Merge lp:~chipaca/snappy/use-etc-writable-for-atomics into lp:~snappy-dev/snappy/snappy-moved-to-github

[John Lenton]

Use /etc/writable from config now that config does AtomicWriteFile.

[Michael Vogt (mvo)]

\o/

review: Approve

[Michael Vogt (mvo)]

Unapproving again, as ogra points out the code should follow the link, I don't think our atomicWrite code is doing this right now though :/

[Gustavo Niemeyer (niemeyer)]

Hmmm.. /etc/writable is a curious artifact. On one hand it feels like the whole /etc should be writable, which is what we agreed to move towards in Budapest.. on the other hand, how do we update such a system? Something to talk about for all-snaps..

[Oliver Grawert (ogra)]

/etc/writable has been on the phones forever to support atomic writing of single files and to not rip extra security attack vectors and making the boot extra slow by having to sync the whole of etc every boot ...

[Gustavo Niemeyer (niemeyer)]

Interesting.. so why would the boot become extra slow if /etc is mounted read-write? Also, do you have a list of everything that is under /etc/writable ATM on the phones?

Thanks

=== modified file 'coreconfig/config.go'
--- coreconfig/config.go	2015-10-20 20:00:08 +0000
+++ coreconfig/config.go	2015-10-22 10:45:39 +0000
@@ -39,12 +39,12 @@
 
 const (
 	tzPathEnvironment string = "UBUNTU_CORE_CONFIG_TZ_FILE"
-	tzPathDefault     string = "/etc/timezone"
+	tzPathDefault     string = "/etc/writable/timezone"
 )
 
 var (
 	tzZoneInfoPath   = "/usr/share/zoneinfo"
-	tzZoneInfoTarget = "/etc/localtime"
+	tzZoneInfoTarget = "/etc/writable/localtime"
 )
 
 const (
@@ -58,8 +58,8 @@
 	modulesPath         = "/etc/modules-load.d/ubuntu-core.conf"
 	interfacesRoot      = "/etc/network/interfaces.d/"
 	pppRoot             = "/etc/ppp/"
-	watchdogConfigPath  = "/etc/watchdog.conf"
-	watchdogStartupPath = "/etc/default/watchdog"
+	watchdogConfigPath  = "/etc/writable/watchdog.conf"
+	watchdogStartupPath = "/etc/writable/default/watchdog"
 )
 
 var (