musl libc's implementation of `realpath` works by opening the path and then
doing a lookup in `/proc/self/fd` to find the canonical path. This fails
if `/proc` is not mounted. This causes problems for us if
`ostree-prepare-root` is `init` as `/proc` won't be mounted.
We have to mount `/proc` anyway for `/proc/cmdline` so this fix just
expands the scope over which `/proc` is mounted to include both our
`realpath` calls.
See also:
* http://www.openwall.com/lists/musl/2016/06/08/2 and
* http://git.musl-libc.org/cgit/musl/tree/src/misc/realpath.c?id=e738b8cbe64b6dd3ed9f47b6d4cd7eb2c422b38dCloses: #485
Approved by: cgwalters
I've seen it fail with musl which needs `/proc` to be mounted for it to
work. The error messages we're rather confusing before. At least this
now points to the right location.
Closes: #485
Approved by: cgwalters
This simplifies the build system by removing the need for
`libswitchroot-mountutil.la`.
Original idea by @cgwalters in #477.
Closes: #478
Approved by: cgwalters
The `warn()` libc extension has exactly the same behaviour as our own
`perrorv` function, but is available in (at least) glibc and musl. As an
added bonus the similar function `err()` which will exit with an error
code afterwards.
This implementation is tidier and allows us to get rid of our own
`perrorv`. It paves the way to removing `ostree-mount-util.c` to simplify
the build scripts.
Original idea by @cgwalters in #477.
Closes: #478
Approved by: cgwalters
POSIX and GNU define conflicting versions of `strerror_r`. The GNU
version returns the string but doesn't necessilary write into buf.
The POSIX version writes into buf and returns the length but doesn't
necessilary append a terminate the string with a NUL if it's too long
to fit in buf.
This commit fixes building ostree-prepare-root with musl libc. The
stripped static build with musl on my machine is 30K vs. 724K with glibc
static and 11K with glibc shared.
Closes: #477
Approved by: cgwalters
This allows ostree-prepare-root outside of the initramfs context where the
real rootfs is already mounted at /. We can't use `mount --move` in this
case because we would be trying to move / into a subdirectory of itself.
Closes: #403
Approved by: cgwalters
...for simplicity. This way we don't need to keep concatenating
deploy_path to everything. We can just refer relative to the current
working directory.
We need to do this after bind-mounting it over itself otherwise our cwd
is still on the non-bind-mounted filesystem below.
Closes: #403
Approved by: cgwalters
Typically we have our ready made-up up root at
`/sysroot/ostree/deploy/.../` (`deploy_path`) and the real rootfs at
`/sysroot` (`root_mountpoint`). We want to end up with our made-up root
at `/sysroot/` and the real rootfs under `/sysroot/sysroot` as systemd
will be responsible for moving `/sysroot` to `/`.
We need to do this in 3 moves to avoid trying to move `/sysroot` under
itself:
1. `/sysroot/ostree/deploy/...` -> `/sysroot.tmp`
2. `/sysroot` -> `/sysroot.tmp/sysroot`
3. `/sysroot.tmp` -> `/sysroot`
This is a refactoring to group all these operations together so I can
implement an alternative in terms of `pivot_root`.
Closes: #403
Approved by: cgwalters
This supports running ostree on embedded platforms without an initrd.
Specificially I'm trying to do bringup on an NVidia Tegra based Jetson TK1
dev board.
Closes: #403
Approved by: cgwalters
I'm trying to improve the developer experience on OSTree-managed
systems, and I had an epiphany the other day - there's no reason we
have to be absolutely against mutating the current rootfs live. The
key should be making it easy to rollback/reset to a known good state.
I see this command as useful for two related but distinct workflows:
- `ostree admin unlock` will assume you're doing "development". The
semantics hare are that we mount an overlayfs on `/usr`, but the
overlay data is in `/var/tmp`, and is thus discarded on reboot.
- `ostree admin unlock --hotfix` first clones your current deployment,
then creates an overlayfs over `/usr` persistent
to this deployment. Persistent in that now the initramfs switchroot
tool knows how to mount it as well. In this model, if you want
to discard the hotfix, at the moment you roll back/reboot into
the clone.
Note originally, I tried using `rofiles-fuse` over `/usr` for this,
but then everything immediately explodes because the default (at least
CentOS 7) SELinux policy denies tons of things (including `sshd_t`
access to `fusefs_t`). Sigh.
So the switch to `overlayfs` came after experimentation. It still
seems to have some issues...specifically `unix_chkpwd` is broken,
possibly because it's setuid? Basically I can't ssh in anymore.
But I *can* `rpm -Uvh strace.rpm` which is handy.
NOTE: I haven't tested the hotfix path fully yet, specifically
the initramfs bits.
ostree-prepare-root was logging normal, informational messages
to stderr which the systemd unit points to the console.
To achieve silent boot, log these ordinary messages to stdout only.
prepare-root works with the mount that has been set up at /sysroot.
It creates a bind-mount within /sysroot (the deployment) and then moves
that mount to /sysroot.
Now we have 2 mounts both at /sysroot, and once we do switch_root, we will
never be able to unmount both of them. I'm not sure if this is ultimately
a kernel bug, but either way, ostree could do a bit more tidying up
after itself.
http://thread.gmane.org/gmane.linux.file-systems/92411
Easy way to reproduce:
1. Boot with rd.break param
2. At initramfs shell, run: ostree-prepare-root /sysroot
3. Observe two /sysroot mounts in /proc/mounts
Fix this by setting up the mounts at /sysroot.tmp, and unmounting the
original /sysroot before our new mount is MS_MOVEd on top of it.
