LST - Development

Troubleshooting

_cffi_backend.so woes

Problem:

ImportError: /tmp/easy_install-Scu8_1/cryptography-1.0.2/.eggs/cffi-1.2.1-py2.7-linux-x86_64.egg/_cffi_backend.so: failed to map segment from shared object: Operation not permitted

Reason:

/tmp has noexec mount attribute set, it is not allowed to execute stuff there.

Solution:

TMPDIR=/var/tmp python setup.py develop

h2m-message Exception

Symptom

An exception is raised when using h2m-message.

Problem

TypeError: bit fields not allowed for type c_char

Analysis

The exception would be raised when e.g. using the char type, which is a non-integer:

char     send_ser        :1; //w 3.0 FlagByte 1
char     cfg_loaded      :1; //w 3.1
char     clamped         :1; //w 3.2
// [...]

Solution

Bit fields must be encoded with integers:

uint8_t  send_ser        :1; //w 3.0 FlagByte 1
uint8_t  cfg_loaded      :1; //w 3.1
uint8_t  clamped         :1; //w 3.2
uint8_t  gps_input       :1; //w 3.3
uint8_t  check_input     :1; //w 3.4
uint8_t  gps_akt         :1; //w 3.5
uint8_t  base_clock      :1; //w 3.6
uint8_t  do_O2_IN        :1; //w 3.7

h2m-message Warning

Symptom

One or more WARNING log messages occur when using h2m-message.

Problem

2015-11-08 02:22:30,400 [kotori.daq.intercom.c    ]
WARNING:
    Struct "struct_system_r" has ID "0", but this is already owned by "struct_gps_w".
    Please check if struct provides reasonable default values for attribute "ID".

Analysis

When initializing a struct, it looks like it doesn’t have a unique value in its ID attribute. Another message struct already is registered with that ID.

Solution

Apply initial values properly. Unfortunately, this initializer syntax currently doesn’t work:

struct_system_r()
: length(15), ID(14)
{}
uint8_t  length;        //  1 Length of struct (byte)
uint8_t  ID;            //  2 Struct ID
// [...]

So please amend your header file towards:

uint8_t  length = 15;   //  1 Length of struct (byte)
uint8_t  ID     = 14;   //  2 Struct ID
// [...]

UDP sending and receiving

The simple UDP sender program is currently configured to send UDP messages to localhost:8888:

udp_client_server::udp_client client("localhost", 8888);

Amend, build and send some binary messages using udp_sender.cpp:

amo offgrid $ cd ~/dev/foss/open.nshare.de/kotori-daq/kotori/vendor/lst/client/cpp

$ make run
---
name:   program
id:     0
length: 13
  0000  0d 00 03 00 41 01 00 00 00 00 00 00 00           ....A........
---
name:   request
id:     1
length: 9
  0000  09 01 21 00 00 00 00 00 00 00 00                 ..!........
---
name:   cap_r
id:     2
length: 5
  0000  05 02 28 00 00                                   ..(..
---
name:   cap_w
id:     3
length: 15
  0000  0f 03 0a 00 00 00 00 00 00 00 00 00 00 00 00     ...............
---
name:   fuelcell_r
id:     4
length: 11
  0000  0b 04 03 00 00 00 00 00 00 00 00                 ...........
---
name:   fuelcell_w
id:     5
length: 19
  0000  13 05 50 00 78 00 00 00 00 00 00 00 00 00 00 00  ..P.x...........
  0010  00 00 00                                         ...
---
name:   gps_w
id:     19
length: 63
  0000  3f 13 b5 62 01 06 34 00 00 00 00 00 00 00 00 00  ?..b..4.........
  0010  00 00 00 00 63 00 00 00 65 00 00 00 00 00 00 00  ....c...e.......
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00     ...............

Receive binary messages and dump them hexlified:

$ socat -x udp-listen:8888 stdout
> 2015/11/07 18:44:49.945555  length=14 from=0 to=13
 0d 00 03 00 41 01 00 00 00 00 00 00 00 00
A> 2015/11/07 18:44:49.945715  length=12 from=14 to=25
 09 01 21 00 00 00 00 00 00 00 00 00
    !> 2015/11/07 18:44:49.945746  length=6 from=26 to=31
 05 02 28 00 00 00
(> 2015/11/07 18:44:49.945766  length=16 from=32 to=47
 0f 03 0a 00 00 00 00 00 00 00 00 00 00 00 00 00

> 2015/11/07 18:44:49.945828  length=12 from=48 to=59
 0b 04 03 00 00 00 00 00 00 00 00 00

> 2015/11/07 18:44:49.945869  length=20 from=60 to=79
 13 05 50 00 78 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Px> 2015/11/07 18:44:49.945914  length=64 from=80 to=143
 3f 13 b5 62 01 06 34 00 00 00 00 00 00 00 00 00 00 00 00 00 63 00 00 00 65 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

< 2015/11/07 18:45:49.202989  length=1 from=0 to=0
 0a

Dry-dock: Use things from “h2m_structs.h” headers

Build a library from the h2m_structs.h headers:

amo offgrid $ cd ~/dev/foss/open.nshare.de/kotori-daq/kotori/vendor/lst/client/cpp
$ make lib

Run some simple examples:

(.venv27)amo offgrid $ cd ~/dev/foss/open.nshare.de/kotori-daq
$ python kotori/vendor/lst/h2m/message.py


# create a "cap_r" struct and print attributes with default values
------------------------------------------
sr.create('struct_cap_r')

thing:  <ctypes struct 'struct_cap_r'>
length: 5
ID:     2


# create a "cap_r" struct overriding default values and print the relevant attributes
------------------------------------------
sr.create('struct_cap_r', ID=88)

thing:  <ctypes struct 'struct_cap_r'>
length: 5
ID:     88


# get lowlevel pyclibrary ctypes backend handle of "struct_program"
------------------------------------------
struct_program = sr.get('struct_program')

struct_program (schema):
<__main__.StructAdapter object at 0x106e37d90>
thing:       <class 'kotori.daq.intercom.pyclibrary_ext.backend_ctypes.s'>
length:      <Field type=c_ubyte, ofs=0, size=1>
ID:          <Field type=c_ubyte, ofs=1, size=1>
send_ser:    <Field type=c_ubyte, ofs=2:0, bits=1>
cfg_loaded:  <Field type=c_ubyte, ofs=2:1, bits=1>
------------------------------------------
struct_program (instance):
thing:       <ctypes struct 'struct_program'>
length:      13
ID:          0


# get lowlevel pyclibrary ctypes backend handle of "struct_cap_r"
------------------------------------------
thing:  <class 'kotori.daq.intercom.pyclibrary_ext.backend_ctypes.s'>
length: <Field type=c_ubyte, ofs=0, size=1>
ID:     <Field type=c_ubyte, ofs=1, size=1>
FIELDS:
[(u'length', <class 'ctypes.c_ubyte'>),
 (u'ID', <class 'ctypes.c_ubyte'>),
 (u'voltage_act', <class 'ctypes.c_ushort'>),
 (u'ck', <class 'ctypes.c_ubyte'>)]
DEFAULTS:
{u'ID': 2, u'length': 5}