[mirror_edk2.git] / OvmfPkg / XenBusDxe / XenStore.c

/** @file\r
  Low-level kernel interface to the XenStore.\r
\r
  The XenStore interface is a simple storage system that is a means of\r
  communicating state and configuration data between the Xen Domain 0\r
  and the various guest domains.  All configuration data other than\r
  a small amount of essential information required during the early\r
  boot process of launching a Xen aware guest, is managed using the\r
  XenStore.\r
\r
  The XenStore is ASCII string based, and has a structure and semantics\r
  similar to a filesystem.  There are files and directories, the directories\r
  able to contain files or other directories.  The depth of the hierarchy\r
  is only limited by the XenStore's maximum path length.\r
\r
  The communication channel between the XenStore service and other\r
  domains is via two, guest specific, ring buffers in a shared memory\r
  area.  One ring buffer is used for communicating in each direction.\r
  The grant table references for this shared memory are given to the\r
  guest either via the xen_start_info structure for a fully para-\r
  virtualized guest, or via HVM hypercalls for a hardware virtualized\r
  guest.\r
\r
  The XenStore communication relies on an event channel and thus\r
  interrupts.  But under OVMF this XenStore client will pull the\r
  state of the event channel.\r
\r
  Several Xen services depend on the XenStore, most notably the\r
  XenBus used to discover and manage Xen devices.\r
\r
  Copyright (C) 2005 Rusty Russell, IBM Corporation\r
  Copyright (C) 2009,2010 Spectra Logic Corporation\r
  Copyright (C) 2014, Citrix Ltd.\r
\r
  This file may be distributed separately from the Linux kernel, or\r
  incorporated into other software packages, subject to the following license:\r
\r
  SPDX-License-Identifier: MIT\r
**/\r
\r
#include "XenStore.h"\r
\r
#include <Library/PrintLib.h>\r
\r
#include <IndustryStandard/Xen/hvm/params.h>\r
\r
#include "EventChannel.h"\r
#include <Library/XenHypercallLib.h>\r
\r
//\r
// Private Data Structures\r
//\r
\r
typedef struct {\r
  CONST VOID    *Data;\r
  UINT32        Len;\r
} WRITE_REQUEST;\r
\r
/* Register callback to watch subtree (node) in the XenStore. */\r
#define XENSTORE_WATCH_SIGNATURE  SIGNATURE_32 ('X','S','w','a')\r
struct _XENSTORE_WATCH {\r
  UINT32        Signature;\r
  LIST_ENTRY    Link;\r
\r
  /* Path being watched. */\r
  CHAR8         *Node;\r
};\r
\r
#define XENSTORE_WATCH_FROM_LINK(l) \\r
  CR (l, XENSTORE_WATCH, Link, XENSTORE_WATCH_SIGNATURE)\r
\r
/**\r
 * Structure capturing messages received from the XenStore service.\r
 */\r
#define XENSTORE_MESSAGE_SIGNATURE  SIGNATURE_32 ('X', 'S', 's', 'm')\r
typedef struct {\r
  UINT32                Signature;\r
  LIST_ENTRY            Link;\r
\r
  struct xsd_sockmsg    Header;\r
\r
  union {\r
    /* Queued replies. */\r
    struct {\r
      CHAR8    *Body;\r
    } Reply;\r
\r
    /* Queued watch events. */\r
    struct {\r
      XENSTORE_WATCH    *Handle;\r
      CONST CHAR8       **Vector;\r
      UINT32            VectorSize;\r
    } Watch;\r
  } u;\r
} XENSTORE_MESSAGE;\r
#define XENSTORE_MESSAGE_FROM_LINK(r) \\r
  CR (r, XENSTORE_MESSAGE, Link, XENSTORE_MESSAGE_SIGNATURE)\r
\r
/**\r
 * Container for all XenStore related state.\r
 */\r
typedef struct {\r
  /**\r
   * Pointer to shared memory communication structures allowing us\r
   * to communicate with the XenStore service.\r
   */\r
  struct xenstore_domain_interface    *XenStore;\r
\r
  XENBUS_DEVICE                       *Dev;\r
\r
  /**\r
   * A list of replies to our requests.\r
   *\r
   * The reply list is filled by xs_rcv_thread().  It\r
   * is consumed by the context that issued the request\r
   * to which a reply is made.  The requester blocks in\r
   * XenStoreReadReply ().\r
   *\r
   * /note Only one requesting context can be active at a time.\r
   */\r
  LIST_ENTRY       ReplyList;\r
\r
  /** Lock protecting the reply list. */\r
  EFI_LOCK         ReplyLock;\r
\r
  /**\r
   * List of registered watches.\r
   */\r
  LIST_ENTRY       RegisteredWatches;\r
\r
  /** Lock protecting the registered watches list. */\r
  EFI_LOCK         RegisteredWatchesLock;\r
\r
  /**\r
   * List of pending watch callback events.\r
   */\r
  LIST_ENTRY       WatchEvents;\r
\r
  /** Lock protecting the watch callback list. */\r
  EFI_LOCK         WatchEventsLock;\r
\r
  /**\r
   * The event channel for communicating with the\r
   * XenStore service.\r
   */\r
  evtchn_port_t    EventChannel;\r
\r
  /** Handle for XenStore events. */\r
  EFI_EVENT        EventChannelEvent;\r
} XENSTORE_PRIVATE;\r
\r
//\r
// Global Data\r
//\r
static XENSTORE_PRIVATE  xs;\r
\r
//\r
// Private Utility Functions\r
//\r
\r
/**\r
  Count and optionally record pointers to a number of NUL terminated\r
  strings in a buffer.\r
\r
  @param Strings  A pointer to a contiguous buffer of NUL terminated strings.\r
  @param Len      The length of the buffer pointed to by strings.\r
  @param Dst      An array to store pointers to each string found in strings.\r
\r
  @return  A count of the number of strings found.\r
**/\r
STATIC\r
UINT32\r
ExtractStrings (\r
  IN  CONST CHAR8  *Strings,\r
  IN  UINTN        Len,\r
  OUT CONST CHAR8  **Dst OPTIONAL\r
  )\r
{\r
  UINT32       Num = 0;\r
  CONST CHAR8  *Ptr;\r
\r
  for (Ptr = Strings; Ptr < Strings + Len; Ptr += AsciiStrSize (Ptr)) {\r
    if (Dst != NULL) {\r
      *Dst++ = Ptr;\r
    }\r
\r
    Num++;\r
  }\r
\r
  return Num;\r
}\r
\r
/**\r
  Convert a contiguous buffer containing a series of NUL terminated\r
