Revert "Merge branch 'liw/hardlink-staging-area-pre-rebase'"

This reverts commit c859d70d86423a52bc7053abf64e9ca21f62a487, reversing
changes made to 3085a672d1e8b5177be33f0463385de72a0ef5bf.

Unfortunately, hardlinking and linux-user-chroot both break builds
in various ways. Hardlinking breaks the bootstrap process by creating
symlinks like /usr/libexec that can then not be overwritten with real
files by install scripts from morphologies like gcc.

linux-user-chroot caused problems by breaking privileged operations such
as chgrp and CAP_SETFCAP. As a consequence, chunks like util-linux and
libcap can no longer be built.

3 files changed, 33 insertions, 89 deletions

diff --git a/morphlib/builder2.py b/morphlib/builder2.py
index 28a5e0ba..c7d25e1a 100644
--- a/morphlib/builder2.py
+++ b/morphlib/builder2.py
@@ -259,31 +259,53 @@ class ChunkBuilder(BuilderBase):
 
     def build_and_cache(self):  # pragma: no cover
         with self.build_watch('overall-build'):
-            
-            builddir, destdir = \
-                self.staging_area.chroot_open(self.artifact.source)
+            mounted = self.do_mounts()
             log_name = None
             try:
+                builddir = self.staging_area.builddir(self.artifact.source)
                 self.get_sources(builddir)
+                destdir = self.staging_area.destdir(self.artifact.source)
                 with self.local_artifact_cache.put_source_metadata(
                         self.artifact.source, self.artifact.cache_key,
                         'build-log') as log:
                     log_name = log.real_filename
                     self.run_commands(builddir, destdir, log)
             except:
-                self.staging_area.chroot_close()
+                self.do_unmounts(mounted)
                 if log_name:
                     with open(log_name) as f:
                         for line in f:
                             logging.error('OUTPUT FROM FAILED BUILD: %s' %
                                           line.rstrip('\n'))
                 raise
-            self.staging_area.chroot_close()
+            self.do_unmounts(mounted)
             built_artifacts = self.assemble_chunk_artifacts(destdir)
 
         self.save_build_times()
         return built_artifacts
 
+    to_mount = (
+        ('proc',    'proc',  'none'),
+        ('dev/shm', 'tmpfs', 'none'),
+    )
+
+    def do_mounts(self):  # pragma: no cover
+        mounted = []
+        if not self.setup_mounts:
+            return mounted
+        for mount_point, mount_type, source in ChunkBuilder.to_mount:
+            logging.debug('Mounting %s in staging area' % mount_point)
+            path = os.path.join(self.staging_area.dirname, mount_point)
+            if not os.path.exists(path):
+                os.makedirs(path)
+            self.app.runcmd(['mount', '-t', mount_type, source, path])
+            mounted.append(path)
+        return mounted
+
+    def do_unmounts(self, mounted):  # pragma: no cover
+        for path in mounted:
+            logging.debug('Unmounting %s in staging area' % path)
+            morphlib.fsutils.unmount(self.app.runcmd, path)
 
     def get_sources(self, srcdir):  # pragma: no cover
         '''Get sources from git to a source directory, for building.'''
diff --git a/morphlib/stagingarea.py b/morphlib/stagingarea.py
index 77eeab7d..a87b45c3 100644
--- a/morphlib/stagingarea.py
+++ b/morphlib/stagingarea.py
@@ -40,8 +40,6 @@ class StagingArea(object):
         self._app = app
         self.dirname = dirname
         self.tempdir = tempdir
-        self.builddirname = None
-        self.destdirname = None        
 
