> > I'd liked very much the possibility to hide away Equipment on the main page. It
> > is also nice to have the '+' to get it quickly back when needed. However, this
> > seems not to work anymore (git c9d9d604803). Is this a feature or something went
> > wrong?
> 
> The expansion of the equipment list is handled by a Cookie ("expeq" being 1 or 0). When Konstantin 
> implemented the mongoose server instead of the internal mhttp server, he neglected to evaluate 
> this cookie. I fixed this now (also renamed the cookie to "midas_expeq") in the current development 
> branch. Please check if it's working.
> 
> Stefan

Tested it on two machines and expansion is back and working! Thanks a lot!

Andreas

> > > I'd liked very much the possibility to hide away Equipment on the main page. It
> > > is also nice to have the '+' to get it quickly back when needed. However, this
> > > seems not to work anymore (git c9d9d604803). Is this a feature or something went
> > > wrong?
> > 
> > The expansion of the equipment list is handled by a Cookie ("expeq" being 1 or 0). When Konstantin 
> > implemented the mongoose server instead of the internal mhttp server, he neglected to evaluate 
> > this cookie. I fixed this now (also renamed the cookie to "midas_expeq") in the current development 
> > branch. Please check if it's working.
> > 
> > Stefan
> 
> Tested it on two machines and expansion is back and working! Thanks a lot!
> 

Confirmed fixed. Thanks. Not sure how this got lost.

K.O.

Today I addressed a topic which bugged me since long time. The ODB contains 
settings under /Equipment/<name>/Common which are a "mirror" of the equipment[] 
setting in a frontend (using the mfe.cxx framework). If the "Common" entry in 
the ODB is not present (fresh experiment), the equipment[] settings from the 
frontend are copied to the ODB. But if it exists, it takes precedence over the 
equipment[] entries, which is wrong in my opinion. Like if you change some 
settings in equipment[] (like the logging period of the history), then recompile 
and restart the frontend, the old values in the ODB are kept and your 
modification in the frontend code has no effect.

Starting on commit c3017c6c on Nov. 17th 2020 I reversed the precedence: Now, on 
each start of the frontend program, the values from equipment[] are written to 
the ODB. They are still "live". If one changes them when the frontend is 
running, that change takes effect immediately. But on the next restart of the 
frontend, the old values from equipment[] is put back there.

I fell too many times into this trap, and I hope the modification helps 
everybody. If there are however experiments which rely on the fact that the 
common settings in the ODB are NOT overwritten by the frontend, please let me 
know and I can put a flag "EQUIPMENT_FE_PRECEDENCE = FALSE" somewhere to restore 
the old behaviour.

Stefan

Indeed this "mirror" of the ODB in settings option can cause frustration in 
particular when we think the ODB is empty but is not.
In the other hand, over time the settings are adjusted to a particular 
configuration or touched or not by the individual run preset parameters. Later, if 
a bug or code correction requires multiple restart of the fe, for every start of 
the application, you loose the latest configuration. This can be frustrating as 
well until you force a post-setting or report the specifics parameters in the fe 
code.
BTW I believe, we originally went for the ODB priority for that specific reason.
 
I would be in favour for having a general flag (FALSE) in /experiment which would 
define this global behaviour.  
PAA

> Today I addressed a topic which bugged me since long time. The ODB contains 
> settings under /Equipment/<name>/Common which are a "mirror" of the equipment[] 
> setting in a frontend (using the mfe.cxx framework). If the "Common" entry in 
> the ODB is not present (fresh experiment), the equipment[] settings from the 
> frontend are copied to the ODB. But if it exists, it takes precedence over the 
> equipment[] entries, which is wrong in my opinion. Like if you change some 
> settings in equipment[] (like the logging period of the history), then recompile 
> and restart the frontend, the old values in the ODB are kept and your 
> modification in the frontend code has no effect.
> 
> Starting on commit c3017c6c on Nov. 17th 2020 I reversed the precedence: Now, on 
> each start of the frontend program, the values from equipment[] are written to 
> the ODB. They are still "live". If one changes them when the frontend is 
> running, that change takes effect immediately. But on the next restart of the 
> frontend, the old values from equipment[] is put back there.
> 
> I fell too many times into this trap, and I hope the modification helps 
> everybody. If there are however experiments which rely on the fact that the 
> common settings in the ODB are NOT overwritten by the frontend, please let me 
> know and I can put a flag "EQUIPMENT_FE_PRECEDENCE = FALSE" somewhere to restore 
> the old behaviour.
> 
> Stefan

> Today I addressed a topic which bugged me since long time.

