A lib in APK can depend on other libs in the same APK
This hasn't worked because the path /mnt/apk/lib/<abi> wasn't in the
search paths of the linker namespace that the library is loaded (which
is the default namespace).
Fixing that by creating a new linker namespace 'microdroid' that
inherits the settings from the default namespace but adds the library
directory to the search paths, and loading the library from that
namespace.
Bug: N/A
Test: atest MicrodroidHostTestCases
Change-Id: I30c4ce86a48b80fa65e3b5ffeb90561fa1d2544e
diff --git a/launcher/Android.bp b/launcher/Android.bp
index 2c3f093..93cae96 100644
--- a/launcher/Android.bp
+++ b/launcher/Android.bp
@@ -5,5 +5,8 @@
cc_binary {
name: "microdroid_launcher",
srcs: ["main.cpp"],
- shared_libs: ["libdl"],
+ shared_libs: [
+ "libdl",
+ "libdl_android",
+ ],
}
diff --git a/launcher/main.cpp b/launcher/main.cpp
index fc9477d..4ecef3f 100644
--- a/launcher/main.cpp
+++ b/launcher/main.cpp
@@ -18,6 +18,24 @@
#include <cstdlib>
#include <iostream>
+#include <string>
+
+#include <android/dlext.h>
+
+extern "C" {
+enum {
+ ANDROID_NAMESPACE_TYPE_REGULAR = 0,
+ ANDROID_NAMESPACE_TYPE_ISOLATED = 1,
+ ANDROID_NAMESPACE_TYPE_SHARED = 2,
+};
+
+extern struct android_namespace_t* android_create_namespace(
+ const char* name, const char* ld_library_path, const char* default_library_path,
+ uint64_t type, const char* permitted_when_isolated_path,
+ struct android_namespace_t* parent);
+} // extern "C"
+
+static void* load(const std::string& libname);
int main(int argc, char* argv[]) {
if (argc < 2) {
@@ -27,7 +45,7 @@
}
const char* libname = argv[1];
- void* handle = dlopen(libname, RTLD_NOW);
+ void* handle = load(libname);
if (handle == nullptr) {
std::cerr << "Failed to load " << libname << ": " << dlerror() << "\n";
return EXIT_FAILURE;
@@ -42,3 +60,31 @@
return entry(argc - 1, argv + 1);
}
+
+// Create a new linker namespace whose search path is set to the directory of the library. Then
+// load it from there. Returns the handle to the loaded library if successful. Returns nullptr
+// if failed.
+void* load(const std::string& libname) {
+ // Parent as nullptr means the default namespace
+ android_namespace_t* parent = nullptr;
+ // The search paths of the new namespace are inherited from the parent namespace.
+ const uint64_t type = ANDROID_NAMESPACE_TYPE_SHARED;
+ // The directory of the library is appended to the search paths
+ const std::string libdir = libname.substr(0, libname.find_last_of("/"));
+ const char* ld_library_path = libdir.c_str();
+ const char* default_library_path = libdir.c_str();
+
+ android_namespace_t* new_ns = nullptr;
+ new_ns = android_create_namespace("microdroid_app", ld_library_path, default_library_path, type,
+ /* permitted_when_isolated_path */ nullptr, parent);
+ if (new_ns == nullptr) {
+ std::cerr << "Failed to create linker namespace: " << dlerror() << "\n";
+ return nullptr;
+ }
+
+ const android_dlextinfo info = {
+ .flags = ANDROID_DLEXT_USE_NAMESPACE,
+ .library_namespace = new_ns,
+ };
+ return android_dlopen_ext(libname.c_str(), RTLD_NOW, &info);
+}