commit 85ac050b35be160ba06c3c96b988758f37438fb3
author Maciej Żenczykowski <maze@google.com> Wed Oct 04 01:12:14 2023 +0000
committer Maciej Żenczykowski <maze@google.com> Wed Oct 04 19:14:43 2023 +0000
tree 4a9e5d0eb9fe629adec2397e606ffeeab4f759d1
parent 5b2611d044fbd976e14225e91bacb715f4d4d47d

bpf jni: add native_getProgramIdFromCgroup

Test: TreeHugger
Bug: 292156770
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ib7b194b9cbf6519f9fbcfd1fcefcbe5d825f5c3a

staticlibs/device/com/android/net/module/util/BpfUtils.java

diff --git a/staticlibs/device/com/android/net/module/util/BpfUtils.java b/staticlibs/device/com/android/net/module/util/BpfUtils.java
index 94af11b..f1546c0 100644
--- a/staticlibs/device/com/android/net/module/util/BpfUtils.java
+++ b/staticlibs/device/com/android/net/module/util/BpfUtils.java
@@ -66,4 +66,6 @@
             throws IOException;
     private static native boolean native_detachSingleProgramFromCgroup(int type,
             String programPath, String cgroupPath) throws IOException;
+    private static native int native_getProgramIdFromCgroup(int type, String cgroupPath)
+            throws IOException;
 }

staticlibs/native/bpfutiljni/com_android_net_module_util_BpfUtils.cpp

diff --git a/staticlibs/native/bpfutiljni/com_android_net_module_util_BpfUtils.cpp b/staticlibs/native/bpfutiljni/com_android_net_module_util_BpfUtils.cpp
index 0f2ebbd..df9e586 100644
--- a/staticlibs/native/bpfutiljni/com_android_net_module_util_BpfUtils.cpp
+++ b/staticlibs/native/bpfutiljni/com_android_net_module_util_BpfUtils.cpp
@@ -110,6 +110,29 @@
     return true;
 }
 
+static jint com_android_net_module_util_BpfUtil_getProgramIdFromCgroup(JNIEnv *env,
+        jclass clazz, jint type, jstring cgroupPath) {
+
+    ScopedUtfChars dirPath(env, cgroupPath);
+    unique_fd cg_fd(open(dirPath.c_str(), O_DIRECTORY | O_RDONLY | O_CLOEXEC));
+    if (cg_fd == -1) {
+        jniThrowExceptionFmt(env, "java/io/IOException",
+                             "Failed to open the cgroup directory %s: %s",
+                             dirPath.c_str(), strerror(errno));
+        return -1;
+    }
+
+    int id = bpf::queryProgram(cg_fd, (bpf_attach_type) type);
+    if (id < 0) {
+        jniThrowExceptionFmt(env, "java/io/IOException",
+                             "Failed to query bpf program %d at %s: %s",
+                             type, dirPath.c_str(), strerror(errno));
+        return -1;
+    }
+    return id;  // may return 0 meaning none
+}
+
+
 /*
  * JNI registration.
  */
@@ -121,6 +144,8 @@
         (void*) com_android_net_module_util_BpfUtil_detachProgramFromCgroup },
     { "native_detachSingleProgramFromCgroup", "(ILjava/lang/String;Ljava/lang/String;)Z",
         (void*) com_android_net_module_util_BpfUtil_detachSingleProgramFromCgroup },
+    { "native_getProgramIdFromCgroup", "(ILjava/lang/String;)I",
+        (void*) com_android_net_module_util_BpfUtil_getProgramIdFromCgroup },
 };
 
 int register_com_android_net_module_util_BpfUtils(JNIEnv* env, char const* class_name) {