  strings into an array of pointers to strings.\r
\r
  The returned pointer references the array of string pointers which\r
  is followed by the storage for the string data.  It is the client's\r
  responsibility to free this storage.\r
\r
  The storage addressed by Strings is free'd prior to Split returning.\r
\r
  @param Strings  A pointer to a contiguous buffer of NUL terminated strings.\r
  @param Len      The length of the buffer pointed to by strings.\r
  @param NumPtr   The number of strings found and returned in the strings\r
                  array.\r
\r
  @return  An array of pointers to the strings found in the input buffer.\r
**/\r
STATIC\r
CONST CHAR8 **\r
Split (\r
  IN  CHAR8   *Strings,\r
  IN  UINTN   Len,\r
  OUT UINT32  *NumPtr\r
  )\r
{\r
  CONST CHAR8  **Dst;\r
\r
  ASSERT (NumPtr != NULL);\r
  ASSERT (Strings != NULL);\r
\r
  /* Protect against unterminated buffers. */\r
  if (Len > 0) {\r
    Strings[Len - 1] = '\0';\r
  }\r
\r
  /* Count the Strings. */\r
  *NumPtr = ExtractStrings (Strings, Len, NULL);\r
\r
  /* Transfer to one big alloc for easy freeing by the caller. */\r
  Dst = AllocatePool (*NumPtr * sizeof (CHAR8 *) + Len);\r
  CopyMem ((VOID *)&Dst[*NumPtr], Strings, Len);\r
  FreePool (Strings);\r
\r
  /* Extract pointers to newly allocated array. */\r
  Strings = (CHAR8 *)&Dst[*NumPtr];\r
  ExtractStrings (Strings, Len, Dst);\r
\r
  return (Dst);\r
}\r
\r
/**\r
  Convert from watch token (unique identifier) to the associated\r
  internal tracking structure for this watch.\r
\r
  @param Tocken  The unique identifier for the watch to find.\r
\r
  @return  A pointer to the found watch structure or NULL.\r
**/\r
STATIC\r
XENSTORE_WATCH *\r
XenStoreFindWatch (\r
  IN CONST CHAR8  *Token\r
  )\r
{\r
  XENSTORE_WATCH  *Watch, *WantedWatch;\r
  LIST_ENTRY      *Entry;\r
\r
  WantedWatch = (VOID *)AsciiStrHexToUintn (Token);\r
\r
  if (IsListEmpty (&xs.RegisteredWatches)) {\r
    return NULL;\r
  }\r
\r
  for (Entry = GetFirstNode (&xs.RegisteredWatches);\r
       !IsNull (&xs.RegisteredWatches, Entry);\r
       Entry = GetNextNode (&xs.RegisteredWatches, Entry))\r
  {\r
    Watch = XENSTORE_WATCH_FROM_LINK (Entry);\r
    if (Watch == WantedWatch) {\r
      return Watch;\r
    }\r
  }\r
\r
  return NULL;\r
}\r
\r
//\r
// Public Utility Functions\r
// API comments for these methods can be found in XenStore.h\r
//\r
\r
CHAR8 *\r
XenStoreJoin (\r
  IN CONST CHAR8  *DirectoryPath,\r
  IN CONST CHAR8  *Node\r
  )\r
{\r
  CHAR8  *Buf;\r
  UINTN  BufSize;\r
\r
  /* +1 for '/' and +1 for '\0' */\r
  BufSize = AsciiStrLen (DirectoryPath) + AsciiStrLen (Node) + 2;\r
  Buf     = AllocatePool (BufSize);\r
  ASSERT (Buf != NULL);\r
\r
  if (Node[0] == '\0') {\r
    AsciiSPrint (Buf, BufSize, "%a", DirectoryPath);\r
  } else {\r
    AsciiSPrint (Buf, BufSize, "%a/%a", DirectoryPath, Node);\r
  }\r
\r
  return Buf;\r
}\r
\r
//\r
// Low Level Communication Management\r
//\r
\r
/**\r
  Verify that the indexes for a ring are valid.\r
\r
  The difference between the producer and consumer cannot\r
  exceed the size of the ring.\r
\r
  @param Cons  The consumer index for the ring to test.\r
  @param Prod  The producer index for the ring to test.\r
\r
  @retval TRUE   If indexes are in range.\r
  @retval FALSE  If the indexes are out of range.\r
**/\r
STATIC\r
BOOLEAN\r
XenStoreCheckIndexes (\r
  XENSTORE_RING_IDX  Cons,\r
  XENSTORE_RING_IDX  Prod\r
  )\r
{\r
  return ((Prod - Cons) <= XENSTORE_RING_SIZE);\r
}\r
\r
/**\r
  Return a pointer to, and the length of, the contiguous\r
  free region available for output in a ring buffer.\r
\r
  @param Cons    The consumer index for the ring.\r
  @param Prod    The producer index for the ring.\r
  @param Buffer  The base address of the ring's storage.\r
  @param LenPtr  The amount of contiguous storage available.\r
\r
  @return  A pointer to the start location of the free region.\r
**/\r
STATIC\r
VOID *\r
XenStoreGetOutputChunk (\r
  IN  XENSTORE_RING_IDX  Cons,\r
  IN  XENSTORE_RING_IDX  Prod,\r
  IN  CHAR8              *Buffer,\r
  OUT UINT32             *LenPtr\r
  )\r
{\r
  UINT32  Len;\r
\r
  Len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX (Prod);\r
  if ((XENSTORE_RING_SIZE - (Prod - Cons)) < Len) {\r
    Len = XENSTORE_RING_SIZE - (Prod - Cons);\r
  }\r
\r
  *LenPtr = Len;\r
  return (Buffer + MASK_XENSTORE_IDX (Prod));\r
}\r
\r
/**\r
  Return a pointer to, and the length of, the contiguous\r
  data available to read from a ring buffer.\r
\r
  @param Cons    The consumer index for the ring.\r
  @param Prod    The producer index for the ring.\r
  @param Buffer  The base address of the ring's storage.\r
  @param LenPtr  The amount of contiguous data available to read.\r
\r
  @return  A pointer to the start location of the available data.\r
**/\r
STATIC\r
CONST VOID *\r
XenStoreGetInputChunk (\r
  IN  XENSTORE_RING_IDX  Cons,\r
  IN  XENSTORE_RING_IDX  Prod,\r
  IN  CONST CHAR8        *Buffer,\r
  OUT UINT32             *LenPtr\r
  )\r
{\r
  UINT32  Len;\r
\r
  Len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX (Cons);\r
  if ((Prod - Cons) < Len) {\r
    Len = Prod - Cons;\r
  }\r
\r
  *LenPtr = Len;\r
  return (Buffer + MASK_XENSTORE_IDX (Cons));\r
}\r
\r
/**\r
  Wait for an event or timeout.\r
\r
  @param Event    Event to wait for.\r
  @param Timeout  A timeout value in 100ns units.\r
\r
  @retval EFI_SUCCESS   Event have been triggered or the current TPL is not\r
                        TPL_APPLICATION.\r
  @retval EFI_TIMEOUT   Timeout have expired.\r
**/\r
STATIC\r