     # Wrapper to be overridden by unit tests.
     def _mkdir(self, dirname):  # pragma: no cover
@@ -92,21 +90,7 @@ class StagingArea(object):
 
         logging.debug('Installing artifact %s' %
                       getattr(handle, 'name', 'unknown name'))
-
-        unpacked_artifact = os.path.join(
-            self._app.settings['cachedir'],
-            'artifacts',
-            os.path.basename(handle.name) + '.d')
-        if not os.path.exists(unpacked_artifact):
-            self._mkdir(unpacked_artifact)
-            morphlib.bins.unpack_binary_from_file(
-                handle, unpacked_artifact + '/')
-            
-        if not os.path.exists(self.dirname):
-            self._mkdir(self.dirname)
-
-        self._app.runcmd(
-            ['cp', '-al', unpacked_artifact + '/.', self.dirname + '/.'])
+        morphlib.bins.unpack_binary_from_file(handle, self.dirname)
 
     def remove(self):
         '''Remove the entire staging area.
@@ -119,61 +103,14 @@ class StagingArea(object):
 
         shutil.rmtree(self.dirname)
 
-    def chroot_open(self, source): # pragma: no cover
-        '''Setup staging area for use as a chroot.'''
-
-        assert self.builddirname == None and self.destdirname == None
-
-        builddir = self.builddir(source)
-        destdir = self.destdir(source)
-        self.builddirname = self.relative(builddir).lstrip('/')
-        self.destdirname = self.relative(destdir).lstrip('/')
-
-        for mount_point in ['proc','dev/shm']:
-            path = os.path.join(self.dirname, mount_point)
-            if not os.path.exists(path):
-                os.makedirs(path)
-
-        return builddir, destdir
-
-    def chroot_close(self): # pragma: no cover
-        '''Undo changes by chroot_open.
-        
-        This should be called after the staging area is no longer needed.
-        
-        '''
-
     def runcmd(self, argv, **kwargs):  # pragma: no cover
-        '''Run a command in the staging area.'''
-
+        '''Run a command in a chroot in the staging area.'''
         cwd = kwargs.get('cwd') or '/'
         if 'cwd' in kwargs:
             cwd = kwargs['cwd']
             del kwargs['cwd']
         else:
             cwd = '/'
-
-        if self._app.settings['staging-chroot']:
-            entries = os.listdir(self.dirname)
-
-            friends = [self.builddirname, self.destdirname,
-                       'dev', 'proc', 'tmp']
-            for friend in friends:
-                if friend in friends:
-                    entries.remove(friend)
-
-            real_argv = ['linux-user-chroot']
-
-            for entry in entries:
-                real_argv += ['--mount-readonly',"/"+entry]
-            
-            real_argv += ['--mount-proc','/proc']
-            real_argv += ['--mount-bind','/dev/shm','/dev/shm']
-            real_argv += [self.dirname]
-        else:
-            real_argv = ['chroot', '/']
-
-        real_argv += ['sh', '-c', 'cd "$1" && shift && exec "$@"', '--', cwd]
-        real_argv += argv
-
+        real_argv = ['chroot', self.dirname, 'sh', '-c',
+                     'cd "$1" && shift && exec "$@"', '--', cwd] + argv
         return self._app.runcmd(real_argv, **kwargs)
diff --git a/morphlib/stagingarea_tests.py b/morphlib/stagingarea_tests.py
index 15131272..3230b9e3 100644
--- a/morphlib/stagingarea_tests.py
+++ b/morphlib/stagingarea_tests.py
@@ -14,7 +14,6 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
-import cliapp
 import os
 import shutil
 import tarfile
@@ -32,28 +31,14 @@ class FakeSource(object):
         }
 
 
-class FakeApplication(object):
-
-    def __init__(self, cachedir):
-        self.settings = {
-            'cachedir': cachedir,
-        }
-
-    def runcmd(self, *args, **kwargs):
-        cliapp.runcmd(*args, **kwargs)
-
-
 class StagingAreaTests(unittest.TestCase):
 
     def setUp(self):
         self.tempdir = tempfile.mkdtemp()
-        self.cachedir = os.path.join(self.tempdir, 'cachedir')
-        os.mkdir(self.cachedir)
-        os.mkdir(os.path.join(self.cachedir, 'artifacts'))
         self.staging = os.path.join(self.tempdir, 'staging')
         self.created_dirs = []
-        self.sa = morphlib.stagingarea.StagingArea(
-            FakeApplication(self.cachedir), self.staging, self.staging)
+        self.sa = morphlib.stagingarea.StagingArea(object(), self.staging,
+                                                   self.staging)
 
     def tearDown(self):
         shutil.rmtree(self.tempdir)