Disallow '_' in bpf source name

Current design:
1. The bpf compiled object name is derived from the source name
   (e.g. foo.c -> foo.o).
2. Full bpf program/map name are concatenated by object name + '_' +
   program/map name in run-time. (e.g. obj name: x.o; program name: y_z;
   full bpf program name will be x_y_z)

Issue:
x.o with map y_z and x_y.o with map z can cause naming collision in
run-time, since both result in x_y_z. This commit prevents it from
happening with a build-time check.

Bug: 236706995
Test: m
Change-Id: Ic03bfcf07a5748ed63246b71d5ae8de0405e658a
diff --git a/apex/apex_test.go b/apex/apex_test.go
index dbe9180..dc505b4 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -619,7 +619,7 @@
 			java_libs: ["myjar"],
 			apps: ["AppFoo"],
 			rros: ["rro"],
-			bpfs: ["bpf", "netd_test"],
+			bpfs: ["bpf", "netdTest"],
 			updatable: false,
 		}
 
@@ -673,8 +673,8 @@
 		}
 
 		bpf {
-			name: "netd_test",
-			srcs: ["netd_test.c"],
+			name: "netdTest",
+			srcs: ["netdTest.c"],
 			sub_dir: "netd",
 		}
 
@@ -687,7 +687,7 @@
 		"overlay/blue/rro.apk",
 		"etc/bpf/bpf.o",
 		"etc/bpf/bpf2.o",
-		"etc/bpf/netd/netd_test.o",
+		"etc/bpf/netd/netdTest.o",
 	})
 }
 
@@ -6151,7 +6151,7 @@
 			name: "override_myapex",
 			base: "myapex",
 			apps: ["override_app"],
-			bpfs: ["override_bpf"],
+			bpfs: ["overrideBpf"],
 			prebuilts: ["override_myetc"],
 			bootclasspath_fragments: ["override_bootclasspath_fragment"],
 			systemserverclasspath_fragments: ["override_systemserverclasspath_fragment"],
@@ -6201,8 +6201,8 @@
 		}
 
 		bpf {
-			name: "override_bpf",
-			srcs: ["override_bpf.c"],
+			name: "overrideBpf",
+			srcs: ["overrideBpf.c"],
 		}
 
 		prebuilt_etc {
@@ -6305,7 +6305,7 @@
 	ensureContains(t, copyCmds, "image.apex/app/override_app@TEST.BUILD_ID/override_app.apk")
 
 	ensureNotContains(t, copyCmds, "image.apex/etc/bpf/bpf.o")
-	ensureContains(t, copyCmds, "image.apex/etc/bpf/override_bpf.o")
+	ensureContains(t, copyCmds, "image.apex/etc/bpf/overrideBpf.o")
 
 	ensureNotContains(t, copyCmds, "image.apex/etc/myetc")
 	ensureContains(t, copyCmds, "image.apex/etc/override_myetc")
@@ -6339,7 +6339,7 @@
 	data.Custom(&builder, name, "TARGET_", "", data)
 	androidMk := builder.String()
 	ensureContains(t, androidMk, "LOCAL_MODULE := override_app.override_myapex")
-	ensureContains(t, androidMk, "LOCAL_MODULE := override_bpf.o.override_myapex")
+	ensureContains(t, androidMk, "LOCAL_MODULE := overrideBpf.o.override_myapex")
 	ensureContains(t, androidMk, "LOCAL_MODULE := apex_manifest.pb.override_myapex")
 	ensureContains(t, androidMk, "LOCAL_MODULE := override_bcplib.override_myapex")
 	ensureContains(t, androidMk, "LOCAL_MODULE := override_systemserverlib.override_myapex")