/var needs to be read-write for a functioning system. Various
systemd services will fail to start if /var is read-only. After we
remount /var (or if we skip remounting /var because / is read-only),
if /var is still readonly, mount a tmpfs file system on /var.
While this isn't strictly part of ostree, keeping it here makes sense
because it keeps twiddling around with the /var mount in one place
for easier coordination and maintenance. This will likely need updating
if systemd gains better support for a readonly root filesystem.
https://bugzilla.gnome.org/show_bug.cgi?id=732979
The previous S_IMMUTABLE commit broke ostree-remount; / is now not
actually writable. All we really wanted to know though was whether it
was *mounted* writable, so check that via statvfs() which is cleaner
anyways (i.e. not via access() which kernel people hate).
https://bugzilla.gnome.org/show_bug.cgi?id=728006
The idea with this is that things like yum should be able to look for
it and determine whether or not they should assume that they can
change things on the system.
https://bugzilla.gnome.org/show_bug.cgi?id=725380
I ran into Jeremy Katz today, and he gave me permission to relicense
the small bits of switch-root.c to LGPLv2+. This combined with
permission from Peter Jones allows OSTree to become fully LGPLv2+.
Not a big deal, it's just a lot clearer to only have one license, and
it makes it easier to turn application code into library code.
Extracting the code for parse_ostree_cmdline() and running it on some
test input (on RHEL6.4 glibc), I can reproduce the odd behavior from
getline() where it apparently returns the size of the default malloc
buffer in the size output, and some non-zero value.
This behavior would be OK except that it breaks the logic for
stripping off the trailing newline, which in turn breaks booting
because we return "ostree=foo\n".
This has worked so far in gnome-ostree because syslinux apparently
injects initrd=/path/to/initrd as a final kernel argment.
Anyways, we don't handle NUL characters here in /proc/cmdline, so
let's just call strlen () to be safe.
https://bugzilla.gnome.org/show_bug.cgi?id=707192
While the systemd integration effectively requires /sysroot, it will
help people trying to use OSTree with other initramfs systems
(e.g. initramfs-tools) if we don't hardcode that requirement in this
tool.
See https://wiki.gnome.org/OSTree/DeploymentModel2
This is a major rework of the on-disk filesystem layout, and the boot
process. OSTree now explicitly supports upgrading kernels, and these
upgrades are also atomic.
The core concept of the new model is the "deployment list", which is
an ordered list of bootable operating system trees. The deployment
list is reflected in the bootloader configuration; which has a kernel
argument that tells the initramfs (dracut) which operating system root
to use.
Invidiual notable changes that come along with this:
1) Operating systems should now come with their etc in usr/etc; OSTree
will perform a 3-way merge at deployment time, and place etc in
the actual root. This avoids the need for a bind mount, and is
just a lot cleaner.
2) OSTree no longer bind mounts /root, /home, and /tmp. It is expected
that the the OS/ has these as symbolic links into /var.
At the moment, OSTree only supports managing syslinux; other
bootloader backends will follow.
Linux creates a copy of the soure mount flags when creating a bind
mount; if the source is read-only, then the bind mount is.
The problem is that systemd will remount the rootfs read/write, but
each mount (/home, /var etc.) will still be read-only. We need to
remount every bind mount except for /usr to read-write too.
This only "worked" with the old ostree-switch-root because it
effectively force mounted the rootfs read-write always, ignoring the
"ro" flag.
Rather than attempting to hack up the "switch-root" functionality of
systemd, this binary allows us to simply prepare the root before we
switch into it.
The real vision of OSTree is to "multiple versions of multiple
operating systems". Up until now, it's worked to install gnome-ostree
inside a host distribution, but several things don't work quite right
if you try to do completely different systems.
In the new model, there's the concept of an "osname" which encompasses
a few properties:
1) Its own /var
2) A set of trees deployed in /ostree/deploy/OSNAME/
3) Its own "current" and "previous" links.
Now it no longer really makes sense to boot with "ostree=current".
Instead, you specify e.g. "ostree=gnome/current".
This is an incompatible change to the deployment code - you will need
to run init-os gnome and redeploy.
All "ostree admin" subcommands now take an OSNAME argument.
First, move deployments to /ostree/deploy. Having them in the
toplevel clutters the filesystem layout too much.
When we deploy a tree like /ostree/deploy/NAME, there is now also a
writable directory /ostree/deploy/NAME-etc. This is mounted as
read-write inside the system.
On an initial install, that directory is copied from
/ostree/deploy/NAME/etc. On subsequent deployments, we find any
changes made in the current deployment's /etc, and apply that set of
changes to the new deployment's /etc.
See https://live.gnome.org/OSTree/EverythingInEtcIsABug
The ostree-switch-root tool expects three arguments (argc=4): new root, OS
tree target, and init(8) binary to launch inside it. Also, the error message
when not enough arguments are passed now tells about the second argument
being the target OS tree.
Reviewed-by: Colin Walters <walters@verbum.org>
Merge the code from ostree-init; now that we're back to targeting an
initramfs (dracut), we don't need to statically link the binary, so
there's no strong reason to have a separate module.
William Manley
Giuseppe Scrivano
Colin Walters
Daniel Drake
Owen W. Taylor
Adrian Perez