include/hw/xen/interface/io/xs_wire.h

   1 /* SPDX-License-Identifier: MIT */
   2 /*
   3  * Details of the "wire" protocol between Xen Store Daemon and client
   4  * library or guest kernel.
   5  *
   6  * Copyright (C) 2005 Rusty Russell IBM Corporation
   7  */
   8
   9 #ifndef _XS_WIRE_H
  10 #define _XS_WIRE_H
  11
  12 enum xsd_sockmsg_type
  13 {
  14     XS_CONTROL,
  15 #define XS_DEBUG XS_CONTROL
  16     XS_DIRECTORY,
  17     XS_READ,
  18     XS_GET_PERMS,
  19     XS_WATCH,
  20     XS_UNWATCH,
  21     XS_TRANSACTION_START,
  22     XS_TRANSACTION_END,
  23     XS_INTRODUCE,
  24     XS_RELEASE,
  25     XS_GET_DOMAIN_PATH,
  26     XS_WRITE,
  27     XS_MKDIR,
  28     XS_RM,
  29     XS_SET_PERMS,
  30     XS_WATCH_EVENT,
  31     XS_ERROR,
  32     XS_IS_DOMAIN_INTRODUCED,
  33     XS_RESUME,
  34     XS_SET_TARGET,
  35     /* XS_RESTRICT has been removed */
  36     XS_RESET_WATCHES = XS_SET_TARGET + 2,
  37     XS_DIRECTORY_PART,
  38
  39     XS_TYPE_COUNT,      /* Number of valid types. */
  40
  41     XS_INVALID = 0xffff /* Guaranteed to remain an invalid type */
  42 };
  43
  44 #define XS_WRITE_NONE "NONE"
  45 #define XS_WRITE_CREATE "CREATE"
  46 #define XS_WRITE_CREATE_EXCL "CREATE|EXCL"
  47
  48 /* We hand errors as strings, for portability. */
  49 struct xsd_errors
  50 {
  51     int errnum;
  52     const char *errstring;
  53 };
  54 #ifdef EINVAL
  55 #define XSD_ERROR(x) { x, #x }
  56 /* LINTED: static unused */
  57 static const struct xsd_errors xsd_errors[]
  58 #if defined(__GNUC__)
  59 __attribute__((unused))
  60 #endif
  61     = {
  62     /* /!\ New errors should be added at the end of the array. */
  63     XSD_ERROR(EINVAL),
  64     XSD_ERROR(EACCES),
  65     XSD_ERROR(EEXIST),
  66     XSD_ERROR(EISDIR),
  67     XSD_ERROR(ENOENT),
  68     XSD_ERROR(ENOMEM),
  69     XSD_ERROR(ENOSPC),
  70     XSD_ERROR(EIO),
  71     XSD_ERROR(ENOTEMPTY),
  72     XSD_ERROR(ENOSYS),
  73     XSD_ERROR(EROFS),
  74     XSD_ERROR(EBUSY),
  75     XSD_ERROR(EAGAIN),
  76     XSD_ERROR(EISCONN),
  77     XSD_ERROR(E2BIG),
  78     XSD_ERROR(EPERM),
  79 };
  80 #endif
  81
  82 struct xsd_sockmsg
  83 {
  84     uint32_t type;  /* XS_??? */
  85     uint32_t req_id;/* Request identifier, echoed in daemon's response.  */
  86     uint32_t tx_id; /* Transaction id (0 if not related to a transaction). */
  87     uint32_t len;   /* Length of data following this. */
  88
  89     /* Generally followed by nul-terminated string(s). */
  90 };
  91
  92 enum xs_watch_type
  93 {
  94     XS_WATCH_PATH = 0,
  95     XS_WATCH_TOKEN
  96 };
  97
  98 /*
  99  * `incontents 150 xenstore_struct XenStore wire protocol.
 100  *
 101  * Inter-domain shared memory communications. */
 102 #define XENSTORE_RING_SIZE 1024
 103 typedef uint32_t XENSTORE_RING_IDX;
 104 #define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
 105 struct xenstore_domain_interface {
 106     char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
 107     char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
 108     XENSTORE_RING_IDX req_cons, req_prod;
 109     XENSTORE_RING_IDX rsp_cons, rsp_prod;
 110     uint32_t server_features; /* Bitmap of features supported by the server */
 111     uint32_t connection;
 112     uint32_t error;
 113 };
 114
 115 /* Violating this is very bad.  See docs/misc/xenstore.txt. */
 116 #define XENSTORE_PAYLOAD_MAX 4096
 117
 118 /* Violating these just gets you an error back */
 119 #define XENSTORE_ABS_PATH_MAX 3072
 120 #define XENSTORE_REL_PATH_MAX 2048
 121
 122 /* The ability to reconnect a ring */
 123 #define XENSTORE_SERVER_FEATURE_RECONNECTION 1
 124 /* The presence of the "error" field in the ring page */
 125 #define XENSTORE_SERVER_FEATURE_ERROR        2
 126
 127 /* Valid values for the connection field */
 128 #define XENSTORE_CONNECTED 0 /* the steady-state */
 129 #define XENSTORE_RECONNECT 1 /* reconnect in progress */
 130
 131 /* Valid values for the error field */
 132 #define XENSTORE_ERROR_NONE    0 /* No error */
 133 #define XENSTORE_ERROR_COMM    1 /* Communication problem */
 134 #define XENSTORE_ERROR_RINGIDX 2 /* Invalid ring index */
 135 #define XENSTORE_ERROR_PROTO   3 /* Protocol violation (payload too long) */
 136
 137 #endif /* _XS_WIRE_H */
 138
 139 /*
 140  * Local variables:
 141  * mode: C
 142  * c-file-style: "BSD"
 143  * c-basic-offset: 4
 144  * tab-width: 4
 145  * indent-tabs-mode: nil
 146  * End:
 147  */