How to browse the code

How to browse the code

[Code Soldier1]

Folks,

Can you tell me how to effectively browse linux kernel code. I am
familiar with lxr etc but they do not do what I want or atleast I do
not know how to.

I am looking for something that can list all the places that a certain
field of a certain structure is used. For example, sk_buff has a field
called destructor, but so do many other data structures. How do I
search for places where just the destructor field of sk_buff.

Thanks a lot.

-- 
CS1

How to browse the code

[Mandeep Sandhu]

>
>
> I am looking for something that can list all the places that a certain
> field of a certain structure is used. For example, sk_buff has a field
> called destructor, but so do many other data structures. How do I
> search for places where just the destructor field of sk_buff.
>

I think lxr has an identifier & free-text search (powered by google). If
that doesn't do it for you, you can go "old school" and try cscope maybe?

HTH,
-mandeep



>
> Thanks a lot.
>
> --
> CS1
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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How to browse the code

[manty kuma]

I like Opengrok. It is insanely fast in giving search results. However it
takes sometime to setup and you need to index it before the first use.

If you are ok with browsing someold kernels, then you can use this link
http://androidxref.com/kernel_3.18/ which is maintained privately.

If you want to use opengrok on more recent linux releases, you may have to
set it up yourself.

On Wed, Apr 12, 2017 at 5:13 AM, Mandeep Sandhu <mandeepsandhu.chd@gmail.com
> wrote:

>
>> I am looking for something that can list all the places that a certain
>> field of a certain structure is used. For example, sk_buff has a field
>> called destructor, but so do many other data structures. How do I
>> search for places where just the destructor field of sk_buff.
>>
>
> I think lxr has an identifier & free-text search (powered by google). If
> that doesn't do it for you, you can go "old school" and try cscope maybe?
>
> HTH,
> -mandeep
>
>
>
>>
>> Thanks a lot.
>>
>> --
>> CS1
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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How to browse the code

[Mandeep Sandhu]

On Wed, Apr 12, 2017 at 2:25 PM, Code Soldier1 <codesoldier1@gmail.com>
wrote:

> Thanks. This does not completely solve my issue. I am looking for
> something that can associate a field name with the structure.
>

Well, you can search for a field's use using free-text search, then looks
at the line of code to figure out what struct it's part of, no? :)

-mandeep



>
> On Tue, Apr 11, 2017 at 1:13 PM, Mandeep Sandhu
> <mandeepsandhu.chd@gmail.com> wrote:
> >>
> >> I am looking for something that can list all the places that a certain
> >> field of a certain structure is used. For example, sk_buff has a field
> >> called destructor, but so do many other data structures. How do I
> >> search for places where just the destructor field of sk_buff.
> >
> >
> > I think lxr has an identifier & free-text search (powered by google). If
> > that doesn't do it for you, you can go "old school" and try cscope maybe?
> >
> > HTH,
> > -mandeep
> >
> >
> >>
> >>
> >> Thanks a lot.
> >>
> >> --
> >> CS1
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> >
>
>
>
> --
> CS1
>
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How to browse the code

[Mandeep Sandhu]

On Wed, Apr 12, 2017 at 2:46 PM, Mandeep Sandhu <mandeepsandhu.chd@gmail.com
> wrote:

> On Wed, Apr 12, 2017 at 2:41 PM, Code Soldier1 <codesoldier1@gmail.com>
> wrote:
>
>> Yes that is possible but it is very time consuming. Let's say I get
>> 500 hits ? Try searching for destructor in linux kernel code. I am
>> only interested in the one that is defined in sk_buff.
>>
>
> Look at cscope & ctags for such queries. Both tools will list all
> instances where the said identifier is declared. If a field is defined in
> multiple structs, you will get multiple results from which you have to sift
> through (it will still be less than free-text search that you'd do on lxr
> though).
>
> Also, please reply to the list (and not to me directly). Others on this
> list might have better suggestions.
>

(and I myself forgot to CC the list! :P)

