/contrib/bind9/lib/isc/include/isc/fsaccess.h
https://bitbucket.org/freebsd/freebsd-head/ · C++ Header · 178 lines · 25 code · 13 blank · 140 comment · 0 complexity · 91965f540e041913afcca60493ebb98e MD5 · raw file
- /*
- * Copyright (C) 2004-2007, 2009 Internet Systems Consortium, Inc. ("ISC")
- * Copyright (C) 2000, 2001 Internet Software Consortium.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
- * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
- * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
- * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- */
- /* $Id: fsaccess.h,v 1.16 2009/01/17 23:47:43 tbox Exp $ */
- #ifndef ISC_FSACCESS_H
- #define ISC_FSACCESS_H 1
- /*! \file isc/fsaccess.h
- * \brief The ISC filesystem access module encapsulates the setting of file
- * and directory access permissions into one API that is meant to be
- * portable to multiple operating systems.
- *
- * The two primary operating system flavors that are initially accommodated
- * are POSIX and Windows NT 4.0 and later. The Windows NT access model is
- * considerable more flexible than POSIX's model (as much as I am loathe to
- * admit it), and so the ISC API has a higher degree of complexity than would
- * be needed to simply address POSIX's needs.
- *
- * The full breadth of NT's flexibility is not available either, for the
- * present time. Much of it is to provide compatibility with what Unix
- * programmers are expecting. This is also due to not yet really needing all
- * of the functionality of an NT system (or, for that matter, a POSIX system)
- * in BIND9, and so resolving how to handle the various incompatibilities has
- * been a purely theoretical exercise with no operational experience to
- * indicate how flawed the thinking may be.
- *
- * Some of the more notable dumbing down of NT for this API includes:
- *
- *\li Each of FILE_READ_DATA and FILE_READ_EA are set with #ISC_FSACCESS_READ.
- *
- * \li All of FILE_WRITE_DATA, FILE_WRITE_EA and FILE_APPEND_DATA are
- * set with #ISC_FSACCESS_WRITE. FILE_WRITE_ATTRIBUTES is not set
- * so as to be consistent with Unix, where only the owner of the file
- * or the superuser can change the attributes/mode of a file.
- *
- * \li Both of FILE_ADD_FILE and FILE_ADD_SUBDIRECTORY are set with
- * #ISC_FSACCESS_CREATECHILD. This is similar to setting the WRITE
- * permission on a Unix directory.
- *
- * \li SYNCHRONIZE is always set for files and directories, unless someone
- * can give me a reason why this is a bad idea.
- *
- * \li READ_CONTROL and FILE_READ_ATTRIBUTES are always set; this is
- * consistent with Unix, where any file or directory can be stat()'d
- * unless the directory path disallows complete access somewhere along
- * the way.
- *
- * \li WRITE_DAC is only set for the owner. This too is consistent with
- * Unix, and is tighter security than allowing anyone else to be
- * able to set permissions.
- *
- * \li DELETE is only set for the owner. On Unix the ability to delete
- * a file is controlled by the directory permissions, but it isn't
- * currently clear to me what happens on NT if the directory has
- * FILE_DELETE_CHILD set but a file within it does not have DELETE
- * set. Always setting DELETE on the file/directory for the owner
- * gives maximum flexibility to the owner without exposing the
- * file to deletion by others.
- *
- * \li WRITE_OWNER is never set. This too is consistent with Unix,
- * and is also tighter security than allowing anyone to change the
- * ownership of the file apart from the superu..ahem, Administrator.
- *
- * \li Inheritance is set to NO_INHERITANCE.
- *
- * Unix's dumbing down includes:
- *
- * \li The sticky bit cannot be set.
- *
- * \li setuid and setgid cannot be set.
- *
- * \li Only regular files and directories can be set.
- *
- * The rest of this comment discusses a few of the incompatibilities
- * between the two systems that need more thought if this API is to
- * be extended to accommodate them.
- *
- * The Windows standard access right "DELETE" doesn't have a direct
- * equivalent in the Unix world, so it isn't clear what should be done
- * with it.
