Merge "init: ignore ENOENT from fewer builtins"
diff --git a/init/action.cpp b/init/action.cpp
index 65ba25d..1a66eee 100644
--- a/init/action.cpp
+++ b/init/action.cpp
@@ -161,18 +161,8 @@
     auto result = command.InvokeFunc(subcontext_);
     auto duration = t.duration();
 
-    // There are many legacy paths in rootdir/init.rc that will virtually never exist on a new
-    // device, such as '/sys/class/leds/jogball-backlight/brightness'.  As of this writing, there
-    // are 198 such failures on bullhead.  Instead of spamming the log reporting them, we do not
-    // report such failures unless we're running at the DEBUG log level.
-    bool report_failure = !result.has_value();
-    if (report_failure && android::base::GetMinimumLogSeverity() > android::base::DEBUG &&
-        result.error().code() == ENOENT) {
-        report_failure = false;
-    }
-
     // Any action longer than 50ms will be warned to user as slow operation
-    if (report_failure || duration > 50ms ||
+    if (!result.has_value() || duration > 50ms ||
         android::base::GetMinimumLogSeverity() <= android::base::DEBUG) {
         std::string trigger_name = BuildTriggersString();
         std::string cmd_str = command.BuildCommandString();
diff --git a/init/builtins.cpp b/init/builtins.cpp
index e75f5cb..a2d782b 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -89,6 +89,43 @@
 namespace android {
 namespace init {
 
+// There are many legacy paths in rootdir/init.rc that will virtually never exist on a new
+// device, such as '/sys/class/leds/jogball-backlight/brightness'.  As of this writing, there
+// are 81 such failures on cuttlefish.  Instead of spamming the log reporting them, we do not
+// report such failures unless we're running at the DEBUG log level.
+class ErrorIgnoreEnoent {
+  public:
+    ErrorIgnoreEnoent()
+        : ignore_error_(errno == ENOENT &&
+                        android::base::GetMinimumLogSeverity() > android::base::DEBUG) {}
+    explicit ErrorIgnoreEnoent(int errno_to_append)
+        : error_(errno_to_append),
+          ignore_error_(errno_to_append == ENOENT &&
+                        android::base::GetMinimumLogSeverity() > android::base::DEBUG) {}
+
+    template <typename T>
+    operator android::base::expected<T, ResultError>() {
+        if (ignore_error_) {
+            return {};
+        }
+        return error_;
+    }
+
+    template <typename T>
+    ErrorIgnoreEnoent& operator<<(T&& t) {
+        error_ << t;
+        return *this;
+    }
+
+  private:
+    Error error_;
+    bool ignore_error_;
+};
+
+inline ErrorIgnoreEnoent ErrnoErrorIgnoreEnoent() {
+    return ErrorIgnoreEnoent(errno);
+}
+
 std::vector<std::string> late_import_paths;
 
 static constexpr std::chrono::nanoseconds kCommandRetryTimeout = 5s;
@@ -330,7 +367,7 @@
                 return ErrnoError() << "fchmodat() failed";
             }
         } else {
-            return ErrnoError() << "mkdir() failed";
+            return ErrnoErrorIgnoreEnoent() << "mkdir() failed";
         }
     }
 
@@ -459,7 +496,7 @@
         if (wait)
             wait_for_file(source, kCommandRetryTimeout);
         if (mount(source, target, system, flags, options) < 0) {
-            return ErrnoError() << "mount() failed";
+            return ErrnoErrorIgnoreEnoent() << "mount() failed";
         }
 
     }
@@ -683,7 +720,7 @@
     Service* svc = ServiceList::GetInstance().FindService(args[1]);
     if (!svc) return Error() << "service " << args[1] << " not found";
     if (auto result = svc->Start(); !result) {
-        return Error() << "Could not start service: " << result.error();
+        return ErrorIgnoreEnoent() << "Could not start service: " << result.error();
     }
     return {};
 }
@@ -729,10 +766,7 @@
     if (MakeSymlink(args[1], args[2]) < 0) {
         // The symlink builtin is often used to create symlinks for older devices to be backwards
         // compatible with new paths, therefore we skip reporting this error.
-        if (errno == EEXIST && android::base::GetMinimumLogSeverity() > android::base::DEBUG) {
-            return {};
-        }
-        return ErrnoError() << "symlink() failed";
+        return ErrnoErrorIgnoreEnoent() << "symlink() failed";
     }
     return {};
 }
@@ -790,7 +824,8 @@
 
 static Result<void> do_write(const BuiltinArguments& args) {
     if (auto result = WriteFile(args[1], args[2]); !result) {
-        return Error() << "Unable to write to file '" << args[1] << "': " << result.error();
+        return ErrorIgnoreEnoent()
+               << "Unable to write to file '" << args[1] << "': " << result.error();
     }
 
     return {};
@@ -908,7 +943,7 @@
     }
 
     if (lchown(path.c_str(), *uid, *gid) == -1) {
-        return ErrnoError() << "lchown() failed";
+        return ErrnoErrorIgnoreEnoent() << "lchown() failed";
     }
 
     return {};
@@ -930,7 +965,7 @@
 static Result<void> do_chmod(const BuiltinArguments& args) {
     mode_t mode = get_mode(args[1].c_str());
     if (fchmodat(AT_FDCWD, args[2].c_str(), mode, AT_SYMLINK_NOFOLLOW) < 0) {
-        return ErrnoError() << "fchmodat() failed";
+        return ErrnoErrorIgnoreEnoent() << "fchmodat() failed";
     }
     return {};
 }
@@ -950,7 +985,7 @@
         }
     }
 
-    if (ret) return ErrnoError() << "selinux_android_restorecon() failed";
+    if (ret) return ErrnoErrorIgnoreEnoent() << "selinux_android_restorecon() failed";
     return {};
 }