commit 732a14164fbfa417b433cc7f6545b5542dcfa523
author Maciej Żenczykowski <maze@google.com> Thu Mar 14 00:17:18 2024 -0700
committer Maciej Żenczykowski <maze@google.com> Tue Mar 19 21:45:21 2024 +0000
tree 368c94665c9b606370e88861e84f811d61f70c16
parent 11141da6239c1b99300f65d6f742dcccce4841fb

NetBpfLoad: rework mainline bpf execution codepath

(for now for better testing we don't make V special)

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Id2835bd393c0ec9e1710644681bc5aab0d7d2aae

netbpfload/NetBpfLoad.cpp

diff --git a/netbpfload/NetBpfLoad.cpp b/netbpfload/NetBpfLoad.cpp
index 9651a3b..83bb98c 100644
--- a/netbpfload/NetBpfLoad.cpp
+++ b/netbpfload/NetBpfLoad.cpp
@@ -257,12 +257,6 @@
 
     logTetheringApexVersion();
 
-    if (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
-    }
-
     if (!isAtLeastT) {
         ALOGE("Impossible - not reachable on Android <T.");
         return 1;
@@ -319,14 +313,16 @@
         return 1;
     }
 
-    if (isAtLeastU) {
+    if (false && isAtLeastV) {
         // Linux 5.16-rc1 changed the default to 2 (disabled but changeable),
         // but we need 0 (enabled)
         // (this writeFile is known to fail on at least 4.19, but always defaults to 0 on
         // pre-5.13, on 5.13+ it depends on CONFIG_BPF_UNPRIV_DEFAULT_OFF)
         if (writeProcSysFile("/proc/sys/kernel/unprivileged_bpf_disabled", "0\n") &&
             android::bpf::isAtLeastKernelVersion(5, 13, 0)) return 1;
+    }
 
+    if (isAtLeastU) {
         // Enable the eBPF JIT -- but do note that on 64-bit kernels it is likely
         // already force enabled by the kernel config option BPF_JIT_ALWAYS_ON.
         // (Note: this (open) will fail with ENOENT 'No such file or directory' if
@@ -384,10 +380,15 @@
         return 1;
     }
 
-    ALOGI("done, transferring control to platform bpfloader.");
+    if (false && isAtLeastV) {
+        ALOGI("done, transferring control to platform bpfloader.");
 
-    const char * args[] = { platformBpfLoader, NULL, };
-    execve(args[0], (char**)args, envp);
-    ALOGE("FATAL: execve('%s'): %d[%s]", platformBpfLoader, errno, strerror(errno));
-    return 1;
+        const char * args[] = { platformBpfLoader, NULL, };
+        execve(args[0], (char**)args, envp);
+        ALOGE("FATAL: execve('%s'): %d[%s]", platformBpfLoader, errno, strerror(errno));
+        return 1;
+    }
+
+    ALOGI("mainline done!");
+    return 0;
 }