Move pwd grp functions to pwdgrp module; require binary fields

[bup.git] / lib / bup / pwdgrp.py

diff --git a/lib/bup/pwdgrp.py b/lib/bup/pwdgrp.py
new file mode 100644 (file)
index 0000000..89912ba
--- /dev/null
+++ b/lib/bup/pwdgrp.py
@@ -0,0 +1,141 @@
+
+from __future__ import absolute_import, print_function
+import os, pwd, grp
+
+from bup import compat  # to force the LC_CTYPE check
+from bup.compat import py_maj
+from bup.helpers import cache_key_value
+
+
+# Using __slots__ makes these much smaller (even than a namedtuple)
+
+class Passwd:
+    """Drop in replacement for pwd's structure with bytes instead of strings."""
+    __slots__ = ('pw_name', 'pw_passwd', 'pw_uid', 'pw_gid', 'pw_gecos',
+                 'pw_dir', 'pw_shell')
+    def __init__(self, name, passwd, uid, gid, gecos, dir, shell):
+        assert type(name) == bytes
+        assert type(passwd) == bytes
+        assert type(gecos) == bytes
+        assert type(dir) == bytes
+        assert type(shell) == bytes
+        (self.pw_name, self.pw_passwd, self.pw_uid, self.pw_gid,
+         self.pw_gecos, self.pw_dir, self.pw_shell) = \
+             name, passwd, uid, gid, gecos, dir, shell
+
+def _passwd_from_py(py):
+    if py_maj < 3:
+        return py
+    return Passwd(py.pw_name.encode('iso-8859-1'),
+                  py.pw_passwd.encode("iso-8859-1"),
+                  py.pw_uid, py.pw_gid,
+                  py.pw_gecos.encode('iso-8859-1'),
+                  py.pw_dir.encode('iso-8859-1'),
+                  py.pw_shell.encode('iso-8859-1'))
+
+def getpwuid(uid):
+    return _passwd_from_py(pwd.getpwuid(uid))
+
+def getpwnam(name):
+    return _passwd_from_py(pwd.getpwnam(name))
+
+
+class Group:
+    """Drop in replacement for grp's structure with bytes instead of strings."""
+    __slots__ = 'gr_name', 'gr_passwd', 'gr_gid', 'gr_mem'
+    def __init__(self, name, passwd, gid, mem):
+        assert type(name) == bytes
+        assert type(passwd) == bytes
+        for m in mem:
+            assert type(m) == bytes
+        self.gr_name, self.gr_passwd, self.gr_gid, self.gr_mem = \
+            name, passwd, gid, mem
+
+def _group_from_py(py):
+    if py_maj < 3:
+        return py
+    return Group(py.gr_name.encode('iso-8859-1'),
+                 py.gr_passwd.encode('iso-8859-1'),
+                 py.gr_gid,
+                 tuple(x.encode('iso-8859-1') for x in py.gr_mem))
+
+def getgrgid(uid):
+    return _group_from_py(pwd.getgrgid(uid))
+
+def getgrnam(name):
+    return _group_from_py(pwd.getgrnam(name))
+
+
+_uid_to_pwd_cache = {}
+_name_to_pwd_cache = {}
+
+def pwd_from_uid(uid):
+    """Return password database entry for uid (may be a cached value).
+    Return None if no entry is found.
+    """
+    global _uid_to_pwd_cache, _name_to_pwd_cache
+    entry, cached = cache_key_value(getpwuid, uid, _uid_to_pwd_cache)
+    if entry and not cached:
+        _name_to_pwd_cache[entry.pw_name] = entry
+    return entry
+
+def pwd_from_name(name):
+    """Return password database entry for name (may be a cached value).
+    Return None if no entry is found.
+    """
+    assert type(name) == bytes
+    global _uid_to_pwd_cache, _name_to_pwd_cache
+    entry, cached = cache_key_value(getpwnam, name, _name_to_pwd_cache)
+    if entry and not cached:
+        _uid_to_pwd_cache[entry.pw_uid] = entry
+    return entry
+
+
+_gid_to_grp_cache = {}
+_name_to_grp_cache = {}
+
+def grp_from_gid(gid):
+    """Return password database entry for gid (may be a cached value).
+    Return None if no entry is found.
+    """
+    global _gid_to_grp_cache, _name_to_grp_cache
+    entry, cached = cache_key_value(grp.getgrgid, gid, _gid_to_grp_cache)
+    if entry and not cached:
+        _name_to_grp_cache[entry.gr_name] = entry
+    return entry
+
+
+def grp_from_name(name):
+    """Return password database entry for name (may be a cached value).
+    Return None if no entry is found.
+    """
+    assert type(name) == bytes
+    global _gid_to_grp_cache, _name_to_grp_cache
+    entry, cached = cache_key_value(grp.getgrnam, name, _name_to_grp_cache)
+    if entry and not cached:
+        _gid_to_grp_cache[entry.gr_gid] = entry
+    return entry
+
+
+_username = None
+def username():
+    """Get the user's login name."""
+    global _username
+    if not _username:
+        uid = os.getuid()
+        _username = pwd_from_uid(uid).pw_name or b'user%d' % uid
+    return _username
+
+
+_userfullname = None
+def userfullname():
+    """Get the user's full name."""
+    global _userfullname
+    if not _userfullname:
+        uid = os.getuid()
+        entry = pwd_from_uid(uid)
+        if entry:
+            _userfullname = entry.pw_gecos.split(b',')[0] or entry.pw_name
+        if not _userfullname:
+            _userfullname = b'user%d' % uid
+    return _userfullname