xs_wire.h

/*
 * Details of the "wire" protocol between Xen Store Daemon and client
 * library or guest kernel.
 *
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2005 Rusty Russell IBM Corporation
 */
 
#ifndef _XS_WIRE_H
#define _XS_WIRE_H
 
enum xsd_sockmsg_type {
  XS_DEBUG,
  XS_DIRECTORY,
  XS_READ,
  XS_GET_PERMS,
  XS_WATCH,
  XS_UNWATCH,
  XS_TRANSACTION_START,
  XS_TRANSACTION_END,
  XS_INTRODUCE,
  XS_RELEASE,
  XS_GET_DOMAIN_PATH,
  XS_WRITE,
  XS_MKDIR,
  XS_RM,
  XS_SET_PERMS,
  XS_WATCH_EVENT,
  XS_ERROR,
  XS_IS_DOMAIN_INTRODUCED,
  XS_RESUME,
  XS_SET_TARGET,
  XS_RESTRICT,
  XS_RESET_WATCHES,
 
  XS_INVALID = 0xffff   /* Guaranteed to remain an invalid type */
};
 
#define XS_WRITE_NONE         "NONE"
#define XS_WRITE_CREATE       "CREATE"
#define XS_WRITE_CREATE_EXCL  "CREATE|EXCL"
 
/* We hand errors as strings, for portability. */
struct xsd_errors {
  INT32          errnum;
  const CHAR8    *errstring;
};
 
#ifdef EINVAL
#define XSD_ERROR(x)  { x, #x }
/* LINTED: static unused */
static struct xsd_errors xsd_errors[]
  #if defined (__GNUC__)
__attribute__ ((unused))
  #endif
  = {
  XSD_ERROR (EINVAL),
  XSD_ERROR (EACCES),
  XSD_ERROR (EEXIST),
  XSD_ERROR (EISDIR),
  XSD_ERROR (ENOENT),
  XSD_ERROR (ENOMEM),
  XSD_ERROR (ENOSPC),
  XSD_ERROR (EIO),
  XSD_ERROR (ENOTEMPTY),
  XSD_ERROR (ENOSYS),
  XSD_ERROR (EROFS),
  XSD_ERROR (EBUSY),
  XSD_ERROR (EAGAIN),
  XSD_ERROR (EISCONN),
  XSD_ERROR (E2BIG)
  };
#endif
 
struct xsd_sockmsg {
  UINT32    type;   /* XS_??? */
  UINT32    req_id; /* Request identifier, echoed in daemon's response.  */
  UINT32    tx_id;  /* Transaction id (0 if not related to a transaction). */
  UINT32    len;    /* Length of data following this. */
 
  /* Generally followed by nul-terminated string(s). */
};
 
enum xs_watch_type {
  XS_WATCH_PATH = 0,
  XS_WATCH_TOKEN
};
 
/*
 * `incontents 150 xenstore_struct XenStore wire protocol.
 *
 * Inter-domain shared memory communications. */
#define XENSTORE_RING_SIZE  1024
typedef UINT32 XENSTORE_RING_IDX;
#define MASK_XENSTORE_IDX(idx)  ((idx) & (XENSTORE_RING_SIZE-1))
struct xenstore_domain_interface {
  CHAR8                req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
  CHAR8                rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
  XENSTORE_RING_IDX    req_cons, req_prod;
  XENSTORE_RING_IDX    rsp_cons, rsp_prod;
  UINT32               server_features; /* Bitmap of features supported by the server */
  UINT32               connection;
};
 
/* Violating this is very bad.  See docs/misc/xenstore.txt. */
#define XENSTORE_PAYLOAD_MAX  4096
 
/* Violating these just gets you an error back */
#define XENSTORE_ABS_PATH_MAX  3072
#define XENSTORE_REL_PATH_MAX  2048
 
/* The ability to reconnect a ring */
#define XENSTORE_SERVER_FEATURE_RECONNECTION  1
 
/* Valid values for the connection field */
#define XENSTORE_CONNECTED  0 /* the steady-state */
#define XENSTORE_RECONNECT  1 /* guest has initiated a reconnect */
 
#endif /* _XS_WIRE_H */
 
/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */