fix: improve process name resolution for DBus clients

dconfig-center/dde-dconfig-daemon/dconfig_global.h

@@ -4,12 +4,13 @@
 
 #pragma once
 
 #include <QFile>
 #include <QQueue>
 #include <QString>
+#include <QFileInfo>
 #include <functional>
 #include <QRegularExpression>
 #include <DStandardPaths>
 #include <QLoggingCategory>
 #include "helper.hpp"
 
@@ -175,15 +176,24 @@
     InitFunc m_initFunc;
 };
 
 inline QString getProcessNameByPid(const uint pid)
 {
 #ifdef Q_OS_LINUX
-    const QString desc = QString("/proc/%1/cmdline").arg(pid);
-
-    QFile file(desc);
-    if(file.open(QIODevice::ReadOnly)) {
+    // Prefer /proc/{pid}/exe symlink for process name.
+    // May fail due to permission (daemon runs as deepin-daemon, target process
+    // may belong to another user). Fallback to /proc/{pid}/cmdline in that case.
+    const QString exePath = QFile::symLinkTarget(QString("/proc/%1/exe").arg(pid));
+    if (!exePath.isEmpty())
+        return exePath;
+
+    // Fallback: /proc/{pid}/cmdline is world-readable (0444)
+    const QString cmdlinePath = QString("/proc/%1/cmdline").arg(pid);
+    QFile file(cmdlinePath);
+    if (file.open(QIODevice::ReadOnly)) {
         const QByteArray &name = file.readLine();
-        return name.split('\0').join(" ").trimmed();
+        const QString cmd = name.split('\0').join(" ").trimmed();
+        if (!cmd.isEmpty())
+            return cmd;
     }
 #endif // Q_OS_LINUX
     return QString::number(pid);

dconfig-center/dde-dconfig-daemon/dconfigconn.cpp

@@ -240,15 +240,15 @@ int DSGConfigConn::flags(const QString &key)
 
 QString DSGConfigConn::getAppid() const
 {
-    if (m_appName.isEmpty()) {
-        if (calledFromDBus()) {
-            const QString &service = message().service();
+    if (calledFromDBus()) {
+        const QString &service = message().service();
+        if (m_lastService != service) {
+            const_cast<DSGConfigConn *>(this)->m_lastService = service;
             const_cast<DSGConfigConn *>(this)->m_appName = getProcessNameByPid(connection().interface()->servicePid(service));
-        } else {
-            const_cast<DSGConfigConn *>(this)->m_appName = QString("testappid");
         }
+        return m_appName;
     }
-    return m_appName;
+    return QString("testappid");
 }
 
 bool DSGConfigConn::contains(const QString &key)

dconfig-center/dde-dconfig-daemon/dconfigconn.h

@@ -72,5 +72,5 @@ public Q_SLOTS: // METHODS
     ConnKey m_key;
     DSGConfigResource *m_resource = nullptr;
     QString m_appName;
+    QString m_lastService;
 };
-