2008-01-30 03:30:48

by Eric Sandeen

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

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 <[email protected]>
---

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]);
}

2008-02-18 16:35:40

by Eric Sandeen

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

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 <[email protected]>
> ---
>
> 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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2008-02-19 03:16:40

by Theodore Ts'o

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

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