[Buildroot] RTLD_DEEPBIND and uClibc

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

Hello everyone

Yesterday evening I managed to compile cairo-dock-core and
cairo-dock-plugins
version 3.1.2 for buildroot 2012.08.

It's a nice, lightweight (made with C), Mac OSX feeling application dock.

The problem is that cairo-dock-core has the following line in it's code:

pCairoDockModule->handle = dlopen (pCairoDockModule->cSoFilePath,
RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);

And uClibc does not have RTLD_DEEPBIND. Removing it will allow
cairo-dock to compile but the result is
that cairo-dock plugins won't work.

Is there any workaround to this RTLD_DEEPBIND stuff ?

Regards
Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Thomas Petazzoni]

Dear Stefan Fr?berg,

On Wed, 16 Jan 2013 14:51:57 +0200, Stefan Fr?berg wrote:

> Yesterday evening I managed to compile cairo-dock-core and
> cairo-dock-plugins
> version 3.1.2 for buildroot 2012.08.
> 
> It's a nice, lightweight (made with C), Mac OSX feeling application
> dock.
> 
> The problem is that cairo-dock-core has the following line in it's
> code:
> 
> pCairoDockModule->handle = dlopen (pCairoDockModule->cSoFilePath,
> RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
> 
> And uClibc does not have RTLD_DEEPBIND. Removing it will allow
> cairo-dock to compile but the result is
> that cairo-dock plugins won't work.

Strange, from a quick look, it seems that it is used to get a single
symbol, called "pre_init" from each plugin. I don't see how pre_init
may conflict with some other global symbol, which is what RTLD_DEEPBIND
is all about. But I've only done a 5 minutes look at cairo-dock code,
so I might have missed the point.

> Is there any workaround to this RTLD_DEEPBIND stuff ?

Since you're using a big stuff like X.org, why do you persist in using
uClibc? Using glibc or eglibc would make a very small size difference,
and would avoid the hassle of all those small, but annoying, uClibc
limitations.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

Hi Thomas

17.1.2013 1:00, Thomas Petazzoni kirjoitti:
> Dear Stefan Fr?berg,
>
> On Wed, 16 Jan 2013 14:51:57 +0200, Stefan Fr?berg wrote:
>
>> Yesterday evening I managed to compile cairo-dock-core and
>> cairo-dock-plugins
>> version 3.1.2 for buildroot 2012.08.
>>
>> It's a nice, lightweight (made with C), Mac OSX feeling application
>> dock.
>>
>> The problem is that cairo-dock-core has the following line in it's
>> code:
>>
>> pCairoDockModule->handle = dlopen (pCairoDockModule->cSoFilePath,
>> RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
>>
>> And uClibc does not have RTLD_DEEPBIND. Removing it will allow
>> cairo-dock to compile but the result is
>> that cairo-dock plugins won't work.
> Strange, from a quick look, it seems that it is used to get a single
> symbol, called "pre_init" from each plugin. I don't see how pre_init
> may conflict with some other global symbol, which is what RTLD_DEEPBIND
> is all about. But I've only done a 5 minutes look at cairo-dock code,
> so I might have missed the point.
>
>> Is there any workaround to this RTLD_DEEPBIND stuff ?
> Since you're using a big stuff like X.org, why do you persist in using
> uClibc? Using glibc or eglibc would make a very small size difference,
> and would avoid the hassle of all those small, but annoying, uClibc
> limitations.
>
> Best regards,
>
> Thomas

Well, it's not *that* big.

I mean, yeah, I have Xorg but besides that I only have Fluxbox as my
environment
and I just wanted to have much more feature richer & "cooler"
application launcher than what
Fluxbox offers (that is, none).

As a matter of fact, my biggest uClibc-compiled application is not Xorg
but firefox 18.0 (patch coming soon)

And IMHO those limitations are not really uClibc's fault at all.

It's because glibc offers stuff like (execinfo.h, mcheck.h,
RTLD_DEEPBIND etc...) which are not listed in any standard (POSIX or
otherwise)
and which people happily use in their own coding projects while being
unaware that they are not standard comforming
and hence not easily portable.
Im sure you noticed this when making that elfutils package Thomas. I had
as hellish experience as you did when doing
the initial build of that thing. All because the author of that software
happened to be Ulrich Drepped, the father of glibc,
so no wonder that it's code was littered with (non-standard) glibc-stuff.