EFI_STATUS\r
XenStoreWaitForEvent (\r
  IN EFI_EVENT  Event,\r
  IN UINT64     Timeout\r
  )\r
{\r
  UINTN       Index;\r
  EFI_STATUS  Status;\r
  EFI_EVENT   TimerEvent;\r
  EFI_EVENT   WaitList[2];\r
\r
  gBS->CreateEvent (EVT_TIMER, 0, NULL, NULL, &TimerEvent);\r
  gBS->SetTimer (TimerEvent, TimerRelative, Timeout);\r
\r
  WaitList[0] = xs.EventChannelEvent;\r
  WaitList[1] = TimerEvent;\r
  Status      = gBS->WaitForEvent (2, WaitList, &Index);\r
  ASSERT (Status != EFI_INVALID_PARAMETER);\r
  gBS->CloseEvent (TimerEvent);\r
  if (Status == EFI_UNSUPPORTED) {\r
    return EFI_SUCCESS;\r
  }\r
\r
  if (Index == 1) {\r
    return EFI_TIMEOUT;\r
  } else {\r
    return EFI_SUCCESS;\r
  }\r
}\r
\r
/**\r
  Transmit data to the XenStore service.\r
\r
  The buffer pointed to by DataPtr is at least Len bytes in length.\r
\r
  @param DataPtr  A pointer to the contiguous data to send.\r
  @param Len      The amount of data to send.\r
\r
  @return  On success 0, otherwise an errno value indicating the\r
           cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreWriteStore (\r
  IN CONST VOID  *DataPtr,\r
  IN UINT32      Len\r
  )\r
{\r
  XENSTORE_RING_IDX  Cons, Prod;\r
  CONST CHAR8        *Data = (CONST CHAR8 *)DataPtr;\r
\r
  while (Len != 0) {\r
    void    *Dest;\r
    UINT32  Available;\r
\r
    Cons = xs.XenStore->req_cons;\r
    Prod = xs.XenStore->req_prod;\r
    if ((Prod - Cons) == XENSTORE_RING_SIZE) {\r
      /*\r
       * Output ring is full. Wait for a ring event.\r
       *\r
       * Note that the events from both queues are combined, so being woken\r
       * does not guarantee that data exist in the read ring.\r
       */\r
      EFI_STATUS  Status;\r
\r
      Status = XenStoreWaitForEvent (\r
                 xs.EventChannelEvent,\r
                 EFI_TIMER_PERIOD_SECONDS (1)\r
                 );\r
      if (Status == EFI_TIMEOUT) {\r
        DEBUG ((DEBUG_WARN, "XenStore Write, waiting for a ring event.\n"));\r
      }\r
\r
      continue;\r
    }\r
\r
    /* Verify queue sanity. */\r
    if (!XenStoreCheckIndexes (Cons, Prod)) {\r
      xs.XenStore->req_cons = xs.XenStore->req_prod = 0;\r
      return XENSTORE_STATUS_EIO;\r
    }\r
\r
    Dest = XenStoreGetOutputChunk (Cons, Prod, xs.XenStore->req, &Available);\r
    if (Available > Len) {\r
      Available = Len;\r
    }\r
\r
    CopyMem (Dest, Data, Available);\r
    Data += Available;\r
    Len  -= Available;\r
\r
    /*\r
     * The store to the producer index, which indicates\r
     * to the other side that new data has arrived, must\r
     * be visible only after our copy of the data into the\r
     * ring has completed.\r
     */\r
    MemoryFence ();\r
    xs.XenStore->req_prod += Available;\r
\r
    /*\r
     * The other side will see the change to req_prod at the time of the\r
     * interrupt.\r
     */\r
    MemoryFence ();\r
    XenEventChannelNotify (xs.Dev, xs.EventChannel);\r
  }\r
\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
/**\r
  Receive data from the XenStore service.\r
\r
  The buffer pointed to by DataPtr is at least Len bytes in length.\r
\r
  @param DataPtr  A pointer to the contiguous buffer to receive the data.\r
  @param Len      The amount of data to receive.\r
\r
  @return  On success 0, otherwise an errno value indicating the\r
           cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreReadStore (\r
  OUT VOID    *DataPtr,\r
  IN  UINT32  Len\r
  )\r
{\r
  XENSTORE_RING_IDX  Cons, Prod;\r
  CHAR8              *Data = (CHAR8 *)DataPtr;\r
\r
  while (Len != 0) {\r
    UINT32       Available;\r
    CONST CHAR8  *Src;\r
\r
    Cons = xs.XenStore->rsp_cons;\r
    Prod = xs.XenStore->rsp_prod;\r
    if (Cons == Prod) {\r
      /*\r
       * Nothing to read. Wait for a ring event.\r
       *\r
       * Note that the events from both queues are combined, so being woken\r
       * does not guarantee that data exist in the read ring.\r
       */\r
      EFI_STATUS  Status;\r
\r
      Status = XenStoreWaitForEvent (\r
                 xs.EventChannelEvent,\r
                 EFI_TIMER_PERIOD_SECONDS (1)\r
                 );\r
      if (Status == EFI_TIMEOUT) {\r
        DEBUG ((DEBUG_WARN, "XenStore Read, waiting for a ring event.\n"));\r
      }\r
\r
      continue;\r
    }\r
\r
    /* Verify queue sanity. */\r
    if (!XenStoreCheckIndexes (Cons, Prod)) {\r
      xs.XenStore->rsp_cons = xs.XenStore->rsp_prod = 0;\r
      return XENSTORE_STATUS_EIO;\r
    }\r
\r
    Src = XenStoreGetInputChunk (Cons, Prod, xs.XenStore->rsp, &Available);\r
    if (Available > Len) {\r
      Available = Len;\r
    }\r
\r
    /*\r
     * Insure the data we read is related to the indexes\r
     * we read above.\r
     */\r
    MemoryFence ();\r
\r
    CopyMem (Data, Src, Available);\r
    Data += Available;\r
    Len  -= Available;\r
\r
    /*\r
     * Insure that the producer of this ring does not see\r
     * the ring space as free until after we have copied it\r
     * out.\r
     */\r
    MemoryFence ();\r
    xs.XenStore->rsp_cons += Available;\r
\r
    /*\r
     * The producer will see the updated consumer index when the event is\r
     * delivered.\r
     */\r
    MemoryFence ();\r
    XenEventChannelNotify (xs.Dev, xs.EventChannel);\r
  }\r
\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
//\r
// Received Message Processing\r
//\r
\r
/**\r
  Block reading the next message from the XenStore service and\r
  process the result.\r
\r
  @return  XENSTORE_STATUS_SUCCESS on success.  Otherwise an errno value\r
