UserAgent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0
Platform: soraka

Steps to reproduce the problem:
The steps below reference soraka, but the issue is not particularly board specific. Granted this is not the typical development flow, but a quick way to reproduce the issue. With that said, I do periodically bump into the issue doing normal repo syncs and build_packages on already built platforms.

(1) ./setup_board --board=soraka --force
(2) emerge-soraka chromeos-kernel-4_4
(3) emerge-soraka ecryptfs-utils

What is the expected behavior?
Build succeeds.

What went wrong?
Emerging ecryptfs-utils fails in src_unpack().

(cr) ((ef121e2...)) ed@edcubedev ~/trunk/src/scripts $ emerge-soraka ecryptfs-utils
Calculating dependencies... done!

>>> Emerging (1 of 1) sys-fs/ecryptfs-utils-101::portage-stable for /build/soraka/
 * ecryptfs-utils_101.orig.tar.gz RMD160 SHA1 SHA256 size ;-) ...                                                                                                                                                                     [ ok ]
 * Running stacked hooks for pre_pkg_setup
 *    sysroot_build_bin_dir ...                                                                                                                                                                                                       [ ok ]
 * Determining the location of the kernel source code
 * Found kernel source directory:
 *     /build/soraka/usr/src/linux
 * Found sources for kernel version:
 *     4.4.149
 * Unable to check for the following kernel config options due
 * to absence of any configured kernel sources or compiled
 * config:
 *  - ECRYPT_FS
 * You're on your own to make sure they are set if needed.
 * Running stacked hooks for post_pkg_setup
 *    python_eclass_hack ...                                                                                                                                                                                                          [ ok ]
 * Running stacked hooks for pre_src_unpack
 *    python_multilib_setup ...                                                                                                                                                                                                       [ ok ]
>>> Unpacking source...
>>> Unpacking ecryptfs-utils_101.orig.tar.gz to /build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/work
tar: ecryptfs-utils-101/NEWS: Cannot open: Permission denied
tar: ecryptfs-utils-101/README: Cannot open: Permission denied
tar: ecryptfs-utils-101/depcomp: Cannot open: Permission denied
tar: ecryptfs-utils-101/configure: Cannot open: Permission denied
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage: Cannot mkdir: No such file or directory
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage/ecryptfs-rewrap-passphrase.1: Cannot open: No such file or directory
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage/ecryptfs-mount-private.1: Cannot open: No such file or directory
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage/ecryptfs-generate-tpm-key.1: Cannot open: No such file or directory
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage/ecryptfs-setup-private.1: Cannot open: No such file or directory
<snip>
tar: Exiting with failure status due to previous errors
 * ERROR: sys-fs/ecryptfs-utils-101::portage-stable failed (unpack phase):
 *   unpack: failure unpacking ecryptfs-utils_101.orig.tar.gz
 *
 * Call stack:
 *               ebuild.sh, line  133:  Called src_unpack
 *             environment, line 6860:  Called default
 *      phase-functions.sh, line  805:  Called default_src_unpack
 *      phase-functions.sh, line  832:  Called __eapi0_src_unpack
 *        phase-helpers.sh, line  736:  Called unpack 'ecryptfs-utils_101.orig.tar.gz'
 *        phase-helpers.sh, line  386:  Called __unpack_tar 'gzip -d'
 *        phase-helpers.sh, line  317:  Called __assert_sigpipe_ok 'unpack: failure unpacking ecryptfs-utils_101.orig.tar.gz'
 *   isolated-functions.sh, line   41:  Called __helpers_die 'unpack: failure unpacking ecryptfs-utils_101.orig.tar.gz'
 *   isolated-functions.sh, line  117:  Called die
 * The specific snippet of code:
 *              die "$@"
 *
 * If you need support, post the output of `emerge --info '=sys-fs/ecryptfs-utils-101::portage-stable'`,
 * the complete build log and the output of `emerge -pqv '=sys-fs/ecryptfs-utils-101::portage-stable'`.
 * The complete build log is located at '/build/soraka/tmp/portage/logs/sys-fs:ecryptfs-utils-101:20180831-053141.log'.
 * For convenience, a symlink to the build log is located at '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/temp/build.log'.
 * The ebuild environment file is located at '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/temp/environment'.
 * Working directory: '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/work'
 * S: '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/work/ecryptfs-utils-101'

>>> Failed to emerge sys-fs/ecryptfs-utils-101 for /build/soraka/, Log file:

>>>  '/build/soraka/tmp/portage/logs/sys-fs:ecryptfs-utils-101:20180831-053141.log'

Did this work before? N/A 

Chrome version: Chromium 70.0.3532.0  Channel: dev
OS Version: 11009.0.2018_08_31_1434 (Test Build - ed) developer-build soraka-unibuild (soraka)
Flash Version: 

I started investigating this partly because it kept cropping up on my local machine, but also because I found it intriguing :). Why would a package fail in src_unpack? To dig further I setup two similar boards. For one of the boards I then ran build_packages.

With the two boards configured I started emerges for ecryptfs-utils. On the board with build_packages previously run, the above failure occured. On the board without build_packages, it built a number of dependencies, and then successfully completed ecryptfs-utils. I then added src_unpack to ecryptfs-utils (normally it relies on the default) and inserted some extra logging.

First the good logs:
 * Running ls -la in workdir
total 8
drwxr-xr-x 2 ed portage 4096 Aug 30 10:48 .
drwxr-xr-x 6 ed portage 4096 Aug 30 10:48 ..