Also, it's a good learning experience for me while porting stuff to uClibc

Regards
Stefan

P.S:

I found out that they started using RTLD_DEEPBIND in cairo-dock-core
2.4.0 version.
So I will try 2.3.0 and report my findings.

[Buildroot] RTLD_DEEPBIND and uClibc

[Thomas Petazzoni]

Dear Stefan Fr?berg,

On Thu, 17 Jan 2013 02:36:06 +0200, Stefan Fr?berg wrote:

> Well, it's not *that* big.

It's not that big, but compared it to the size difference between
uClibc and glibc, and you'll see that switching to glibc is reasonable.

My perception is that uClibc is very relevant for non-MMU systems or
small systems (having limited quantity of flash/RAM), and on those
systems, we are not going to run a full-blown X.org stack with a window
manager and so on.

Whenever you start having X.org on a system and a window manager, most
likely you have hundreds of megabytes of flash, and therefore, the size
difference between uClibc and glibc (probably somewhere between 1 and
1.5 MB) isn't that much of a problem anymore.

> And IMHO those limitations are not really uClibc's fault at all.
> 
> It's because glibc offers stuff like (execinfo.h, mcheck.h,
> RTLD_DEEPBIND etc...) which are not listed in any standard (POSIX or
> otherwise)
> and which people happily use in their own coding projects while being
> unaware that they are not standard comforming
> and hence not easily portable.
> Im sure you noticed this when making that elfutils package Thomas. I
> had as hellish experience as you did when doing
> the initial build of that thing. All because the author of that
> software happened to be Ulrich Drepped, the father of glibc,
> so no wonder that it's code was littered with (non-standard)
> glibc-stuff.

Indeed. And I agree that fixing those compatibility problems in
elfutils is important, because using perf on low-end systems is useful.
However, getting cairo-dock to work with uClibc seems less important to
me, but...

> Also, it's a good learning experience for me while porting stuff to
> uClibc

... of course, for learning purposes, it's always useful!

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

Hi Thomas

17.1.2013 10:31, Thomas Petazzoni kirjoitti:
> Dear Stefan Fr?berg,
>
> On Thu, 17 Jan 2013 02:36:06 +0200, Stefan Fr?berg wrote:
>
>> Well, it's not *that* big.
> It's not that big, but compared it to the size difference between
> uClibc and glibc, and you'll see that switching to glibc is reasonable.
>
> My perception is that uClibc is very relevant for non-MMU systems or
> small systems (having limited quantity of flash/RAM), and on those
> systems, we are not going to run a full-blown X.org stack with a window
> manager and so on.
>
> Whenever you start having X.org on a system and a window manager, most
> likely you have hundreds of megabytes of flash, and therefore, the size
> difference between uClibc and glibc (probably somewhere between 1 and
> 1.5 MB) isn't that much of a problem anymore.

Eh... I think it's more than 1 - 1.5 MB :-)


http://www.etalabs.net/compare_libcs.html

In that comparison it's eglibc (the smaller brother of glibc) vs. other,
more lighter c-libraries.
And even then it's 1.5 MB or more vs uClibc's 336 KB with .a files and 2
MB or more vs. 520 KB.

Even tought in my case, Im targeting to running my system with low-end,
ancient PC desktop's (2000 or earlier),
so it's not really exactly comparable with todays embedded systems, it's
still a huge saving of space when
you start thinking about all the lib's and binaries that go to normal
desktop system.

In a related note, my *full* Live-CD system is now uncompressed to 520
MB (194 MB, if using squashfs xz-compressed image with loopdevice),
and the absolute minimum runtime RAM requirement for starting it
(Xorg,fluxbox, firefox,  etc...) is
now about 120 MB (bigger part of that goes to tmp files and other stuff
that are automatically created in initramfs from which it runs directly).

I don't think I could have done that with glibc or eglibc ...

And I haven't even started using GCC 4.7.2 Linktime optimizations yet.
which I expect to cut about 10 - 20 KB per binary away
and finally UPX compression of selected few binaries and libs.

And if even *that* is not enought then I could consider maybe switching
to musl ... maybe ...

