etherlab/runtime_etherlab.py
author Edouard Tisserant
Mon, 09 Dec 2019 14:53:42 +0100
branchsvghmi
changeset 2820 d9b5303d43dc
parent 2422 45aa510d7a2a
child 2643 b98d9e08231f
permissions -rw-r--r--
SVGHMI : had to move the problem of wkaing up python thread from plc thread to platform specific code.
Since Xenomai's cobalt thread are definitely incompatible with normal posix python interpreter binary's thread, we must synchronize them with arcane rt_pipes (the only ones that really work cross domain) as already done in debug and python async eval blocks.
from __future__ import absolute_import
import os
import signal
import subprocess
import ctypes
from threading import Thread
import time
import re

import runtime.PLCObject as PLCObject
from runtime.loglevels import LogLevelsDict

SDOAnswered = PLCBinary.SDOAnswered
SDOAnswered.restype = None
SDOAnswered.argtypes = []

SDOThread = None
SDOProc = None
Result = None


def SDOThreadProc(*params):
    global Result, SDOProc
    if params[0] == "upload":
        cmdfmt = "ethercat upload -p %d -t %s 0x%.4x 0x%.2x"
    else:
        cmdfmt = "ethercat download -p %d -t %s 0x%.4x 0x%.2x %s"

    command = cmdfmt % params[1:]
    SDOProc = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)
    res = SDOProc.wait()
    output = SDOProc.communicate()[0]

    if params[0] == "upload":
        Result = None
        if res == 0:
            if params[2] in ["float", "double"]:
                Result = float(output)
            elif params[2] in ["string", "octet_string", "unicode_string"]:
                Result = output
            else:
                hex_value, dec_value = output.split()
                if int(hex_value, 16) == int(dec_value):
                    Result = int(dec_value)
    else:
        Result = res == 0

    SDOAnswered()
    if res != 0:
        PLCObject.LogMessage(
            LogLevelsDict["WARNING"],
            "%s : %s" % (command, output))


def EthercatSDOUpload(pos, index, subindex, var_type):
    global SDOThread
    SDOThread = Thread(target=SDOThreadProc, args=["upload", pos, var_type, index, subindex])
    SDOThread.start()


def EthercatSDODownload(pos, index, subindex, var_type, value):
    global SDOThread
    SDOThread = Thread(target=SDOThreadProc, args=["download", pos, var_type, index, subindex, value])
    SDOThread.start()


def GetResult():
    return Result


KMSGPollThread = None
StopKMSGThread = False


def KMSGPollThreadProc():
    """
    Logs Kernel messages starting with EtherCAT
    Uses GLibc wrapper to Linux syscall "klogctl"
    Last 4 KB are polled, and lines compared to last
    captured line to detect new lines
    """
    libc = ctypes.CDLL("libc.so.6")
    klog = libc.klogctl
    klog.argtypes = [ctypes.c_int, ctypes.c_char_p, ctypes.c_int]
    klog.restype = ctypes.c_int
    s = ctypes.create_string_buffer(4*1024)
    last = None
    while not StopKMSGThread:
        bytes_to_read = klog(3, s, len(s)-1)
        log = s.value[:bytes_to_read-1]
        if last:
            log = log.rpartition(last)[2]
        if log:
            last = log.rpartition('\n')[2]
            for lvl, msg in re.findall(
                    r'<(\d)>\[\s*\d*\.\d*\]\s*(EtherCAT\s*.*)$',
                    log, re.MULTILINE):
                PLCObject.LogMessage(
                    LogLevelsDict[{
                        "4": "WARNING",
                        "3": "CRITICAL"}.get(lvl, "DEBUG")],
                    msg)
        time.sleep(0.5)


def _runtime_etherlab_init():
    global KMSGPollThread, StopKMSGThread
    StopKMSGThread = False
    KMSGPollThread = Thread(target=KMSGPollThreadProc)
    KMSGPollThread.start()


def _runtime_etherlab_cleanup():
    global KMSGPollThread, StopKMSGThread, SDOThread
    try:
        os.kill(SDOProc.pid, signal.SIGTERM)
    except Exception:
        pass
    SDOThread = None
    StopKMSGThread = True
    KMSGPollThread = None