           indicating the type of failure encountered.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreProcessMessage (\r
  VOID\r
  )\r
{\r
  XENSTORE_MESSAGE  *Message;\r
  CHAR8             *Body;\r
  XENSTORE_STATUS   Status;\r
\r
  Message            = AllocateZeroPool (sizeof (XENSTORE_MESSAGE));\r
  Message->Signature = XENSTORE_MESSAGE_SIGNATURE;\r
  Status             = XenStoreReadStore (&Message->Header, sizeof (Message->Header));\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    FreePool (Message);\r
    DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));\r
    return Status;\r
  }\r
\r
  Body   = AllocatePool (Message->Header.len + 1);\r
  Status = XenStoreReadStore (Body, Message->Header.len);\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    FreePool (Body);\r
    FreePool (Message);\r
    DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));\r
    return Status;\r
  }\r
\r
  Body[Message->Header.len] = '\0';\r
\r
  if (Message->Header.type == XS_WATCH_EVENT) {\r
    Message->u.Watch.Vector = Split (\r
                                Body,\r
                                Message->Header.len,\r
                                &Message->u.Watch.VectorSize\r
                                );\r
\r
    EfiAcquireLock (&xs.RegisteredWatchesLock);\r
    Message->u.Watch.Handle =\r
      XenStoreFindWatch (Message->u.Watch.Vector[XS_WATCH_TOKEN]);\r
    DEBUG ((\r
      DEBUG_INFO,\r
      "XenStore: Watch event %a\n",\r
      Message->u.Watch.Vector[XS_WATCH_TOKEN]\r
      ));\r
    if (Message->u.Watch.Handle != NULL) {\r
      EfiAcquireLock (&xs.WatchEventsLock);\r
      InsertHeadList (&xs.WatchEvents, &Message->Link);\r
      EfiReleaseLock (&xs.WatchEventsLock);\r
    } else {\r
      DEBUG ((\r
        DEBUG_WARN,\r
        "XenStore: Watch handle %a not found\n",\r
        Message->u.Watch.Vector[XS_WATCH_TOKEN]\r
        ));\r
      FreePool ((VOID *)Message->u.Watch.Vector);\r
      FreePool (Message);\r
    }\r
\r
    EfiReleaseLock (&xs.RegisteredWatchesLock);\r
  } else {\r
    Message->u.Reply.Body = Body;\r
    EfiAcquireLock (&xs.ReplyLock);\r
    InsertTailList (&xs.ReplyList, &Message->Link);\r
    EfiReleaseLock (&xs.ReplyLock);\r
  }\r
\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
//\r
// XenStore Message Request/Reply Processing\r
//\r
\r
/**\r
  Convert a XenStore error string into an errno number.\r
\r
  Unknown error strings are converted to EINVAL.\r
\r
  @param errorstring  The error string to convert.\r
\r
  @return  The errno best matching the input string.\r
\r
**/\r
typedef struct {\r
  XENSTORE_STATUS    Status;\r
  CONST CHAR8        *ErrorStr;\r
} XenStoreErrors;\r
\r
static XenStoreErrors  gXenStoreErrors[] = {\r
  { XENSTORE_STATUS_EINVAL,    "EINVAL"    },\r
  { XENSTORE_STATUS_EACCES,    "EACCES"    },\r
  { XENSTORE_STATUS_EEXIST,    "EEXIST"    },\r
  { XENSTORE_STATUS_EISDIR,    "EISDIR"    },\r
  { XENSTORE_STATUS_ENOENT,    "ENOENT"    },\r
  { XENSTORE_STATUS_ENOMEM,    "ENOMEM"    },\r
  { XENSTORE_STATUS_ENOSPC,    "ENOSPC"    },\r
  { XENSTORE_STATUS_EIO,       "EIO"       },\r
  { XENSTORE_STATUS_ENOTEMPTY, "ENOTEMPTY" },\r
  { XENSTORE_STATUS_ENOSYS,    "ENOSYS"    },\r
  { XENSTORE_STATUS_EROFS,     "EROFS"     },\r
  { XENSTORE_STATUS_EBUSY,     "EBUSY"     },\r
  { XENSTORE_STATUS_EAGAIN,    "EAGAIN"    },\r
  { XENSTORE_STATUS_EISCONN,   "EISCONN"   },\r
  { XENSTORE_STATUS_E2BIG,     "E2BIG"     }\r
};\r
\r
STATIC\r
XENSTORE_STATUS\r
XenStoreGetError (\r
  CONST CHAR8  *ErrorStr\r
  )\r
{\r
  UINT32  Index;\r
\r
  for (Index = 0; Index < ARRAY_SIZE (gXenStoreErrors); Index++) {\r
    if (!AsciiStrCmp (ErrorStr, gXenStoreErrors[Index].ErrorStr)) {\r
      return gXenStoreErrors[Index].Status;\r
    }\r
  }\r
\r
  DEBUG ((DEBUG_WARN, "XenStore gave unknown error %a\n", ErrorStr));\r
  return XENSTORE_STATUS_EINVAL;\r
}\r
\r
/**\r
  Block waiting for a reply to a message request.\r
\r
  @param TypePtr The returned type of the reply.\r
  @param LenPtr  The returned body length of the reply.\r
  @param Result  The returned body of the reply.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreReadReply (\r
  OUT enum xsd_sockmsg_type  *TypePtr,\r
  OUT UINT32                 *LenPtr OPTIONAL,\r
  OUT VOID                   **Result\r
  )\r
{\r
  XENSTORE_MESSAGE  *Message;\r
  LIST_ENTRY        *Entry;\r
  CHAR8             *Body;\r
\r
  while (IsListEmpty (&xs.ReplyList)) {\r
    XENSTORE_STATUS  Status;\r
    Status = XenStoreProcessMessage ();\r
    if ((Status != XENSTORE_STATUS_SUCCESS) && (Status != XENSTORE_STATUS_EAGAIN)) {\r
      DEBUG ((\r
        DEBUG_ERROR,\r
        "XenStore, error while reading the ring (%d).",\r
        Status\r
        ));\r
      return Status;\r
    }\r
  }\r
\r
  EfiAcquireLock (&xs.ReplyLock);\r
  Entry   = GetFirstNode (&xs.ReplyList);\r
  Message = XENSTORE_MESSAGE_FROM_LINK (Entry);\r
  RemoveEntryList (Entry);\r
  EfiReleaseLock (&xs.ReplyLock);\r
\r
  *TypePtr = Message->Header.type;\r
  if (LenPtr != NULL) {\r
    *LenPtr = Message->Header.len;\r
  }\r
\r
  Body = Message->u.Reply.Body;\r
\r
  FreePool (Message);\r
  *Result = Body;\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
/**\r
  Send a message with an optionally multi-part body to the XenStore service.\r
\r
  @param Transaction    The transaction to use for this request.\r
  @param RequestType    The type of message to send.\r
  @param WriteRequest   Pointers to the body sections of the request.\r
  @param NumRequests    The number of body sections in the request.\r
