From 03ef12cc799aed7bec3cde3a260b797632b087a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>
Date: Sat, 10 Feb 2024 21:34:22 +0000
Subject: [PATCH] netbpfload: enable on U QPR2 (aka 24Q1)
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(this will land in M-2024-05 ie. May mainline tethering module)

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I250b691eb03751da05ce10d41d6721f4964dd1d5
---
 netbpfload/Android.bp     |  9 ++++-----
 netbpfload/NetBpfLoad.cpp | 30 ++++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/netbpfload/Android.bp b/netbpfload/Android.bp
index b5e4722ece..b71890ebd2 100644
--- a/netbpfload/Android.bp
+++ b/netbpfload/Android.bp
@@ -44,7 +44,7 @@ cc_binary {
         "com.android.tethering",
         "//apex_available:platform",
     ],
-    // really should be Android 14/U (34), but we cannot include binaries built
+    // really should be Android 13/T (33), but we cannot include binaries built
     // against newer sdk in the apex, which still targets 30(R):
     // module "netbpfload" variant "android_x86_apex30": should support
     // min_sdk_version(30) for "com.android.tethering": newer SDK(34).
@@ -54,15 +54,14 @@ cc_binary {
     required: ["bpfloader"],
 }
 
-// Versioned netbpfload init rc: init system will process it only on api V/35+ devices
-// (TODO: consider reducing to T/33+ - adjust the comment up above in line 43 as well)
-// Note: S[31] Sv2[32] T[33] U[34] V[35])
+// Versioned netbpfload init rc: init system will process it only on api T/33+ devices
+// Note: R[30] S[31] Sv2[32] T[33] U[34] V[35])
 //
 // For details of versioned rc files see:
 // https://android.googlesource.com/platform/system/core/+/HEAD/init/README.md#versioned-rc-files-within-apexs
 prebuilt_etc {
     name: "netbpfload.mainline.rc",
     src: "netbpfload.mainline.rc",
-    filename: "netbpfload.35rc",
+    filename: "netbpfload.33rc",
     installable: false,
 }
diff --git a/netbpfload/NetBpfLoad.cpp b/netbpfload/NetBpfLoad.cpp
index 3c5e4c30d0..2d8867e216 100644
--- a/netbpfload/NetBpfLoad.cpp
+++ b/netbpfload/NetBpfLoad.cpp
@@ -243,9 +243,15 @@ int main(int argc, char** argv, char * const envp[]) {
     const bool isAtLeastU = (device_api_level >= __ANDROID_API_U__);
     const bool isAtLeastV = (device_api_level >= __ANDROID_API_V__);
 
-    ALOGI("NetBpfLoad api:%d/%d kver:%07x platform:%d mainline:%d",
+    // last in U QPR2 beta1
+    const bool has_platform_bpfloader_rc = exists("/system/etc/init/bpfloader.rc");
+    // first in U QPR2 beta~2
+    const bool has_platform_netbpfload_rc = exists("/system/etc/init/netbpfload.rc");
+
+    ALOGI("NetBpfLoad api:%d/%d kver:%07x platform:%d mainline:%d rc:%d%d",
           android_get_application_target_sdk_version(), device_api_level,
-          android::bpf::kernelVersion(), is_platform, is_mainline);
+          android::bpf::kernelVersion(), is_platform, is_mainline,
+          has_platform_bpfloader_rc, has_platform_netbpfload_rc);
 
     if (!is_platform && !is_mainline) {
         ALOGE("Unable to determine if we're platform or mainline netbpfload.");
@@ -258,8 +264,28 @@ int main(int argc, char** argv, char * const envp[]) {
         ALOGW("exec '%s' fail: %d[%s]", apexNetBpfLoad, errno, strerror(errno));
     }
 
+    if (!has_platform_bpfloader_rc && !has_platform_netbpfload_rc) {
+        ALOGE("Unable to find platform's bpfloader & netbpfload init scripts.");
+        return 1;
+    }
+
+    if (has_platform_bpfloader_rc && has_platform_netbpfload_rc) {
+        ALOGE("Platform has *both* bpfloader & netbpfload init scripts.");
+        return 1;
+    }
+
     logTetheringApexVersion();
 
+    if (is_mainline && has_platform_bpfloader_rc && !has_platform_netbpfload_rc) {
+        // Tethering apex shipped initrc file causes us to reach here
+        // but we're not ready to correctly handle anything before U QPR2
+        // in which the 'bpfloader' vs 'netbpfload' split happened
+        const char * args[] = { platformBpfLoader, NULL, };
+        execve(args[0], (char**)args, envp);
+        ALOGE("exec '%s' fail: %d[%s]", platformBpfLoader, errno, strerror(errno));
+        return 1;
+    }
+
     if (isAtLeastT && !android::bpf::isAtLeastKernelVersion(4, 9, 0)) {
         ALOGE("Android T requires kernel 4.9.");
         return 1;