Right. No easy subject. For me, too, this has been a problem in MIDAS for a long time.

> Now, on each start of the frontend program, the values from equipment[] are written to 
> the ODB. They are still "live". If one changes them when the frontend is 
> running, that change takes effect immediately. But on the next restart of the 
> frontend, the old values from equipment[] is put back there.

There is a downside from this behaviour.

If some values in equipment/common are "live" and the user is expected to change them,
the user will be unpleasantly surprised when their changes magically disappear (after reboot,
after frontend crash, after run restart if experiment requires restarting some frontends
before starting a new run).

This change will also break some experiments that rely in things like specifying
event buffer names through ODB. But experiments can adapt and specify buffer names
through command line switch instead of ODB.

This new way also it makes the "live" Common/Period unusable. Sure I can speed up or slow
down a frontend even during the run, but if my change does not "stick", what good is it?

Personally, I think there is no easy solution for all these troubles.

I would advocate the following approach:

- think of MIDAS as a "mature" system,
- treasure backward compatibility
- (if we must break backward compatibility to introduce a new "must have" improvement, so be it)
- document how things work. if it is clearly written down what different fields in "common" do, fewer people 
"get burned" by unexpected or illogical things. (and any non-trivial system has plenty of those).

Going back to ODB equipment/common, my experience with midas and odb tells me
that one should avoid mixing together ODB entries set by user and ODB entries set by code.

For example, separating them as equipment/settings and equipment/variables works well. Mixing
them as in equipment/common and sequencer/state causes trouble.

So perhaps we should split Equipment/common into two pieces, user settable fields like
"Period" and "event buffer name" would move to equipment/settings or whatever.

This will open the discussion of which items in equipment/common should be user settable,
and some people would want event buffer specified in the code to prevail, while other
people would want the name from odb to prevail, and both are valid but conflicting preferences.

Or we could bite the bullet and say, equipment/common is controlled by the frontend code,
the user should not change it. (and mark it read-only in ODB).

For all the pain this may cause, at least this will make it self-consistent.

Per this proposal, in addition to Stefan's change, the hotlink on equipment/common goes away,
"period" is no longer "live" and the whole subdirectory is made "read-only".

K.O.

Ok, so what about the following proposal:

- I change back the mfe.cxx code to behave like before (ODB has precedence and does not get overwritten when the 
front-end restarts)

- I add a global flag

BOOL equipment_common_overwrite;

and pre-set it to FALSE;

- So if nothing is changed the flag stays false and ODB keeps precedence

- If a frontend wants to overwrite equipment/common on each start, the user sets

BOOL equipment_common_overwrite = TRUE;

near the equipment[] structure in the front-end code. 

- If the flag is true, the mfe.cxx init code copies the equipment[] structure to the ODB on each frontend start

I believe this way we can keep backward compatibility, and add the new way with minimal effort. The only downside 
is that all frontends on this plane have to add at least "BOOL equipment_common_overwrite = FALSE;" in their 
code.

I know global variables are evil, but this way the user can just add the line above to the equipment[] array, so 
one sees this when one edits the equipment[] array, giving motivation to change as needed. So the code would be



BOOL equipment_common_overwrite = TRUE;

EQUIPMENT equipment[] = {
 ....
}



An alternative way would be to add a function

  set_equipment_common_overwrite(TRUE);

into the frontend_init() code. That's somehow cleaner (still needs an internal global variable), but it has to go 
into frontend_init() so won't be at the same place as the EQUIPMENT list in the frontend.

Thoughts?

Best,
Stefan

Yes, I think this will work.

For old mfe.c frontends, global variable set to "do it the new way" should be okey,
new experiments will have it the new way. Old experiments, will be forced to add a one-line definition
of this global variable (otherwise mfe.o will not link), at that time they get to chose "new way" or "old way".

For the new TMFE c++ frontend, this will work naturally when they create the Equipment Common object,
in the object constructor, you can see how it explicitly honors or overwrites the ODB common entries.

The TMFE frontend does not do a live "period", so there should be no issue with that.

Should I open a bitbucket issue "update TMFE frontend to new Equipment/Common scheme", to make sure
I do not forget about it?

K.O.