  @param LenPtr         The returned length of the reply.\r
  @param ResultPtr      The returned body of the reply.\r
\r
  @return  XENSTORE_STATUS_SUCCESS on success.  Otherwise an errno indicating\r
           the cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreTalkv (\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  enum xsd_sockmsg_type       RequestType,\r
  IN  CONST WRITE_REQUEST         *WriteRequest,\r
  IN  UINT32                      NumRequests,\r
  OUT UINT32                      *LenPtr OPTIONAL,\r
  OUT VOID                        **ResultPtr OPTIONAL\r
  )\r
{\r
  struct xsd_sockmsg  Message;\r
  void                *Return = NULL;\r
  UINT32              Index;\r
  XENSTORE_STATUS     Status;\r
\r
  if (Transaction == XST_NIL) {\r
    Message.tx_id = 0;\r
  } else {\r
    Message.tx_id = Transaction->Id;\r
  }\r
\r
  Message.req_id = 0;\r
  Message.type   = RequestType;\r
  Message.len    = 0;\r
  for (Index = 0; Index < NumRequests; Index++) {\r
    Message.len += WriteRequest[Index].Len;\r
  }\r
\r
  Status = XenStoreWriteStore (&Message, sizeof (Message));\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    DEBUG ((DEBUG_ERROR, "XenStoreTalkv failed %d\n", Status));\r
    goto Error;\r
  }\r
\r
  for (Index = 0; Index < NumRequests; Index++) {\r
    Status = XenStoreWriteStore (WriteRequest[Index].Data, WriteRequest[Index].Len);\r
    if (Status != XENSTORE_STATUS_SUCCESS) {\r
      DEBUG ((DEBUG_ERROR, "XenStoreTalkv failed %d\n", Status));\r
      goto Error;\r
    }\r
  }\r
\r
  Status = XenStoreReadReply ((enum xsd_sockmsg_type *)&Message.type, LenPtr, &Return);\r
\r
Error:\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    return Status;\r
  }\r
\r
  if (Message.type == XS_ERROR) {\r
    Status = XenStoreGetError (Return);\r
    FreePool (Return);\r
    return Status;\r
  }\r
\r
  /* Reply is either error or an echo of our request message type. */\r
  ASSERT ((enum xsd_sockmsg_type)Message.type == RequestType);\r
\r
  if (ResultPtr) {\r
    *ResultPtr = Return;\r
  } else {\r
    FreePool (Return);\r
  }\r
\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
/**\r
  Wrapper for XenStoreTalkv allowing easy transmission of a message with\r
  a single, contiguous, message body.\r
\r
  The returned result is provided in malloced storage and thus must be free'd\r
  by the caller.\r
\r
  @param Transaction    The transaction to use for this request.\r
  @param RequestType    The type of message to send.\r
  @param Body           The body of the request.\r
  @param LenPtr         The returned length of the reply.\r
  @param Result         The returned body of the reply.\r
\r
  @return  0 on success.  Otherwise an errno indicating\r
           the cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreSingle (\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  enum xsd_sockmsg_type       RequestType,\r
  IN  CONST CHAR8                 *Body,\r
  OUT UINT32                      *LenPtr OPTIONAL,\r
  OUT VOID                        **Result OPTIONAL\r
  )\r
{\r
  WRITE_REQUEST  WriteRequest;\r
\r
  WriteRequest.Data = (VOID *)Body;\r
  WriteRequest.Len  = (UINT32)AsciiStrSize (Body);\r
\r
  return XenStoreTalkv (\r
           Transaction,\r
           RequestType,\r
           &WriteRequest,\r
           1,\r
           LenPtr,\r
           Result\r
           );\r
}\r
\r
//\r
// XenStore Watch Support\r
//\r
\r
/**\r
  Transmit a watch request to the XenStore service.\r
\r
  @param Path    The path in the XenStore to watch.\r
  @param Tocken  A unique identifier for this watch.\r
\r
  @return  XENSTORE_STATUS_SUCCESS on success.  Otherwise an errno indicating the\r
           cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreWatch (\r
  CONST CHAR8  *Path,\r
  CONST CHAR8  *Token\r
  )\r
{\r
  WRITE_REQUEST  WriteRequest[2];\r
\r
  WriteRequest[0].Data = (VOID *)Path;\r
  WriteRequest[0].Len  = (UINT32)AsciiStrSize (Path);\r
  WriteRequest[1].Data = (VOID *)Token;\r
  WriteRequest[1].Len  = (UINT32)AsciiStrSize (Token);\r
\r
  return XenStoreTalkv (XST_NIL, XS_WATCH, WriteRequest, 2, NULL, NULL);\r
}\r
\r
/**\r
  Transmit an uwatch request to the XenStore service.\r
\r
  @param Path    The path in the XenStore to watch.\r
  @param Tocken  A unique identifier for this watch.\r
\r
  @return  XENSTORE_STATUS_SUCCESS on success.  Otherwise an errno indicating\r
           the cause of failure.\r
**/\r
STATIC\r
XENSTORE_STATUS\r
XenStoreUnwatch (\r
  CONST CHAR8  *Path,\r
  CONST CHAR8  *Token\r
  )\r
{\r
  WRITE_REQUEST  WriteRequest[2];\r
\r
  WriteRequest[0].Data = (VOID *)Path;\r
  WriteRequest[0].Len  = (UINT32)AsciiStrSize (Path);\r
  WriteRequest[1].Data = (VOID *)Token;\r
  WriteRequest[1].Len  = (UINT32)AsciiStrSize (Token);\r
\r
  return XenStoreTalkv (XST_NIL, XS_UNWATCH, WriteRequest, 2, NULL, NULL);\r
}\r
\r
STATIC\r
XENSTORE_STATUS\r
XenStoreWaitWatch (\r
  VOID  *Token\r
  )\r
{\r
  XENSTORE_MESSAGE  *Message;\r
  LIST_ENTRY        *Entry = NULL;\r
  LIST_ENTRY        *Last  = NULL;\r
  XENSTORE_STATUS   Status;\r
\r
  while (TRUE) {\r
    EfiAcquireLock (&xs.WatchEventsLock);\r
    if (IsListEmpty (&xs.WatchEvents) ||\r
        (Last == GetFirstNode (&xs.WatchEvents)))\r
    {\r
      EfiReleaseLock (&xs.WatchEventsLock);\r
      Status = XenStoreProcessMessage ();\r
      if ((Status != XENSTORE_STATUS_SUCCESS) && (Status != XENSTORE_STATUS_EAGAIN)) {\r
        return Status;\r
      }\r
\r
      continue;\r
    }\r
\r
    for (Entry = GetFirstNode (&xs.WatchEvents);\r
         Entry != Last && !IsNull (&xs.WatchEvents, Entry);\r
