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From: Paul Eggert <eggert@cs.ucla.edu>
To: Ondrej Valousek <ondrej.valousek.xm@renesas.com>,
	Bruno Haible <bruno@clisp.org>,
	"bug-gnulib@gnu.org" <bug-gnulib@gnu.org>
Subject: Re: [PATCH] Use xattr (Linux) in qcopy-acl.c
Date: Wed, 4 Jan 2023 17:19:21 -0800	[thread overview]
Message-ID: <ea13d345-a80e-580b-42a0-5c0592139087@cs.ucla.edu> (raw)
In-Reply-To: <TYXPR01MB1854E3B8F44013CC232E4ECED9F59@TYXPR01MB1854.jpnprd01.prod.outlook.com>

On 2023-01-04 12:54, Ondrej Valousek wrote:

> LIB_HAS_ACL has value only if glibc does not know getxattr() system call. It has nothing to do with libattr (yes, it's bit confusing).

No kidding. This stuff is waaaayy too complicated.

> Why don't we solve the linker problem with the "--as-needed" option? 

--as-needed isn't portable, but Gnulib has a lib-ignore module that 
should be more portable. I suppose we could make the qcopy-acl module 
depend on the lib-ignore module, but we've never done anything like that 
before. Another possibility would be to implement a new variable 
LIB_XATTR_FALLBACK (or perhaps a better name), that acts like LIB_ACL if 
the xattr library is absent and the acl library is present, and is empty 
otherwise.

Perhaps Bruno has an opinion here. I'm not sure how well lib-ignore 
would work for packages that build libraries rather than apps.

> It depends on a kernel ACL implementation. On Linux the ACLs make the permissions only more opened (hence my code would be fine).
> In contrast, on Solaris/ZFS, the opposite could happen.

Ouch, in that case perhaps we should not use the new code on Solaris. 
Solaris is a dead end now anyway, no point trying to make it go faster.

What about OpenZFS on GNU/Linux? That's more important.

> NetApp NFSv4 server even allows you to break RFC7530 the way that chmod 0 <file> will still allow the inherited ACLs to be applied.

We should be OK there, right? We do the chmod 0 first.



  reply	other threads:[~2023-01-05  1:19 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-04 14:34 [PATCH] Use xattr (Linux) in qcopy-acl.c Ondrej Valousek
2023-01-04 14:46 ` Bruno Haible
2023-01-04 19:29   ` Paul Eggert
2023-01-04 20:54     ` Ondrej Valousek
2023-01-05  1:19       ` Paul Eggert [this message]
2023-01-13  9:15         ` ACL complexity Bruno Haible
2023-01-13 10:03           ` Ondrej Valousek
2023-01-13 11:05             ` Bruno Haible
2023-01-13 11:22               ` Ondrej Valousek
2023-01-05  9:00       ` [PATCH] Use xattr (Linux) in qcopy-acl.c Bruno Haible
2023-01-05  9:05         ` Ondrej Valousek
2023-01-05 10:32           ` Bruno Haible
2023-01-05 19:06             ` Paul Eggert
2023-01-11  9:11               ` Ondrej Valousek
2023-01-12 20:42                 ` Bruno Haible
2023-01-13  7:51                   ` Bruno Haible
2023-01-13  8:09                     ` Bruno Haible
2023-01-13  8:32                       ` Ondrej Valousek
2023-01-13  8:46                         ` Bruno Haible
2023-01-14  1:52                           ` Paul Eggert
2023-01-14  7:26                             ` Ondrej Valousek
2023-01-14  7:55                               ` Bruno Haible
2023-01-14  8:02                                 ` Ondrej Valousek
2023-01-13  8:33               ` Bruno Haible
2023-01-13  8:50                 ` Bruno Haible
2023-01-30 10:18                 ` Bruno Haible
2023-01-05  8:56     ` Bruno Haible
     [not found] ` <TYXPR01MB18544D0A5C213BF0204BF0D4D9FD9@TYXPR01MB1854.jpnprd01.prod.outlook.com>
     [not found]   ` <c1ddff8c-2734-bfa1-11a3-3279ae9e92cb@cs.ucla.edu>
2023-01-12 20:58     ` Bruno Haible
2023-01-12 22:53       ` Paul Eggert

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