* Running ls -la in distdir
total 12
drwxr-xr-x 2 root portage 4096 Aug 30 10:48 .
drwxr-xr-x 6 ed   portage 4096 Aug 30 10:48 ..
lrwxrwxrwx 1 root root      73 Aug 30 10:48 ecryptfs-utils_101.orig.tar.gz -> /var/cache/chromeos-cache/distfiles/target/ecryptfs-utils_101.orig.tar.gz

* Running ls -la in workdir/..
total 24
drwxr-xr-x 6 ed   portage 4096 Aug 30 10:48 .
drwxrwxr-x 3 ed   portage 4096 Aug 30 10:48 ..
prwxrwx--- 1 root portage    0 Aug 30 10:48 .ipc_in
prwxrwx--- 1 root portage    0 Aug 30 10:48 .ipc_out
-rw-r--r-- 1 root root       0 Aug 30 10:48 .logid
-rw-r--r-- 1 root root       0 Aug 30 10:48 .setuped
drwxr-xr-x 2 root portage 4096 Aug 30 10:48 distdir
drwxr-xr-x 2 ed   portage 4096 Aug 30 10:48 homedir
drwxr-xr-x 3 ed   portage 4096 Aug 30 10:48 temp
drwxr-xr-x 2 ed   portage 4096 Aug 30 10:48 work

 * Trying a manual tar command on /build/pyro/tmp/portage/sys-fs/ecryptfs-utils-101/distdir/ecryptfs-utils_101.orig.tar.gz
ecryptfs-utils-101/
ecryptfs-utils-101/NEWS
ecryptfs-utils-101/README
ecryptfs-utils-101/depcomp
ecryptfs-utils-101/configure
ecryptfs-utils-101/doc/
<snip>

Then the logs from failed builds.
* Running ls -la in workdir
total 12
drwxr-xr-x 3 root root    4096 Aug 30 10:47 .
drwxr-xr-x 6 ed   portage 4096 Aug 30 10:47 ..
drwxr-xr-x 2 root root    4096 Aug 30 10:47 ecryptfs-utils-101
 * Running ls -la in distdir
total 12
drwxr-xr-x 2 root portage 4096 Aug 30 10:47 .
drwxr-xr-x 6 ed   portage 4096 Aug 30 10:47 ..
lrwxrwxrwx 1 root root      73 Aug 30 10:47 ecryptfs-utils_101.orig.tar.gz -> /var/cache/chromeos-cache/distfiles/target/ecryptfs-utils_101.orig.tar.gz

 * Running ls -la in workdir/..
total 24
drwxr-xr-x 6 ed   portage 4096 Aug 30 10:47 .
drwxrwxr-x 3 ed   portage 4096 Aug 30 10:47 ..
prwxrwx--- 1 root portage    0 Aug 30 10:47 .ipc_in
prwxrwx--- 1 root portage    0 Aug 30 10:47 .ipc_out
-rw-r--r-- 1 root root       0 Aug 30 10:47 .logid
-rw-r--r-- 1 root root       0 Aug 30 10:47 .setuped
drwxr-xr-x 2 root portage 4096 Aug 30 10:47 distdir
drwxr-xr-x 2 ed   portage 4096 Aug 30 10:47 homedir
drwxr-xr-x 3 ed   portage 4096 Aug 30 10:47 temp
drwxr-xr-x 3 root root    4096 Aug 30 10:47 work

 * Trying a manual tar command on /build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/distdir/ecryptfs-utils_101.orig.tar.gz
ecryptfs-utils-101/
ecryptfs-utils-101/NEWS
tar: ecryptfs-utils-101/NEWS: Cannot open: Permission denied
ecryptfs-utils-101/README
tar: ecryptfs-utils-101/README: Cannot open: Permission denied
ecryptfs-utils-101/depcomp
tar: ecryptfs-utils-101/depcomp: Cannot open: Permission denied
ecryptfs-utils-101/configure
tar: ecryptfs-utils-101/configure: Cannot open: Permission denied
ecryptfs-utils-101/doc/
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
ecryptfs-utils-101/doc/manpage/
tar: ecryptfs-utils-101/doc: Cannot mkdir: Permission denied
tar: ecryptfs-utils-101/doc/manpage: Cannot mkdir: No such file or directory
<snip>

Comparing the above logs we now know that the work directory is incorrectly set to root:root. I then started reviewing pkg_setup() (https://chromium.googlesource.com/chromiumos/overlays/portage-stable/+/14fa96/sys-fs/ecryptfs-utils/ecryptfs-utils-101.ebuild#39) to determine when work was being created. With only three lines to step through I commented linux-info_pkg_setup first and got lucky. Building ecryptfs-utils completed.

As a quick side check I then tried building other packages which use linux-info. Consolekit failed on permission problems in src_unpack. Powertop finished OK. More on that in a bit, stepping through linux-info was up next. There might be a simpler method, but I decided to step through linux-info with ewarns and ls -ld ${WORKDIR} checks :).

This eventually led me to inserting 'ewarn "In getfilevar() EBUILD_PHASE_FUNC=${EBUILD_PHASE_FUNC}"' right before line 184 https://chromium.googlesource.com/chromiumos/overlays/portage-stable/+/14fa96c/eclass/linux-info.eclass#184 . EBUILD_PHASE_FUNC was empty. This then resulted in M being set to '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/work/ecryptfs-utils-101'. Ah, starting to make sense! Gentoo introduced EBUILD_PHASE_FUNC in EAPI 5. Chrome OS versions of ecryptfs-utils and consolekit are currently EAPI 4. Powertop on the other hand is EAPI 5.

As a quick check, increasing the EAPI to 5 resulted in EBUILD_PHASE_FUNC being set to 'pkg-setup' which then resulted in M being set to '/build/soraka/tmp/portage/sys-fs/ecryptfs-utils-101/temp' and the build succeeded.