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105 lines
3.8 KiB
C
105 lines
3.8 KiB
C
/* Copy access control list from one file to another. -*- coding: utf-8 -*-
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Copyright (C) 2002-2003, 2005-2024 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible. */
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#include <config.h>
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#include "acl.h"
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#include "acl-internal.h"
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#if USE_XATTR
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# include <attr/libattr.h>
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# include <string.h>
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# if HAVE_LINUX_XATTR_H
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# include <linux/xattr.h>
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# endif
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# ifndef XATTR_NAME_NFSV4_ACL
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# define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"
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# endif
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# ifndef XATTR_NAME_POSIX_ACL_ACCESS
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# define XATTR_NAME_POSIX_ACL_ACCESS "system.posix_acl_access"
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# endif
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# ifndef XATTR_NAME_POSIX_ACL_DEFAULT
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# define XATTR_NAME_POSIX_ACL_DEFAULT "system.posix_acl_default"
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# endif
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/* Returns 1 if NAME is the name of an extended attribute that is related
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to permissions, i.e. ACLs. Returns 0 otherwise. */
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static int
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is_attr_permissions (const char *name, struct error_context *ctx)
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{
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/* We need to explicitly test for the known extended attribute names,
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because at least on CentOS 7, attr_copy_action does not do it. */
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return strcmp (name, XATTR_NAME_POSIX_ACL_ACCESS) == 0
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|| strcmp (name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0
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|| strcmp (name, XATTR_NAME_NFSV4_ACL) == 0
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|| attr_copy_action (name, ctx) == ATTR_ACTION_PERMISSIONS;
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}
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#endif /* USE_XATTR */
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/* Copy access control lists from one file to another. If SOURCE_DESC is
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a valid file descriptor, use file descriptor operations, else use
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filename based operations on SRC_NAME. Likewise for DEST_DESC and
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DST_NAME.
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If access control lists are not available, fchmod the target file to
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MODE. Also sets the non-permission bits of the destination file
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(S_ISUID, S_ISGID, S_ISVTX) to those from MODE if any are set.
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Return 0 if successful.
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Return -2 and set errno for an error relating to the source file.
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Return -1 and set errno for an error relating to the destination file. */
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int
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qcopy_acl (const char *src_name, int source_desc, const char *dst_name,
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int dest_desc, mode_t mode)
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{
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int ret;
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#ifdef USE_XATTR
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/* in case no ACLs present and also to set higher mode bits
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we chmod before setting ACLs as doing it after could overwrite them
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(especially true for NFSv4, posix ACL has that ugly "mask" hack that
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nobody understands) */
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ret = chmod_or_fchmod (dst_name, dest_desc, mode);
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/* Rather than fiddling with acls one by one, we just copy the whole ACL xattrs
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(Posix or NFSv4). Of course, that won't address ACLs conversion
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(i.e. posix <-> nfs4) but we can't do it anyway, so for now, we don't care
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Functions attr_copy_* return 0 in case we copied something OR nothing
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to copy */
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if (ret == 0)
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ret = source_desc <= 0 || dest_desc <= 0
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? attr_copy_file (src_name, dst_name, is_attr_permissions, NULL)
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: attr_copy_fd (src_name, source_desc, dst_name, dest_desc,
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is_attr_permissions, NULL);
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#else
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/* no XATTR, so we proceed the old dusty way */
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struct permission_context ctx;
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ret = get_permissions (src_name, source_desc, mode, &ctx);
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if (ret != 0)
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return -2;
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ret = set_permissions (&ctx, dst_name, dest_desc);
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free_permission_context (&ctx);
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#endif
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return ret;
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}
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