Add error trace in BpfHandler::initPrograms

Debugging the SIGABRT of this function is annoying because the module
can be built from source or pre-built. It requires finding the correct
version of the symbol to get the correct line number. In addition, there
are 7 consecutive aborts in source code, it is hard to tell whether the
symbolized call stack shows the right line number or not. Adds error
trace before abort so we can identify the root cause without even
symbolizing the call stack of SIGABRT.

Bug: 312094533
Test: make; flash; adb logcat
Change-Id: I74713029d059e10bf5d34694cdb96712bc806696

netd/BpfHandler.cpp

@@ -76,23 +76,43 @@ static Status checkProgramAccessible(const char* programPath) {
 }
 
 static Status initPrograms(const char* cg2_path) {
+    if (!cg2_path) {
+        ALOGE("cg2_path is NULL");
+        return statusFromErrno(EINVAL, "cg2_path is NULL");
+    }
+
     // This code was mainlined in T, so this should be trivially satisfied.
-    if (!modules::sdklevel::IsAtLeastT()) abort();
+    if (!modules::sdklevel::IsAtLeastT()) {
+        ALOGE("S- platform is unsupported");
+        abort();
+    }
 
     // S requires eBPF support which was only added in 4.9, so this should be satisfied.
-    if (!bpf::isAtLeastKernelVersion(4, 9, 0)) abort();
+    if (!bpf::isAtLeastKernelVersion(4, 9, 0)) {
+        ALOGE("kernel version < 4.9.0 is unsupported");
+        abort();
+    }
 
     // U bumps the kernel requirement up to 4.14
-    if (modules::sdklevel::IsAtLeastU() && !bpf::isAtLeastKernelVersion(4, 14, 0)) abort();
+    if (modules::sdklevel::IsAtLeastU() && !bpf::isAtLeastKernelVersion(4, 14, 0)) {
+        ALOGE("U+ platform with kernel version < 4.14.0 is unsupported");
+        abort();
+    }
 
     if (modules::sdklevel::IsAtLeastV()) {
         // V bumps the kernel requirement up to 4.19
         // see also: //system/netd/tests/kernel_test.cpp TestKernel419
-        if (!bpf::isAtLeastKernelVersion(4, 19, 0)) abort();
+        if (!bpf::isAtLeastKernelVersion(4, 19, 0)) {
+            ALOGE("V+ platform with kernel version < 4.19.0 is unsupported");
+            abort();
+        }
 
         // Technically already required by U, but only enforce on V+
         // see also: //system/netd/tests/kernel_test.cpp TestKernel64Bit
-        if (bpf::isKernel32Bit() && bpf::isAtLeastKernelVersion(5, 16, 0)) abort();
+        if (bpf::isKernel32Bit() && bpf::isAtLeastKernelVersion(5, 16, 0)) {
+            ALOGE("V+ platform with 32 bit kernel, version >= 5.16.0 is unsupported");
+            abort();
+        }
     }
 
     // Linux 6.1 is highest version supported by U, starting with V new kernels,
@@ -102,10 +122,16 @@ static Status initPrograms(const char* cg2_path) {
     // it does not affect unprivileged apps, the 32-on-64 compatibility
     // problems are AFAIK limited to various CAP_NET_ADMIN protected interfaces.
     // see also: //system/bpf/bpfloader/BpfLoader.cpp main()
-    if (bpf::isUserspace32bit() && bpf::isAtLeastKernelVersion(6, 2, 0)) abort();
+    if (bpf::isUserspace32bit() && bpf::isAtLeastKernelVersion(6, 2, 0)) {
+        ALOGE("32 bit userspace with Kernel version >= 6.2.0 is unsupported");
+        abort();
+    }
 
     // U mandates this mount point (though it should also be the case on T)
-    if (modules::sdklevel::IsAtLeastU() && !!strcmp(cg2_path, "/sys/fs/cgroup")) abort();
+    if (modules::sdklevel::IsAtLeastU() && !!strcmp(cg2_path, "/sys/fs/cgroup")) {
+        ALOGE("U+ platform with cg2_path != /sys/fs/cgroup is unsupported");
+        abort();
+    }
 
     unique_fd cg_fd(open(cg2_path, O_DIRECTORY | O_RDONLY | O_CLOEXEC));
     if (!cg_fd.ok()) {