Add helpers to read the executable path for a given PID

src/wayland/CMakeLists.txt

@@ -285,6 +285,16 @@ ecm_add_qtwayland_server_protocol_kde(SERVER_LIB_SRCS
 )
 
 add_library(KWaylandServer ${SERVER_LIB_SRCS})
+
+if(CMAKE_SYSTEM_NAME MATCHES "Linux")
+    target_sources(KWaylandServer PRIVATE utils/executable_path_proc.cpp)
+elseif(CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+    target_sources(KWaylandServer PRIVATE utils/executable_path_sysctl.cpp)
+else()
+    message(FATAL_ERROR "Unsupported platform ${CMAKE_SYSTEM_NAME}")
+endif()
+
+
 add_library(Plasma::KWaylandServer ALIAS KWaylandServer)
 ecm_generate_export_header(KWaylandServer
     BASE_NAME

src/wayland/clientconnection.cpp

@@ -5,6 +5,7 @@
 */
 #include "clientconnection.h"
 #include "display.h"
+#include "utils/executable_path.h"
 // Qt
 #include <QFileInfo>
 #include <QVector>
@@ -44,7 +45,7 @@ ClientConnectionPrivate::ClientConnectionPrivate(wl_client *c, Display *display,
     listener.notify = destroyListenerCallback;
     wl_client_add_destroy_listener(c, &listener);
     wl_client_get_credentials(client, &pid, &user, &group);
-    executablePath = QFileInfo(QStringLiteral("/proc/%1/exe").arg(pid)).symLinkTarget();
+    executablePath = executablePathFromPid(pid);
 }
 
 ClientConnectionPrivate::~ClientConnectionPrivate()

src/wayland/utils/executable_path.h

@@ -0,0 +1,11 @@
+/*
+    SPDX-FileCopyrightText: 2021 Tobias C. Berner <tcberner@FreeBSD.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#pragma once
+
+#include <QString>
+
+QString executablePathFromPid(pid_t);

src/wayland/utils/executable_path_proc.cpp

@@ -0,0 +1,14 @@
+/*
+    SPDX-FileCopyrightText: 2021 Tobias C. Berner <tcberner@FreeBSD.org>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "executable_path.h"
+
+#include <QFileInfo>
+
+QString executablePathFromPid(pid_t pid)
+{
+    return QFileInfo(QStringLiteral("/proc/%1/exe").arg(pid)).symLinkTarget();
+}

src/wayland/utils/executable_path_sysctl.cpp

@@ -0,0 +1,22 @@
+/*
+   SPDX-FileCopyrightText: 2021 Tobias C. Berner <tcberner@FreeBSD.org>
+
+   SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+
+#include "executable_path.h"
+
+QString executablePathFromPid(pid_t pid)
+{
+    const int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, static_cast<int>(pid)};
+    char buf[MAXPATHLEN];
+    size_t cb = sizeof(buf);
+    if (sysctl(mib, 4, buf, &cb, nullptr, 0) == 0) {
+        return QString::fromLocal8Bit(realpath(buf, nullptr));
+    }
+    return QString();
+}