sysx/xattr: fix and improve

[kolyshkin]

1. fix getxattrAll

The current implementation is suboptimal for two reasons:

• the initial buffer size of 5 bytes makes no sense (my guess @stevvooe forgot to change it back to a sane value after the initial retry logic testing);

• it never gets the real buffer size, resulting in extra iterations (5 -> 10 -> 20 -> ...).

This commit

• sets the initial size to 128;
• uses the logic to get the real size in case we get ERANGE (rather than doubling the buffer)

2. improve listxattrAll

The current code

• is hard to read (at least for me, that is);
• is suboptimal (always calls listxattr() twice);
• doesn't handle the condition when attributes size is changed in between the two calls to listxattr().

Fix all three issues at once by reusing the logic from getxattrAll().

[kolyshkin]

I like it, but please sign your commits.

@Zyqsempai Sorry, I don't get it. Do you mean something other than the

Signed-off-by: Kir Kolyshkin kolyshkin@gmail.com

line which is present in both commits?