From ff3048349abc72d3bf0c0b261287263b2bd25276 Mon Sep 17 00:00:00 2001
From: Jiyong Park <jiyong@google.com>
Date: Mon, 22 Nov 2021 14:18:03 +0900
Subject: [PATCH] Add logd.ready

logd.ready is a system property that logd sets when it is ready to
serve incoming socket requests for reading and writing logs. Clients of
logd (e.g. logcat) can use this to synchronize with logd, otherwise they
may experience a crash due to the refused socket connection to logd when
they are started before logd is ready.

Bug: 206826522
Test: run microdroid. see logcat logs are shown immediately
Change-Id: Iee13485b0f4c2beda9bc8434f514c4e32e119492
---
 microdroid/system/private/logcat.te         | 4 ++++
 microdroid/system/private/property_contexts | 1 +
 private/logpersist.te                       | 1 +
 public/shell.te                             | 1 +
 4 files changed, 7 insertions(+)

diff --git a/microdroid/system/private/logcat.te b/microdroid/system/private/logcat.te
index be6e42a46..a26cff389 100644
--- a/microdroid/system/private/logcat.te
+++ b/microdroid/system/private/logcat.te
@@ -12,4 +12,8 @@ allow logcat serial_device:chr_file ra_file_perms;
 # logcat can get logs from logd
 read_logd(logcat)
 
+# Allow logcat to read ro.logd.ready so that it waits until logd is ready to
+# accept commands
+get_prop(logcat, logd_prop)
+
 allow logcat self:global_capability_class_set { sys_nice };
diff --git a/microdroid/system/private/property_contexts b/microdroid/system/private/property_contexts
index 9384a75ee..abd14fdad 100644
--- a/microdroid/system/private/property_contexts
+++ b/microdroid/system/private/property_contexts
@@ -38,6 +38,7 @@ sys.powerctl            u:object_r:powerctl_prop:s0
 service.adb.root u:object_r:shell_prop:s0 exact bool
 
 ro.logd.kernel u:object_r:logd_prop:s0 exact bool
+logd.ready     u:object_r:logd_prop:s0 exact bool
 
 ro.config.low_ram u:object_r:build_prop:s0 exact bool
 
diff --git a/private/logpersist.te b/private/logpersist.te
index ab2c9c63f..e1518103d 100644
--- a/private/logpersist.te
+++ b/private/logpersist.te
@@ -15,6 +15,7 @@ userdebug_or_eng(`
 
   control_logd(logpersist)
   unix_socket_connect(logpersist, logdr, logd)
+  get_prop(logpersist, logd_prop)
   read_runtime_log_tags(logpersist)
 
 ')
diff --git a/public/shell.te b/public/shell.te
index 7751d63dc..60e3521bc 100644
--- a/public/shell.te
+++ b/public/shell.te
@@ -8,6 +8,7 @@ net_domain(shell)
 # logcat
 read_logd(shell)
 control_logd(shell)
+get_prop(shell, logd_prop)
 # logcat -L (directly, or via dumpstate)
 allow shell pstorefs:dir search;
 allow shell pstorefs:file r_file_perms;