-mandeep


> HTH,
> -mandeep
>
>
>
>>
>> On Wed, Apr 12, 2017 at 2:28 PM, Mandeep Sandhu
>> <mandeepsandhu.chd@gmail.com> wrote:
>> > On Wed, Apr 12, 2017 at 2:25 PM, Code Soldier1 <codesoldier1@gmail.com>
>> > wrote:
>> >>
>> >> Thanks. This does not completely solve my issue. I am looking for
>> >> something that can associate a field name with the structure.
>> >
>> >
>> > Well, you can search for a field's use using free-text search, then
>> looks at
>> > the line of code to figure out what struct it's part of, no? :)
>> >
>> > -mandeep
>> >
>> >
>> >>
>> >>
>> >> On Tue, Apr 11, 2017 at 1:13 PM, Mandeep Sandhu
>> >> <mandeepsandhu.chd@gmail.com> wrote:
>> >> >>
>> >> >> I am looking for something that can list all the places that a
>> certain
>> >> >> field of a certain structure is used. For example, sk_buff has a
>> field
>> >> >> called destructor, but so do many other data structures. How do I
>> >> >> search for places where just the destructor field of sk_buff.
>> >> >
>> >> >
>> >> > I think lxr has an identifier & free-text search (powered by
>> google). If
>> >> > that doesn't do it for you, you can go "old school" and try cscope
>> >> > maybe?
>> >> >
>> >> > HTH,
>> >> > -mandeep
>> >> >
>> >> >
>> >> >>
>> >> >>
>> >> >> Thanks a lot.
>> >> >>
>> >> >> --
>> >> >> CS1
>> >> >>
>> >> >> _______________________________________________
>> >> >> Kernelnewbies mailing list
>> >> >> Kernelnewbies at kernelnewbies.org
>> >> >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >> >
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> CS1
>> >
>> >
>>
>>
>>
>> --
>> CS1
>>
>
>
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How to browse the code

[Aruna Hewapathirane]

> On Tue, Apr 11, 2017 at 3:17 PM, Code Soldier1 <codesoldier1@gmail.com>
wrote:
> Folks,

> Can you tell me how to effectively browse linux kernel code. I am
> familiar with lxr etc but they do not do what I want or atleast I do
> not know how to.

> I am looking for something that can list all the places that a certain
> field of a certain structure is used. For example, sk_buff has a field
> called destructor, but so do many other data structures. How do I
> search for places where just the destructor field of sk_buff.

> Thanks a lot.

Ask yourself *how* is the destructor invoked ? You can find *how* here: SKB
socket accounting <http://vger.kernel.org/%7Edavem/skb_sk.html>

So now if you run:
find . -name '*.c' | xargs grep -r -F "skb->destructor"

you will have what you are looking for :)

Hope this helps and this will help: http://vger.kernel.org/~davem/skb.html

<http://vger.kernel.org/%7Edavem/skb_sk.html>
Aruna
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How to browse the code

[manty kuma]

Here you can see where sk_buff structure is delared.
http://androidxref.com/kernel_3.18/xref/include/linux/skbuff.h#506

May be you want to get familiar on how to use opengroks interface by seeing
some youtube video or some online documents...

Whatever you want to do wrt to source code browsing, this can do it for you
very quickly.

On Thu, Apr 13, 2017 at 6:24 AM, Code Soldier1 <codesoldier1@gmail.com>
wrote:

> Thanks a lot. I am still not able to lookup structures, such as
> sk_buff and where does it's fields get set/used.
>
> On Tue, Apr 11, 2017 at 4:56 PM, manty kuma <mantykuma@gmail.com> wrote:
> > I like Opengrok. It is insanely fast in giving search results. However it
> > takes sometime to setup and you need to index it before the first use.
> >
> > If you are ok with browsing someold kernels, then you can use this link
> > http://androidxref.com/kernel_3.18/ which is maintained privately.
> >
> > If you want to use opengrok on more recent linux releases, you may have
> to
> > set it up yourself.
> >
> > On Wed, Apr 12, 2017 at 5:13 AM, Mandeep Sandhu
> > <mandeepsandhu.chd@gmail.com> wrote:
> >>>
> >>>
> >>> I am looking for something that can list all the places that a certain
> >>> field of a certain structure is used. For example, sk_buff has a field
> >>> called destructor, but so do many other data structures. How do I
> >>> search for places where just the destructor field of sk_buff.
> >>
> >>
> >> I think lxr has an identifier & free-text search (powered by google). If
> >> that doesn't do it for you, you can go "old school" and try cscope
> maybe?
> >>
> >> HTH,
> >> -mandeep
> >>
> >>
> >>>
> >>>
> >>> Thanks a lot.
> >>>
> >>> --
> >>> CS1
> >>>
> >>> _______________________________________________
> >>> Kernelnewbies mailing list
> >>> Kernelnewbies at kernelnewbies.org
> >>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>
> >>
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>
> >
>
>
>
> --
> CS1
>
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How to browse the code

