Fix SIGSEGV in i1Pro 2 teardown and cleanup

- Relocate LED turn-off to i1pro_close_port() before closing communication port
- Guard LED turn-off and log updates against NULL pointers and closed ports in del_i1proimp()
- Ensure clean termination, unblock, and joining of i1pro switch and trigger threads in both i1pro_close_port() and del_i1proimp()
- Protect against NULL terminate callback on Unix/macOS

.github/workflows/build-macos.yml

@@ -11,11 +11,11 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-15-intel
+          - os: macos-26-intel
             arch: x86_64
             machtype: x86_64-apple-darwin
             artifact: macOS_x86_64_bin
-          - os: macos-15
+          - os: macos-latest
             arch: arm64
             machtype: arm64-apple-darwin
             artifact: macOS_arm64_bin
@@ -43,6 +43,16 @@ jobs:
           export CCOPTFLAG="-O0"
           jam -q -d2 -fJambase -j1 -sBUILTIN_TIFF=true -sBUILTIN_JPEG=true -sBUILTIN_PNG=true -sBUILTIN_Z=true -sBUILTIN_SSL=true install
           
+      - name: Ad-hoc Sign & Verify Binaries
+        run: |
+          for f in bin/*; do
+            if [ -f "$f" ] && file "$f" | grep -q "Mach-O"; then
+              echo "Ad-hoc signing $f"
+              codesign -f -s - "$f"
+              codesign -dvv "$f"
+            fi
+          done
+
       - name: Smoke Tests
         env:
           ARGYLL_NOT_INTERACTIVE: "1"
@@ -64,6 +74,12 @@ jobs:
           echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
           mv Argyll_V*_${{ matrix.artifact }}.tgz "Argyll_${TAG}_${SHORT_SHA}_${{ matrix.artifact }}.tgz"
           
+      - name: Upload Raw Binaries
+        uses: actions/upload-artifact@v4
+        with:
+          name: raw-bin-${{ matrix.arch }}
+          path: bin/
+          
       - name: Upload Artifact
         uses: actions/upload-artifact@v4
         with:
@@ -77,3 +93,103 @@ jobs:
           name: Release ${{ github.ref_name }}
           body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
           files: Argyll_*_${{ matrix.artifact }}.tgz
+
+  universal:
+    needs: build
+    runs-on: macos-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Download x86_64 binaries
+        uses: actions/download-artifact@v4
+        with:
+          name: raw-bin-x86_64
+          path: raw-bin-x86_64
+
+      - name: Download arm64 binaries
+        uses: actions/download-artifact@v4
+        with:
+          name: raw-bin-arm64
+          path: raw-bin-arm64
+
+      - name: Create Universal Binaries
+        run: |
+          mkdir -p bin
+          for file in raw-bin-arm64/*; do
+            bin_name=$(basename "$file")
+            if [ -f "raw-bin-x86_64/$bin_name" ]; then
+              if file "raw-bin-arm64/$bin_name" | grep -q "Mach-O" && file "raw-bin-x86_64/$bin_name" | grep -q "Mach-O"; then
+                echo "Creating universal binary with lipo: $bin_name"
+                lipo -create "raw-bin-x86_64/$bin_name" "raw-bin-arm64/$bin_name" -output "bin/$bin_name"
+                chmod +x "bin/$bin_name"
+                codesign -f -s - "bin/$bin_name"
+              else
+                echo "Non Mach-O file, copying directly: $bin_name"
+                cp "$file" "bin/$bin_name"
+              fi
+            else
+              echo "Warning: $bin_name not found in raw-bin-x86_64, copying arm64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+          for file in raw-bin-x86_64/*; do
+            bin_name=$(basename "$file")
+            if [ ! -f "bin/$bin_name" ]; then
+              echo "Warning: $bin_name only found in raw-bin-x86_64, copying x86_64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+
+      - name: Verify Architecture & Code Signatures
+        env:
+          ARGYLL_NOT_INTERACTIVE: "1"
+          ARGYLL_EXCLUDE_SERIAL_SCAN: "1"
+        run: |
+          echo "=== Binary Architecture & Signature Verification ==="
+          for file in bin/*; do
+            if [ -f "$file" ] && file "$file" | grep -q "Mach-O"; then
+              file "$file"
+              codesign -dvv "$file"
+            fi
+          done
+          echo "=== Smoke Tests ==="
+          ./bin/dispcal -? || true
+          ./bin/chartread -? || true
+          ./bin/colprof -? || true
+          ./bin/targen -? || true
+
+      - name: Package Universal Release
+        run: |
+          export OSTYPE=darwin
+          export MACHTYPE=universal-apple-darwin
+          export HOSTTYPE=universal
+          export NO_BUILD=1
+          ./makepackagebin.sh
+          TAG="${{ github.ref_name }}"
+          SHORT_SHA="$(git rev-parse --short HEAD)"
+          echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
+          mv Argyll_V*_macOS_universal_bin.tgz "Argyll_${TAG}_${SHORT_SHA}_macOS_universal_bin.tgz"
+
+      - name: Upload Universal Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Argyll_${{ github.ref_name }}_${{ env.SHORT_SHA }}_macOS_universal_bin
+          path: Argyll_*_macOS_universal_bin.tgz
+
+      - name: Upload Universal Release Asset
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: softprops/action-gh-release@v2
+        with:
+          name: Release ${{ github.ref_name }}
+          body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
+          files: Argyll_*_macOS_universal_bin.tgz