So all in all, Im very happy with buildroot and uClibc and not going to
turn back to glibc and bloat

Regards
Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Alex Bradbury]

On 17 January 2013 13:50, Stefan Fr?berg
<stefan.froberg@petroprogram.com> wrote:
> And if even *that* is not enought then I could consider maybe switching
> to musl ... maybe ...

I've been following musl for a while - it really might be worth giving
a go. They're aiming to be more lightweight than Glibc, while more
functional than uclibc. Plus some musl patches for buildroot and
crosstool-ng would be kind of awesome ;)

Alex

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

Hello Alex!

17.1.2013 18:18, Alex Bradbury kirjoitti:
> On 17 January 2013 13:50, Stefan Fr?berg
> <stefan.froberg@petroprogram.com> wrote:
>> And if even *that* is not enought then I could consider maybe switching
>> to musl ... maybe ...
> I've been following musl for a while - it really might be worth giving
> a go. They're aiming to be more lightweight than Glibc, while more
> functional than uclibc. Plus some musl patches for buildroot and
> crosstool-ng would be kind of awesome ;)
>
> Alex

Is it true that musl supports (at least most) of the glibc ABI ?
(my biggest worry so far when using uClibc is that I encounter an
application that is provided as glibc-only
binary and no source code provided.)

What about it's configuration ? Does it have nice kconf style  "make
menuconfig" like uClibc or what ?

Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Alex Bradbury]

On 17 January 2013 16:51, Stefan Fr?berg
<stefan.froberg@petroprogram.com> wrote:
> Is it true that musl supports (at least most) of the glibc ABI ?
> (my biggest worry so far when using uClibc is that I encounter an
> application that is provided as glibc-only
> binary and no source code provided.)

Yes, this is one of the goals. There was a big discussion on the musl
mailing list <http://dir.gmane.org/gmane.linux.lib.musl.general> in
December. One of the aims is glibc ABI compatibility, with
applications like Opera being discussed on the list. Development is
*very* active and Rich Felker (lead dev) seems to respond very quickly
to issues or bug reports.

In fact, I've fallen behind following the musl mailing list the last
couple of months but see a recent posts that indicate there has been
good glibc ABI progress
<http://article.gmane.org/gmane.linux.lib.musl.general/2549>. Of
course many of the proprietary apps are likely to use C++, and the C++
ABI is...fiddly.

> What about it's configuration ? Does it have nice kconf style  "make
> menuconfig" like uClibc or what ?

I don't *think* so, but could be wrong. Still, it aims to be
substantially lighterweight than glibc, while hopefully providing more
performant implementations of functions than either glibc or uclibc.

Alex

[Buildroot] RTLD_DEEPBIND and uClibc

[Yann E. MORIN]

Stefan, All,

On Thursday 17 January 2013 Stefan Fr?berg wrote:
> 17.1.2013 10:31, Thomas Petazzoni kirjoitti:
> > Whenever you start having X.org on a system and a window manager, most
> > likely you have hundreds of megabytes of flash, and therefore, the size
> > difference between uClibc and glibc (probably somewhere between 1 and
> > 1.5 MB) isn't that much of a problem anymore.
> 
> Eh... I think it's more than 1 - 1.5 MB :-)

The full set of libraries from a full-blown eglibc, for an ARM gnueabihf
target, is:
                      Unstripped    Stripped
Only eglibc libs      3.6MiB         2.3MiB
With gcc's libs       8.8MiB         3.0MiB

And for a relatively complete uClibc for x86_64 target:
                      Unstripped    Stripped
Only eglibc libs      2.0MiB         1.0MiB
With gcc's libs       6.9MiB         1.9MiB

(gcc libs: libstdc++ and libgcc_s)
(These are not the same architecture, but I went for the toolchains I have
locally)

So, typically, speaking only about the C library libs, the gain would be
around ~1.5MiB.

How large is your Xorg stack?
Then, compare that 1.5MiB to the size of your Xorg stack. What's the ratio?

If you're 1.5MiB short of space, then probably Xorg is not the solution for
your platform.

