reactos/ntoskrnl/ob/symlink.c

   1 /* $Id: symlink.c,v 1.8 2003/12/30 18:52:05 fireball Exp $
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ob/symlink.c
   6  * PURPOSE:         Implements symbolic links
   7  * PROGRAMMER:      David Welch (welch@mcmail.com)
   8  * UPDATE HISTORY:
   9  *                  Created 22/05/98
  10  */
  11
  12 /* INCLUDES *****************************************************************/
  13
  14 #include <limits.h>
  15 #define NTOS_MODE_KERNEL
  16 #include <ntos.h>
  17 #include <internal/ob.h>
  18 #include <rosrtl/string.h>
  19
  20 #define NDEBUG
  21 #include <internal/debug.h>
  22
  23
  24 /* GLOBALS ******************************************************************/
  25
  26 POBJECT_TYPE ObSymbolicLinkType = NULL;
  27
  28 static GENERIC_MAPPING ObpSymbolicLinkMapping = {
  29         STANDARD_RIGHTS_READ|SYMBOLIC_LINK_QUERY,
  30         STANDARD_RIGHTS_WRITE,
  31         STANDARD_RIGHTS_EXECUTE|SYMBOLIC_LINK_QUERY,
  32         SYMBOLIC_LINK_ALL_ACCESS};
  33
  34 #define TAG_SYMLINK_TTARGET     TAG('S', 'Y', 'T', 'T')
  35 #define TAG_SYMLINK_TARGET      TAG('S', 'Y', 'M', 'T')
  36
  37
  38 /* FUNCTIONS ****************************************************************/
  39
  40 /**********************************************************************
  41  * NAME                                                 INTERNAL
  42  *      ObpCreateSymbolicLink
  43  *
  44  * DESCRIPTION
  45  *
  46  * ARGUMENTS
  47  *
  48  * RETURNN VALUE
  49  *      Status.
  50  *
  51  * REVISIONS
  52  */
  53 NTSTATUS STDCALL
  54 ObpCreateSymbolicLink(PVOID Object,
  55                       PVOID Parent,
  56                       PWSTR RemainingPath,
  57                       POBJECT_ATTRIBUTES ObjectAttributes)
  58 {
  59   return(STATUS_SUCCESS);
  60 }
  61
  62
  63 /**********************************************************************
  64  * NAME                                                 INTERNAL
  65  *      ObpDeleteSymbolicLink
  66  *
  67  * DESCRIPTION
  68  *
  69  * ARGUMENTS
  70  *
  71  * RETURNN VALUE
  72  *      Status.
  73  *
  74  * REVISIONS
  75  */
  76 VOID STDCALL
  77 ObpDeleteSymbolicLink(PVOID ObjectBody)
  78 {
  79   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT)ObjectBody;
  80
  81   RtlFreeUnicodeString(&SymlinkObject->TargetName);
  82 }
  83
  84
  85 /**********************************************************************
  86  * NAME                                                 INTERNAL
  87  *      ObpParseSymbolicLink
  88  *
  89  * DESCRIPTION
  90  *
  91  * ARGUMENTS
  92  *
  93  * RETURN VALUE
  94  *
  95  * REVISIONS
  96  */
  97 NTSTATUS STDCALL
  98 ObpParseSymbolicLink(PVOID Object,
  99                      PVOID * NextObject,
 100                      PUNICODE_STRING FullPath,
 101                      PWSTR * RemainingPath,
 102                      ULONG Attributes)
 103 {
 104   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT) Object;
 105   UNICODE_STRING TargetPath;
 106
 107   DPRINT("ObpParseSymbolicLink (RemainingPath %S)\n", *RemainingPath);
 108
 109   /*
 110    * Stop parsing if the entire path has been parsed and
 111    * the desired object is a symbolic link object.
