cros_sdk: Switch chroot image maintenance to python
The python code to create/mount/delete chroot.img was introduced in
https://crrev.com/c/611156. This CL uses this to move the chroot.img
setup from make_chroot.sh into cros_sdk. Having the setup in
make_chroot.sh was originally desirable to keep all the chroot
maintenance together, but the complexity of keeping the outer and inner
mount namespaces synced up had too many problems.
By moving chroot.img setup into cros_sdk, we eliminate:
1. Tracking the parent namespace and exiting from the child namespace.
2. Moving mounts between namespaces.
3. Passing --noudevsync to the lvm commands.
4. The whole chroot.build temporary directory.
I will send another CL to remove chroot.img setup from make_chroot.sh
once this CL has gone through the CQ.
BUG=chromium:730144, chromium:754014, chromium:752562
TEST=Created and removed a bunch of chroots; trybots.
Change-Id: Ie461def2b9d3dbb3215e844ceb4e281e905d5ff8
Reviewed-on: https://chromium-review.googlesource.com/614761
Commit-Ready: Benjamin Gordon <bmgordon@chromium.org>
Tested-by: David Schneider <dnschneid@chromium.org>
Tested-by: Benjamin Gordon <bmgordon@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
diff --git a/scripts/cros_sdk.py b/scripts/cros_sdk.py
index ce75768..1b192f3 100644
--- a/scripts/cros_sdk.py
+++ b/scripts/cros_sdk.py
@@ -190,8 +190,19 @@
def CreateChroot(chroot_path, sdk_tarball, toolchains_overlay_tarball,
- cache_dir, nousepkg=False, useimage=False):
- """Creates a new chroot from a given SDK"""
+ cache_dir, nousepkg=False):
+ """Creates a new chroot from a given SDK.
+
+ Args:
+ chroot_path: Path where the new chroot will be created.
+ sdk_tarball: Path to a downloaded Gentoo Stage3 or Chromium OS SDK tarball.
+ toolchains_overlay_tarball: Optional path to a second tarball that will be
+ unpacked into the chroot on top of the SDK tarball.
+ cache_dir: Path to a directory that will be used for caching portage files,
+ etc.
+ nousepkg: If True, pass --nousepkg to cros_setup_toolchains inside the
+ chroot.
+ """
cmd = MAKE_CHROOT + ['--stage3_path', sdk_tarball,
'--chroot', chroot_path,
@@ -203,9 +214,6 @@
if nousepkg:
cmd.append('--nousepkg')
- if useimage:
- cmd.append('--useimage')
-
logging.notice('Creating chroot. This may take a few minutes...')
try:
cros_build_lib.RunCommand(cmd, print_cmd=False)
@@ -261,6 +269,21 @@
raise SystemExit(ret.returncode)
+def _ImageFileForChroot(chroot):
+ """Find the image file that should be associated with |chroot|.
+
+ This function does not check if the image exists; it simply returns the
+ filename that would be used.
+
+ Args:
+ chroot: Path to the chroot.
+
+ Returns:
+ Path to an image file that would be associated with chroot.
+ """
+ return chroot.rstrip('/') + '.img'
+
+
def _FindSubmounts(*args):
"""Find all mounts matching each of the paths in |args| and any submounts.
@@ -622,6 +645,7 @@
_ReportMissing(osutils.FindMissingBinaries(NEEDED_TOOLS))
if options.proxy_sim:
_ReportMissing(osutils.FindMissingBinaries(PROXY_NEEDED_TOOLS))
+ missing_image_tools = osutils.FindMissingBinaries(IMAGE_NEEDED_TOOLS)
if (sdk_latest_version == '<unknown>' or
bootstrap_latest_version == '<unknown>'):
@@ -634,6 +658,10 @@
_ReExecuteIfNeeded([sys.argv[0]] + argv)
+ lock_path = os.path.dirname(options.chroot)
+ lock_path = os.path.join(
+ lock_path, '.%s_lock' % os.path.basename(options.chroot).lstrip('.'))
+
# Expand out the aliases...
if options.replace:
options.delete = options.create = True
@@ -654,9 +682,38 @@
parser.error("Trying to enter the chroot when --delete "
"was specified makes no sense.")
+ # Clean up potential leftovers from previous interrupted builds.
+ # TODO(bmgordon): Remove this at the end of 2017. That should be long enough
+ # to get rid of them all.