Of course, switching to uClibc as a learning experience is very
intreresting. But no more. ;-)

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

Hi Yann

17.1.2013 19:44, Yann E. MORIN kirjoitti:
> Stefan, All,
>
> On Thursday 17 January 2013 Stefan Fr?berg wrote:
>> 17.1.2013 10:31, Thomas Petazzoni kirjoitti:
>>> Whenever you start having X.org on a system and a window manager, most
>>> likely you have hundreds of megabytes of flash, and therefore, the size
>>> difference between uClibc and glibc (probably somewhere between 1 and
>>> 1.5 MB) isn't that much of a problem anymore.
>> Eh... I think it's more than 1 - 1.5 MB :-)
> The full set of libraries from a full-blown eglibc, for an ARM gnueabihf
> target, is:
>                       Unstripped    Stripped
> Only eglibc libs      3.6MiB         2.3MiB
> With gcc's libs       8.8MiB         3.0MiB
>
> And for a relatively complete uClibc for x86_64 target:
>                       Unstripped    Stripped
> Only eglibc libs      2.0MiB         1.0MiB
> With gcc's libs       6.9MiB         1.9MiB
>
> (gcc libs: libstdc++ and libgcc_s)
> (These are not the same architecture, but I went for the toolchains I have
> locally)
>
> So, typically, speaking only about the C library libs, the gain would be
> around ~1.5MiB.

Here's the contents of my target /lib

*yhteens? 1,4M*
drwxr-xr-x.  6 root root 3,0K 17.1. 15:32 .
drwxr-xr-x. 20 root root 1,0K 13.1. 17:35 ..
drwxr-xr-x. 64 root root  10K 17.1. 15:31 firmware
-rwxr-xr-x.  1 root root  29K 17.1. 15:32 ld-uClibc-0.9.33.2.so
lrwxrwxrwx.  1 root root   21  7.1. 00:27 ld-uClibc.so.0 ->
ld-uClibc-0.9.33.2.so
lrwxrwxrwx.  1 root root   17  8.1. 20:20 libblkid.so.1 -> libblkid.so.1.1.0
-rwxr-xr-x.  1 root root 152K 17.1. 15:31 libblkid.so.1.1.0
-rwxr-xr-x.  1 root root  25K 17.1. 15:32 libcrypt-0.9.33.2.so
lrwxrwxrwx.  1 root root   20  7.1. 00:27 libcrypt.so.0 ->
libcrypt-0.9.33.2.so
lrwxrwxrwx.  1 root root   21  7.1. 00:27 libc.so.0 -> libuClibc-0.9.33.2.so
-rwxr-xr-x.  1 root root  13K 17.1. 15:32 libdl-0.9.33.2.so
lrwxrwxrwx.  1 root root   17  7.1. 00:27 libdl.so.0 -> libdl-0.9.33.2.so
lrwxrwxrwx.  1 root root   13  7.1. 00:44 libgcc_s.so -> libgcc_s.so.1
-rw-r--r--.  1 root root  89K 17.1. 15:32 libgcc_s.so.1
-rwxr-xr-x.  1 root root  49K 17.1. 15:31 libm-0.9.33.2.so
lrwxrwxrwx.  1 root root   17  8.1. 20:20 libmount.so.1 -> libmount.so.1.1.0
-rwxr-xr-x.  1 root root 152K 17.1. 15:31 libmount.so.1.1.0
lrwxrwxrwx.  1 root root   16  7.1. 00:27 libm.so.0 -> libm-0.9.33.2.so
-rwxr-xr-x.  1 root root 4,5K 17.1. 15:32 libnsl-0.9.33.2.so
lrwxrwxrwx.  1 root root   18  7.1. 00:27 libnsl.so.0 -> libnsl-0.9.33.2.so
lrwxrwxrwx.  1 root root   17  7.1. 20:47 libpamc.so -> libpamc.so.0.82.1
lrwxrwxrwx.  1 root root   17  7.1. 20:47 libpamc.so.0 -> libpamc.so.0.82.1
-rwxr-xr-x.  1 root root 9,6K 17.1. 15:32 libpamc.so.0.82.1
lrwxrwxrwx.  1 root root   21  7.1. 20:47 libpam_misc.so ->
libpam_misc.so.0.82.0
lrwxrwxrwx.  1 root root   21  7.1. 20:47 libpam_misc.so.0 ->
libpam_misc.so.0.82.0
-rwxr-xr-x.  1 root root 8,1K 17.1. 15:32 libpam_misc.so.0.82.0
lrwxrwxrwx.  1 root root   16  7.1. 20:47 libpam.so -> libpam.so.0.83.1
lrwxrwxrwx.  1 root root   16  7.1. 20:47 libpam.so.0 -> libpam.so.0.83.1
-rwxr-xr-x.  1 root root  45K 17.1. 15:31 libpam.so.0.83.1
-rwxr-xr-x.  1 root root  74K 17.1. 15:31 libpthread-0.9.33.2.so
lrwxrwxrwx.  1 root root   22  7.1. 00:27 libpthread.so.0 ->
libpthread-0.9.33.2.so
-rwxr-xr-x.  1 root root 4,5K 17.1. 15:32 libresolv-0.9.33.2.so
lrwxrwxrwx.  1 root root   21  7.1. 00:27 libresolv.so.0 ->
libresolv-0.9.33.2.so
-rwxr-xr-x.  1 root root  13K 17.1. 15:31 librt-0.9.33.2.so
lrwxrwxrwx.  1 root root   17  7.1. 00:27 librt.so.0 -> librt-0.9.33.2.so
-rwxr-xr-x.  1 root root 690K 17.1. 15:31 libuClibc-0.9.33.2.so
-rwxr-xr-x.  1 root root 4,7K 17.1. 15:31 libutil-0.9.33.2.so
lrwxrwxrwx.  1 root root   19  7.1. 00:27 libutil.so.0 ->
libutil-0.9.33.2.so
lrwxrwxrwx.  1 root root   16  8.1. 20:20 libuuid.so.1 -> libuuid.so.1.3.0
-rwxr-xr-x.  1 root root  14K 17.1. 15:31 libuuid.so.1.3.0
drwxr-xr-x.  3 root root 1,0K  9.1. 04:01 modules
drwxr-xr-x.  3 root root 5,0K 17.1. 15:31 security
drwxr-xr-x.  3 root root 1,0K  8.1. 22:41 udev