Ok, I implemented it the following way:

- Added a boolean flag "equipment_common_overwrite", which must be contained in EACH frontend, preferably just 
before the EQUIPMENT structure, such as:

BOOL equipment_common_overwrite = TRUE;

EQUIPMENT equipment[] = {
...
};

- If that flag is TRUE, then the contents of the "equipment" structure is copied to the ODB on each start of the 
front-end

- If the flag is FALSE, then the ODB values are kept on the start of the front-end

The setting of the flag depends now on the philosophy of the experiment. Some experiments say that everything 
needed should be in the front-end code, so when it starts everything gets set correctly. They don't change the 
values in the ODB, but in the frontend code, which then goes into their repository. Other experiments just need 
some default values from the frontend code, and the fine-tune things by changing values in the ODB. These 
experiments should set this flag to FALSE.

*****

Please note that EVERY frontend now needs this flag, so all of you have to add it to all of your front-ends, 
otherwise the front-end will not compile! I could not figure out how to this could be done without this 
requirement, since you can define a global variable only once.

*****


Stefan

One more change: 

After using the new code for some hours, we realized that the "enabled" flag should not come from the frontend code, 
but always be defined by the ODB. So if you quickly have to disable some equipment because the associated hardware is 
off, you want to change this flag only in the ODB and not have to recompile the frontend. So we exclude that flag from 
being set by the frontend. It is anyhow special, because one sees all disable equipment in the main midas status page, 
so one knows what's on and what's off.

Please comment here if you think that change causes problem. Anyhow it's working now for the enabled flag as before 
all these changes.

Stefan

> One more change: 
> 
> After using the new code for some hours, we realized that the "enabled" flag should not come from the frontend code, 
> but always be defined by the ODB. So if you quickly have to disable some equipment because the associated hardware is 
> off, you want to change this flag only in the ODB and not have to recompile the frontend. So we exclude that flag from 
> being set by the frontend. It is anyhow special, because one sees all disable equipment in the main midas status page, 
> so one knows what's on and what's off.
> 
> Please comment here if you think that change causes problem. Anyhow it's working now for the enabled flag as before 
> all these changes.
> 

Good catch. I still think this is fundamentally impossible to "get right". But good, you
are now in the same boat with me. The documentation will read: "if flag is TRUE, these data fields
are read from ODB, if flag is FALSE, those other fields are read from ODB". I will have to check
how this will work out for the TMFE C++ frontend (I think both mfe.c and TMFE frontends should
work "the same").

I think we have at least one month to play with this, I do not think we can do the next release
of midas until January.

K.O.

  /* swap event header if in wrong format */
  if (pevent->serial_number > 0x1000000) {
     WORD_SWAP(&pevent->event_id);
     WORD_SWAP(&pevent->trigger_mask);
     DWORD_SWAP(&pevent->serial_number);
     DWORD_SWAP(&pevent->time_stamp);
     DWORD_SWAP(&pevent->data_size);
  }

  /* swap event header if in wrong format */
#ifdef SWAP_EVENTS
  WORD_SWAP(&pevent->event_id);
  WORD_SWAP(&pevent->trigger_mask);
  DWORD_SWAP(&pevent->serial_number);
  DWORD_SWAP(&pevent->time_stamp);
  DWORD_SWAP(&pevent->data_size);
#endif

Javascript "AJAX" functions (and their MIDAS wrappers - ODBGet/ODBSet) are subject to something called 
"same origin policy" intended to prevent something called "cross-site scripting attacks", i.e. see
http://en.wikipedia.org/wiki/Same-origin_policy

In practice it means that if you load the MIDAS custom web page from test.foo.com and try to access 
mhttpd at midas.foo.com, ODBSet/ODBGet will not work.

I always thought that this meant that the requests are blocked by the browser and are a form of 
protection of the web server - only scripts loaded from mhttpd can do AJAX (ODBGet/ODBSet) to mhttpd.

It turns out that I was wrong. This is what actually happens: the "cross-site" requests are still sent to the 
server (mhttpd), the response it received, parsed and discarded if "same origin" conditions are not met.

This means that the "same origin" policy does not protect mhttpd at all - any script from any page 
anywhere can issue AJAX requests into any mhttpd, these requests will be successfully sent, received
and processed by mhttpd, including requests for writing into ODB ("jset" command using the HTTP GET 
method).

So for the case of MIDAS, "same origin" does not prevent malicious (or buggy) scripts from writing into the 
wrong mhttpd of the wrong experiment.