doc/ChangesSummary.html

@@ -19,6 +19,7 @@
     <h1>[V3.4.1 -&gt; V3.5.0] 4th February 2026<br>
     </h1>
     <ul>
+      <li>Added macOS Universal Binary release archive (Intel x86_64 + Apple Silicon arm64).</li>
       <li>Fixed non-blocking stdin polling deadlock on MSWindows anonymous pipes when running interactive measurement tools in subprocess mode.</li>
       <li>Added -d switch to printtarg to allow custom chart label strings or omit labelling entirely.</li>
       <li>Added MSWindows ARM release.</li>

makepackagebin.sh

@@ -7,7 +7,7 @@ echo "Script to invoke Jam and then package the binary release."
 PRODUCT=Argyll
 
 # Set the environment string VERSION from the #define, ie 1.0.0
-VERSION=`grep ARGYLL_VERSION_STR h/aconfig.h | head -1 | sed 's/# define ARGYLL_VERSION_STR //' | sed 's/"//g'`
+VERSION=`grep ARGYLL_VERSION_STR h/aconfig.h | head -1 | sed 's/# define ARGYLL_VERSION_STR //' | sed 's/\"//g'`
 
 #   Typical environment variables:
 #   (NOTE some systems don't export these ENV vars. by default !!!)
@@ -113,6 +113,13 @@ else if [ "${OSTYPE#*darwin*}" != "$OSTYPE" ] ; then
 		echo "We're on MacOS arm64!"
 		PACKAGE=${PRODUCT}_V${VERSION}_macOS_arm64_bin.tgz
 		export MACOSX_DEPLOYMENT_TARGET="11.0"	# Minimum target platform version
+	else if [ X$HOSTTYPE = "Xuniversal" \
+		  -o X$MACHTYPE = "Xuniversal-apple-darwin" \
+		  -o X$COMPILER = "XUNIVERSAL" ] ; then
+		echo "We're on MacOS Universal!"
+		PACKAGE=${PRODUCT}_V${VERSION}_macOS_universal_bin.tgz
+		export MACOSX_DEPLOYMENT_TARGET="10.15"	# Minimum target platform version
+	fi
 	fi
 	fi
 	fi
@@ -145,6 +152,7 @@ fi
 
 echo "Making GNU $PRODUCT binary distribution $PACKAGE for Version $VERSION"
 
