code review 5369076: syscall: fix zerrors for openbsd 386

syscall: fix zerrors for openbsd 386

[jsing, 2011-11-11 17:29:10]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2011-11-11 17:32:42]

You did this by hand?  Or did you fix cgo -godefs?


On Fri, Nov 11, 2011 at 9:29 AM, <jsing@google.com> wrote:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> syscall: fix zerrors for openbsd 386
>
> Please review this at
http://codereview.appspot.com/**5369076/<http://codereview.appspot.com/5369076/>
>
> Affected files:
>  M src/pkg/syscall/zerrors_**openbsd_386.go
>
>
>

[jsing, 2011-11-11 17:35:31]

I ran "mkerrors.sh -m32" on an openbsd amd64 machine (which fails to
generate correctly on openbsd 386) and manually appended the errors section
(which fails to generate with -m32 on openbsd amd64). This is the same
process I used when I did the original version.

On 12 November 2011 04:32, Brad Fitzpatrick <bradfitz@golang.org> wrote:

> You did this by hand?  Or did you fix cgo -godefs?
>
>
> On Fri, Nov 11, 2011 at 9:29 AM, <jsing@google.com> wrote:
>
>> Reviewers: golang-dev_googlegroups.com,
>>
>> Message:
>> Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),
>>
>> I'd like you to review this change to
>> https://go.googlecode.com/hg/
>>
>>
>> Description:
>> syscall: fix zerrors for openbsd 386
>>
>> Please review this at
http://codereview.appspot.com/**5369076/<http://codereview.appspot.com/5369076/>
>>
>> Affected files:
>>  M src/pkg/syscall/zerrors_**openbsd_386.go
>>
>>
>>
>

[rsc, 2011-11-11 18:11:33]

LGTM

Can you dig up the definition of BIOCGDLTLIST
or any of the other constants that was formatted wrong?
In godefs we had little chance of getting this right using
stabs data, but in cgo with dwarf we have a much better chance.

Thanks.

Russ

[jsing, 2011-11-11 18:19:04]

*** Submitted as http://code.google.com/p/go/source/detail?r=f0c16390bfab ***

syscall: fix zerrors for openbsd 386

R=golang-dev, bradfitz, rsc
CC=golang-dev
http://codereview.appspot.com/5369076

[jsing, 2011-11-17 12:20:49]

On 12 November 2011 05:11, Russ Cox <rsc@golang.org> wrote:

> LGTM
>
> Can you dig up the definition of BIOCGDLTLIST
> or any of the other constants that was formatted wrong?
> In godefs we had little chance of getting this right using
> stabs data, but in cgo with dwarf we have a much better chance.
>

BIOCGDLTLIST is defined as _IOWR('B',123, struct bpf_dltlist) which expands
to:

 $ printf '
#include <sys/ioccom.h>
#include <net/bpf.h>
$BIOCGDLTLIST = BIOCGDLTLIST
' | gcc -E - | grep BIOCGDLTLIST
$BIOCGDLTLIST = (((unsigned long)0x80000000|(unsigned long)0x40000000) |
((sizeof(struct bpf_dltlist) & 0x1fff) << 16) | ((('B')) << 8) | ((123)))

I can provide details for _IOWR and the associated macros, however my guess
is that gcc is converting and storing the unsigned long as a signed long,
which godefs/cgo is then printing as a signed value. Please let me know if
you need further information.

[mikio, 2011-11-17 13:06:12]

Thank you.
I filed the issue 2470.

On Thu, Nov 17, 2011 at 9:20 PM, Joel Sing <jsing@google.com> wrote:

> BIOCGDLTLIST is defined as _IOWR('B',123, struct bpf_dltlist) which expands
> to:
>  $ printf '
> #include <sys/ioccom.h>
> #include <net/bpf.h>
> $BIOCGDLTLIST = BIOCGDLTLIST
> ' | gcc -E - | grep BIOCGDLTLIST
> $BIOCGDLTLIST = (((unsigned long)0x80000000|(unsigned long)0x40000000) |
> ((sizeof(struct bpf_dltlist) & 0x1fff) << 16) | ((('B')) << 8) | ((123)))
> I can provide details for _IOWR and the associated macros, however my guess
> is that gcc is converting and storing the unsigned long as a signed long,
> which godefs/cgo is then printing as a signed value. Please let me know if
> you need further information.