Re: [Qemu-devel] [PATCH 07/22] qemu-error: Introduce get_errno_string()

[Luiz Capitulino]

On Wed, 21 Apr 2010 18:42:38 +0400 (MSD)
malc <address@hidden> wrote:

> On Wed, 21 Apr 2010, Kevin Wolf wrote:
> 
> > Am 21.04.2010 10:28, schrieb Daniel P. Berrange:
> > > On Tue, Apr 20, 2010 at 06:09:37PM -0300, Luiz Capitulino wrote:
> > >> There are error handling functions in QEMU which print errno codes
> > >> to the user. While it's debatable if this is good from a user
> > >> perspective, sometimes it's the best you can do because it's what
> > >> system calls return and this is also useful for debugging.
> > >>
> > >> So, we need a way to expose those codes in QMP. We can't use the
> > >> codes themselfs because they may vary between systems.
> > >>
> > >> The best solution I can think of is returning the string
> > >> representation of the name. For example, EIO becomes "EIO".
> > >>
> > >> This is what get_errno_string() does.
> > >>
> > >> Signed-off-by: Luiz Capitulino <address@hidden>
> > >> ---
> > >>  qemu-error.c |   25 +++++++++++++++++++++++++
> > >>  qemu-error.h |    1 +
> > >>  2 files changed, 26 insertions(+), 0 deletions(-)
> > >>
> > >> diff --git a/qemu-error.c b/qemu-error.c
> > >> index 5a35e7c..55ce133 100644
> > >> --- a/qemu-error.c
> > >> +++ b/qemu-error.c
> > >> @@ -207,3 +207,28 @@ void error_report(const char *fmt, ...)
> > >>      va_end(ap);
> > >>      error_printf("\n");
> > >>  }
> > >> +
> > >> +/*
> > >> + * This is probably only useful for QMP
> > >> + */
> > >> +const char *get_errno_string(int err)
> > >> +{
> > >> +    assert(err < 0);
> > >> +
> > >> +    switch (err) {
> > >> +    case -EINVAL:
> > >> +        return "EINVAL";
> > >> +    case -EIO:
> > >> +        return "EIO";
> > >> +    case -ENOENT:
> > >> +        return "ENOENT";
> > >> +    case -ENOMEDIUM:
> > >> +        return "ENOMEDIUM";
> > >> +    case -ENOTSUP:
> > >> +        return "ENOTSUP";
> > >> +    default:
> > >> +        return "unknown";
> > >> +    }
> > >> +
> > >> +    abort();
> > >> +}
> > > 
> > > Wouldn't it be nicer to return strerror_r()  output instead of errno
> > > names ?
> > 
> > I agree. And it would be more complete, too.
> 
> OTOH it has a problem of returning translated messages (subject to
> LC_MESSAGES value).

 Exactly, and I'm not sure if there's anything that ensure they're
exactly the same among different systems.