dumpstate: notes on usage

This is what a few old maintainers of dumpstate told me
when I made changes to it back ~2016 or so: always exec
stuff, never link it.

Well, there have been quite a few divergences from this,
and it's come up in a couple of reviews I've seen here.

So, I've added notes on this into the readme and comments
on some of the worst offender. For instance, we could
have probably avoided a lot of this async/exec logic
for these custom cases if we used the standard run
command with timeout stuff.

Bug: N/A
Test: N/A
Change-Id: I4c33f3042ca16d4433082b8d78ebdd29cb75f0b3
diff --git a/cmds/dumpstate/Android.bp b/cmds/dumpstate/Android.bp
index be96306..1397ae6 100644
--- a/cmds/dumpstate/Android.bp
+++ b/cmds/dumpstate/Android.bp
@@ -83,14 +83,16 @@
         "aconfig_lib_cc_static_link.defaults",
         "dumpstate_cflag_defaults",
     ],
+    // See README.md: "Dumpstate philosophy: exec not link"
+    // Do not add things here - keep dumpstate as simple as possible and exec where possible.
     shared_libs: [
         "android.hardware.dumpstate@1.0",
         "android.hardware.dumpstate@1.1",
         "android.hardware.dumpstate-V1-ndk",
         "libziparchive",
         "libbase",
-        "libbinder",
-        "libbinder_ndk",
+        "libbinder", // BAD: dumpstate should not link code directly, should only exec binaries
+        "libbinder_ndk", // BAD: dumpstate should not link code directly, should only exec binaries
         "libcrypto",
         "libcutils",
         "libdebuggerd_client",
@@ -98,11 +100,11 @@
         "libdumpstateutil",
         "libdumputils",
         "libhardware_legacy",
-        "libhidlbase",
+        "libhidlbase", // BAD: dumpstate should not link code directly, should only exec binaries
         "liblog",
         "libutils",
-        "libvintf",
-        "libbinderdebug",
+        "libvintf", // BAD: dumpstate should not link code directly, should only exec binaries
+        "libbinderdebug", // BAD: dumpstate should not link code directly, should only exec binaries
         "packagemanager_aidl-cpp",
         "server_configurable_flags",
         "device_policy_aconfig_flags_c_lib",