server/symlink.c

   1 /*
   2  * Server-side symbolic link object management
   3  *
   4  * Copyright (C) 2005 Vitaliy Margolen
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  */
  21
  22 #include "config.h"
  23
  24 #include <assert.h>
  25 #include <stdarg.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <sys/types.h>
  29
  30 #include "ntstatus.h"
  31 #define WIN32_NO_STATUS
  32 #include "winternl.h"
  33 #include "ddk/wdm.h"
  34
  35 #include "handle.h"
  36 #include "request.h"
  37 #include "object.h"
  38 #include "unicode.h"
  39
  40 static const WCHAR symlink_name[] = {'S','y','m','b','o','l','i','c','L','i','n','k'};
  41
  42 struct type_descr symlink_type =
  43 {
  44     { symlink_name, sizeof(symlink_name) },   /* name */
  45     SYMBOLIC_LINK_ALL_ACCESS,                 /* valid_access */
  46     {                                         /* mapping */
  47         STANDARD_RIGHTS_READ | SYMBOLIC_LINK_QUERY,
  48         STANDARD_RIGHTS_WRITE,
  49         STANDARD_RIGHTS_EXECUTE | SYMBOLIC_LINK_QUERY,
  50         SYMBOLIC_LINK_ALL_ACCESS
  51     },
  52 };
  53
  54 struct symlink
  55 {
  56     struct object    obj;       /* object header */
  57     WCHAR           *target;    /* target of the symlink */
  58     data_size_t      len;       /* target len in bytes */
  59 };
  60
  61 static void symlink_dump( struct object *obj, int verbose );
  62 static struct object *symlink_lookup_name( struct object *obj, struct unicode_str *name,
  63                                            unsigned int attr, struct object *root );
  64 static void symlink_destroy( struct object *obj );
  65
  66 static const struct object_ops symlink_ops =
  67 {
  68     sizeof(struct symlink),       /* size */
  69     &symlink_type,                /* type */
  70     symlink_dump,                 /* dump */
  71     no_add_queue,                 /* add_queue */
  72     NULL,                         /* remove_queue */
  73     NULL,                         /* signaled */
  74     NULL,                         /* satisfied */
  75     no_signal,                    /* signal */
  76     no_get_fd,                    /* get_fd */
  77     default_map_access,           /* map_access */
  78     default_get_sd,               /* get_sd */
  79     default_set_sd,               /* set_sd */
  80     default_get_full_name,        /* get_full_name */
  81     symlink_lookup_name,          /* lookup_name */
  82     directory_link_name,          /* link_name */
  83     default_unlink_name,          /* unlink_name */
  84     no_open_file,                 /* open_file */
  85     no_kernel_obj_list,           /* get_kernel_obj_list */
  86     no_close_handle,              /* close_handle */
  87     symlink_destroy               /* destroy */
  88 };
  89
  90 static void symlink_dump( struct object *obj, int verbose )
  91 {
  92     struct symlink *symlink = (struct symlink *)obj;
  93     assert( obj->ops == &symlink_ops );
  94
  95     fputs( "Symlink target=\"", stderr );
  96     dump_strW( symlink->target, symlink->len, stderr, "\"\"" );
  97     fputs( "\"\n", stderr );
  98 }
  99
 100 static struct object *symlink_lookup_name( struct object *obj, struct unicode_str *name,
 101                                            unsigned int attr, struct object *root )
 102 {
 103     struct symlink *symlink = (struct symlink *)obj;
 104     struct unicode_str target_str, name_left;
 105     struct object *target;
 106
 107     assert( obj->ops == &symlink_ops );
 108
 109     if (!name) return NULL;
 110     if (!name->len && (attr & OBJ_OPENLINK)) return NULL;
 111     if (obj == root) return NULL;
 112
 113     if (!symlink->len) return get_root_directory();
 114
 115     target_str.str = symlink->target;
 116     target_str.len = symlink->len;
 117     if ((target = lookup_named_object( NULL, &target_str, attr, &name_left )))
 118     {
 119         if (name_left.len)
 120         {
 121             release_object( target );
 122             target = NULL;
 123             set_error( STATUS_OBJECT_PATH_NOT_FOUND );
 124         }
 125     }
 126     return target;