 112    */
 113   if (((*RemainingPath == NULL) || (**RemainingPath == 0)) &&
 114       (Attributes & OBJ_OPENLINK))
 115     {
 116       DPRINT("Parsing stopped!\n");
 117       *NextObject = NULL;
 118       return(STATUS_SUCCESS);
 119     }
 120
 121    /* build the expanded path */
 122    TargetPath.MaximumLength = SymlinkObject->TargetName.Length + sizeof(WCHAR);
 123    if (RemainingPath && *RemainingPath)
 124      {
 125         TargetPath.MaximumLength += (wcslen(*RemainingPath) * sizeof(WCHAR));
 126      }
 127    TargetPath.Length = TargetPath.MaximumLength - sizeof(WCHAR);
 128    TargetPath.Buffer = ExAllocatePoolWithTag(NonPagedPool,
 129                                              TargetPath.MaximumLength,
 130                                              TAG_SYMLINK_TTARGET);
 131    wcscpy(TargetPath.Buffer, SymlinkObject->TargetName.Buffer);
 132    if (RemainingPath && *RemainingPath)
 133      {
 134         wcscat(TargetPath.Buffer, *RemainingPath);
 135      }
 136
 137    /* transfer target path buffer into FullPath */
 138    RtlFreeUnicodeString(FullPath);
 139    FullPath->Length = TargetPath.Length;
 140    FullPath->MaximumLength = TargetPath.MaximumLength;
 141    FullPath->Buffer = TargetPath.Buffer;
 142
 143    /* reinitialize RemainingPath for reparsing */
 144    *RemainingPath = FullPath->Buffer;
 145
 146    *NextObject = NULL;
 147    return STATUS_REPARSE;
 148 }
 149
 150
 151 /**********************************************************************
 152  * NAME                                                 INTERNAL
 153  *      ObInitSymbolicLinkImplementation
 154  *
 155  * DESCRIPTION
 156  *
 157  * ARGUMENTS
 158  *      None.
 159  *
 160  * RETURNN VALUE
 161  *      None.
 162  *
 163  * REVISIONS
 164  */
 165 VOID INIT_FUNCTION
 166 ObInitSymbolicLinkImplementation (VOID)
 167 {
 168   ObSymbolicLinkType = ExAllocatePool(NonPagedPool, sizeof(OBJECT_TYPE));
 169
 170   ObSymbolicLinkType->Tag = TAG('S', 'Y', 'M', 'T');
 171   ObSymbolicLinkType->TotalObjects = 0;
 172   ObSymbolicLinkType->TotalHandles = 0;
 173   ObSymbolicLinkType->MaxObjects = ULONG_MAX;
 174   ObSymbolicLinkType->MaxHandles = ULONG_MAX;
 175   ObSymbolicLinkType->PagedPoolCharge = 0;
 176   ObSymbolicLinkType->NonpagedPoolCharge = sizeof(SYMLINK_OBJECT);
 177   ObSymbolicLinkType->Mapping = &ObpSymbolicLinkMapping;
 178   ObSymbolicLinkType->Dump = NULL;
 179   ObSymbolicLinkType->Open = NULL;
 180   ObSymbolicLinkType->Close = NULL;
 181   ObSymbolicLinkType->Delete = ObpDeleteSymbolicLink;
 182   ObSymbolicLinkType->Parse = ObpParseSymbolicLink;
 183   ObSymbolicLinkType->Security = NULL;
 184   ObSymbolicLinkType->QueryName = NULL;
 185   ObSymbolicLinkType->OkayToClose = NULL;
 186   ObSymbolicLinkType->Create = ObpCreateSymbolicLink;
 187   ObSymbolicLinkType->DuplicationNotify = NULL;
 188
 189   RtlRosInitUnicodeStringFromLiteral(&ObSymbolicLinkType->TypeName,
 190                                   L"SymbolicLink");
 191
 192   ObpCreateTypeObject(ObSymbolicLinkType);
 193 }
 194
 195
 196 /**********************************************************************
 197  * NAME                                         EXPORTED
 198  *      NtCreateSymbolicLinkObject
 199  *
 200  * DESCRIPTION
 201  *
 202  * ARGUMENTS
 203  *
 204  * RETURN VALUE
 205  *
 206  * REVISIONS
 207  *
 208  */
 209 NTSTATUS STDCALL
 210 NtCreateSymbolicLinkObject(OUT PHANDLE SymbolicLinkHandle,
 211                            IN ACCESS_MASK DesiredAccess,
 212                            IN POBJECT_ATTRIBUTES ObjectAttributes,
 213                            IN PUNICODE_STRING DeviceName)
 214 {
 215   PSYMLINK_OBJECT SymbolicLink;
 216   NTSTATUS Status;
 217
 218   assert_irql(PASSIVE_LEVEL);
 219
 220   DPRINT("NtCreateSymbolicLinkObject(SymbolicLinkHandle %p, DesiredAccess %ul, ObjectAttributes %p, DeviceName %wZ)\n",
 221          SymbolicLinkHandle,
 222          DesiredAccess,
 223          ObjectAttributes,
 224          DeviceName);
 225
 226   Status = ObCreateObject(ExGetPreviousMode(),
 227                           ObSymbolicLinkType,
