[yocto] Bug 11307 - sstate.bbclass tries to modify mirror files

[Paulo Neves]

Commit 51edde653707e7a3cd2186082458f01f32cd1996 makes a wrong
assumption that SSTATE_MIRRORS have write permissions.

A mirror is by definition outside of it's user control. In my use case
it happens I does not have permissions to update the access time of
the dereferenced symbolic-link file.

If we had the possibility to modify the sstate-mirror we would have
set SSTATE_DIR instead. There are 3 possible fixes:

* Revert this patch. It seems tailored to a very special use case
which breaks the definition of mirror.
* Only touch the file if the file access time is writeable.
* Set (yet) another option to touch SSTATE_MIRROR files.

I also can imagine this raising sever performance issues if the mirror
is used by several users at the same time. The server will need to
update the file meta data every time

This patch fixes the bug with minimal impact on the original
functionality. Option 2


Related to (https://bugzilla.yoctoproject.org/show_bug.cgi?id=10857)

>From aa8cab9660744c8d5277f8e82f10a844884aff78 Mon Sep 17 00:00:00 2001
From: Paulo Neves <paulo.de_sousa_neves at nokia.com>
Date: Tue, 11 Apr 2017 10:57:47 +0300
Subject: [PATCH] Added test for write ability of sstate-mirror .siginfo

---
 meta/classes/sstate.bbclass | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index af588548c2ef85d966787df7ae1432e1744bdba6..36cbbd151aa1c93f4ca377b3a23c011a527389d8
100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -753,7 +753,7 @@ python sstate_sign_package () {
 sstate_unpack_package () {
  tar -xvzf ${SSTATE_PKG}
  # update .siginfo atime on local/NFS mirror
- [ -h ${SSTATE_PKG}.siginfo ] && touch -a ${SSTATE_PKG}.siginfo
+ [ -w ${SSTATE_PKG}.siginfo ] && [ -h ${SSTATE_PKG}.siginfo ] &&
touch -a ${SSTATE_PKG}.siginfo
  # Use "! -w ||" to return true for read only files
  [ ! -w ${SSTATE_PKG} ] || touch --no-dereference ${SSTATE_PKG}
  [ ! -w ${SSTATE_PKG}.sig ] || [ ! -e ${SSTATE_PKG}.sig ] || touch
--no-dereference ${SSTATE_PKG}.sig
-- 
2.6.2



Best regards
Paulo Neves