migration/qemu-file.h

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #ifndef MIGRATION_QEMU_FILE_H
  26 #define MIGRATION_QEMU_FILE_H
  27
  28 /* Read a chunk of data from a file at the given position.  The pos argument
  29  * can be ignored if the file is only be used for streaming.  The number of
  30  * bytes actually read should be returned.
  31  */
  32 typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
  33                                         int64_t pos, size_t size);
  34
  35 /* Close a file
  36  *
  37  * Return negative error number on error, 0 or positive value on success.
  38  *
  39  * The meaning of return value on success depends on the specific back-end being
  40  * used.
  41  */
  42 typedef int (QEMUFileCloseFunc)(void *opaque);
  43
  44 /* Called to return the OS file descriptor associated to the QEMUFile.
  45  */
  46 typedef int (QEMUFileGetFD)(void *opaque);
  47
  48 /* Called to change the blocking mode of the file
  49  */
  50 typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled);
  51
  52 /*
  53  * This function writes an iovec to file. The handler must write all
  54  * of the data or return a negative errno value.
  55  */
  56 typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
  57                                            int iovcnt, int64_t pos);
  58
  59 /*
  60  * This function provides hooks around different
  61  * stages of RAM migration.
  62  * 'opaque' is the backend specific data in QEMUFile
  63  * 'data' is call specific data associated with the 'flags' value
  64  */
  65 typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
  66                               void *data);
  67
  68 /*
  69  * Constants used by ram_control_* hooks
  70  */
  71 #define RAM_CONTROL_SETUP     0
  72 #define RAM_CONTROL_ROUND     1
  73 #define RAM_CONTROL_HOOK      2
  74 #define RAM_CONTROL_FINISH    3
  75 #define RAM_CONTROL_BLOCK_REG 4
  76
  77 /*
  78  * This function allows override of where the RAM page
  79  * is saved (such as RDMA, for example.)
  80  */
  81 typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
  82                                ram_addr_t block_offset,
  83                                ram_addr_t offset,
  84                                size_t size,
  85                                uint64_t *bytes_sent);
  86
  87 /*
  88  * Return a QEMUFile for comms in the opposite direction
  89  */
  90 typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
  91
  92 /*
  93  * Stop any read or write (depending on flags) on the underlying
  94  * transport on the QEMUFile.
  95  * Existing blocking reads/writes must be woken
  96  * Returns 0 on success, -err on error
  97  */
  98 typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr);
  99
 100 typedef struct QEMUFileOps {
 101     QEMUFileGetBufferFunc *get_buffer;
 102     QEMUFileCloseFunc *close;
 103     QEMUFileSetBlocking *set_blocking;
 104     QEMUFileWritevBufferFunc *writev_buffer;
 105     QEMURetPathFunc *get_return_path;
 106     QEMUFileShutdownFunc *shut_down;
 107 } QEMUFileOps;
 108
 109 typedef struct QEMUFileHooks {
 110     QEMURamHookFunc *before_ram_iterate;
 111     QEMURamHookFunc *after_ram_iterate;
 112     QEMURamHookFunc *hook_ram_load;
 113     QEMURamSaveFunc *save_page;
 114 } QEMUFileHooks;
 115
 116 QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
 117 void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
 118 int qemu_get_fd(QEMUFile *f);
 119 int qemu_fclose(QEMUFile *f);
 120 int64_t qemu_ftell(QEMUFile *f);
 121 int64_t qemu_ftell_fast(QEMUFile *f);
 122 /*
 123  * put_buffer without copying the buffer.
 124  * The buffer should be available till it is sent asynchronously.
 125  */
 126 void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
 127                            bool may_free);
 128 bool qemu_file_mode_is_not_valid(const char *mode);
 129 bool qemu_file_is_writable(QEMUFile *f);
 130
 131 #include "migration/qemu-file-types.h"
 132
 133 size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset);
 134 size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size);
 135 ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
 136                                   int level);
 137 int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src);
 138
 139 /*
 140  * Note that you can only peek continuous bytes from where the current pointer
 141  * is; you aren't guaranteed to be able to peak to +n bytes unless you've
 142  * previously peeked +n-1.
 143  */
 144 int qemu_peek_byte(QEMUFile *f, int offset);
 145 void qemu_file_skip(QEMUFile *f, int size);
 146 void qemu_update_position(QEMUFile *f, size_t size);
 147 void qemu_file_reset_rate_limit(QEMUFile *f);
 148 void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
 149 int64_t qemu_file_get_rate_limit(QEMUFile *f);
 150 int qemu_file_get_error(QEMUFile *f);
 151 void qemu_file_set_error(QEMUFile *f, int ret);
 152 int qemu_file_shutdown(QEMUFile *f);
 153 QEMUFile *qemu_file_get_return_path(QEMUFile *f);
 154 void qemu_fflush(QEMUFile *f);
 155 void qemu_file_set_blocking(QEMUFile *f, bool block);
 156
 157 size_t qemu_get_counted_string(QEMUFile *f, char buf[256]);
 158
 159 void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
 160 void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
 161 void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
 162
 163 /* Whenever this is found in the data stream, the flags
 164  * will be passed to ram_control_load_hook in the incoming-migration
 165  * side. This lets before_ram_iterate/after_ram_iterate add
 166  * transport-specific sections to the RAM migration data.
 167  */
 168 #define RAM_SAVE_FLAG_HOOK     0x80
 169
 170 #define RAM_SAVE_CONTROL_NOT_SUPP -1000
 171 #define RAM_SAVE_CONTROL_DELAYED  -2000
 172
 173 size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
 174                              ram_addr_t offset, size_t size,
 175                              uint64_t *bytes_sent);
 176
 177 #endif