+ chroot_build_path = options.chroot + '.build'
+ if options.use_image and os.path.exists(chroot_build_path):
+ try:
+ with cgroups.SimpleContainChildren('cros_sdk'):
+ with locking.FileLock(lock_path, 'chroot lock') as lock:
+ logging.notice('Cleaning up leftover build directory %s',
+ chroot_build_path)
+ lock.write_lock()
+ osutils.UmountTree(chroot_build_path)
+ osutils.RmDir(chroot_build_path)
+ except cros_build_lib.RunCommandError as e:
+ logging.warning("Unable to remove %s: %s", chroot_build_path, e)
+
# Discern if we need to create the chroot.
- chroot_exists = os.path.exists(os.path.join(
- options.chroot, 'etc', 'cros_chroot_version'))
+ chroot_ver_file = os.path.join(options.chroot, 'etc', 'cros_chroot_version')
+ chroot_exists = os.path.exists(chroot_ver_file)
+ if (options.use_image and not chroot_exists and not options.delete and
+ not missing_image_tools and
+ os.path.exists(_ImageFileForChroot(options.chroot))):
+ # Try to re-mount an existing image in case the user has rebooted.
+ with cgroups.SimpleContainChildren('cros_sdk'):
+ with locking.FileLock(lock_path, 'chroot lock') as lock:
+ logging.debug('Checking if existing chroot image can be mounted.')
+ lock.write_lock()
+ cros_build_lib.MountChroot(options.chroot, create=False)
+ chroot_exists = os.path.exists(chroot_ver_file)
+ if chroot_exists:
+ logging.notice('Mounted existing image %s on chroot',
+ _ImageFileForChroot(options.chroot))
if options.create or options.enter:
# Only create if it's being wiped, or if it doesn't exist.
if not options.delete and chroot_exists:
@@ -668,53 +725,49 @@
if options.enter:
options.create |= not chroot_exists
- # If we're going to be using a loopback image for the chroot, we need
- # LVM tools installed. We can skip the check if something that looks
- # like a chroot is already visible in the expected place, since we won't
- # actually call any LVM commands in that case.
- if options.use_image and options.create:
- missing = osutils.FindMissingBinaries(IMAGE_NEEDED_TOOLS)
- if missing:
- raise SystemExit(
- 'The tool(s) %s were not found.\n'
- 'Please make sure the lvm2 and thin-provisioning-tools packages '
- 'are installed on your host.\n'
- 'Example(ubuntu):\n'
- ' sudo apt-get install lvm2 thin-provisioning-tools\n\n'
- 'If you want to run without lvm2, pass --nouse-image (chroot '
- 'snapshots will be unavailable).'
- % ', '.join(missing))
-
- # This dance is to support mounting the chroot inside a separate mount
- # namespace. While we're here in the original namespace, we set up a
- # temporary shared subtree
- # (https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt) and
- # then let CreateChroot operate inside there. Since it's shared, we can see
- # the mount that gets created. make_chroot.sh marks its mount private inside
- # the namespace, so none of the inner mounts leak out. After the chroot has
- # been created, we will return to this mount namespace (using an fd that we
- # open here and save) and move the mount from the temporary spot to the
- # requested final location. Once this is done, future uses of the same chroot
- # don't have to jump through any of these hoops until it gets unmounted. If
- # we're running on a system where things are mounted shared by default then
- # all this isn't necessary, but it seems safer to assume we need this setup
- # rather than try to detect it.
- if options.use_image:
- chroot_temp_parent = options.chroot + '.build'
- chroot_temp_mount = os.path.join(chroot_temp_parent, 'chroot')
- already_mounted = [m for m in osutils.IterateMountPoints()
- if m.destination == chroot_temp_parent]
- if not already_mounted and options.create:
- osutils.SafeMakedirsNonRoot(chroot_temp_mount)
- osutils.Mount(chroot_temp_parent, chroot_temp_parent, '', osutils.MS_BIND)
- osutils.Mount('', chroot_temp_parent, '', osutils.MS_SHARED)
- parent_ns_file = open('/proc/%d/ns/mnt' % (os.getppid(),))
- parent_ns = parent_ns_file.fileno()
-
# If we're going to delete, also make sure the chroot isn't mounted
- # before we enter the new mount namespace.
+ # before we enter the new mount namespace. We do this regardless of
+ # the use_image flag so that a previously-created loopback chroot can
+ # also be cleaned up.
+ # TODO(bmgordon): See if the DeleteChroot call below can be removed in
+ # favor of this block.
+ chroot_deleted = False
if options.delete:
- osutils.UmountTree(options.chroot)
+ with cgroups.SimpleContainChildren('cros_sdk'):
+ with locking.FileLock(lock_path, 'chroot lock') as lock:
+ lock.write_lock()
+ if missing_image_tools:
+ logging.notice('Unmounting chroot.')
