[PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Joel Sherrill]

This is not provided by the newlib malloc implementation but may
be available in external implementations.
---
 newlib/libc/include/malloc.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
index a9dc5bca6..e73095e1e 100644
--- a/newlib/libc/include/malloc.h
+++ b/newlib/libc/include/malloc.h
@@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
 
 extern void __malloc_unlock(struct _reent *);
 
+#if __GNU_VISIBLE
+extern size_t malloc_usable_size(void *);
+#endif
+
 /* A compatibility routine for an earlier version of the allocator.  */
 
 extern void mstats (char *);
-- 
2.24.4

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[C Howland]

>
> ------------------------------
> *From:* Newlib <newlib-bounces+craig.howland=caci.com@sourceware.org> on
> behalf of Joel Sherrill <joel@rtems.org>
> *Sent:* Tuesday, March 15, 2022 11:16 AM
> *To:* newlib@sourceware.org <newlib@sourceware.org>
> *Subject:* [PATCH newlib] libc/include/malloc.h: Add prototype for GNU
> extension malloc_usable_size()
>
>
> This is not provided by the newlib malloc implementation but may
> be available in external implementations.
> ---
>  newlib/libc/include/malloc.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
> index a9dc5bca6..e73095e1e 100644
> --- a/newlib/libc/include/malloc.h
> +++ b/newlib/libc/include/malloc.h
> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
>
>  extern void __malloc_unlock(struct _reent *);
>
> +#if __GNU_VISIBLE
> +extern size_t malloc_usable_size(void *);
> +#endif
> +
>  /* A compatibility routine for an earlier version of the allocator.  */
>
>  extern void mstats (char *);
> --
> 2.24.4
>
>
     Sorry, but I fail to see why adding this makes sense.  If there's an
application which adds a function they should be editing the header file
when they add it.  (There's not even a stub being supplied here.)
Additionally, the Linux man page for the function says "The main use of
this function is for debugging and introspection."  That is, it is not even
a general application utility, but of very limited use.  Either provide the
function with the prototype or no prototype.
                                    Craig

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Joel Sherrill]

On Tue, Mar 15, 2022, 10:38 AM C Howland <cc1964t@gmail.com> wrote:

> >
> > ------------------------------
> > *From:* Newlib <newlib-bounces+craig.howland=caci.com@sourceware.org> on
> > behalf of Joel Sherrill <joel@rtems.org>
> > *Sent:* Tuesday, March 15, 2022 11:16 AM
> > *To:* newlib@sourceware.org <newlib@sourceware.org>
> > *Subject:* [PATCH newlib] libc/include/malloc.h: Add prototype for GNU
> > extension malloc_usable_size()
> >
> >
> > This is not provided by the newlib malloc implementation but may
> > be available in external implementations.
> > ---
> >  newlib/libc/include/malloc.h | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
> > index a9dc5bca6..e73095e1e 100644
> > --- a/newlib/libc/include/malloc.h
> > +++ b/newlib/libc/include/malloc.h
> > @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
> >
> >  extern void __malloc_unlock(struct _reent *);
> >
> > +#if __GNU_VISIBLE
> > +extern size_t malloc_usable_size(void *);
> > +#endif
> > +
> >  /* A compatibility routine for an earlier version of the allocator.  */
> >
> >  extern void mstats (char *);
> > --
> > 2.24.4
> >
> >
>      Sorry, but I fail to see why adding this makes sense.  If there's an
> application which adds a function they should be editing the header file
> when they add it.  (There's not even a stub being supplied here.)
> Additionally, the Linux man page for the function says "The main use of
> this function is for debugging and introspection."  That is, it is not even
> a general application utility, but of very limited use.  Either provide the
> function with the prototype or no prototype.
>

RTEMS provides its own malloc family implementation and we are providing
it. I can wrap all that in an RTEMS conditional if you like.

I have no experience with the malloc implementation in Newlib or any idea
how to implement it.

--joel

>                                     Craig
>

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Mike Frysinger]

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On 15 Mar 2022 10:16, Joel Sherrill wrote:
> This is not provided by the newlib malloc implementation but may
> be available in external implementations.
> ---
>  newlib/libc/include/malloc.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
> index a9dc5bca6..e73095e1e 100644
> --- a/newlib/libc/include/malloc.h
> +++ b/newlib/libc/include/malloc.h
> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
>  
>  extern void __malloc_unlock(struct _reent *);
>  
> +#if __GNU_VISIBLE
> +extern size_t malloc_usable_size(void *);
> +#endif
> +

i'm confused.  isn't this prototype already defined in this header file
on line 101 above where you added this ?
-mike

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Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[C Howland]