 228                           ObjectAttributes,
 229                           ExGetPreviousMode(),
 230                           NULL,
 231                           sizeof(SYMLINK_OBJECT),
 232                           0,
 233                           0,
 234                           (PVOID*)&SymbolicLink);
 235   if (!NT_SUCCESS(Status))
 236     {
 237       return(Status);
 238     }
 239
 240   Status = ObInsertObject ((PVOID)SymbolicLink,
 241                            NULL,
 242                            DesiredAccess,
 243                            0,
 244                            NULL,
 245                            SymbolicLinkHandle);
 246   if (!NT_SUCCESS(Status))
 247     {
 248       ObDereferenceObject (SymbolicLink);
 249       return Status;
 250     }
 251
 252   SymbolicLink->TargetName.Length = 0;
 253   SymbolicLink->TargetName.MaximumLength =
 254     ((wcslen(DeviceName->Buffer) + 1) * sizeof(WCHAR));
 255   SymbolicLink->TargetName.Buffer =
 256     ExAllocatePoolWithTag(NonPagedPool,
 257                           SymbolicLink->TargetName.MaximumLength,
 258                           TAG_SYMLINK_TARGET);
 259   RtlCopyUnicodeString(&SymbolicLink->TargetName,
 260                        DeviceName);
 261
 262   DPRINT("DeviceName %S\n", SymbolicLink->TargetName.Buffer);
 263
 264   NtQuerySystemTime (&SymbolicLink->CreateTime);
 265
 266   DPRINT("%s() = STATUS_SUCCESS\n",__FUNCTION__);
 267   ObDereferenceObject(SymbolicLink);
 268
 269   return(STATUS_SUCCESS);
 270 }
 271
 272
 273 /**********************************************************************
 274  * NAME                                                 EXPORTED
 275  *      NtOpenSymbolicLinkObject
 276  *
 277  * DESCRIPTION
 278  *
 279  * ARGUMENTS
 280  *
 281  * RETURN VALUE
 282  *
 283  * REVISIONS
 284  *
 285  */
 286 NTSTATUS STDCALL
 287 NtOpenSymbolicLinkObject(OUT PHANDLE LinkHandle,
 288                          IN ACCESS_MASK DesiredAccess,
 289                          IN POBJECT_ATTRIBUTES ObjectAttributes)
 290 {
 291   DPRINT("NtOpenSymbolicLinkObject (Name %wZ)\n",
 292          ObjectAttributes->ObjectName);
 293
 294   return(ObOpenObjectByName(ObjectAttributes,
 295                             ObSymbolicLinkType,
 296                             NULL,
 297                             (KPROCESSOR_MODE)KeGetPreviousMode(),
 298                             DesiredAccess,
 299                             NULL,
 300                             LinkHandle));
 301 }
 302
 303
 304 /**********************************************************************
 305  * NAME                                                 EXPORTED
 306  *      NtQuerySymbolicLinkObject
 307  *
 308  * DESCRIPTION
 309  *
 310  * ARGUMENTS
 311  *
 312  * RETURN VALUE
 313  *
 314  * REVISIONS
 315  *
 316  */
 317 NTSTATUS STDCALL
 318 NtQuerySymbolicLinkObject(IN HANDLE LinkHandle,
 319                           IN OUT PUNICODE_STRING LinkTarget,
 320                           OUT PULONG ReturnedLength OPTIONAL)
 321 {
 322   PSYMLINK_OBJECT SymlinkObject;
 323   NTSTATUS Status;
 324
 325   Status = ObReferenceObjectByHandle(LinkHandle,
 326                                      SYMBOLIC_LINK_QUERY,
 327                                      ObSymbolicLinkType,
 328                                      (KPROCESSOR_MODE)KeGetPreviousMode(),
 329                                      (PVOID *)&SymlinkObject,
 330                                      NULL);
 331   if (!NT_SUCCESS(Status))
 332     {
 333       return Status;
 334     }
 335
 336   if (ReturnedLength != NULL)
 337     {
 338       *ReturnedLength = (ULONG)SymlinkObject->TargetName.Length + sizeof(WCHAR);
 339     }
 340
 341   if (LinkTarget->MaximumLength >= SymlinkObject->TargetName.Length + sizeof(WCHAR))
 342     {
 343       RtlCopyUnicodeString(LinkTarget,
 344                            &SymlinkObject->TargetName);
 345       Status = STATUS_SUCCESS;
 346     }
 347   else
 348     {
 349       Status = STATUS_BUFFER_TOO_SMALL;
 350     }
 351
 352   ObDereferenceObject(SymlinkObject);
 353
 354   return Status;
 355 }
 356
 357 /* EOF */