1 /* 2 * Copyright IBM Corporation, 2010 3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/fs.h> 17 #include <net/9p/9p.h> 18 #include <net/9p/client.h> 19 #include <linux/slab.h> 20 #include <linux/posix_acl_xattr.h> 21 #include "xattr.h" 22 #include "acl.h" 23 24 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name) 25 { 26 ssize_t size; 27 void *value = NULL; 28 struct posix_acl *acl = NULL;; 29 30 size = v9fs_fid_xattr_get(fid, name, NULL, 0); 31 if (size > 0) { 32 value = kzalloc(size, GFP_NOFS); 33 if (!value) 34 return ERR_PTR(-ENOMEM); 35 size = v9fs_fid_xattr_get(fid, name, value, size); 36 if (size > 0) { 37 acl = posix_acl_from_xattr(value, size); 38 if (IS_ERR(acl)) 39 goto err_out; 40 } 41 } else if (size == -ENODATA || size == 0 || 42 size == -ENOSYS || size == -EOPNOTSUPP) { 43 acl = NULL; 44 } else 45 acl = ERR_PTR(-EIO); 46 47 err_out: 48 kfree(value); 49 return acl; 50 } 51 52 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) 53 { 54 int retval = 0; 55 struct posix_acl *pacl, *dacl; 56 57 /* get the default/access acl values and cache them */ 58 dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT); 59 pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS); 60 61 if (!IS_ERR(dacl) && !IS_ERR(pacl)) { 62 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl); 63 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl); 64 posix_acl_release(dacl); 65 posix_acl_release(pacl); 66 } else 67 retval = -EIO; 68 69 return retval; 70 } 71 72 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type) 73 { 74 struct posix_acl *acl; 75 /* 76 * 9p Always cache the acl value when 77 * instantiating the inode (v9fs_inode_from_fid) 78 */ 79 acl = get_cached_acl(inode, type); 80 BUG_ON(acl == ACL_NOT_CACHED); 81 return acl; 82 } 83 84 int v9fs_check_acl(struct inode *inode, int mask) 85 { 86 struct posix_acl *acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS); 87 88 if (IS_ERR(acl)) 89 return PTR_ERR(acl); 90 if (acl) { 91 int error = posix_acl_permission(inode, acl, mask); 92 posix_acl_release(acl); 93 return error; 94 } 95 return -EAGAIN; 96 } 97 98 static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name, 99 void *buffer, size_t size, int type) 100 { 101 struct posix_acl *acl; 102 int error; 103 104 if (strcmp(name, "") != 0) 105 return -EINVAL; 106 107 acl = v9fs_get_cached_acl(dentry->d_inode, type); 108 if (IS_ERR(acl)) 109 return PTR_ERR(acl); 110 if (acl == NULL) 111 return -ENODATA; 112 error = posix_acl_to_xattr(acl, buffer, size); 113 posix_acl_release(acl); 114 115 return error; 116 } 117 118 static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name, 119 const void *value, size_t size, 120 int flags, int type) 121 { 122 return 0; 123 } 124 125 const struct xattr_handler v9fs_xattr_acl_access_handler = { 126 .prefix = POSIX_ACL_XATTR_ACCESS, 127 .flags = ACL_TYPE_ACCESS, 128 .get = v9fs_xattr_get_acl, 129 .set = v9fs_xattr_set_acl, 130 }; 131 132 const struct xattr_handler v9fs_xattr_acl_default_handler = { 133 .prefix = POSIX_ACL_XATTR_DEFAULT, 134 .flags = ACL_TYPE_DEFAULT, 135 .get = v9fs_xattr_get_acl, 136 .set = v9fs_xattr_set_acl, 137 }; 138