From ffa52e9c6f8b37e8a9430c66ef117a07c43c797e Mon Sep 17 00:00:00 2001
From: Mark Salyzyn <salyzyn@google.com>
Date: Thu, 14 May 2020 09:20:30 -0700
Subject: [PATCH] init: support wait timeout with more precision

A one second timeout is so coarse and can affect boot time when
the possibility that the file does not exist.  Switch to accepting
a floating point number for seconds for the wait for file command.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 151950334
Test: wait_for_file sleep 0.05 reports an appropriate delay
Change-Id: I8d8ed386519ab54270b05ce91663d0add30f12e7
---
 init/README.md          | 3 ++-
 init/builtins.cpp       | 8 +++++---
 init/check_builtins.cpp | 5 +++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/init/README.md b/init/README.md
index 726c0cc94..b70366b8f 100644
--- a/init/README.md
+++ b/init/README.md
@@ -644,7 +644,8 @@ provides the `aidl_lazy_test_1` interface.
 `wait <path> [ <timeout> ]`
 > Poll for the existence of the given file and return when found,
   or the timeout has been reached. If timeout is not specified it
-  currently defaults to five seconds.
+  currently defaults to five seconds. The timeout value can be
+  fractional seconds, specified in floating point notation.
 
 `wait_for_prop <name> <value>`
 > Wait for system property _name_ to be _value_. Properties are expanded
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 200bfff7d..149a766b3 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -49,6 +49,7 @@
 #include <android-base/chrono_utils.h>
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/parsedouble.h>
 #include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
@@ -1065,11 +1066,12 @@ static Result<void> do_load_system_props(const BuiltinArguments& args) {
 static Result<void> do_wait(const BuiltinArguments& args) {
     auto timeout = kCommandRetryTimeout;
     if (args.size() == 3) {
-        int timeout_int;
-        if (!android::base::ParseInt(args[2], &timeout_int)) {
+        double timeout_double;
+        if (!android::base::ParseDouble(args[2], &timeout_double, 0)) {
             return Error() << "failed to parse timeout";
         }
-        timeout = std::chrono::seconds(timeout_int);
+        timeout = std::chrono::duration_cast<std::chrono::nanoseconds>(
+                std::chrono::duration<double>(timeout_double));
     }
 
     if (wait_for_file(args[1].c_str(), timeout) != 0) {
diff --git a/init/check_builtins.cpp b/init/check_builtins.cpp
index d62ecb080..d1a84f306 100644
--- a/init/check_builtins.cpp
+++ b/init/check_builtins.cpp
@@ -25,6 +25,7 @@
 #include <sys/time.h>
 
 #include <android-base/logging.h>
+#include <android-base/parsedouble.h>
 #include <android-base/parseint.h>
 #include <android-base/strings.h>
 
@@ -205,8 +206,8 @@ Result<void> check_sysclktz(const BuiltinArguments& args) {
 
 Result<void> check_wait(const BuiltinArguments& args) {
     if (args.size() == 3 && !args[2].empty()) {
-        int timeout_int;
-        if (!android::base::ParseInt(args[2], &timeout_int)) {
+        double timeout_double;
+        if (!android::base::ParseDouble(args[2], &timeout_double, 0)) {
             return Error() << "failed to parse timeout";
         }
     }