[Buildroot] where is 'ldd'?

[Buildroot] where is 'ldd'?

[Woody Wu]

Hi,

I just cann't find what is the menu item in buildroot to enable building
of 'ldd' for my target.  Does anyone know it?

Thanks in advance.

-- 
I can't go back to yesterday - because I was a different person then

[Buildroot] where is 'ldd'?

[Zoltan Gyarmati]

On 07/08/2013 03:56 PM, Woody Wu wrote:
> Hi,
>
> I just cann't find what is the menu item in buildroot to enable building
> of 'ldd' for my target.  Does anyone know it?
>
> Thanks in advance.
>
Sure you don't have it already on your system? What toolchain / libc 
are you using?

-- 
br, 
Zoltan Gyarmati
mail: mr.zoltan.gyarmati at gmail.com
freenode nick: zgyarmati

[Buildroot] where is 'ldd'?

[Woody Wu]

On Mon, Jul 08, 2013 at 04:14:37PM +0200, Zoltan Gyarmati wrote:
> On 07/08/2013 03:56 PM, Woody Wu wrote:
> > Hi,
> >
> > I just cann't find what is the menu item in buildroot to enable building
> > of 'ldd' for my target.  Does anyone know it?
> >
> > Thanks in advance.
> >
> Sure you don't have it already on your system? What toolchain / libc 
> are you using?

I also feel strange, but its sure. I am using Code Sorucery, downloaded
it's lite version (arm linux eabi version, 2013-05-24). It comes with an
installer, which created a seperated directory in my home. I searched
through its installation directory (via 'find'), sure not have anything
like "*ldd".

-
woody

[Buildroot] where is 'ldd'?

[Thomas De Schampheleire]

Hi,

On Mon, Jul 8, 2013 at 4:27 PM, Woody Wu <narkewoody@gmail.com> wrote:
> On Mon, Jul 08, 2013 at 04:14:37PM +0200, Zoltan Gyarmati wrote:
>> On 07/08/2013 03:56 PM, Woody Wu wrote:
>> > Hi,
>> >
>> > I just cann't find what is the menu item in buildroot to enable building
>> > of 'ldd' for my target.  Does anyone know it?
>> >
>> > Thanks in advance.
>> >
>> Sure you don't have it already on your system? What toolchain / libc
>> are you using?
>
> I also feel strange, but its sure. I am using Code Sorucery, downloaded
> it's lite version (arm linux eabi version, 2013-05-24). It comes with an
> installer, which created a seperated directory in my home. I searched
> through its installation directory (via 'find'), sure not have anything
> like "*ldd".

You really don't need a special ldd.
ldd is just a script. In its most basic usage (ldd <executable>), it just runs:
# LD_TRACE_LOADED_OBJECTS=1 <executable>

For example on busybox:
# LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
        linux-vdso32.so.1 =>  (0x00100000)
        libc.so.6 => /lib/libc.so.6 (0x0fe70000)
        /lib/ld.so.1 (0x48000000

So for sporadic usage, an ldd script isn't even needed.

See 'man ld.so' for information on this LD_TRACE_LOADED_OBJECTS
variable (and several other useful variables that change the behavior
of the executable.

See also: http://www.catonmat.net/blog/ldd-arbitrary-code-execution/

Best regards,
Thomas

[Buildroot] where is 'ldd'?

[Woody Wu]

On Mon, Jul 08, 2013 at 06:49:40PM +0200, Thomas De Schampheleire wrote:
> Hi,
> 
> On Mon, Jul 8, 2013 at 4:27 PM, Woody Wu <narkewoody@gmail.com> wrote:
> > On Mon, Jul 08, 2013 at 04:14:37PM +0200, Zoltan Gyarmati wrote:
> >> On 07/08/2013 03:56 PM, Woody Wu wrote:
> >> > Hi,
> >> >
> >> > I just cann't find what is the menu item in buildroot to enable building
> >> > of 'ldd' for my target.  Does anyone know it?
> >> >
> >> > Thanks in advance.
> >> >
> >> Sure you don't have it already on your system? What toolchain / libc
> >> are you using?
> >
> > I also feel strange, but its sure. I am using Code Sorucery, downloaded
> > it's lite version (arm linux eabi version, 2013-05-24). It comes with an
> > installer, which created a seperated directory in my home. I searched
> > through its installation directory (via 'find'), sure not have anything
> > like "*ldd".
> 
> You really don't need a special ldd.
> ldd is just a script. In its most basic usage (ldd <executable>), it just runs:
> # LD_TRACE_LOADED_OBJECTS=1 <executable>
> 
> For example on busybox:
> # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
>         linux-vdso32.so.1 =>  (0x00100000)
>         libc.so.6 => /lib/libc.so.6 (0x0fe70000)
>         /lib/ld.so.1 (0x48000000
> 
> So for sporadic usage, an ldd script isn't even needed.
> 
> See 'man ld.so' for information on this LD_TRACE_LOADED_OBJECTS
> variable (and several other useful variables that change the behavior
> of the executable.
> 
> See also: http://www.catonmat.net/blog/ldd-arbitrary-code-execution/
> 

Cool! learned a thing!

[Buildroot] where is 'ldd'?

