Add a notion of "physical" sysroot, use for remote writing

(Note this PR was reverted in <https://github.com/ostreedev/ostree/pull/902>;
 this version should be better)

Using `${sysroot}` to mean the physical storage root: We don't want to write to
`${sysroot}/etc/ostree/remotes.d`, since nothing will read it, and really
`${sysroot}` should just have `/ostree` (ideally). Today the Anaconda rpmostree
code ends up writing there. Fix this by adding a notion of "physical" sysroot.
We determine whether the path is physical by checking for `/sysroot`, which
exists in deployment roots (and there shouldn't be a `${sysroot}/sysroot`).

In order to unit test this, I added a `--sysroot` argument to `remote add`.
However, doing this better would require reworking the command line parsing for
the `remote` argument to support specifying `--repo` or `--sysroot`, and I
didn't quite want to do that yet in this patch.

This second iteration of this patch fixes the bug we hit the first time;
embarassingly enough I broke `ostree remote list` finding system remotes.
The fix is to have `ostree_repo_open()` figure out whether it's the same
as `/ostree/repo` for now.

Down the line...we might consider having the `ostree remote` command line itself
instatiate an `OstreeSysroot` by default, but this maximizes compatibility; we
just have to pay a small cost that `ostree` usage outside of that case like
`ostree static-delta` in a releng Jenkins job or whatever will do this `stat()`
too.

Closes: https://github.com/ostreedev/ostree/issues/892

Closes: #1008
Approved by: mbarnes

tests/admin-test.sh

@@ -234,3 +234,18 @@ curr_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buil
 assert_streq ${curr_rev} ${head_rev}
 
 echo "ok upgrade with and without override-commit"
+
+deployment=$(${CMD_PREFIX} ostree admin --sysroot=sysroot --print-current-dir)
+${CMD_PREFIX} ostree --sysroot=sysroot remote add --set=gpg-verify=false remote-test-physical file://$(pwd)/testos-repo
+assert_not_has_file ${deployment}/etc/ostree/remotes.d/remote-test-physical.conf testos-repo
+assert_file_has_content sysroot/ostree/repo/config remote-test-physical
+echo "ok remote add physical sysroot"
+
+# Now a hack...symlink ${deployment}/sysroot to the sysroot in lieu of a bind
+# mount which we can't do in unit tests.
+ln -sr sysroot ${deployment}/sysroot
+ln -s sysroot/ostree ${deployment}/ostree
+${CMD_PREFIX} ostree --sysroot=${deployment} remote add --set=gpg-verify=false remote-test-nonphysical file://$(pwd)/testos-repo
+assert_not_file_has_content sysroot/ostree/repo/config remote-test-nonphysical
+assert_file_has_content ${deployment}/etc/ostree/remotes.d/remote-test-nonphysical.conf testos-repo
+echo "ok remote add nonphysical sysroot"

tests/installed/itest-remotes.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# Test that we didn't regress /etc/ostree/remotes.d handling
+
+set -xeuo pipefail
+
+dn=$(dirname $0)
+. ${dn}/libinsttest.sh
+
+test_tmpdir=$(prepare_tmpdir)
+trap _tmpdir_cleanup EXIT
+
+ostree remote list > remotes.txt
+if ! test -s remotes.txt; then
+    assert_not_reached "no ostree remotes"
+fi

tests/test-admin-deploy-grub2.sh

@@ -19,7 +19,7 @@
 
 set -euo pipefail
 
-echo "1..16"
+echo "1..18"
 
 . $(dirname $0)/libtest.sh
 

tests/test-admin-deploy-syslinux.sh

@@ -19,7 +19,7 @@
 
 set -euo pipefail
 
-echo "1..16"
+echo "1..18"
 
 . $(dirname $0)/libtest.sh
 

tests/test-admin-deploy-uboot.sh

@@ -20,7 +20,7 @@
 
 set -euo pipefail
 
-echo "1..17"
+echo "1..19"
 
 . $(dirname $0)/libtest.sh