optimize linux tun capability

sys/linux/LinuxCap.cpp

@@ -0,0 +1,33 @@
+#include "LinuxCap.h"
+
+#include <QProcess>
+
+#define EXIT_CODE(p) (p.exitStatus() == QProcess::NormalExit ? p.exitCode() : -1)
+
+QString Linux_GetCapString(const QString &path) {
+    QProcess p;
+    p.setProgram("getcap");
+    p.setArguments({path});
+    p.start();
+    p.waitForFinished(500);
+    return p.readAllStandardOutput();
+}
+
+int Linux_Pkexec_SetCapString(const QString &path, const QString &cap) {
+    QProcess p;
+    p.setProgram("pkexec");
+    p.setArguments({"setcap", cap, path});
+    p.start();
+    p.waitForFinished(-1);
+    return EXIT_CODE(p);
+}
+
+bool Linux_HavePkexec() {
+    QProcess p;
+    p.setProgram("pkexec");
+    p.setArguments({"--help"});
+    p.setProcessChannelMode(QProcess::SeparateChannels);
+    p.start();
+    p.waitForFinished(500);
+    return EXIT_CODE(p) == 0;
+}

sys/linux/LinuxCap.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <QString>
+
+QString Linux_GetCapString(const QString &path);
+
+int Linux_Pkexec_SetCapString(const QString &path, const QString &cap);
+
+bool Linux_HavePkexec();