+ osutils.UmountTree(options.chroot)
+ else:
+ logging.notice('Deleting chroot.')
+ cros_build_lib.CleanupChrootMount(options.chroot, delete_image=True)
+ osutils.RmDir(options.chroot, ignore_missing=True)
+ chroot_deleted = True
+
+ # If we're going to create a new chroot, set it up before we change
+ # mount namespaces so that it will be visible to processes other than
+ # cros_sdk's children.
+ if options.create and options.use_image:
+ if missing_image_tools:
+ raise SystemExit(
+ '''The tool(s) %s were not found.
+Please make sure the lvm2 and thin-provisioning-tools packages
+are installed on your host.
+Example(ubuntu):
+ sudo apt-get install lvm2 thin-provisioning-tools
+
+If you want to run without lvm2, pass --nouse-image (chroot
+snapshots will be unavailable).''' % ', '.join(missing_image_tools))
+ logging.debug('Making sure chroot image is mounted.')
+ with cgroups.SimpleContainChildren('cros_sdk'):
+ with locking.FileLock(lock_path, 'chroot lock') as lock:
+ lock.write_lock()
+ if not cros_build_lib.MountChroot(options.chroot, create=True):
+ cros_build_lib.Die('Unable to mount %s on chroot',
+ _ImageFileForChroot(options.chroot))
+ logging.notice('Mounted %s on chroot',
+ _ImageFileForChroot(options.chroot))
namespaces.SimpleUnshare()
if options.ns_pid:
@@ -751,9 +804,6 @@
toolchains_overlay_urls = GetToolchainsOverlayUrls(sdk_version,
toolchains)
- lock_path = os.path.dirname(options.chroot)
- lock_path = os.path.join(
- lock_path, '.%s_lock' % os.path.basename(options.chroot).lstrip('.'))
with cgroups.SimpleContainChildren('cros_sdk', pid=first_pid):
with locking.FileLock(lock_path, 'chroot lock') as lock:
toolchains_overlay_tarball = None
@@ -761,8 +811,9 @@
if options.proxy_sim:
_ProxySimSetup(options)
- if options.delete and (os.path.exists(options.chroot) or
- os.path.exists(options.chroot + '.img')):
+ if (options.delete and not chroot_deleted and
+ (os.path.exists(options.chroot) or
+ os.path.exists(_ImageFileForChroot(options.chroot)))):
lock.write_lock()
DeleteChroot(options.chroot)
@@ -808,8 +859,7 @@
lock.write_lock()
CreateChroot(options.chroot, sdk_tarball, toolchains_overlay_tarball,
options.cache_dir,
- nousepkg=(options.bootstrap or options.nousepkg),
- useimage=options.use_image)
+ nousepkg=(options.bootstrap or options.nousepkg))
if options.enter:
lock.read_lock()
@@ -817,30 +867,3 @@
options.chrome_root_mount, options.workspace,
options.goma_dir, options.goma_client_json,
chroot_command)
-
- # Remount the inner chroot mount back up to the original namespace. See above
- # for details.
- if options.use_image and options.create:
- vg, lv = cros_build_lib.FindChrootMountSource(chroot_temp_mount)
-
- # Clean up inside the child mount namespace. Normally these will disappear
- # as soon as the last process exits the mount namespace, but we want to be
- # able to clean up the underlying directories without waiting for the forked
- # "init" copes of cros_sdk to exit the namespace. This is safe to do even
- # with multiple processes in the same chroot because the other cros_sdk
- # copies will have their own mount namespace.
- chroot_mounts = _FindSubmounts(chroot_temp_parent, options.chroot)
- osutils.UmountTree(chroot_temp_parent)
- osutils.UmountTree(options.chroot)
-
- namespaces.SetNS(parent_ns, 0)
- chroot_mounts = _FindSubmounts(chroot_temp_parent, options.chroot)
- if not options.chroot in chroot_mounts:
- if not vg or not lv:
- cros_build_lib.Die('Unable to find VG/LV mounted on %s after building '
- 'chroot.' % chroot_temp_mount)
- osutils.UmountTree(chroot_temp_parent)
- osutils.RmDir(chroot_temp_parent, ignore_missing=True)
-
- chroot_dev_path = '/dev/mapper/%s-%s' % (vg, lv)
- osutils.Mount(chroot_dev_path, options.chroot, 'ext4', osutils.MS_NOATIME)