On Tue, 15 Mar 2022 at 11:44, Joel Sherrill <joel@rtems.org> wrote:

>
>
> On Tue, Mar 15, 2022, 10:38 AM C Howland <cc1964t@gmail.com> wrote:
>
>> >
>> > ------------------------------
>> > *From:* Newlib <newlib-bounces+craig.howland=caci.com@sourceware.org>
>> on
>> > behalf of Joel Sherrill <joel@rtems.org>
>> > *Sent:* Tuesday, March 15, 2022 11:16 AM
>> > *To:* newlib@sourceware.org <newlib@sourceware.org>
>> > *Subject:* [PATCH newlib] libc/include/malloc.h: Add prototype for GNU
>> > extension malloc_usable_size()
>> >
>> >
>> > This is not provided by the newlib malloc implementation but may
>> > be available in external implementations.
>> > ---
>> >  newlib/libc/include/malloc.h | 4 ++++
>> >  1 file changed, 4 insertions(+)
>> >
>> > diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
>> > index a9dc5bca6..e73095e1e 100644
>> > --- a/newlib/libc/include/malloc.h
>> > +++ b/newlib/libc/include/malloc.h
>> > @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
>> >
>> >  extern void __malloc_unlock(struct _reent *);
>> >
>> > +#if __GNU_VISIBLE
>> > +extern size_t malloc_usable_size(void *);
>> > +#endif
>> > +
>> >  /* A compatibility routine for an earlier version of the allocator.  */
>> >
>> >  extern void mstats (char *);
>> > --
>> > 2.24.4
>> >
>> >
>>      Sorry, but I fail to see why adding this makes sense.  If there's an
>> application which adds a function they should be editing the header file
>> when they add it.  (There's not even a stub being supplied here.)
>> Additionally, the Linux man page for the function says "The main use of
>> this function is for debugging and introspection."  That is, it is not
>> even
>> a general application utility, but of very limited use.  Either provide
>> the
>> function with the prototype or no prototype.
>>
>
> RTEMS provides its own malloc family implementation and we are providing
> it. I can wrap all that in an RTEMS conditional if you like.
>
> I have no experience with the malloc implementation in Newlib or any idea
> how to implement it.
>
> --joel
>

RTEMS wrapper is good.  (Sorry, but you didn't mention you were providing
it in RTEMS, although in hindsight I should have assumed so when wording my
response.)  No reason to try to retrofit it to the Newlib implementation.
Craig

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Sebastian Huber]

On 15/03/2022 16:47, Mike Frysinger wrote:
> On 15 Mar 2022 10:16, Joel Sherrill wrote:
>> This is not provided by the newlib malloc implementation but may
>> be available in external implementations.
>> ---
>>   newlib/libc/include/malloc.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
>> index a9dc5bca6..e73095e1e 100644
>> --- a/newlib/libc/include/malloc.h
>> +++ b/newlib/libc/include/malloc.h
>> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
>>   
>>   extern void __malloc_unlock(struct _reent *);
>>   
>> +#if __GNU_VISIBLE
>> +extern size_t malloc_usable_size(void *);
>> +#endif
>> +
> i'm confused.  isn't this prototype already defined in this header file
> on line 101 above where you added this ?

Yes, and it is implemented by the Newlib malloc.

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Dornierstr. 4
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Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Mike Frysinger]

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On 15 Mar 2022 19:42, Sebastian Huber wrote:
> On 15/03/2022 16:47, Mike Frysinger wrote:
> > On 15 Mar 2022 10:16, Joel Sherrill wrote:
> >> This is not provided by the newlib malloc implementation but may
> >> be available in external implementations.
> >> ---
> >>   newlib/libc/include/malloc.h | 4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
> >> index a9dc5bca6..e73095e1e 100644
> >> --- a/newlib/libc/include/malloc.h
> >> +++ b/newlib/libc/include/malloc.h
> >> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
> >>   
> >>   extern void __malloc_unlock(struct _reent *);
> >>   
> >> +#if __GNU_VISIBLE
> >> +extern size_t malloc_usable_size(void *);
> >> +#endif
> >> +
> > i'm confused.  isn't this prototype already defined in this header file
> > on line 101 above where you added this ?
> 
> Yes, and it is implemented by the Newlib malloc.

while true, we disable malloc in newlib for rtems:

newlib/configure.host:
# RTEMS supplies its own versions of some routines:
#       malloc()            (reentrant version)
#...
  *-*-rtems*)
    ...
    newlib_cflags="${newlib_cflags} ... -DMALLOC_PROVIDED ...

so i'm not sure what trouble Joel is running into.  maybe rtems also provides
its own malloc.h and that's what is missing this prototype.
-mike