- *
- * The Unix sticky bit is not supported. While NT does have a concept
- * of allowing users to create files in a directory but not delete or
- * rename them, it does not have a concept of allowing them to be deleted
- * if they are owned by the user trying to delete/rename. While it is
- * probable that something could be cobbled together in NT 5 with inheritance,
- * it can't really be done in NT 4 as a single property that you could
- * set on a directory. You'd need to coordinate something with file creation
- * so that every file created had DELETE set for the owner but noone else.
- *
- * On Unix systems, setting #ISC_FSACCESS_LISTDIRECTORY sets READ.
- * ... setting either #ISC_FSACCESS_CREATECHILD or #ISC_FSACCESS_DELETECHILD
- * sets WRITE.
- * ... setting #ISC_FSACCESS_ACCESSCHILD sets EXECUTE.
- *
- * On NT systems, setting #ISC_FSACCESS_LISTDIRECTORY sets FILE_LIST_DIRECTORY.
- * ... setting #ISC_FSACCESS_CREATECHILD sets FILE_CREATE_CHILD independently.
- * ... setting #ISC_FSACCESS_DELETECHILD sets FILE_DELETE_CHILD independently.
- * ... setting #ISC_FSACCESS_ACCESSCHILD sets FILE_TRAVERSE.
- *
- * Unresolved: XXXDCL
- * \li What NT access right controls the ability to rename a file?
- * \li How does DELETE work? If a directory has FILE_DELETE_CHILD but a
- * file or directory within it does not have DELETE, is that file
- * or directory deletable?
- * \li To implement isc_fsaccess_get(), mapping an existing Unix permission
- * mode_t back to an isc_fsaccess_t is pretty trivial; however, mapping
- * an NT DACL could be impossible to do in a responsible way.
- * \li Similarly, trying to implement the functionality of being able to
- * say "add group writability to whatever permissions already exist"
- * could be tricky on NT because of the order-of-entry issue combined
- * with possibly having one or more matching ACEs already explicitly
- * granting or denying access. Because this functionality is
- * not yet needed by the ISC, no code has been written to try to
- * solve this problem.
- */
- #include <isc/lang.h>
- #include <isc/types.h>
- /*
- * Trustees.
- */
- #define ISC_FSACCESS_OWNER 0x1 /*%< User account. */
- #define ISC_FSACCESS_GROUP 0x2 /*%< Primary group owner. */
- #define ISC_FSACCESS_OTHER 0x4 /*%< Not the owner or the group owner. */
- #define ISC_FSACCESS_WORLD 0x7 /*%< User, Group, Other. */
- /*
- * Types of permission.
- */
- #define ISC_FSACCESS_READ 0x00000001 /*%< File only. */
- #define ISC_FSACCESS_WRITE 0x00000002 /*%< File only. */
- #define ISC_FSACCESS_EXECUTE 0x00000004 /*%< File only. */
- #define ISC_FSACCESS_CREATECHILD 0x00000008 /*%< Dir only. */
- #define ISC_FSACCESS_DELETECHILD 0x00000010 /*%< Dir only. */
- #define ISC_FSACCESS_LISTDIRECTORY 0x00000020 /*%< Dir only. */
- #define ISC_FSACCESS_ACCESSCHILD 0x00000040 /*%< Dir only. */
- /*%
- * Adding any permission bits beyond 0x200 would mean typedef'ing
- * isc_fsaccess_t as isc_uint64_t, and redefining this value to
- * reflect the new range of permission types, Probably to 21 for
- * maximum flexibility. The number of bits has to accommodate all of
- * the permission types, and three full sets of them have to fit
- * within an isc_fsaccess_t.
- */
- #define ISC__FSACCESS_PERMISSIONBITS 10
- ISC_LANG_BEGINDECLS
- void
- isc_fsaccess_add(int trustee, int permission, isc_fsaccess_t *access);
- void
- isc_fsaccess_remove(int trustee, int permission, isc_fsaccess_t *access);
- isc_result_t
- isc_fsaccess_set(const char *path, isc_fsaccess_t access);
- ISC_LANG_ENDDECLS
- #endif /* ISC_FSACCESS_H */