Re: [Qemu-devel] [PATCH v2] error: passing a negative value to an os_errno is wrong

[SeokYeon Hwang]

> -----Original Message-----
> From: Markus Armbruster [mailto:address@hidden
> Sent: Friday, November 07, 2014 4:41 PM
> To: Amos Kong
> Cc: SeokYeon Hwang; address@hidden; address@hidden; qemu-
> address@hidden
> Subject: Re: [Qemu-devel] [PATCH v2] error: passing a negative value to an
> os_errno is wrong
> 
> Amos Kong <address@hidden> writes:
> 
> > On Fri, Nov 07, 2014 at 11:24:55AM +0900, SeokYeon Hwang wrote:
> >> Added 'assert(os_errno > 0)' in 'error_set_errno()'.
> >> Fixed errno since it passes wrong value to 'error_set_errno()'.
> >>
> >> Signed-off-by: SeokYeon Hwang <address@hidden>
> >> ---
> >>  hw/pci/pcie.c | 2 +-
> >>  util/error.c  | 1 +
> >>  2 files changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c index 58455bd..2902f7d
> >> 100644
> >> --- a/hw/pci/pcie.c
> >> +++ b/hw/pci/pcie.c
> >> @@ -229,7 +229,7 @@ static void pcie_cap_slot_hotplug_common(PCIDevice
> *hotplug_dev,
> >>          /* the slot is electromechanically locked.
> >>           * This error is propagated up to qdev and then to HMP/QMP.
> >>           */
> >> -        error_setg_errno(errp, -EBUSY, "slot is electromechanically
> locked");
> >> +        error_setg_errno(errp, EBUSY, "slot is electromechanically
> >> + locked");
> >>      }
> >>  }
> >>
> >> diff --git a/util/error.c b/util/error.c index 2ace0d8..4ce22cc
> >> 100644
> >> --- a/util/error.c
> >> +++ b/util/error.c
> >> @@ -62,6 +62,7 @@ void error_set_errno(Error **errp, int os_errno,
> ErrorClass err_class,
> >>          return;
> >>      }
> >>      assert(*errp == NULL);
> >> +    assert(os_errno > 0);
> >
> > strerror(0) will return string 'Success', do we need to reserve zero
> here?
> >
> >       assert(os_errno >= 0);
> 
> Yes, because...
> 
> >>      err = g_malloc0(sizeof(*err));
> >>
>         va_start(ap, fmt);
>         msg1 = g_strdup_vprintf(fmt, ap);
> --->    if (os_errno != 0) {
>             err->msg = g_strdup_printf("%s: %s", msg1,
strerror(os_errno));
>             g_free(msg1);
>         } else {
>             err->msg = msg1;
>         }
> 
> Please fix.

You're right. I posted patch v3.
Thank you for your advice.