As you can see from the top of the line the total sum of uClibc + *all
the other stuff (pam etc..)* is just
1.4 MB (the size of libuClibc-0.9.33.2.so itself is just 690 KB)

So uClibc wins this round :-)

> How large is your Xorg stack?
> Then, compare that 1.5MiB to the size of your Xorg stack. What's the ratio?
You mean how much Xorg stuff from buildroot I have installed into my
target system???
Short answer: Full
Well, almost, left only xterm (replaced with rxvt-unicode which
lighter), twm (replaced with fluxbox)
and xeyes (totally useless application) out.

> If you're 1.5MiB short of space, then probably Xorg is not the solution for
> your platform.
>
> Of course, switching to uClibc as a learning experience is very
> intreresting. But no more. ;-)
>
> Regards,
> Yann E. MORIN.

BTW, I forgot to mention in my message to Thomas that that 520 MB
uncompressed Live-CD stuff does
also contain the full linux 3.3.1 kernel and *all* the drivers compiled
as modules
(Live-CD without that would be useless when running it in myriad x86
machines with allkinds of hardware)

Regards
Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

17.1.2013 19:09, Alex Bradbury kirjoitti:
> On 17 January 2013 16:51, Stefan Fr?berg
> <stefan.froberg@petroprogram.com> wrote:
>> Is it true that musl supports (at least most) of the glibc ABI ?
>> (my biggest worry so far when using uClibc is that I encounter an
>> application that is provided as glibc-only
>> binary and no source code provided.)
> Yes, this is one of the goals. There was a big discussion on the musl
> mailing list <http://dir.gmane.org/gmane.linux.lib.musl.general> in
> December. One of the aims is glibc ABI compatibility, with
> applications like Opera being discussed on the list. Development is
> *very* active and Rich Felker (lead dev) seems to respond very quickly
> to issues or bug reports.
>
> In fact, I've fallen behind following the musl mailing list the last
> couple of months but see a recent posts that indicate there has been
> good glibc ABI progress
> <http://article.gmane.org/gmane.linux.lib.musl.general/2549>. Of
> course many of the proprietary apps are likely to use C++, and the C++
> ABI is...fiddly.
>
>> What about it's configuration ? Does it have nice kconf style  "make
>> menuconfig" like uClibc or what ?
> I don't *think* so, but could be wrong. Still, it aims to be
> substantially lighterweight than glibc, while hopefully providing more
> performant implementations of functions than either glibc or uclibc.
>
> Alex

Thanks Alex!
I will keep watching that list.

Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Yann E. MORIN]

Stefan, All,

On Thursday 17 January 2013 Stefan Fr?berg wrote:
> 17.1.2013 19:44, Yann E. MORIN kirjoitti:
> > The full set of libraries from a full-blown eglibc, for an ARM gnueabihf
> > target, is:
> >                       Unstripped    Stripped
> > Only eglibc libs      3.6MiB         2.3MiB
> > With gcc's libs       8.8MiB         3.0MiB
> >
> > And for a relatively complete uClibc for x86_64 target:
> >                       Unstripped    Stripped
> > Only eglibc libs      2.0MiB         1.0MiB
> > With gcc's libs       6.9MiB         1.9MiB
> >
> > (gcc libs: libstdc++ and libgcc_s)
> > (These are not the same architecture, but I went for the toolchains I have
> > locally)
> >
> > So, typically, speaking only about the C library libs, the gain would be
> > around ~1.5MiB.
> 
> Here's the contents of my target /lib
[--SNIP--]
> As you can see from the top of the line the total sum of uClibc + *all
> the other stuff (pam etc..)* is just
> 1.4 MB (the size of libuClibc-0.9.33.2.so itself is just 690 KB)

uClibc == libuClibc.so + libutil.so + ld-uClibc.so + librt.so + libnsl.so
          + libm.so + libdl.so + libcrypt.so

Which totals around 905KiB in your case. Just about the number I gave
you in my previous mail (mine was exactly 1004KiB). And the eglibc numbers
are for the same set of libraries (plus all the libnss libs uClibc does
not have).

> So uClibc wins this round :-)

Yes, in absolute numbers, uClibc *is* smaller than (e)glibc.
We *never* said it was bigger.

What Thomas and I are saying, is that you gained about 1.5MiB on your
520MiB filesystem. That's about a 0.29% gain. Was that worth the hassle?
(Beside learning, of course.)

At one point, one must must leave the keyboard alone, cross one's arms,
look deeply at the screen, and just ask oneself: "Well, where am I
heading, now?"

  - if the point is to prove how smaller a complete system can be by
    using uClibc instead of (e)glibc, then the answer is "marginaly
    smaller", and "no, I should not bother suferring like in Hell"

  - if the point is to prove that building a complete system using
    uClibc instead of (e)glibc, then the answer is "doable, with some
    gotchas in the corners", and "no, I should not suffer like in Hell"

  - if the point is to learn, then yes, go on, learn; this is of course a
    very valid and respectful reason. But, still, the answer is "Whoa, I
    learned quite a bit!" and "no, I should not bother suferring like in
    Hell".

Well, 0.29% smaller... Damn! That's some kind of an achievment! ;-)

Regards,
Yann E. MORIN.

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[Buildroot] RTLD_DEEPBIND and uClibc

[Yann E. MORIN]

Stefan, All,

On Thursday 17 January 2013 Yann E. MORIN wrote:
> On Thursday 17 January 2013 Stefan Fr?berg wrote:
> > As you can see from the top of the line the total sum of uClibc + *all
> > the other stuff (pam etc..)* is just
> > 1.4 MB (the size of libuClibc-0.9.33.2.so itself is just 690 KB)
> 
> uClibc == libuClibc.so + libutil.so + ld-uClibc.so + librt.so + libnsl.so
>           + libm.so + libdl.so + libcrypt.so

Forgot: + libresolv.so + libpthread.so  (still 905KiB already accounted
for those libs)

Regards,
Yann E. MORIN.

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[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

