[GSOC/RFC] configure script failing

[Dmitry V. Levin]

Hi,

On Fri, Feb 28, 2020 at 01:48:40AM +0530, Rohit Sarkar wrote:
> Hey,
> I am Rohit and interested in being a part of the strace community,
> through gsoc.
> 
> I was trying to build strace from source and while running the configure
> script I faced this error:
> 
> "
> checking for m32 personality compile support (using gcc  -I.  -m32)... no
> checking whether to enable m32 personality support... no
> configure: error: Cannot enable m32 personality support
> "
> 
> I am running a x86_64 system and using gcc as my compiler.

It's very unusual to have a x86_64 system where gcc -m32 doesn't work
at all, I wonder what kind of x86_64 system provides gcc without -m32.
Have you looked into config.log for any hints?

> On doing some googling I found this thread: [1]
> 
> Adding the --disable-mpers flag to the configure script seemed to work.
> (Need to figure out what is this mpers now!)
> 
> Aha: Found this [2]. I read up a bit about the Multiple Personality
> feature and it seems super cool.

Yes, it's a really cool stuff indeed.

> I presume my compiler doesn't have mpers support, but I think in this
> case the configure script should either not fail or give an informative
> error message asking to run the script with --disable-mpers.

There was some help written for cases like this but you probably wasn't
aware of it:

$ ./configure --help |sed -n '/mpers/,/default/p'
  --enable-mpers=yes|no|check|m32|mx32
                          whether to enable multiple personalities support
                          required for proper decoding of structures used by
                          tracees with personalities that differ from the
                          personality of strace, default is yes.

You could use e.g. --enable-mpers=check to check whether mpers support can
be enabled and enable it if the answer is yes.


-- 
ldv