[Daniel.]

ctags + cscope + vim

The Makefile has targets for indexing the kernel.. Sometimes "find -exec
grep" helps... I will take a look in opengrok

Em 13/04/2017 7:40 AM, "manty kuma" <mantykuma@gmail.com> escreveu:

> Here you can see where sk_buff structure is delared.
> http://androidxref.com/kernel_3.18/xref/include/linux/skbuff.h#506
>
> May be you want to get familiar on how to use opengroks interface by
> seeing some youtube video or some online documents...
>
> Whatever you want to do wrt to source code browsing, this can do it for
> you very quickly.
>
> On Thu, Apr 13, 2017 at 6:24 AM, Code Soldier1 <codesoldier1@gmail.com>
> wrote:
>
>> Thanks a lot. I am still not able to lookup structures, such as
>> sk_buff and where does it's fields get set/used.
>>
>> On Tue, Apr 11, 2017 at 4:56 PM, manty kuma <mantykuma@gmail.com> wrote:
>> > I like Opengrok. It is insanely fast in giving search results. However
>> it
>> > takes sometime to setup and you need to index it before the first use.
>> >
>> > If you are ok with browsing someold kernels, then you can use this link
>> > http://androidxref.com/kernel_3.18/ which is maintained privately.
>> >
>> > If you want to use opengrok on more recent linux releases, you may have
>> to
>> > set it up yourself.
>> >
>> > On Wed, Apr 12, 2017 at 5:13 AM, Mandeep Sandhu
>> > <mandeepsandhu.chd@gmail.com> wrote:
>> >>>
>> >>>
>> >>> I am looking for something that can list all the places that a certain
>> >>> field of a certain structure is used. For example, sk_buff has a field
>> >>> called destructor, but so do many other data structures. How do I
>> >>> search for places where just the destructor field of sk_buff.
>> >>
>> >>
>> >> I think lxr has an identifier & free-text search (powered by google).
>> If
>> >> that doesn't do it for you, you can go "old school" and try cscope
>> maybe?
>> >>
>> >> HTH,
>> >> -mandeep
>> >>
>> >>
>> >>>
>> >>>
>> >>> Thanks a lot.
>> >>>
>> >>> --
>> >>> CS1
>> >>>
>> >>> _______________________________________________
>> >>> Kernelnewbies mailing list
>> >>> Kernelnewbies at kernelnewbies.org
>> >>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >>
>> >>
>> >>
>> >> _______________________________________________
>> >> Kernelnewbies mailing list
>> >> Kernelnewbies at kernelnewbies.org
>> >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >>
>> >
>>
>>
>>
>> --
>> CS1
>>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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How to browse the code

[Quentin Lambert]

Something else you could look at is Coccinelle.
http://coccinelle.lip6.fr/

The tool can be used to find very specific pattern in
the code. For instance specific structure field that are
used without initialization.

It takes some learning but the tool is very powerful.
You can also check here for the basics:
https://kernelnewbies.org/JuliaLawall
http://btrlinux.inria.fr/coccinelle/

If you have any questions Julia(the main developer) is
very active on the mailling list:

cocci at systeme.lip6.fr

Quentin

How to browse the code

[valdis.kletnieks at vt.edu]

On Thu, 13 Apr 2017 08:41:18 -0300, "Daniel." said:

> The Makefile has targets for indexing the kernel.. Sometimes "find -exec
> grep" helps... I will take a look in opengrok

find |xargs grep.   Will run a lot faster because it runs one grep for several
hundred files, rather than one per file.  For bonus points, if you have
a git tree, 'find *' at the top level will run faster than 'find .', because
* will glob into something that doesn't incude .git so no traversal into
that section of the source tree.

git grep   works too, if you have a git tree like any serious kernel hacker.
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