diff options
Diffstat (limited to 'Lib/os.py')
| -rw-r--r-- | Lib/os.py | 31 |
1 files changed, 21 insertions, 10 deletions
@@ -179,16 +179,27 @@ if _exists("_have_functions"): _set = set() _add("HAVE_FACCESSAT", "access") - # Current linux (kernel 3.2, glibc 2.15) doesn't support lchmod. - # (The function exists, but it's a stub that always returns ENOSUP.) - # Now, linux *does* have fchmodat, which says it can ignore - # symbolic links. But that doesn't work either (also returns ENOSUP). - # I'm guessing that if they fix fchmodat, they'll also add lchmod at - # the same time. So, for now, assume that fchmodat doesn't support - # follow_symlinks unless lchmod works. - if ((sys.platform != "linux") or - ("HAVE_LCHMOD" in _have_functions)): - _add("HAVE_FCHMODAT", "chmod") + # Some platforms don't support lchmod(). Often the function exists + # anyway, as a stub that always returns ENOSUP or perhaps EOPNOTSUPP. + # (No, I don't know why that's a good design.) ./configure will detect + # this and reject it--so HAVE_LCHMOD still won't be defined on such + # platforms. This is Very Helpful. + # + # However, sometimes platforms without a working lchmod() *do* have + # fchmodat(). (Examples: Linux kernel 3.2 with glibc 2.15, + # OpenIndiana 3.x.) And fchmodat() has a flag that theoretically makes + # it behave like lchmod(). So in theory it would be a suitable + # replacement for lchmod(). But when lchmod() doesn't work, fchmodat()'s + # flag doesn't work *either*. Sadly ./configure isn't sophisticated + # enough to detect this condition--it only determines whether or not + # fchmodat() minimally works. + # + # Therefore we simply ignore fchmodat() when deciding whether or not + # os.chmod supports follow_symlinks. Just checking lchmod() is + # sufficient. After all--if you have a working fchmodat(), your + # lchmod() almost certainly works too. + # + # _add("HAVE_FCHMODAT", "chmod") _add("HAVE_FCHOWNAT", "chown") _add("HAVE_FSTATAT", "stat") _add("HAVE_LCHFLAGS", "chflags") |