Friendlier EPERM.

[Andreas Jaeger]

On 01/08/2013 06:57 PM, Daniel J Walsh wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Traditionally, if a process attempts a forbidden  operation, errno for that
> thread is set to EACCES or EPERM, and a call to strerror() returns a localized
> version of "Permission Denied" or "Operation not permitted". This string
> appears throughout textual uis and syslogs. For example, it will show up in
> command-line tools, in exceptions within scripting languages, etc.
>
> There are an increasing number of ways in which you can fail to have
> permission to do something:
>
>      classic POSIX discretionary access controls
>      Linux security modules (e.g. SELinux mandatory access controls)
>      capabilities
>      seccomp denials
>      ...
>
> As we continue to add mechanisms for the Kernel to deny permissions, the
> Administrator/User is faced with just a message that says "Permission Denied"
> Then if the administrator is lucky enough or skilled enough to know where to
> look, he might be able to understand why the process was denied access.
>
> In Fedora we had an idea about making it possible for strerror() to contain
> richer information about permissions failures.
>
> See:
>    https://fedoraproject.org/wiki/Features/FriendlyEPERM
>
> We would like to open up discussion about this with the glibc developers to
> see what they think of the idea before opening it up to a larger community.
>
> How does this sound from a glibc perspective?


I like the idea but don't think we should restrict the interface to 
EPERM/EACCES only. Other error conditions could use the same framework. 
EPERM might be the first to use it and show us whether it works but the 
framework needs to be extensible.

Andreas
-- 
  Andreas Jaeger aj@{suse.com,opensuse.org} Twitter/Identica: jaegerandi
   SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
    GF: Jeff Hawn,Jennifer Guild,Felix Imendörffer,HRB16746 (AG Nürnberg)
     GPG fingerprint = 93A3 365E CE47 B889 DF7F  FED1 389A 563C C272 A126