         Entry = GetNextNode (&xs.WatchEvents, Entry))\r
    {\r
      Message = XENSTORE_MESSAGE_FROM_LINK (Entry);\r
      if (Message->u.Watch.Handle == Token) {\r
        RemoveEntryList (Entry);\r
        EfiReleaseLock (&xs.WatchEventsLock);\r
        FreePool ((VOID *)Message->u.Watch.Vector);\r
        FreePool (Message);\r
        return XENSTORE_STATUS_SUCCESS;\r
      }\r
    }\r
\r
    Last = GetFirstNode (&xs.WatchEvents);\r
    EfiReleaseLock (&xs.WatchEventsLock);\r
  }\r
}\r
\r
VOID\r
EFIAPI\r
NotifyEventChannelCheckForEvent (\r
  IN EFI_EVENT  Event,\r
  IN VOID       *Context\r
  )\r
{\r
  XENSTORE_PRIVATE  *xsp;\r
\r
  xsp = (XENSTORE_PRIVATE *)Context;\r
  if (TestAndClearBit (xsp->EventChannel, xsp->Dev->SharedInfo->evtchn_pending)) {\r
    gBS->SignalEvent (Event);\r
  }\r
}\r
\r
/**\r
  Setup communication channels with the XenStore service.\r
\r
  @retval EFI_SUCCESS if everything went well.\r
**/\r
STATIC\r
EFI_STATUS\r
XenStoreInitComms (\r
  XENSTORE_PRIVATE  *xsp\r
  )\r
{\r
  EFI_STATUS                        Status;\r
  EFI_EVENT                         TimerEvent;\r
  struct xenstore_domain_interface  *XenStore = xsp->XenStore;\r
\r
  Status = gBS->CreateEvent (EVT_TIMER, 0, NULL, NULL, &TimerEvent);\r
  Status = gBS->SetTimer (\r
                  TimerEvent,\r
                  TimerRelative,\r
                  EFI_TIMER_PERIOD_SECONDS (5)\r
                  );\r
  while (XenStore->rsp_prod != XenStore->rsp_cons) {\r
    Status = gBS->CheckEvent (TimerEvent);\r
    if (!EFI_ERROR (Status)) {\r
      DEBUG ((\r
        DEBUG_WARN,\r
        "XENSTORE response ring is not quiescent "\r
        "(%08x:%08x): fixing up\n",\r
        XenStore->rsp_cons,\r
        XenStore->rsp_prod\r
        ));\r
      XenStore->rsp_cons = XenStore->rsp_prod;\r
    }\r
  }\r
\r
  gBS->CloseEvent (TimerEvent);\r
\r
  Status = gBS->CreateEvent (\r
                  EVT_NOTIFY_WAIT,\r
                  TPL_NOTIFY,\r
                  NotifyEventChannelCheckForEvent,\r
                  xsp,\r
                  &xsp->EventChannelEvent\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return Status;\r
}\r
\r
/**\r
  Initialize XenStore.\r
\r
  @param Dev  A XENBUS_DEVICE instance.\r
\r
  @retval EFI_SUCCESS if everything went well.\r
**/\r
EFI_STATUS\r
XenStoreInit (\r
  XENBUS_DEVICE  *Dev\r
  )\r
{\r
  EFI_STATUS  Status;\r
\r
  /**\r
   * The HVM guest pseudo-physical frame number.  This is Xen's mapping\r
   * of the true machine frame number into our "physical address space".\r
   */\r
  UINTN  XenStoreGpfn;\r
\r
  xs.Dev = Dev;\r
\r
  xs.EventChannel = (evtchn_port_t)XenHypercallHvmGetParam (HVM_PARAM_STORE_EVTCHN);\r
  XenStoreGpfn    = (UINTN)XenHypercallHvmGetParam (HVM_PARAM_STORE_PFN);\r
  xs.XenStore     = (VOID *)(XenStoreGpfn << EFI_PAGE_SHIFT);\r
  DEBUG ((\r
    DEBUG_INFO,\r
    "XenBusInit: XenBus rings @%p, event channel %x\n",\r
    xs.XenStore,\r
    xs.EventChannel\r
    ));\r
\r
  InitializeListHead (&xs.ReplyList);\r
  InitializeListHead (&xs.WatchEvents);\r
  InitializeListHead (&xs.RegisteredWatches);\r
\r
  EfiInitializeLock (&xs.ReplyLock, TPL_NOTIFY);\r
  EfiInitializeLock (&xs.RegisteredWatchesLock, TPL_NOTIFY);\r
  EfiInitializeLock (&xs.WatchEventsLock, TPL_NOTIFY);\r
\r
  /* Initialize the shared memory rings to talk to xenstored */\r
  Status = XenStoreInitComms (&xs);\r
\r
  return Status;\r
}\r
\r
VOID\r
XenStoreDeinit (\r
  IN XENBUS_DEVICE  *Dev\r
  )\r
{\r
  //\r
  // Emptying the list RegisteredWatches, but this list should already be\r
  // empty. Every driver that is using Watches should unregister them when\r
  // it is stopped.\r
  //\r
  if (!IsListEmpty (&xs.RegisteredWatches)) {\r
    XENSTORE_WATCH  *Watch;\r
    LIST_ENTRY      *Entry;\r
    DEBUG ((DEBUG_WARN, "XenStore: RegisteredWatches is not empty, cleaning up..."));\r
    Entry = GetFirstNode (&xs.RegisteredWatches);\r
    while (!IsNull (&xs.RegisteredWatches, Entry)) {\r
      Watch = XENSTORE_WATCH_FROM_LINK (Entry);\r
      Entry = GetNextNode (&xs.RegisteredWatches, Entry);\r
\r
      XenStoreUnregisterWatch (Watch);\r
    }\r
  }\r
\r
  //\r
  // Emptying the list WatchEvents, but this list should already be empty after\r
  // having cleanup the list RegisteredWatches.\r
  //\r
  if (!IsListEmpty (&xs.WatchEvents)) {\r
    LIST_ENTRY  *Entry;\r
    DEBUG ((DEBUG_WARN, "XenStore: WatchEvents is not empty, cleaning up..."));\r
    Entry = GetFirstNode (&xs.WatchEvents);\r
    while (!IsNull (&xs.WatchEvents, Entry)) {\r
      XENSTORE_MESSAGE  *Message = XENSTORE_MESSAGE_FROM_LINK (Entry);\r
      Entry = GetNextNode (&xs.WatchEvents, Entry);\r
      RemoveEntryList (&Message->Link);\r
      FreePool ((VOID *)Message->u.Watch.Vector);\r
      FreePool (Message);\r
    }\r
  }\r
\r
  if (!IsListEmpty (&xs.ReplyList)) {\r
    XENSTORE_MESSAGE  *Message;\r
    LIST_ENTRY        *Entry;\r
    Entry = GetFirstNode (&xs.ReplyList);\r
    while (!IsNull (&xs.ReplyList, Entry)) {\r
      Message = XENSTORE_MESSAGE_FROM_LINK (Entry);\r
      Entry   = GetNextNode (&xs.ReplyList, Entry);\r
      RemoveEntryList (&Message->Link);\r
      FreePool (Message->u.Reply.Body);\r
      FreePool (Message);\r
    }\r
  }\r
\r
  gBS->CloseEvent (xs.EventChannelEvent);\r
\r
  if (xs.XenStore->server_features & XENSTORE_SERVER_FEATURE_RECONNECTION) {\r
    xs.XenStore->connection = XENSTORE_RECONNECT;\r
    XenEventChannelNotify (xs.Dev, xs.EventChannel);\r
    while (*(volatile UINT32 *)&xs.XenStore->connection == XENSTORE_RECONNECT) {\r