 127 }
 128
 129 static void symlink_destroy( struct object *obj )
 130 {
 131     struct symlink *symlink = (struct symlink *)obj;
 132     assert( obj->ops == &symlink_ops );
 133     free( symlink->target );
 134 }
 135
 136 struct object *create_root_symlink( struct object *root, const struct unicode_str *name,
 137                                     unsigned int attr, const struct security_descriptor *sd )
 138 {
 139     struct symlink *symlink;
 140
 141     if (!(symlink = create_named_object( root, &symlink_ops, name, attr, sd ))) return NULL;
 142     symlink->target = NULL;
 143     symlink->len = 0;
 144     return &symlink->obj;
 145 }
 146
 147 struct object *create_symlink( struct object *root, const struct unicode_str *name,
 148                                unsigned int attr, const struct unicode_str *target,
 149                                const struct security_descriptor *sd )
 150 {
 151     struct symlink *symlink;
 152
 153     if (!target->len)
 154     {
 155         set_error( STATUS_INVALID_PARAMETER );
 156         return NULL;
 157     }
 158     if (!(symlink = create_named_object( root, &symlink_ops, name, attr, sd ))) return NULL;
 159     if (get_error() != STATUS_OBJECT_NAME_EXISTS && !(symlink->target = memdup( target->str, target->len )))
 160     {
 161         release_object( symlink );
 162         return NULL;
 163     }
 164     symlink->len = target->len;
 165     return &symlink->obj;
 166 }
 167
 168 /* create a symlink pointing to an existing object */
 169 struct object *create_obj_symlink( struct object *root, const struct unicode_str *name,
 170                                     unsigned int attr, struct object *target,
 171                                     const struct security_descriptor *sd )
 172 {
 173     struct symlink *symlink;
 174     data_size_t len;
 175     WCHAR *target_name;
 176
 177     if (!(target_name = target->ops->get_full_name( target, &len )))
 178     {
 179         set_error( STATUS_INVALID_PARAMETER );
 180         return NULL;
 181     }
 182     if ((symlink = create_named_object( root, &symlink_ops, name, attr, sd )) &&
 183         (get_error() != STATUS_OBJECT_NAME_EXISTS))
 184     {
 185         symlink->target = target_name;
 186         symlink->len = len;
 187     }
 188     else free( target_name );
 189
 190     return &symlink->obj;
 191 }
 192
 193
 194 /* create a symbolic link object */
 195 DECL_HANDLER(create_symlink)
 196 {
 197     struct object *symlink;
 198     struct unicode_str name, target;
 199     struct object *root;
 200     const struct security_descriptor *sd;
 201     const struct object_attributes *objattr = get_req_object_attributes( &sd, &name, &root );
 202
 203     if (!objattr) return;
 204
 205     target.str = get_req_data_after_objattr( objattr, &target.len );
 206     target.len = (target.len / sizeof(WCHAR)) * sizeof(WCHAR);
 207
 208     if ((symlink = create_symlink( root, &name, objattr->attributes, &target, sd )))
 209     {
 210         reply->handle = alloc_handle( current->process, symlink, req->access, objattr->attributes );
 211         release_object( symlink );
 212     }
 213
 214     if (root) release_object( root );
 215 }
 216
 217 /* open a symbolic link object */
 218 DECL_HANDLER(open_symlink)
 219 {
 220     struct unicode_str name = get_req_unicode_str();
 221
 222     reply->handle = open_object( current->process, req->rootdir, req->access,
 223                                  &symlink_ops, &name, req->attributes | OBJ_OPENLINK );
 224 }
 225
 226 /* query a symbolic link object */
 227 DECL_HANDLER(query_symlink)
 228 {
 229     struct symlink *symlink;
 230
 231     symlink = (struct symlink *)get_handle_obj( current->process, req->handle,
 232                                                 SYMBOLIC_LINK_QUERY, &symlink_ops );
 233     if (!symlink) return;
 234
 235     reply->total = symlink->len;
 236     if (get_reply_max_size() < symlink->len)
 237         set_error( STATUS_BUFFER_TOO_SMALL );
 238     else
 239         set_reply_data( symlink->target, symlink->len );
 240     release_object( symlink );
 241 }