[Thomas Petazzoni]

Dear Thomas De Schampheleire,

On Mon, 8 Jul 2013 18:49:40 +0200, Thomas De Schampheleire wrote:

> You really don't need a special ldd.
> ldd is just a script. In its most basic usage (ldd <executable>), it just runs:
> # LD_TRACE_LOADED_OBJECTS=1 <executable>
> 
> For example on busybox:
> # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
>         linux-vdso32.so.1 =>  (0x00100000)
>         libc.so.6 => /lib/libc.so.6 (0x0fe70000)
>         /lib/ld.so.1 (0x48000000
> 
> So for sporadic usage, an ldd script isn't even needed.

Right, but does this work with the uClibc dynamic loader? Anyway, if
those features don't exist with the uClibc dynamic loader, then
implementing ldd is simply impossible.

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

[Buildroot] where is 'ldd'?

[Thomas De Schampheleire]

Op 9-jul.-2013 12:40 schreef "Thomas Petazzoni" <
thomas.petazzoni@free-electrons.com> het volgende:
>
> Dear Thomas De Schampheleire,
>
> On Mon, 8 Jul 2013 18:49:40 +0200, Thomas De Schampheleire wrote:
>
> > You really don't need a special ldd.
> > ldd is just a script. In its most basic usage (ldd <executable>), it
just runs:
> > # LD_TRACE_LOADED_OBJECTS=1 <executable>
> >
> > For example on busybox:
> > # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
> >         linux-vdso32.so.1 =>  (0x00100000)
> >         libc.so.6 => /lib/libc.so.6 (0x0fe70000)
> >         /lib/ld.so.1 (0x48000000
> >
> > So for sporadic usage, an ldd script isn't even needed.
>
> Right, but does this work with the uClibc dynamic loader? Anyway, if
> those features don't exist with the uClibc dynamic loader, then
> implementing ldd is simply impossible.

I haven't tried this on uClibc yet. Anyone that has such a target at hand
willing to give it a shot?
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[Buildroot] where is 'ldd'?

[Baruch Siach]

Hi Thomas,

On Tue, Jul 09, 2013 at 07:39:49PM +0200, Thomas De Schampheleire wrote:
> Op 9-jul.-2013 12:40 schreef "Thomas Petazzoni" <
> thomas.petazzoni at free-electrons.com> het volgende:
> >
> > Dear Thomas De Schampheleire,
> >
> > On Mon, 8 Jul 2013 18:49:40 +0200, Thomas De Schampheleire wrote:
> >
> > > You really don't need a special ldd.
> > > ldd is just a script. In its most basic usage (ldd <executable>), it
> just runs:
> > > # LD_TRACE_LOADED_OBJECTS=1 <executable>
> > >
> > > For example on busybox:
> > > # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
> > >         linux-vdso32.so.1 =>  (0x00100000)
> > >         libc.so.6 => /lib/libc.so.6 (0x0fe70000)
> > >         /lib/ld.so.1 (0x48000000
> > >
> > > So for sporadic usage, an ldd script isn't even needed.
> >
> > Right, but does this work with the uClibc dynamic loader? Anyway, if
> > those features don't exist with the uClibc dynamic loader, then
> > implementing ldd is simply impossible.
> 
> I haven't tried this on uClibc yet. Anyone that has such a target at hand
> willing to give it a shot?

Trying on uClibc (0.9.33.2) xtensa target I see:

# LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
    libc.so.0 => /lib/libc.so.0 (0x20008000)
    ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x20000000)

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

[Buildroot] where is 'ldd'?

[Thomas De Schampheleire]

Op 9-jul.-2013 19:43 schreef "Baruch Siach" <baruch@tkos.co.il> het
volgende:
>
> Hi Thomas,
>
> On Tue, Jul 09, 2013 at 07:39:49PM +0200, Thomas De Schampheleire wrote:
> > Op 9-jul.-2013 12:40 schreef "Thomas Petazzoni" <
> > thomas.petazzoni at free-electrons.com> het volgende:
> > >
> > > Dear Thomas De Schampheleire,
> > >
> > > On Mon, 8 Jul 2013 18:49:40 +0200, Thomas De Schampheleire wrote:
> > >
> > > > You really don't need a special ldd.
> > > > ldd is just a script. In its most basic usage (ldd <executable>), it
> > just runs:
> > > > # LD_TRACE_LOADED_OBJECTS=1 <executable>
> > > >
> > > > For example on busybox:
> > > > # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
> > > >         linux-vdso32.so.1 =>  (0x00100000)
> > > >         libc.so.6 => /lib/libc.so.6 (0x0fe70000)
> > > >         /lib/ld.so.1 (0x48000000
> > > >
> > > > So for sporadic usage, an ldd script isn't even needed.
> > >
> > > Right, but does this work with the uClibc dynamic loader? Anyway, if
> > > those features don't exist with the uClibc dynamic loader, then
> > > implementing ldd is simply impossible.
> >
> > I haven't tried this on uClibc yet. Anyone that has such a target at
hand
> > willing to give it a shot?
>
> Trying on uClibc (0.9.33.2) xtensa target I see:
>
> # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
>     libc.so.0 => /lib/libc.so.0 (0x20008000)
>     ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x20000000)

Thanks! So, it seems to work fine on uClibc as well...
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[Buildroot] where is 'ldd'?

[Thomas Petazzoni]

Dear Baruch Siach,

On Tue, 9 Jul 2013 20:43:06 +0300, Baruch Siach wrote:

> Trying on uClibc (0.9.33.2) xtensa target I see:
> 
> # LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
>     libc.so.0 => /lib/libc.so.0 (0x20008000)
>     ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x20000000)

Nice, thanks for testing!

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