Autodetect "/proc/self/exe"-equivalent on FreeBSD (#1999)

CMakeLists.txt

@@ -300,6 +300,17 @@ if(UNIX AND NOT APPLE)
 	if(Backward_FOUND)
 		set(HAVE_BACKWARD 1)
 	endif()
+
+	if(NOT DEFINED PROC_SELF_EXE)
+		macro(FIND_PROC_SELF_EXE path)
+			if(EXISTS ${path})
+				set(PROC_SELF_EXE ${path} CACHE FILEPATH "Path to /proc/self/exe (Linux) or equivalent")
+			endif()
+		endmacro()
+		FIND_PROC_SELF_EXE(/proc/self/exe)     # Linux
+		FIND_PROC_SELF_EXE(/proc/curproc/file) # FreeBSD
+		FIND_PROC_SELF_EXE(/proc/curproc/exe)  # NetBSD
+	endif()
 endif()
 
 if (WIN32)

config.h.cmake

@@ -118,3 +118,6 @@
 
 /* Include OpenAL extensions (alext.h) for sound modifiers */
 #cmakedefine HAVE_ALEXT 1
+
+/* Path to /proc/self/exe (Linux) or equivalent */
+#cmakedefine PROC_SELF_EXE "${PROC_SELF_EXE}"

src/config/C4Config.cpp

@@ -443,9 +443,9 @@ void C4ConfigGeneral::DeterminePaths()
 	GetTempPathW(CFG_MaxString,apath);
 	TempPath = StdStrBuf(apath);
 	if (TempPath[0]) TempPath.AppendBackslash();
-#elif defined(__linux__)
+#elif defined(PROC_SELF_EXE)
 	ExePath.SetLength(1024);
-	ssize_t l = readlink("/proc/self/exe", ExePath.getMData(), 1024);
+	ssize_t l = readlink(PROC_SELF_EXE, ExePath.getMData(), 1024);
 	if (l < -1)
 	{
 		ExePath.Ref(".");

src/platform/PlatformAbstraction.cpp

@@ -98,7 +98,7 @@ bool RestartApplication(std::vector<const char *> parameters)
 		intptr_t iError = (intptr_t)::ShellExecute(nullptr, nullptr, buf, params.GetWideChar(), Config.General.ExePath.GetWideChar(), SW_SHOW);
 		if (iError > 32) success = true;
 	}
-#else
+#elif defined(PROC_SELF_EXE)
 	pid_t pid;
 	switch (pid = fork())
 	{
@@ -108,7 +108,7 @@ bool RestartApplication(std::vector<const char *> parameters)
 		std::vector<const char*> params = {"openclonk"};
 		params.insert(params.end(), parameters.begin(), parameters.end());
 		params.push_back(nullptr);
-		execv("/proc/self/exe", const_cast<char *const *>(params.data()));
+		execv(PROC_SELF_EXE, const_cast<char *const *>(params.data()));
 		perror("editor launch failed");
 		exit(1);
 	}