>  }
> 
> -
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Re: [PATCH e2fsprogs] print "mostly-printable" xattr strings in debugfs

[Theodore Tso]

On Mon, Feb 18, 2008 at 10:35:37AM -0600, Eric Sandeen wrote:
> Eric Sandeen wrote:
> > Taking a cue from getfattr... if a string is "mostly"
> > printable characters, go ahead & print as a string,
> > and escape what's left over.
> 
> Ted, ping on this?  Since we use selinux a lot, it'd be nice to have
> something readable in debugfs output.

Thanks for reminding me.  It's been applied into the maint branch.

       	   	     	       	    	    - Ted