Make mmap optional in Fcitx5Utils

CMakeLists.txt

@@ -16,6 +16,7 @@ include(WriteBasicConfigVersionFile)
 include(ECMUninstallTarget)
 include(src/lib/fcitx-utils/Fcitx5Macros.cmake)
 include(CheckSymbolExists)
+include(CheckIncludeFile)
 
 #######################################################################
 # Options
@@ -225,6 +226,7 @@ else()
 endif()
 
 check_function_exists(pipe2 HAVE_PIPE2)
+check_include_file(sys/mman.h HAVE_SYS_MMAN_H)
 
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/config.h)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})

config.h.in

@@ -44,6 +44,7 @@
 #define DBUS_SYSTEM_BUS_DEFAULT_ADDRESS "@DBUS_SYSTEM_BUS_DEFAULT_ADDRESS@"
 
 #cmakedefine HAVE_PIPE2
+#cmakedefine HAVE_SYS_MMAN_H
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE

src/lib/fcitx-utils/library.cpp

@@ -8,7 +8,6 @@
 #include "library.h"
 #include <dlfcn.h>
 #include <fcntl.h>
-#include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <cerrno>
@@ -23,8 +22,22 @@
 #include "misc.h"
 #include "stringutils.h"
 
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
 namespace fcitx {
 
+namespace {
+
+#ifdef RTLD_NODELETE
+constexpr bool hasRTLDNoDelete = true;
+#else
+constexpr bool hasRTLDNoDelete = false;
+#endif
+
+} // namespace
+
 class LibraryPrivate {
 public:
     LibraryPrivate(std::string path) : path_(std::move(path)) {}
@@ -34,9 +47,15 @@ class LibraryPrivate {
         if (!handle_) {
             return false;
         }
-        if (dlclose(handle_)) {
-            error_ = dlerror();
-            return false;
+
+        // If there is no RTLD_NODELETE and we don't want to unload, we leak
+        // it on purpose.
+        if (hasRTLDNoDelete ||
+            !loadFlag_.test(LibraryLoadHint::PreventUnloadHint)) {
+            if (dlclose(handle_)) {
+                error_ = dlerror();
+                return false;
+            }
         }
 
         handle_ = nullptr;
@@ -46,6 +65,7 @@ class LibraryPrivate {
     std::string path_;
     void *handle_ = nullptr;
     std::string error_;
+    Flags<fcitx::LibraryLoadHint> loadFlag_;
 };
 
 Library::Library(const std::string &path)
@@ -54,6 +74,9 @@ Library::Library(const std::string &path)
 FCITX_DEFINE_DEFAULT_DTOR_AND_MOVE(Library)
 
 bool Library::load(Flags<fcitx::LibraryLoadHint> hint) {
+    if (loaded()) {
+        return true;
+    }
     FCITX_D();
     int flag = 0;
     if (hint & LibraryLoadHint::ResolveAllSymbolsHint) {
@@ -62,9 +85,11 @@ bool Library::load(Flags<fcitx::LibraryLoadHint> hint) {
         flag |= RTLD_LAZY;
     }
 
+#ifdef RTLD_NODELETE
     if (hint & LibraryLoadHint::PreventUnloadHint) {
         flag |= RTLD_NODELETE;
     }
+#endif
 
     if (hint & LibraryLoadHint::ExportExternalSymbolsHint) {
         flag |= RTLD_GLOBAL;
@@ -86,6 +111,8 @@ bool Library::load(Flags<fcitx::LibraryLoadHint> hint) {
         return false;
     }
 
+    d->loadFlag_ = hint;
+
     return true;
 }
 
@@ -141,9 +168,12 @@ bool Library::findData(const char *slug, const char *magic, size_t lenOfMagic,
             d->error_ = strerror(errno);
             break;
         }
+        void *data = nullptr;
+#ifdef HAVE_SYS_MMAN_H
+        data = mmap(nullptr, statbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
         void *needunmap = nullptr;
-        void *data = needunmap =
-            mmap(nullptr, statbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+        needunmap = data;
+#endif
         if (!data) {
             data = malloc(statbuf.st_size);
             needfree.reset(data);
@@ -163,9 +193,11 @@ bool Library::findData(const char *slug, const char *magic, size_t lenOfMagic,
             parser(pos);
         }
         result = true;
+#ifdef HAVE_SYS_MMAN_H
         if (needunmap) {
             munmap(needunmap, statbuf.st_size);
         }
+#endif
     } while (false);
 
     close(fd);