Proc mode: try to guess PID based on PPID when multiple found

app/server/config/integration/proc.ts

@@ -61,14 +61,37 @@ export default class ProcIntegration extends Integration<T> {
 
 			log.debug('config', 'Found Headscale processes: %o', pids);
 			if (pids.length > 1) {
-				log.error(
+				log.warn(
 					'config',
 					'Found %d Headscale processes: %s',
 					pids.length,
 					pids.join(', '),
 				);
-				return false;
-			}
+
+        log.debug('config', 'Checking if any of them have Parent PID = 1, assuming thats the correct PID');
+        const ppidRegex = /(?:PPid:\s)(\d+)(?:\n?)/;
+        for (const pid of pids) {
+          const pidStatusPath = join('/proc', pid.toString(), 'status');
+          try {
+            log.debug('config', 'Reading %s', pidStatusPath);
+            const pidData = await readFile(pidStatusPath, 'utf8');
+            const ppidResult = pidData.match(ppidRegex);
+
+            if (ppidResult !== null) {
+              const potentialPPid = Number.parseInt(ppidResult[1], 10);
+              if (potentialPPid === 1) {
+                this.pid = pid;
+                log.info('config', 'Found potential Headscale process with PID: %d based on Parent PID = 1', this.pid);
+                return true;
+              }
+            }
+          } catch (error) {
+            log.error('config', 'Failed to read %s: %s', pidStatusPath, error);
+          }
+        }
+
+        return false;
+      }
 
 			if (pids.length === 0) {
 				log.error('config', 'Could not find Headscale process');