Make TarArchive preserve permissions and SELinux context

Make the TarArchive class preserve permissions and SELinux context on
all files and directories it collects. This requires us to recursively
add the parent directories of any files copied in by full path (or the
directory would only be implicitly created and so receive default
ownership and permissions and no SELinux context).

To make this work, don't call tarfile.add() to recursively add
directories - the doCopyFileOrDir machinery in the Plugin class already
handles directory recursion properly. Instead when a directory is passed
to add_file(), just create a TarInfo record of type tarfile.DIRTYPE and
propagate the permissions from the host file system.

The SELinux contexts have the unfortunate side-effect of spewing errors
if unpacked without --no-selinux as some contexts cannot be placed on
some file systems.

It may be more useful to eventually store the contexts in the
in a file rather than directly in the tarball.

Before:

drwxr-xr-x.  9 root root  640 Dec  7 00:57 proc
lrwxrwxrwx.  1 root root   30 Dec  7 00:57 ps -> sos_commands/process/ps_auxwww
drwxr-xr-x.  2 root root   60 Dec  7 00:57 root
drwxr-xr-x.  2 root root   80 Dec  7 00:57 sbin

After:

dr-xr-xr-x.  9 root root  640 Dec  5 19:07 proc
lrwxrwxrwx.  1 root root   30 Dec  7 00:58 ps -> sos_commands/process/ps_auxwww
dr-xr-x---.  2 root root   60 Dec  7 00:48 root
dr-xr-xr-x.  2 root root   80 Dec  7 00:57 sbin

More fixes issue #76

sos/utilities.py

@@ -36,6 +36,7 @@
 import hashlib
 import logging
 import fnmatch
+import selinux
 
 from contextlib import closing
 try:
@@ -201,39 +202,74 @@ def compress(self, method):
 
         self.close()
 
-
 class TarFileArchive(Archive):
 
     def __init__(self, name):
         self._name = name
         self._suffix = "tar"
-        self.tarfile = tarfile.open(self.name(), mode="w")
-
+        self.tarfile = tarfile.open(self.name(),
+                    mode="w", format=tarfile.PAX_FORMAT)
+
+    # this can be used to set permissions if using the
+    # tarfile.add() interface to add directory trees.
+    def copy_permissions_filter(self, tar_info):
+        orig_path = tar_info.name[len(os.path.split(self._name)[-1]):]
+        fstat = os.stat(orig_path)
+        context = self.get_selinux_context(orig_path)
+        if(context):
+            tar_info.pax_headers['RHT.security.selinux'] = context
+        self.set_tar_info_from_stat(tar_info,fstat)
+        print "filtering orig_path=%s context=%s" % (orig_path, context)
+        return tar_info
+
+    def get_selinux_context(self, path):
+        try:
+            (rc, c) = selinux.getfilecon(path)
+            return c
+        except:
+            return None
+
+    def set_tar_info_from_stat(self, tar_info, fstat):
+        tar_info.mtime = "%.9f" % fstat.st_mtime
+        tar_info.pax_headers['atime'] = "%.9f" % fstat.st_atime
+        tar_info.pax_headers['ctime'] = "%.9f" % fstat.st_ctime
+        tar_info.mode = fstat.st_mode
+        tar_info.uid = fstat.st_uid
+        tar_info.gid = fstat.st_gid
+
     def name(self):
         return "%s.%s" % (self._name, self._suffix)
 
+    def add_parent(self, path):
+        if (path == '/'):
+            return
+        path = os.path.split(path)[0]
+        self.add_file(path)
+
     def add_file(self, src, dest=None):
         if dest:
             dest = self.prepend(dest)
         else:
             dest = self.prepend(src)
 
+        tar_info = tarfile.TarInfo(name=dest)
+
         if os.path.isdir(src):
-            self.tarfile.add(src, dest)
+            tar_info.type = tarfile.DIRTYPE            
+            fileobj = None
         else:
             fp = open(src, 'rb')
             content = fp.read()
             fp.close()
-            fstat = os.stat(src)
-            tar_info = tarfile.TarInfo(name=dest)
             tar_info.size = len(content)
-            tar_info.mtime = fstat.st_mtime
-            tar_info.pax_headers['atime'] = fstat.st_atime
-            tar_info.mode = fstat.st_mode
-            tar_info.uid = fstat.st_uid
-            tar_info.gid = fstat.st_gid
-
-            self.tarfile.addfile(tar_info, StringIO(content))
+            fileobj = StringIO(content)
+        fstat = os.stat(src)
+        context = self.get_selinux_context(src)
+        if context:
+            tar_info.pax_headers['RHT.security.selinux'] = context
+        self.set_tar_info_from_stat(tar_info,fstat)
+        self.add_parent(src)
+        self.tarfile.addfile(tar_info, fileobj)
 
     def add_string(self, content, dest):
         fstat = None
@@ -243,11 +279,10 @@ def add_string(self, content, dest):
         tar_info = tarfile.TarInfo(name=dest)
         tar_info.size = len(content)
         if fstat:
-            tar_info.mtime = fstat.st_mtime
-            tar_info.pax_headers['atime'] = fstat.st_atime
-            tar_info.mode = fstat.st_mode
-            tar_info.uid = fstat.st_uid
-            tar_info.gid = fstat.st_gid
+            context = self.get_selinux_context(dest)
+            if context:
+                tar_info.pax_headers['RHT.security.selinux'] = context
+            self.set_tar_info_from_stat(tar_info, fstat)
         else:
             tar_info.mtime = time.time()
         self.tarfile.addfile(tar_info, StringIO(content))