All it does is prevent desired and intentional access to mhttpd (ODBGet) from scripts that happen to have 
been loaded outside of mhttpd (i.e. from a developer own test page).

Then it turns out that there is an "official" way to disable this unwanted protection policy, called CORS, see
http://www.w3.org/TR/cors/

I have now implemented this in mhttpd and added an mhttpd.js function ODBSetURL() to explicitly set the 
URL of mhttpd that we want to talk to.

This work is on the feature/ajax branch, to be merged soon. For the impatient, here is what you need to 
do in mhttpd:

diff --git a/src/mhttpd.cxx b/src/mhttpd.cxx
index 1d9d1cc..0460cec 100755
--- a/src/mhttpd.cxx
+++ b/src/mhttpd.cxx
@@ -1070,6 +1070,7 @@ void show_text_header()
 {
    rsprintf("HTTP/1.0 200 Document follows\r\n");
    rsprintf("Server: MIDAS HTTP %d\r\n", mhttpd_revision());
+   rsprintf("Access-Control-Allow-Origin: *\r\n");
    rsprintf("Pragma: no-cache\r\n");
    rsprintf("Expires: Fri, 01 Jan 1983 00:00:00 GMT\r\n");
    rsprintf("Content-Type: text/plain; charset=iso-8859-1\r\n\r\n");

K.O.

Hi, we are part of the Mu3e research based at University of Bristol. We have a 
remote 32 bit frontend (raspberry pi) connected to a 64 bit Data Acquisition 
system.we are following the instructions at installation/quickstart linux/Build 
32-bit MIDAS libraries. when we execute the commands: 
[mhostpc] cd /home/packages/midas
[mhostpc] make linux32             

we get an error:

make NO_ROOT=1 NO_MYSQL=1 NO_ODBC=1 NO_SQLITE=1 OS_DIR=linux-m32 USERFLAGS=-m32
make[1]: Entering directory `/home/hh19285/packages/midas'
g++ -m32 -c -g -O2 -Wall -Wno-strict-aliasing -Wuninitialized -Iinclude -
Idrivers -Imxml -Imscb/include -DHAVE_FTPLIB -D_LARGEFILE64_SOURCE -DHAVE_ZLIB -
DHAVE_MSCB -DHAVE_MONGOOSE6 -DMG_ENABLE_THREADS -DMG_DISABLE_CGI -DMG_ENABLE_SSL 
-DOS_LINUX -fPIC -Wno-unused-function -o lib/crc32c.o src/crc32c.cxx
src/crc32c.cxx: In function ‘uint32_t crc32c_hw(uint32_t, const void*, size_t)’:
src/crc32c.cxx:283:66: error: ‘asm’ operand has impossible constraints
                     : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
                                                                  ^
src/crc32c.cxx:303:66: error: ‘asm’ operand has impossible constraints
                     : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
                                                                  ^
src/crc32c.cxx: In function ‘uint32_t crc32c(uint32_t, const void*, size_t)’:
src/crc32c.cxx:348:34: error: PIC register clobbered by ‘%ebx’ in ‘asm’
                 : "%ebx", "%edx"); \
                                  ^
src/crc32c.cxx:362:5: note: in expansion of macro ‘SSE42’
     SSE42(sse42);
     ^
make[1]: *** [lib/crc32c.o] Error 1
make[1]: Leaving directory `/home/hh19285/packages/midas'
make: *** [linux32] Error 2

Could you please help with getting past this? otherwise we may need to change 
our whole experimental setup.

Thank you in advance

Why don't your try the (yet undocumented) new installation procedure:

$ git clone https://bitbucket.com/tmidas/midas --recursive
$ cd midas
$ mkdir build
$ cd build
$ cmake ..
$ make
$ make install

In case your RPi does not have cmake pre-installed, you need

$ sudo apt-get install cmake.

Works for my RPi.

Best,
Stefan

Update: "make" instead of "make linux32" should also work. I believe the "linux32" target came 
from some special case at TRIUMF for some FPGA embedded linux, which is not applicable for 
the Raspberry Pi.

Note that the build process has to be initiated on the Raspberry Pi, NOT a host PC.

Stefan

Yikes, the error is in the CRC library. The assembly-optimized crc32c function fails to build, and the 
error does not look familiar to me. I do not see this error here. What is your host system ("uname -
a") and what is your gcc ("gcc -v")?