+if [ X$NO_BUILD = "X" ] ; then
 	# Clean up so we get a solid build
 	# .sp come from profile, .cht from scanin and .ti3 from spectro
 	rm -f bin/*.exe bin/*.dll
@@ -163,6 +171,18 @@ if ! jam -q -fJambase -j${NUMBER_OF_PROCESSORS:-1} -sBUILTIN_TIFF=true -sBUILTIN
 		echo "Build failed!"
 		exit 1
 	fi 
+fi 
+
+# Apply ad-hoc code signatures to macOS Mach-O binaries before staging
+if [ "${OSTYPE#*darwin*}" != "$OSTYPE" ] ; then
+	echo "=== Applying ad-hoc code signatures to macOS Mach-O binaries ==="
+	for f in bin/* ; do
+		if [ -f "$f" ] && file "$f" | grep -q "Mach-O" ; then
+			echo "Signing $f..."
+			codesign -f -s - "$f" || true
+		fi
+	done
+fi
 
 rm -rf $TOPDIR
 mkdir $TOPDIR

spectro/i1pro.c

@@ -948,6 +948,8 @@ static void
 i1pro_del(inst *pp) {
 	i1pro *p = (i1pro *)pp;
 
+	/* Shut down instrument hardware and close the port, then free state */
+	i1pro_close_port(p);
 	del_i1proimp(p);
 	if (p->icom != NULL)
 		p->icom->del(p->icom);

spectro/i1pro_imp.c

@@ -389,8 +389,106 @@ i1pro_code add_i1proimp(i1pro *p) {
 	return I1PRO_OK;
 }
 
-/* Shutdown instrument, and then destroy */
-/* implementation structure */
+/* Stop background threads (switch monitoring & delayed trigger) */
+static void
+i1pro_stop_threads(i1pro *p) {
+	i1proimp *m;
+	int i;
+
+	if (p == NULL || p->m == NULL)
+		return;
+	m = (i1proimp *)p->m;
+
+	/* Stop the switch monitoring thread first so it isn't using the */
+	/* communication channel while we shut down the instrument. */
+	if (m->th != NULL) {
+		m->th_term = 1;			/* Tell thread to exit on error */
+
+		/* Ask the instrument to stop sending switch events and cancel */
+		/* any outstanding switch read. Only do this if the port is still  */
+		/* open and the required method pointers are valid. */
+		if (p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL
+		 && p->icom->usb_cancel_io != NULL) {
+			i1pro_terminate_switch(p);
+		}
+
+		/* Give the thread a chance to exit cleanly (up to 5 seconds). */
+		for (i = 0; m->th_termed == 0 && i < 100; i++)
+			msec_sleep(50);
+
+		if (m->th_termed == 0) {
+			a1logd(p->log,3,"i1pro switch thread did not terminate, forcing\n");
+			if (m->th->terminate != NULL)
+				m->th->terminate(m->th);
+		}
+
+		if (m->th->wait != NULL)
+			m->th->wait(m->th);
+		if (m->th->del != NULL)
+			m->th->del(m->th);
+		m->th = NULL;
+
+		usb_uninit_cancel(&m->sw_cancel);		/* Don't need cancel token now */
+		usb_uninit_cancel(&m->rd_sync);			/* Don't need sync token now */
+		a1logd(p->log,5,"i1pro switch thread terminated\n");
+	}
+
+	/* Stop the delayed trigger thread if it is still running */
+	if (m->trig_thread != NULL) {
+		if (m->trig_thread->wait != NULL)
+			m->trig_thread->wait(m->trig_thread);
+		if (m->trig_thread->del != NULL)
+			m->trig_thread->del(m->trig_thread);
+		m->trig_thread = NULL;
+		a1logd(p->log,5,"i1pro trigger thread terminated\n");
+	}
+}
+
+/* Stop any pending I/O, shut down the instrument hardware, and close the */
+/* communication port. This is separate from freeing the implementation data. */
+i1pro_code
+i1pro_close_port(i1pro *p) {
+	i1pro_code ev = I1PRO_OK;
+	i1proimp *m;
+
+	a1logd(p->log,3,"i1pro_close_port: called\n");
+
+	if (p->m == NULL)
+		return I1PRO_OK;
+	m = (i1proimp *)p->m;
+
+	/* Stop the switch monitoring thread and trigger thread first so they */
+	/* aren't using the communication channel while we shut down the instrument. */
+	i1pro_stop_threads(p);
+
+	/* Update usage log/calibration for Rev A..D before closing the port */
+	if (p->dtype != instI1Pro2 && p->icom != NULL && p->icom->is_open
+	 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+		i1pro_code uev;
+		if ((uev = i1pro_update_log(p)) != I1PRO_OK) {
+			a1logd(p->log,2,"i1pro_update_log: Updating the cal and log parameters to"
+			                                              " EEProm failed failed\n");
+		}
+	}
+
+	/* Turn off i1Pro2/Rev E indicator LEDs before closing the port. */
+	/* Only attempt the write if the port is still actively open and the */
+	/* required USB method pointers are valid. Rev A..D do not have LEDs. */
+	if (p->dtype == instI1Pro2 && p->icom != NULL && p->icom->is_open
+	 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+		i1pro2_indLEDoff(p);	/* Ignore error - we're shutting down */
+	}
+
+	/* Close the underlying communication port */
+	if (p->icom != NULL && p->icom->is_open && p->icom->close_port != NULL) {
+		p->icom->close_port(p->icom);
+	}
+
+	return ev;
+}
+
+/* Destroy implementation structure */
 void del_i1proimp(i1pro *p) {
 