17.1.2013 22:38, Yann E. MORIN kirjoitti:
> Stefan, All,
>
> On Thursday 17 January 2013 Stefan Fr?berg wrote:
>> 17.1.2013 19:44, Yann E. MORIN kirjoitti:
>>> The full set of libraries from a full-blown eglibc, for an ARM gnueabihf
>>> target, is:
>>>                       Unstripped    Stripped
>>> Only eglibc libs      3.6MiB         2.3MiB
>>> With gcc's libs       8.8MiB         3.0MiB
>>>
>>> And for a relatively complete uClibc for x86_64 target:
>>>                       Unstripped    Stripped
>>> Only eglibc libs      2.0MiB         1.0MiB
>>> With gcc's libs       6.9MiB         1.9MiB
>>>
>>> (gcc libs: libstdc++ and libgcc_s)
>>> (These are not the same architecture, but I went for the toolchains I have
>>> locally)
>>>
>>> So, typically, speaking only about the C library libs, the gain would be
>>> around ~1.5MiB.
>> Here's the contents of my target /lib
> [--SNIP--]
>> As you can see from the top of the line the total sum of uClibc + *all
>> the other stuff (pam etc..)* is just
>> 1.4 MB (the size of libuClibc-0.9.33.2.so itself is just 690 KB)
> uClibc == libuClibc.so + libutil.so + ld-uClibc.so + librt.so + libnsl.so
>           + libm.so + libdl.so + libcrypt.so
>
> Which totals around 905KiB in your case. Just about the number I gave
> you in my previous mail (mine was exactly 1004KiB). And the eglibc numbers
> are for the same set of libraries (plus all the libnss libs uClibc does
> not have).
>
>> So uClibc wins this round :-)
> Yes, in absolute numbers, uClibc *is* smaller than (e)glibc.
> We *never* said it was bigger.
>
> What Thomas and I are saying, is that you gained about 1.5MiB on your
> 520MiB filesystem. That's about a 0.29% gain. Was that worth the hassle?
> (Beside learning, of course.)

My gentoo box with similar configuration is 1500 MB. So yeah I think it
was worth the hassle :-)

Regards
Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Yann E. MORIN]

Stefan, All,

On Thursday 17 January 2013 Stefan Fr?berg wrote:
> 17.1.2013 22:38, Yann E. MORIN kirjoitti:
> > What Thomas and I are saying, is that you gained about 1.5MiB on your
> > 520MiB filesystem. That's about a 0.29% gain. Was that worth the hassle?
> > (Beside learning, of course.)
> 
> My gentoo box with similar configuration is 1500 MB. So yeah I think it
> was worth the hassle :-)

No, you're not comparing comparable things.

Of course, I can tell you that my Debian Squeeze is much bigger than my
busybox-based router, but that's not the same thing.

Rebuild your LiveCD with (e)glibc, and compare the sizes. Then you will
notice that the size with eglibc is marginaly bigger than with uClibc.
*That* is what we are saying.

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
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'------------------------------^-------^------------------^--------------------'

[Buildroot] RTLD_DEEPBIND and uClibc

[Stefan Fröberg]

17.1.2013 23:17, Yann E. MORIN kirjoitti:
> Stefan, All,
>
> On Thursday 17 January 2013 Stefan Fr?berg wrote:
>> 17.1.2013 22:38, Yann E. MORIN kirjoitti:
>>> What Thomas and I are saying, is that you gained about 1.5MiB on your
>>> 520MiB filesystem. That's about a 0.29% gain. Was that worth the hassle?
>>> (Beside learning, of course.)
>> My gentoo box with similar configuration is 1500 MB. So yeah I think it
>> was worth the hassle :-)
> No, you're not comparing comparable things.
>
> Of course, I can tell you that my Debian Squeeze is much bigger than my
> busybox-based router, but that's not the same thing.
Actually in my case it is. The only difference between my gentoo box and
buildroot version
is that gentoo uses bash and coreutils instead busybox.

> Rebuild your LiveCD with (e)glibc, and compare the sizes. Then you will
> notice that the size with eglibc is marginaly bigger than with uClibc.
> *That* is what we are saying.
>
> Regards,
> Yann E. MORIN.
>

And why I would want to make my system fatter again ? Hmmmh ???
Marginal or not

No, I will take my system as far as I can go with all the optimizations
I still have left and
then maybe start considering musl (Thanks Alex)

Regards
Stefan

[Buildroot] RTLD_DEEPBIND and uClibc

[Peter Korsgaard]

>>>>> "Alex" == Alex Bradbury <asb@asbradbury.org> writes:

 Alex> On 17 January 2013 13:50, Stefan Fr?berg
 Alex> <stefan.froberg@petroprogram.com> wrote:
 >> And if even *that* is not enought then I could consider maybe switching
 >> to musl ... maybe ...

 Alex> I've been following musl for a while - it really might be worth giving
 Alex> a go. They're aiming to be more lightweight than Glibc, while more
 Alex> functional than uclibc. Plus some musl patches for buildroot and
 Alex> crosstool-ng would be kind of awesome ;)

I would certainly be open for patches adding musl support in buildroot.

-- 
Bye, Peter Korsgaard