BTW, "make linux32" will build an Intel 32-bit version (see "-m32" in "man gcc"). For ARM 32-bit 
you need a different switch, I think, also depending how you are cross-compiling it.

For straight cross-compilation, look at the Makefile target "make linuxarm" (you will need to change 
the location of your ARM gcc cross-compiler).

For running MIDAS frontend on the Raspberry Pi 3, I build MIDAS on the Pi3 itself, the machine is big 
enough to run CentOS7 linux and gcc to build the full MIDAS.

But if you have a different cross-compilation scheme, I am happy to help you and to add your 
scheme to the MIDAS Makefile. We can start by looking at "uname -a" and "gcc -v" and "lsb_release 
-a" (if you have it).

K.O.


> Hi, we are part of the Mu3e research based at University of Bristol. We have a 
> remote 32 bit frontend (raspberry pi) connected to a 64 bit Data Acquisition 
> system.we are following the instructions at installation/quickstart linux/Build 
> 32-bit MIDAS libraries. when we execute the commands: 
> [mhostpc] cd /home/packages/midas
> [mhostpc] make linux32             
> 
> we get an error:
> 
> make NO_ROOT=1 NO_MYSQL=1 NO_ODBC=1 NO_SQLITE=1 OS_DIR=linux-m32 USERFLAGS=-
m32
> make[1]: Entering directory `/home/hh19285/packages/midas'
> g++ -m32 -c -g -O2 -Wall -Wno-strict-aliasing -Wuninitialized -Iinclude -
> Idrivers -Imxml -Imscb/include -DHAVE_FTPLIB -D_LARGEFILE64_SOURCE -DHAVE_ZLIB -
> DHAVE_MSCB -DHAVE_MONGOOSE6 -DMG_ENABLE_THREADS -DMG_DISABLE_CGI -
DMG_ENABLE_SSL 
> -DOS_LINUX -fPIC -Wno-unused-function -o lib/crc32c.o src/crc32c.cxx
> src/crc32c.cxx: In function ‘uint32_t crc32c_hw(uint32_t, const void*, size_t)’:
> src/crc32c.cxx:283:66: error: ‘asm’ operand has impossible constraints
>                      : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
>                                                                   ^
> src/crc32c.cxx:303:66: error: ‘asm’ operand has impossible constraints
>                      : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
>                                                                   ^
> src/crc32c.cxx: In function ‘uint32_t crc32c(uint32_t, const void*, size_t)’:
> src/crc32c.cxx:348:34: error: PIC register clobbered by ‘%ebx’ in ‘asm’
>                  : "%ebx", "%edx"); \
>                                   ^
> src/crc32c.cxx:362:5: note: in expansion of macro ‘SSE42’
>      SSE42(sse42);
>      ^
> make[1]: *** [lib/crc32c.o] Error 1
> make[1]: Leaving directory `/home/hh19285/packages/midas'
> make: *** [linux32] Error 2
> 
> Could you please help with getting past this? otherwise we may need to change 
> our whole experimental setup.
> 
> Thank you in advance

Thanks for your advice. We now have Midas installed on both our machines (remote machine-Rpi &
hostmachine-Centos). 

=========================================================================================================
One the host machine:
[hh19285@it038146 bin]$ uname -a
Linux it038146.users.bris.ac.uk 3.10.0-957.21.2.el7.x86_64 #1 SMP Wed Jun 5 14:26:44 UTC 2019 x86_64 x86_64
x86_64 GNU/Linux
[hh19285@it038146 bin]$ uname -a
Linux it038146.users.bris.ac.uk 3.10.0-957.21.2.el7.x86_64 #1 SMP Wed Jun 5 14:26:44 UTC 2019 x86_64 x86_64
x86_64 GNU/Linux
[hh19285@it038146 bin]$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
--enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array
--disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install
--with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install
--enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC) 
[hh19285@it038146 bin]$ lsb_release -a
LSB Version:	:core-4.1-amd64:core-4.1-noarch
Distributor ID:	CentOS
Description:	CentOS Linux release 7.6.1810 (Core) 
Release:	7.6.1810
Codename:	Core

