nbd/nbd-internal.h

   1 /*
   2  * NBD Internal Declarations
   3  *
   4  * Copyright (C) 2016 Red Hat, Inc.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #ifndef NBD_INTERNAL_H
  11 #define NBD_INTERNAL_H
  12 #include "block/nbd.h"
  13 #include "sysemu/block-backend.h"
  14
  15 #include "qemu/coroutine.h"
  16
  17 #include <errno.h>
  18 #include <string.h>
  19 #ifndef _WIN32
  20 #include <sys/ioctl.h>
  21 #endif
  22 #if defined(__sun__) || defined(__HAIKU__)
  23 #include <sys/ioccom.h>
  24 #endif
  25 #include <ctype.h>
  26 #include <inttypes.h>
  27
  28 #ifdef __linux__
  29 #include <linux/fs.h>
  30 #endif
  31
  32 #include "qemu/sockets.h"
  33 #include "qemu/queue.h"
  34 #include "qemu/main-loop.h"
  35
  36 /* #define DEBUG_NBD */
  37
  38 #ifdef DEBUG_NBD
  39 #define TRACE(msg, ...) do { \
  40     LOG(msg, ## __VA_ARGS__); \
  41 } while(0)
  42 #else
  43 #define TRACE(msg, ...) \
  44     do { } while (0)
  45 #endif
  46
  47 #define LOG(msg, ...) do { \
  48     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
  49             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
  50 } while(0)
  51
  52 /* This is all part of the "official" NBD API.
  53  *
  54  * The most up-to-date documentation is available at:
  55  * https://github.com/yoe/nbd/blob/master/doc/proto.txt
  56  */
  57
  58 #define NBD_REQUEST_SIZE        (4 + 4 + 8 + 8 + 4)
  59 #define NBD_REPLY_SIZE          (4 + 4 + 8)
  60 #define NBD_REQUEST_MAGIC       0x25609513
  61 #define NBD_REPLY_MAGIC         0x67446698
  62 #define NBD_OPTS_MAGIC          0x49484156454F5054LL
  63 #define NBD_CLIENT_MAGIC        0x0000420281861253LL
  64 #define NBD_REP_MAGIC           0x3e889045565a9LL
  65
  66 #define NBD_SET_SOCK            _IO(0xab, 0)
  67 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  68 #define NBD_SET_SIZE            _IO(0xab, 2)
  69 #define NBD_DO_IT               _IO(0xab, 3)
  70 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  71 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  72 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  73 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  74 #define NBD_DISCONNECT          _IO(0xab, 8)
  75 #define NBD_SET_TIMEOUT         _IO(0xab, 9)
  76 #define NBD_SET_FLAGS           _IO(0xab, 10)
  77
  78 #define NBD_OPT_EXPORT_NAME     (1)
  79 #define NBD_OPT_ABORT           (2)
  80 #define NBD_OPT_LIST            (3)
  81
  82 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
  83  * but only a limited set of errno values is specified in the protocol.
  84  * Everything else is squashed to EINVAL.
  85  */
  86 #define NBD_SUCCESS    0
  87 #define NBD_EPERM      1
  88 #define NBD_EIO        5
  89 #define NBD_ENOMEM     12
  90 #define NBD_EINVAL     22
  91 #define NBD_ENOSPC     28
  92
  93 static inline ssize_t read_sync(int fd, void *buffer, size_t size)
  94 {
  95     /* Sockets are kept in blocking mode in the negotiation phase.  After
  96      * that, a non-readable socket simply means that another thread stole
  97      * our request/reply.  Synchronization is done with recv_coroutine, so
  98      * that this is coroutine-safe.
  99      */
 100     return nbd_wr_sync(fd, buffer, size, true);
 101 }
 102
 103 static inline ssize_t write_sync(int fd, void *buffer, size_t size)
 104 {
 105     int ret;
 106     do {
 107         /* For writes, we do expect the socket to be writable.  */
 108         ret = nbd_wr_sync(fd, buffer, size, false);
 109     } while (ret == -EAGAIN);
 110     return ret;
 111 }
 112
 113 #endif