 	a1logd(p->log,5,"i1pro_del called\n");
@@ -404,38 +502,28 @@ void del_i1proimp(i1pro *p) {
 		int i, j;
 		i1proimp *m = (i1proimp *)p->m;
 		i1pro_state *s;
-		i1pro_code ev;
 
-		if (p->dtype != instI1Pro2 && (ev = i1pro_update_log(p)) != I1PRO_OK) {
+		/* Defensive guard: ensure background threads are terminated and joined */
+		/* before freeing state, in case i1pro_close_port() was not called. */
+		i1pro_stop_threads(p);
+
+		/* Defensive guard: update usage log/cal for Rev A..D if port is still open */
+		if (p->dtype != instI1Pro2 && p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+			i1pro_code uev;
+			if ((uev = i1pro_update_log(p)) != I1PRO_OK) {
 				a1logd(p->log,2,"i1pro_update_log: Updating the cal and log parameters to"
 				                                              " EEProm failed failed\n");
 			}
-
-		/* i1pro_terminate_switch() seems to fail on a rev A & Rev C ?? */
-		if (m->th != NULL) {		/* Terminate switch monitor thread */
-			m->th_term = 1;			/* Tell thread to exit on error */
-			i1pro_terminate_switch(p);
-			
-			for (i = 0; m->th_termed == 0 && i < 5; i++)
-				msec_sleep(50);		/* Wait for thread to terminate */
-			if (i >= 5) {
-				a1logd(p->log,5,"i1pro switch thread termination failed\n");
-				m->th->terminate(m->th);	/* Try and force thread to terminate */
-			}
-			/* Strange Mac M2/rosetta bug ?? */
-			if (m->th->del == NULL) {
-				a1logd(p->log,1,"i1pro_del: ,m->th-del is NULL!!!");
-			} else {
-				m->th->del(m->th);
-			}
-			usb_uninit_cancel(&m->sw_cancel);		/* Don't need cancel token now */
-			usb_uninit_cancel(&m->rd_sync);			/* Don't need sync token now */
-			a1logd(p->log,5,"i1pro switch thread terminated\n");
 		}
 
-		if (m->trig_thread != NULL) {
-			m->trig_thread->del(m->trig_thread);
-			a1logd(p->log,5,"i1pro trigger thread terminated\n");
+		/* Defensive guard: if the com port is still open and this is an */
+		/* i1Pro2, make sure the indicator LEDs are turned off before any */
+		/* memory is freed. In normal teardown i1pro_close_port() has */
+		/* already done this, but the guard protects any direct call paths. */
+		if (p->dtype == instI1Pro2 && p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+			i1pro2_indLEDoff(p);
 		}
 
 		/* Free any per mode data */

spectro/i1pro_imp.h

@@ -348,6 +348,9 @@ i1pro_code add_i1proimp(i1pro *p);
 /* Destroy implementation structure */
 void del_i1proimp(i1pro *p);
 
+/* Close instrument (stop threads, update log, turn off LEDs, close coms) */
+i1pro_code i1pro_close_port(i1pro *p);
+
 /* ============================================================ */
 /* Error codes returned from i1pro_imp */