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Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Joel Sherrill]

On Tue, Mar 15, 2022, 1:43 PM Sebastian Huber <
sebastian.huber@embedded-brains.de> wrote:

> On 15/03/2022 16:47, Mike Frysinger wrote:
> > On 15 Mar 2022 10:16, Joel Sherrill wrote:
> >> This is not provided by the newlib malloc implementation but may
> >> be available in external implementations.
> >> ---
> >>   newlib/libc/include/malloc.h | 4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/newlib/libc/include/malloc.h b/newlib/libc/include/malloc.h
> >> index a9dc5bca6..e73095e1e 100644
> >> --- a/newlib/libc/include/malloc.h
> >> +++ b/newlib/libc/include/malloc.h
> >> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
> >>
> >>   extern void __malloc_unlock(struct _reent *);
> >>
> >> +#if __GNU_VISIBLE
> >> +extern size_t malloc_usable_size(void *);
> >> +#endif
> >> +
> > i'm confused.  isn't this prototype already defined in this header file
> > on line 101 above where you added this ?
>
> Yes, and it is implemented by the Newlib malloc.
>

Thanks Sebastian. Good catch.

The prototype isn't wrapped by __GNU_VISIBLE. Should it be?

--joel

>
> --
> embedded brains GmbH
> Herr Sebastian HUBER
> Dornierstr. 4
> 82178 Puchheim
> Germany
> email: sebastian.huber@embedded-brains.de
> phone: +49-89-18 94 741 - 16
> fax:   +49-89-18 94 741 - 08
>
> Registergericht: Amtsgericht München
> Registernummer: HRB 157899
> Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
> Unsere Datenschutzerklärung finden Sie hier:
> https://embedded-brains.de/datenschutzerklaerung/
>

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Joel Sherrill]

On Tue, Mar 15, 2022 at 4:04 PM Mike Frysinger <vapier@gentoo.org> wrote:

> On 15 Mar 2022 19:42, Sebastian Huber wrote:
> > On 15/03/2022 16:47, Mike Frysinger wrote:
> > > On 15 Mar 2022 10:16, Joel Sherrill wrote:
> > >> This is not provided by the newlib malloc implementation but may
> > >> be available in external implementations.
> > >> ---
> > >>   newlib/libc/include/malloc.h | 4 ++++
> > >>   1 file changed, 4 insertions(+)
> > >>
> > >> diff --git a/newlib/libc/include/malloc.h
> b/newlib/libc/include/malloc.h
> > >> index a9dc5bca6..e73095e1e 100644
> > >> --- a/newlib/libc/include/malloc.h
> > >> +++ b/newlib/libc/include/malloc.h
> > >> @@ -137,6 +137,10 @@ extern void __malloc_lock(struct _reent *);
> > >>
> > >>   extern void __malloc_unlock(struct _reent *);
> > >>
> > >> +#if __GNU_VISIBLE
> > >> +extern size_t malloc_usable_size(void *);
> > >> +#endif
> > >> +
> > > i'm confused.  isn't this prototype already defined in this header file
> > > on line 101 above where you added this ?
> >
> > Yes, and it is implemented by the Newlib malloc.
>
> while true, we disable malloc in newlib for rtems:
>
> newlib/configure.host:
> # RTEMS supplies its own versions of some routines:
> #       malloc()            (reentrant version)
> #...
>   *-*-rtems*)
>     ...
>     newlib_cflags="${newlib_cflags} ... -DMALLOC_PROVIDED ...
>

We disable their implementation -- not the malloc.h header.

>
> so i'm not sure what trouble Joel is running into.  maybe rtems also
> provides
> its own malloc.h and that's what is missing this prototype.
>

I was reviewing the submitted code which added malloc_usable_size
to RTEMS. It also added the prototype to an RTEMS internal file. I took
it on faith that the prototype was missing and looked at the Linux man
page for where the prototype should be. Then I just stupidly missed it.

Their code should have include malloc.h and not an internal RTEMS file.

Sorry and thanks.

--joel

-mike
>

Re: [PATCH newlib] libc/include/malloc.h: Add prototype for GNU extension malloc_usable_size()

[Mike Frysinger]

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On 15 Mar 2022 15:54, Joel Sherrill wrote:
> The prototype isn't wrapped by __GNU_VISIBLE. Should it be?

we're talking about malloc.h here.  this is already a non-standard header.
the standard malloc APIs are defined in stdlib.h:
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stdlib.h.html

so i'm not sure how much value there is annotating standards in a header
that is not in any standard, and whose inclusion clearly declares "i am
not conforming to any standards".

we could put a disclaimer/explanation at the top of the header file to
make this a bit more clear.
-mike

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