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 #include <zlib.h>
  29
  30 /* Read a chunk of data from a file at the given position.  The pos argument
  31  * can be ignored if the file is only be used for streaming.  The number of
  32  * bytes actually read should be returned.
  33  */
  34 typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
  35                                         int64_t pos, size_t size);
  36
  37 /* Close a file
  38  *
  39  * Return negative error number on error, 0 or positive value on success.
  40  *
  41  * The meaning of return value on success depends on the specific back-end being
  42  * used.
  43  */
  44 typedef int (QEMUFileCloseFunc)(void *opaque);
  45
  46 /* Called to return the OS file descriptor associated to the QEMUFile.
  47  */
  48 typedef int (QEMUFileGetFD)(void *opaque);
  49
  50 /* Called to change the blocking mode of the file
  51  */
  52 typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled);
  53
  54 /*
  55  * This function writes an iovec to file. The handler must write all
  56  * of the data or return a negative errno value.
  57  */
  58 typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
  59                                            int iovcnt, int64_t pos);
  60
  61 /*
  62  * This function provides hooks around different
  63  * stages of RAM migration.
  64  * 'opaque' is the backend specific data in QEMUFile
  65  * 'data' is call specific data associated with the 'flags' value
  66  */
  67 typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
  68                               void *data);
  69
  70 /*
  71  * Constants used by ram_control_* hooks
  72  */
  73 #define RAM_CONTROL_SETUP     0
  74 #define RAM_CONTROL_ROUND     1
  75 #define RAM_CONTROL_HOOK      2
  76 #define RAM_CONTROL_FINISH    3
  77 #define RAM_CONTROL_BLOCK_REG 4
  78
  79 /*
  80  * This function allows override of where the RAM page
  81  * is saved (such as RDMA, for example.)
  82  */
  83 typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
  84                                ram_addr_t block_offset,
  85                                ram_addr_t offset,
  86                                size_t size,
  87                                uint64_t *bytes_sent);
  88
  89 /*
  90  * Return a QEMUFile for comms in the opposite direction
  91  */
  92 typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
  93
  94 /*
  95  * Stop any read or write (depending on flags) on the underlying
  96  * transport on the QEMUFile.
  97  * Existing blocking reads/writes must be woken
  98  * Returns 0 on success, -err on error
  99  */
 100 typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr);
 101
 102 typedef struct QEMUFileOps {
 103     QEMUFileGetBufferFunc *get_buffer;
 104     QEMUFileCloseFunc *close;
 105     QEMUFileSetBlocking *set_blocking;
 106     QEMUFileWritevBufferFunc *writev_buffer;
 107     QEMURetPathFunc *get_return_path;
 108     QEMUFileShutdownFunc *shut_down;
 109 } QEMUFileOps;
 110
 111 typedef struct QEMUFileHooks {
 112     QEMURamHookFunc *before_ram_iterate;
 113     QEMURamHookFunc *after_ram_iterate;
 114     QEMURamHookFunc *hook_ram_load;
 115     QEMURamSaveFunc *save_page;
 116 } QEMUFileHooks;
 117
 118 QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
 119 void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
 120 int qemu_get_fd(QEMUFile *f);
 121 int qemu_fclose(QEMUFile *f);
 122 int64_t qemu_ftell(QEMUFile *f);
 123 int64_t qemu_ftell_fast(QEMUFile *f);
 124 /*
 125  * put_buffer without copying the buffer.
 126  * The buffer should be available till it is sent asynchronously.
 127  */
 128 void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
 129                            bool may_free);
 130 bool qemu_file_mode_is_not_valid(const char *mode);
 131 bool qemu_file_is_writable(QEMUFile *f);
 132
 133 #include "migration/qemu-file-types.h"
 134
 135 size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset);
 136 size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size);
 137 ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
 138                                   const uint8_t *p, size_t size);
 139 int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src);
 140
 141 /*
 142  * Note that you can only peek continuous bytes from where the current pointer
 143  * is; you aren't guaranteed to be able to peak to +n bytes unless you've
 144  * previously peeked +n-1.
 145  */
 146 int qemu_peek_byte(QEMUFile *f, int offset);
 147 void qemu_file_skip(QEMUFile *f, int size);
 148 void qemu_update_position(QEMUFile *f, size_t size);
 149 void qemu_file_reset_rate_limit(QEMUFile *f);
 150 void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
 151 int64_t qemu_file_get_rate_limit(QEMUFile *f);
 152 int qemu_file_get_error(QEMUFile *f);
 153 void qemu_file_set_error(QEMUFile *f, int ret);
 154 int qemu_file_shutdown(QEMUFile *f);
 155 QEMUFile *qemu_file_get_return_path(QEMUFile *f);
 156 void qemu_fflush(QEMUFile *f);
 157 void qemu_file_set_blocking(QEMUFile *f, bool block);
 158
 159 size_t qemu_get_counted_string(QEMUFile *f, char buf[256]);
 160
 161 void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
 162 void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
 163 void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
 164
 165 /* Whenever this is found in the data stream, the flags
 166  * will be passed to ram_control_load_hook in the incoming-migration
 167  * side. This lets before_ram_iterate/after_ram_iterate add
 168  * transport-specific sections to the RAM migration data.
 169  */
 170 #define RAM_SAVE_FLAG_HOOK     0x80
 171
 172 #define RAM_SAVE_CONTROL_NOT_SUPP -1000
 173 #define RAM_SAVE_CONTROL_DELAYED  -2000
 174
 175 size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
 176                              ram_addr_t offset, size_t size,
 177                              uint64_t *bytes_sent);
 178
 179 void qemu_put_counted_string(QEMUFile *f, const char *name);
 180
 181 #endif