Move watchdogd out of init

We're moving past a world where static executables are needed,
including watchdogd, so treat this like any other executable and place
it in /system/bin.

Bug: 73660730
Test: watchdogd still runs
Change-Id: I1f7508fd55dce6e9ee72a6ab7a085011a76c0053

Author: Tom Cherry

init/Android.bp

@@ -127,7 +127,6 @@ cc_library_static {
         "ueventd.cpp",
         "ueventd_parser.cpp",
         "util.cpp",
-        "watchdogd.cpp",
     ],
     whole_static_libs: ["libcap"],
     header_libs: ["bootimg_headers"],
@@ -157,7 +156,6 @@ cc_binary {
     srcs: ["main.cpp"],
     symlinks: [
         "sbin/ueventd",
-        "sbin/watchdogd",
     ],
 }
 */

init/Android.mk

@@ -98,7 +98,6 @@ LOCAL_REQUIRED_MODULES := \
 # Create symlinks.
 LOCAL_POST_INSTALL_CMD := $(hide) mkdir -p $(TARGET_ROOT_OUT)/sbin; \
     ln -sf ../init $(TARGET_ROOT_OUT)/sbin/ueventd; \
-    ln -sf ../init $(TARGET_ROOT_OUT)/sbin/watchdogd
 
 LOCAL_SANITIZE := signed-integer-overflow
 include $(BUILD_EXECUTABLE)

init/devices.cpp

@@ -34,7 +34,7 @@
 #include "util.h"
 
 #ifdef _INIT_INIT_H
-#error "Do not include init.h in files used by ueventd or watchdogd; it will expose init's globals"
+#error "Do not include init.h in files used by ueventd; it will expose init's globals"
 #endif
 
 using android::base::Basename;

init/host_init_stubs.cpp

@@ -41,10 +41,9 @@ uint32_t HandlePropertySet(const std::string&, const std::string&, const std::st
 }
 
 // selinux.h
-bool SelinuxHasVendorInit() {
-    return true;
+int SelinuxGetVendorAndroidVersion() {
+    return 10000;
 }
-
 void SelabelInitialize() {}
 
 bool SelabelLookupFileContext(const std::string& key, int type, std::string* result) {

init/host_init_stubs.h

@@ -23,6 +23,9 @@
 
 #include <string>
 
+// android/api-level.h
+#define __ANDROID_API_P__ 28
+
 // sys/system_properties.h
 #define PROP_VALUE_MAX 92
 
@@ -41,7 +44,7 @@ uint32_t HandlePropertySet(const std::string& name, const std::string& value,
                            const std::string& source_context, const ucred& cr, std::string* error);
 
 // selinux.h
-bool SelinuxHasVendorInit();
+int SelinuxGetVendorAndroidVersion();
 void SelabelInitialize();
 bool SelabelLookupFileContext(const std::string& key, int type, std::string* result);
 

init/init.cpp

@@ -58,7 +58,6 @@
 #include "sigchld_handler.h"
 #include "ueventd.h"
 #include "util.h"
-#include "watchdogd.h"
 
 using namespace std::chrono_literals;
 using namespace std::string_literals;
@@ -617,10 +616,6 @@ int main(int argc, char** argv) {
         return ueventd_main(argc, argv);
     }
 
-    if (!strcmp(basename(argv[0]), "watchdogd")) {
-        return watchdogd_main(argc, argv);
-    }
-
     if (argc > 1 && !strcmp(argv[1], "subcontext")) {
         android::base::InitLogging(argv, &android::base::KernelLogger);
         const BuiltinFunctionMap function_map;

init/init.h

@@ -31,8 +31,8 @@
 namespace android {
 namespace init {
 
-// Note: These globals are *only* valid in init, so they should not be used in ueventd,
-// watchdogd, or any files that may be included in those, such as devices.cpp and util.cpp.
+// Note: These globals are *only* valid in init, so they should not be used in ueventd
+// or any files that may be included in ueventd, such as devices.cpp and util.cpp.
 // TODO: Have an Init class and remove all globals.
 extern std::string default_console;
 extern std::vector<std::string> late_import_paths;

init/property_service.cpp

@@ -16,6 +16,7 @@
 
 #include "property_service.h"
 
+#include <android/api-level.h>
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -576,7 +577,7 @@ static void LoadProperties(char* data, const char* filter, const char* filename)
     size_t flen = 0;
 
     const char* context = kInitContext.c_str();
-    if (SelinuxHasVendorInit()) {
+    if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
         for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
             if (StartsWith(filename, path_prefix)) {
                 context = secontext;

init/selinux.cpp

@@ -47,6 +47,7 @@
 
 #include "selinux.h"
 
+#include <android/api-level.h>
 #include <fcntl.h>
 #include <stdlib.h>
 #include <sys/wait.h>
@@ -470,29 +471,27 @@ void SelinuxSetupKernelLogging() {
     selinux_set_callback(SELINUX_CB_LOG, cb);
 }
 
-// This function checks whether the sepolicy supports vendor init.
-bool SelinuxHasVendorInit() {
+// This function returns the Android version with which the vendor SEPolicy was compiled.
+// It is used for version checks such as whether or not vendor_init should be used
+int SelinuxGetVendorAndroidVersion() {
     if (!IsSplitPolicyDevice()) {
-        // If this device does not split sepolicy files, vendor_init will be available in the latest
-        // monolithic sepolicy file.
-        return true;
+        // If this device does not split sepolicy files, it's not a Treble device and therefore,
+        // we assume it's always on the latest platform.
+        return __ANDROID_API_FUTURE__;
     }
 
     std::string version;
     if (!GetVendorMappingVersion(&version)) {
-        // Return true as the default if we failed to load the vendor sepolicy version.
-        return true;
+        LOG(FATAL) << "Could not read vendor SELinux version";
     }
 
     int major_version;
     std::string major_version_str(version, 0, version.find('.'));
     if (!ParseInt(major_version_str, &major_version)) {
-        PLOG(ERROR) << "Failed to parse the vendor sepolicy major version " << major_version_str;
-        // Return true as the default if we failed to parse the major version.
-        return true;
+        PLOG(FATAL) << "Failed to parse the vendor sepolicy major version " << major_version_str;
     }
 
-    return major_version >= 28;
+    return major_version;
 }
 
 // selinux_android_file_context_handle() takes on the order of 10+ms to run, so we want to cache

init/selinux.h

@@ -27,7 +27,7 @@ void SelinuxInitialize();
 void SelinuxRestoreContext();
 
 void SelinuxSetupKernelLogging();
-bool SelinuxHasVendorInit();
+int SelinuxGetVendorAndroidVersion();
 
 void SelabelInitialize();
 bool SelabelLookupFileContext(const std::string& key, int type, std::string* result);