===========================================================================================================
On remote machine:
pi@raspberrypi:~/packages/midas/bin $ uname -a
Linux raspberrypi 4.19.42-v7+ #1219 SMP Tue May 14 21:20:58 BST 2019 armv7l GNU/Linux
pi@raspberrypi:~/packages/midas/bin $ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/6/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Raspbian 6.3.0-18+rpi1+deb9u1'
--with-bugurl=file:///usr/share/doc/gcc-6/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-6
--program-prefix=arm-linux-gnueabihf- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-libitm --disable-libquadmath --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-6-armhf/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-6-armhf
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-6-armhf --with-arch-directory=arm
--with-ecj-jar=/usr/share/java/eclipse-ecj.jar --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-sjlj-exceptions --with-arch=armv6 --with-fpu=vfp --with-float=hard
--enable-checking=release --build=arm-linux-gnueabihf --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf
Thread model: posix
gcc version 6.3.0 20170516 (Raspbian 6.3.0-18+rpi1+deb9u1) 
pi@raspberrypi:~/packages/midas/bin $ lsb_release -a
No LSB modules are available.
Distributor ID:	Raspbian
Description:	Raspbian GNU/Linux 9.9 (stretch)
Release:	9.9
Codename:	stretch







> Yikes, the error is in the CRC library. The assembly-optimized crc32c function fails to build, and the 
> error does not look familiar to me. I do not see this error here. What is your host system ("uname -
> a") and what is your gcc ("gcc -v")?
> 
> BTW, "make linux32" will build an Intel 32-bit version (see "-m32" in "man gcc"). For ARM 32-bit 
> you need a different switch, I think, also depending how you are cross-compiling it.
> 
> For straight cross-compilation, look at the Makefile target "make linuxarm" (you will need to change 
> the location of your ARM gcc cross-compiler).
> 
> For running MIDAS frontend on the Raspberry Pi 3, I build MIDAS on the Pi3 itself, the machine is big 
> enough to run CentOS7 linux and gcc to build the full MIDAS.
> 
> But if you have a different cross-compilation scheme, I am happy to help you and to add your 
> scheme to the MIDAS Makefile. We can start by looking at "uname -a" and "gcc -v" and "lsb_release 
> -a" (if you have it).
> 
> K.O.
> 
> 
> > Hi, we are part of the Mu3e research based at University of Bristol. We have a 
> > remote 32 bit frontend (raspberry pi) connected to a 64 bit Data Acquisition 
> > system.we are following the instructions at installation/quickstart linux/Build 
> > 32-bit MIDAS libraries. when we execute the commands: 
> > [mhostpc] cd /home/packages/midas
> > [mhostpc] make linux32             
> > 
> > we get an error:
> > 
> > make NO_ROOT=1 NO_MYSQL=1 NO_ODBC=1 NO_SQLITE=1 OS_DIR=linux-m32 USERFLAGS=-
> m32
> > make[1]: Entering directory `/home/hh19285/packages/midas'
> > g++ -m32 -c -g -O2 -Wall -Wno-strict-aliasing -Wuninitialized -Iinclude -
> > Idrivers -Imxml -Imscb/include -DHAVE_FTPLIB -D_LARGEFILE64_SOURCE -DHAVE_ZLIB -
> > DHAVE_MSCB -DHAVE_MONGOOSE6 -DMG_ENABLE_THREADS -DMG_DISABLE_CGI -
> DMG_ENABLE_SSL 
> > -DOS_LINUX -fPIC -Wno-unused-function -o lib/crc32c.o src/crc32c.cxx
> > src/crc32c.cxx: In function ‘uint32_t crc32c_hw(uint32_t, const void*, size_t)’:
> > src/crc32c.cxx:283:66: error: ‘asm’ operand has impossible constraints
> >                      : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
> >                                                                   ^
> > src/crc32c.cxx:303:66: error: ‘asm’ operand has impossible constraints
> >                      : "r"(next), "0"(crc0), "1"(crc1), "2"(crc2));
> >                                                                   ^
> > src/crc32c.cxx: In function ‘uint32_t crc32c(uint32_t, const void*, size_t)’:
> > src/crc32c.cxx:348:34: error: PIC register clobbered by ‘%ebx’ in ‘asm’
> >                  : "%ebx", "%edx"); \
> >                                   ^
> > src/crc32c.cxx:362:5: note: in expansion of macro ‘SSE42’
> >      SSE42(sse42);
> >      ^
> > make[1]: *** [lib/crc32c.o] Error 1
> > make[1]: Leaving directory `/home/hh19285/packages/midas'
> > make: *** [linux32] Error 2
> > 
> > Could you please help with getting past this? otherwise we may need to change 
> > our whole experimental setup.
> > 
> > Thank you in advance