      XenStoreWaitForEvent (xs.EventChannelEvent, EFI_TIMER_PERIOD_MILLISECONDS (100));\r
    }\r
  } else {\r
    /* If the backend reads the state while we're erasing it then the\r
     * ring state will become corrupted, preventing guest frontends from\r
     * connecting. This is rare. To help diagnose the failure, we fill\r
     * the ring with XS_INVALID packets. */\r
    SetMem (xs.XenStore->req, XENSTORE_RING_SIZE, 0xff);\r
    SetMem (xs.XenStore->rsp, XENSTORE_RING_SIZE, 0xff);\r
    xs.XenStore->req_cons = xs.XenStore->req_prod = 0;\r
    xs.XenStore->rsp_cons = xs.XenStore->rsp_prod = 0;\r
  }\r
\r
  xs.XenStore = NULL;\r
}\r
\r
//\r
// Public API\r
// API comments for these methods can be found in XenStore.h\r
//\r
\r
XENSTORE_STATUS\r
XenStoreListDirectory (\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  CONST CHAR8                 *DirectoryPath,\r
  IN  CONST CHAR8                 *Node,\r
  OUT UINT32                      *DirectoryCountPtr,\r
  OUT CONST CHAR8                 ***DirectoryListPtr\r
  )\r
{\r
  CHAR8            *Path;\r
  CHAR8            *TempStr;\r
  UINT32           Len = 0;\r
  XENSTORE_STATUS  Status;\r
\r
  Path   = XenStoreJoin (DirectoryPath, Node);\r
  Status = XenStoreSingle (\r
             Transaction,\r
             XS_DIRECTORY,\r
             Path,\r
             &Len,\r
             (VOID **)&TempStr\r
             );\r
  FreePool (Path);\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    return Status;\r
  }\r
\r
  *DirectoryListPtr = Split (TempStr, Len, DirectoryCountPtr);\r
\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
BOOLEAN\r
XenStorePathExists (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *Directory,\r
  IN CONST CHAR8                 *Node\r
  )\r
{\r
  CONST CHAR8      **TempStr;\r
  XENSTORE_STATUS  Status;\r
  UINT32           TempNum;\r
\r
  Status = XenStoreListDirectory (\r
             Transaction,\r
             Directory,\r
             Node,\r
             &TempNum,\r
             &TempStr\r
             );\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    return FALSE;\r
  }\r
\r
  FreePool ((VOID *)TempStr);\r
  return TRUE;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreRead (\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  CONST CHAR8                 *DirectoryPath,\r
  IN  CONST CHAR8                 *Node,\r
  OUT UINT32                      *LenPtr OPTIONAL,\r
  OUT VOID                        **Result\r
  )\r
{\r
  CHAR8            *Path;\r
  VOID             *Value;\r
  XENSTORE_STATUS  Status;\r
\r
  Path   = XenStoreJoin (DirectoryPath, Node);\r
  Status = XenStoreSingle (Transaction, XS_READ, Path, LenPtr, &Value);\r
  FreePool (Path);\r
  if (Status != XENSTORE_STATUS_SUCCESS) {\r
    return Status;\r
  }\r
\r
  *Result = Value;\r
  return XENSTORE_STATUS_SUCCESS;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreWrite (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *DirectoryPath,\r
  IN CONST CHAR8                 *Node,\r
  IN CONST CHAR8                 *Str\r
  )\r
{\r
  CHAR8            *Path;\r
  WRITE_REQUEST    WriteRequest[2];\r
  XENSTORE_STATUS  Status;\r
\r
  Path = XenStoreJoin (DirectoryPath, Node);\r
\r
  WriteRequest[0].Data = (VOID *)Path;\r
  WriteRequest[0].Len  = (UINT32)AsciiStrSize (Path);\r
  WriteRequest[1].Data = (VOID *)Str;\r
  WriteRequest[1].Len  = (UINT32)AsciiStrLen (Str);\r
\r
  Status = XenStoreTalkv (Transaction, XS_WRITE, WriteRequest, 2, NULL, NULL);\r
  FreePool (Path);\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreRemove (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *DirectoryPath,\r
  IN CONST CHAR8                 *Node\r
  )\r
{\r
  CHAR8            *Path;\r
  XENSTORE_STATUS  Status;\r
\r
  Path   = XenStoreJoin (DirectoryPath, Node);\r
  Status = XenStoreSingle (Transaction, XS_RM, Path, NULL, NULL);\r
  FreePool (Path);\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreTransactionStart (\r
  OUT XENSTORE_TRANSACTION  *Transaction\r
  )\r
{\r
  CHAR8            *IdStr;\r
  XENSTORE_STATUS  Status;\r
\r
  Status = XenStoreSingle (\r
             XST_NIL,\r
             XS_TRANSACTION_START,\r
             "",\r
             NULL,\r
             (VOID **)&IdStr\r
             );\r
  if (Status == XENSTORE_STATUS_SUCCESS) {\r
    Transaction->Id = (UINT32)AsciiStrDecimalToUintn (IdStr);\r
    FreePool (IdStr);\r
  }\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreTransactionEnd (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN BOOLEAN                     Abort\r
  )\r
{\r
  CHAR8  AbortStr[2];\r
\r
  AbortStr[0] = Abort ? 'F' : 'T';\r
  AbortStr[1] = '\0';\r
\r
  return XenStoreSingle (Transaction, XS_TRANSACTION_END, AbortStr, NULL, NULL);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenStoreVSPrint (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *DirectoryPath,\r
  IN CONST CHAR8                 *Node,\r
  IN CONST CHAR8                 *FormatString,\r
  IN VA_LIST                     Marker\r
  )\r
{\r
  CHAR8            *Buf;\r
  XENSTORE_STATUS  Status;\r
  UINTN            BufSize;\r
  VA_LIST          Marker2;\r
\r
  VA_COPY (Marker2, Marker);\r
  BufSize = SPrintLengthAsciiFormat (FormatString, Marker2) + 1;\r
  VA_END (Marker2);\r
  Buf = AllocateZeroPool (BufSize);\r
  AsciiVSPrint (Buf, BufSize, FormatString, Marker);\r
  Status = XenStoreWrite (Transaction, DirectoryPath, Node, Buf);\r
  FreePool (Buf);\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenStoreSPrint (\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *DirectoryPath,\r
