1 files changed, 107 insertions, 0 deletions
diff --git a/python/mozbuild/mozpack/archive.py b/python/mozbuild/mozpack/archive.py
new file mode 100644
index 000000000..f3015ff21
--- /dev/null
+++ b/python/mozbuild/mozpack/archive.py
@@ -0,0 +1,107 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from __future__ import absolute_import
+
+import bz2
+import gzip
+import stat
+import tarfile
+
+
+# 2016-01-01T00:00:00+0000
+DEFAULT_MTIME = 1451606400
+
+
+def create_tar_from_files(fp, files):
+    """Create a tar file deterministically.
+
+    Receives a dict mapping names of files in the archive to local filesystem
+    paths.
+
+    The files will be archived and written to the passed file handle opened
+    for writing.
+
+    Only regular files can be written.
+
+    FUTURE accept mozpack.files classes for writing
+    FUTURE accept a filename argument (or create APIs to write files)
+    """
+    with tarfile.open(name='', mode='w', fileobj=fp, dereference=True) as tf:
+        for archive_path, fs_path in sorted(files.items()):
+            ti = tf.gettarinfo(fs_path, archive_path)
+
+            if not ti.isreg():
+                raise ValueError('not a regular file: %s' % fs_path)
+
+            # Disallow setuid and setgid bits. This is an arbitrary restriction.
+            # However, since we set uid/gid to root:root, setuid and setgid
+            # would be a glaring security hole if the archive were
+            # uncompressed as root.
+            if ti.mode & (stat.S_ISUID | stat.S_ISGID):
+                raise ValueError('cannot add file with setuid or setgid set: '
+                                 '%s' % fs_path)
+
+            # Set uid, gid, username, and group as deterministic values.
+            ti.uid = 0
+            ti.gid = 0
+            ti.uname = ''
+            ti.gname = ''
+
+            # Set mtime to a constant value.
+            ti.mtime = DEFAULT_MTIME
+
+            with open(fs_path, 'rb') as fh:
+                tf.addfile(ti, fh)
+
+
+def create_tar_gz_from_files(fp, files, filename=None, compresslevel=9):
+    """Create a tar.gz file deterministically from files.
+
+    This is a glorified wrapper around ``create_tar_from_files`` that
+    adds gzip compression.
+
+    The passed file handle should be opened for writing in binary mode.
+    When the function returns, all data has been written to the handle.
+    """
+    # Offset 3-7 in the gzip header contains an mtime. Pin it to a known
+    # value so output is deterministic.
+    gf = gzip.GzipFile(filename=filename or '', mode='wb', fileobj=fp,
+                       compresslevel=compresslevel, mtime=DEFAULT_MTIME)
+    with gf:
+        create_tar_from_files(gf, files)
+
+
+class _BZ2Proxy(object):
+    """File object that proxies writes to a bz2 compressor."""
+    def __init__(self, fp, compresslevel=9):
+        self.fp = fp
+        self.compressor = bz2.BZ2Compressor(compresslevel=compresslevel)
+        self.pos = 0
+
+    def tell(self):
+        return self.pos
+
+    def write(self, data):
+        data = self.compressor.compress(data)
+        self.pos += len(data)
+        self.fp.write(data)
+
+    def close(self):
+        data = self.compressor.flush()
+        self.pos += len(data)
+        self.fp.write(data)
+
+
+def create_tar_bz2_from_files(fp, files, compresslevel=9):
+    """Create a tar.bz2 file deterministically from files.
+
+    This is a glorified wrapper around ``create_tar_from_files`` that
+    adds bzip2 compression.
+
+    This function is similar to ``create_tar_gzip_from_files()``.
+    """
+    proxy = _BZ2Proxy(fp, compresslevel=compresslevel)
+    create_tar_from_files(proxy, files)
+    proxy.close()