init.rc: logd: Add logpersistd (nee logcatd)

(cherry pick from commit 100658c303919d8f69c76f6f25eac376795712f0)

- logpersistd is defined as a thread or process in the context of the
  logd domain. Here we define logpersistd as logcat -f in logd domain
  and call it logcatd to represent its service mechanics.
- Use logcatd to manage content in /data/misc/logd/ directory.
- Only turn on for persist.logd.logpersistd = logcatd.
- Add logpersist.start, logpersist.stop and logpersist.cat debug
  class executables, thus only in the eng and userdebug builds.

ToDo: Wish to add Developer Options menu to turn this feature on or
off, complicated by the fact that user builds have no tools with
access rights to /data/misc/logd.

Bug: 19608716
Change-Id: I57ad757f121c473d04f9fabe9d4820a0eca06f31

1 files changed, 2 insertions, 0 deletions

diff --git a/logd/README.property b/logd/README.property
index ad7d0cd..a472efd 100644
--- a/logd/README.property
+++ b/logd/README.property
@@ -10,6 +10,8 @@ ro.config.low_ram           bool  false  if true, logd.statistics & logd.klogd
                                          default false
 ro.build.type               string       if user, logd.statistics & logd.klogd
                                          default false
+persist.logd.logpersistd    string       Enable logpersist daemon, "logcatd"
+                                         turns on logcat -f in logd context
 persist.logd.size          number 256K   default size of the buffer for all
                                          log ids at initial startup, at runtime
                                          use: logcat -b all -G <value>