  IN CONST CHAR8                 *Node,\r
  IN CONST CHAR8                 *FormatString,\r
  ...\r
  )\r
{\r
  VA_LIST          Marker;\r
  XENSTORE_STATUS  Status;\r
\r
  VA_START (Marker, FormatString);\r
  Status = XenStoreVSPrint (Transaction, DirectoryPath, Node, FormatString, Marker);\r
  VA_END (Marker);\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
XenStoreRegisterWatch (\r
  IN CONST CHAR8      *DirectoryPath,\r
  IN CONST CHAR8      *Node,\r
  OUT XENSTORE_WATCH  **WatchPtr\r
  )\r
{\r
  /* Pointer in ascii is the token. */\r
  CHAR8            Token[sizeof (XENSTORE_WATCH) * 2 + 1];\r
  XENSTORE_STATUS  Status;\r
  XENSTORE_WATCH   *Watch;\r
\r
  Watch            = AllocateZeroPool (sizeof (XENSTORE_WATCH));\r
  Watch->Signature = XENSTORE_WATCH_SIGNATURE;\r
  Watch->Node      = XenStoreJoin (DirectoryPath, Node);\r
\r
  EfiAcquireLock (&xs.RegisteredWatchesLock);\r
  InsertTailList (&xs.RegisteredWatches, &Watch->Link);\r
  EfiReleaseLock (&xs.RegisteredWatchesLock);\r
\r
  AsciiSPrint (Token, sizeof (Token), "%p", (VOID *)Watch);\r
  Status = XenStoreWatch (Watch->Node, Token);\r
\r
  /* Ignore errors due to multiple registration. */\r
  if (Status == XENSTORE_STATUS_EEXIST) {\r
    Status = XENSTORE_STATUS_SUCCESS;\r
  }\r
\r
  if (Status == XENSTORE_STATUS_SUCCESS) {\r
    *WatchPtr = Watch;\r
  } else {\r
    EfiAcquireLock (&xs.RegisteredWatchesLock);\r
    RemoveEntryList (&Watch->Link);\r
    EfiReleaseLock (&xs.RegisteredWatchesLock);\r
    FreePool (Watch->Node);\r
    FreePool (Watch);\r
  }\r
\r
  return Status;\r
}\r
\r
VOID\r
XenStoreUnregisterWatch (\r
  IN XENSTORE_WATCH  *Watch\r
  )\r
{\r
  CHAR8       Token[sizeof (Watch) * 2 + 1];\r
  LIST_ENTRY  *Entry;\r
\r
  ASSERT (Watch->Signature == XENSTORE_WATCH_SIGNATURE);\r
\r
  AsciiSPrint (Token, sizeof (Token), "%p", (VOID *)Watch);\r
  if (XenStoreFindWatch (Token) == NULL) {\r
    return;\r
  }\r
\r
  EfiAcquireLock (&xs.RegisteredWatchesLock);\r
  RemoveEntryList (&Watch->Link);\r
  EfiReleaseLock (&xs.RegisteredWatchesLock);\r
\r
  XenStoreUnwatch (Watch->Node, Token);\r
\r
  /* Cancel pending watch events. */\r
  EfiAcquireLock (&xs.WatchEventsLock);\r
  Entry = GetFirstNode (&xs.WatchEvents);\r
  while (!IsNull (&xs.WatchEvents, Entry)) {\r
    XENSTORE_MESSAGE  *Message = XENSTORE_MESSAGE_FROM_LINK (Entry);\r
    Entry = GetNextNode (&xs.WatchEvents, Entry);\r
    if (Message->u.Watch.Handle == Watch) {\r
      RemoveEntryList (&Message->Link);\r
      FreePool ((VOID *)Message->u.Watch.Vector);\r
      FreePool (Message);\r
    }\r
  }\r
\r
  EfiReleaseLock (&xs.WatchEventsLock);\r
\r
  FreePool (Watch->Node);\r
  FreePool (Watch);\r
}\r
\r
//\r
// XENBUS protocol\r
//\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusWaitForWatch (\r
  IN XENBUS_PROTOCOL  *This,\r
  IN VOID             *Token\r
  )\r
{\r
  return XenStoreWaitWatch (Token);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreRead (\r
  IN  XENBUS_PROTOCOL             *This,\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  CONST CHAR8                 *Node,\r
  OUT VOID                        **Value\r
  )\r
{\r
  return XenStoreRead (Transaction, This->Node, Node, NULL, Value);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreBackendRead (\r
  IN  XENBUS_PROTOCOL             *This,\r
  IN  CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN  CONST CHAR8                 *Node,\r
  OUT VOID                        **Value\r
  )\r
{\r
  return XenStoreRead (Transaction, This->Backend, Node, NULL, Value);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreRemove (\r
  IN XENBUS_PROTOCOL             *This,\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN const char                  *Node\r
  )\r
{\r
  return XenStoreRemove (Transaction, This->Node, Node);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreTransactionStart (\r
  IN  XENBUS_PROTOCOL       *This,\r
  OUT XENSTORE_TRANSACTION  *Transaction\r
  )\r
{\r
  return XenStoreTransactionStart (Transaction);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreTransactionEnd (\r
  IN XENBUS_PROTOCOL             *This,\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN BOOLEAN                     Abort\r
  )\r
{\r
  return XenStoreTransactionEnd (Transaction, Abort);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusXenStoreSPrint (\r
  IN XENBUS_PROTOCOL             *This,\r
  IN CONST XENSTORE_TRANSACTION  *Transaction,\r
  IN CONST CHAR8                 *DirectoryPath,\r
  IN CONST CHAR8                 *Node,\r
  IN CONST CHAR8                 *FormatString,\r
  ...\r
  )\r
{\r
  VA_LIST          Marker;\r
  XENSTORE_STATUS  Status;\r
\r
  VA_START (Marker, FormatString);\r
  Status = XenStoreVSPrint (Transaction, DirectoryPath, Node, FormatString, Marker);\r
  VA_END (Marker);\r
\r
  return Status;\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusRegisterWatch (\r
  IN  XENBUS_PROTOCOL  *This,\r
  IN  CONST CHAR8      *Node,\r
  OUT VOID             **Token\r
  )\r
{\r
  return XenStoreRegisterWatch (This->Node, Node, (XENSTORE_WATCH **)Token);\r
}\r
\r
XENSTORE_STATUS\r
EFIAPI\r
XenBusRegisterWatchBackend (\r
  IN  XENBUS_PROTOCOL  *This,\r
  IN  CONST CHAR8      *Node,\r
  OUT VOID             **Token\r
  )\r
{\r
  return XenStoreRegisterWatch (This->Backend, Node, (XENSTORE_WATCH **)Token);\r
}\r
\r
VOID\r
EFIAPI\r
XenBusUnregisterWatch (\r
  IN XENBUS_PROTOCOL  *This,\r
  IN VOID             *Token\r
  )\r
{\r
  XenStoreUnregisterWatch ((XENSTORE_WATCH *)Token);\r
}\r