Fix GUI startup ENOMEM on small-RAM machines with an OpenMP OpenBLAS

scripts/linuxcnc.in

@@ -33,6 +33,11 @@ if [[ ! -v LINUXCNC_OPENGL_PLATFORM || "${LINUXCNC_OPENGL_PLATFORM}" == "glx" ]]
     export QT_QPA_PLATFORM="xcb"
 fi
 
+# An OpenMP build of OpenBLAS reserves about 1 GiB per CPU when numpy
+# is imported; with less RAM than that the kernel refuses to fork the
+# GUI (ENOMEM). Nothing here needs threaded BLAS.
+export OMP_NUM_THREADS="${OMP_NUM_THREADS:-1}"
+
 ################################################################################
 # 0. Values that come from configure
 ################################################################################

src/emc/usr_intf/axis/scripts/axis.py

@@ -19,7 +19,7 @@
 
 
 # import pdb
-import sys, os
+import sys, os, subprocess
 import string
 BASE = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), ".."))
 sys.path.insert(0, os.path.join(BASE, "lib", "python"))
@@ -4298,15 +4298,15 @@ def check_dynamic_tabs():
         if postgui_halfile is not None:
             for f in postgui_halfile:
                 if f.lower().endswith('.tcl'):
-                    res = os.spawnvp(os.P_WAIT, "haltcl", ["haltcl", "-i", vars.emcini.get(), f])
+                    res = subprocess.call(["haltcl", "-i", vars.emcini.get(), f])
                 else:
-                    res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", vars.emcini.get(), "-f", f])
+                    res = subprocess.call(["halcmd", "-i", vars.emcini.get(), "-f", f])
                 if res: raise SystemExit(res)
 
         if postgui_halcmds is not None:
             for f in postgui_halcmds:
                 f = os.path.expanduser(f)
-                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
+                res = subprocess.call(["halcmd"] + f.split())
                 if res: raise SystemExit(res)
 
         open_initial_file()

src/emc/usr_intf/gmoccapy/gmoccapy.py

@@ -6678,9 +6678,9 @@ def _make_hal_pins(self):
     if postgui_halfile is not None:
         for f in postgui_halfile:
             if f.lower().endswith('.tcl'):
-                res = os.spawnvp(os.P_WAIT, "haltcl", ["haltcl", "-i", inifile, f])
+                res = subprocess.call(["haltcl", "-i", inifile, f])
             else:
-                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", inifile, "-f", f])
+                res = subprocess.call(["halcmd", "-i", inifile, "-f", f])
                 if res:
                     LOG.error('postgui halfile error:{}'.format(res))
                     raise SystemExit(res)
@@ -6690,7 +6690,7 @@ def _make_hal_pins(self):
         if postgui_halcmds is not None:
             for f in postgui_halcmds:
                 f = os.path.expanduser(f)
-                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
+                res = subprocess.call(["halcmd"] + f.split())
                 if res:
                     LOG.error('postgui command error:{}'.format(res))
                     raise SystemExit(res)
@@ -6718,7 +6718,7 @@ def _terminate(signum, frame):
     signal.signal(signal.SIGINT, _terminate)
 
     # The startup handler's SystemExit is lost where Python ignores
-    # exceptions, as in the os.fork() hooks of the postgui spawns above.
+    # exceptions, such as in an os.fork() hook.
     # The flag still says that a SIGTERM came.
     if _terminate_requested:
         LOG.info("gmoccapy received SIGTERM during startup, shutting down")

src/emc/usr_intf/gscreen/gscreen.py

@@ -4797,9 +4797,9 @@ def __setitem__(self, item, value):
     if postgui_halfile is not None:
         for f in postgui_halfile:
             if f.lower().endswith('.tcl'):
-                res = os.spawnvp(os.P_WAIT, "haltcl", ["haltcl", "-i", inifile, f])
+                res = subprocess.call(["haltcl", "-i", inifile, f])
             else:
-                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", inifile, "-f", f])
+                res = subprocess.call(["halcmd", "-i", inifile, "-f", f])
             if res: raise SystemExit(res)
     Gtk.main()
 

src/emc/usr_intf/qtvcp/qtvcp.py

@@ -499,9 +499,9 @@ def postgui(self):
             for f in postgui_halfile:
                 f = os.path.expanduser(f)
                 if f.lower().endswith('.tcl'):
-                    res = os.spawnvp(os.P_WAIT, "haltcl", ["haltcl", "-i",self.inipath, f])
+                    res = subprocess.call(["haltcl", "-i",self.inipath, f])
                 else:
-                    res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i",self.inipath,"-f", f])
+                    res = subprocess.call(["halcmd", "-i",self.inipath,"-f", f])
                 if res: raise SystemExit(res)
 
     def postgui_cmd(self):
@@ -510,7 +510,7 @@ def postgui_cmd(self):
         if postgui_commands is not None:
             for f in postgui_commands:
                 f = os.path.expanduser(f)
-                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
+                res = subprocess.call(["halcmd"] + f.split())
                 if res: raise SystemExit(res)
 
     # This can be called by control c or an early error.