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

[malc]

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).

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