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                                         Error **errp);
  37
  38 /* Close a file
  39  *
  40  * Return negative error number on error, 0 or positive value on success.
  41  *
  42  * The meaning of return value on success depends on the specific back-end being
  43  * used.
  44  */
  45 typedef int (QEMUFileCloseFunc)(void *opaque, Error **errp);
  46
  47 /* Called to return the OS file descriptor associated to the QEMUFile.
  48  */
  49 typedef int (QEMUFileGetFD)(void *opaque);
  50
  51 /* Called to change the blocking mode of the file
  52  */
  53 typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled, Error **errp);
  54
  55 /*
  56  * This function writes an iovec to file. The handler must write all
  57  * of the data or return a negative errno value.
  58  */
  59 typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
  60                                            int iovcnt, int64_t pos,
  61                                            Error **errp);
  62
  63 /*
  64  * This function provides hooks around different
  65  * stages of RAM migration.
  66  * 'opaque' is the backend specific data in QEMUFile
  67  * 'data' is call specific data associated with the 'flags' value
  68  */
  69 typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
  70                               void *data);
  71
  72 /*
  73  * Constants used by ram_control_* hooks
  74  */
  75 #define RAM_CONTROL_SETUP     0
  76 #define RAM_CONTROL_ROUND     1
  77 #define RAM_CONTROL_HOOK      2
  78 #define RAM_CONTROL_FINISH    3
  79 #define RAM_CONTROL_BLOCK_REG 4
  80
  81 /*
  82  * This function allows override of where the RAM page
  83  * is saved (such as RDMA, for example.)
  84  */
  85 typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
  86                                ram_addr_t block_offset,
  87                                ram_addr_t offset,
  88                                size_t size,
  89                                uint64_t *bytes_sent);
  90
  91 /*
  92  * Return a QEMUFile for comms in the opposite direction
  93  */
  94 typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
  95
  96 /*
  97  * Stop any read or write (depending on flags) on the underlying
  98  * transport on the QEMUFile.
  99  * Existing blocking reads/writes must be woken
 100  * Returns 0 on success, -err on error
 101  */
 102 typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr,
 103                                    Error **errp);
 104
 105 typedef struct QEMUFileOps {
 106     QEMUFileGetBufferFunc *get_buffer;
 107     QEMUFileCloseFunc *close;
 108     QEMUFileSetBlocking *set_blocking;
 109     QEMUFileWritevBufferFunc *writev_buffer;
 110     QEMURetPathFunc *get_return_path;
 111     QEMUFileShutdownFunc *shut_down;
 112 } QEMUFileOps;
 113
 114 typedef struct QEMUFileHooks {
 115     QEMURamHookFunc *before_ram_iterate;
 116     QEMURamHookFunc *after_ram_iterate;
 117     QEMURamHookFunc *hook_ram_load;
 118     QEMURamSaveFunc *save_page;
 119 } QEMUFileHooks;
 120
 121 QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
 122 void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
 123 int qemu_get_fd(QEMUFile *f);
 124 int qemu_fclose(QEMUFile *f);
 125 int64_t qemu_ftell(QEMUFile *f);
 126 int64_t qemu_ftell_fast(QEMUFile *f);
 127 /*
 128  * put_buffer without copying the buffer.
 129  * The buffer should be available till it is sent asynchronously.
 130  */
 131 void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
 132                            bool may_free);
 133 bool qemu_file_mode_is_not_valid(const char *mode);
 134 bool qemu_file_is_writable(QEMUFile *f);
 135
 136 #include "migration/qemu-file-types.h"
 137
 138 size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset);
 139 size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size);
 140 ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
 141                                   const uint8_t *p, size_t size);
 142 int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src);
 143
 144 /*
 145  * Note that you can only peek continuous bytes from where the current pointer
 146  * is; you aren't guaranteed to be able to peak to +n bytes unless you've
 147  * previously peeked +n-1.
 148  */
 149 int qemu_peek_byte(QEMUFile *f, int offset);
 150 void qemu_file_skip(QEMUFile *f, int size);
 151 void qemu_update_position(QEMUFile *f, size_t size);
 152 void qemu_file_reset_rate_limit(QEMUFile *f);
 153 void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
 154 int64_t qemu_file_get_rate_limit(QEMUFile *f);
 155 int qemu_file_get_error_obj(QEMUFile *f, Error **errp);
 156 void qemu_file_set_error_obj(QEMUFile *f, int ret, Error *err);
 157 void qemu_file_set_error(QEMUFile *f, int ret);
 158 int qemu_file_shutdown(QEMUFile *f);
 159 QEMUFile *qemu_file_get_return_path(QEMUFile *f);
 160 void qemu_fflush(QEMUFile *f);
 161 void qemu_file_set_blocking(QEMUFile *f, bool block);
 162
 163 size_t qemu_get_counted_string(QEMUFile *f, char buf[256]);
 164
 165 void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
 166 void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
 167 void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
 168
 169 /* Whenever this is found in the data stream, the flags
 170  * will be passed to ram_control_load_hook in the incoming-migration
 171  * side. This lets before_ram_iterate/after_ram_iterate add
 172  * transport-specific sections to the RAM migration data.
 173  */
 174 #define RAM_SAVE_FLAG_HOOK     0x80
 175
 176 #define RAM_SAVE_CONTROL_NOT_SUPP -1000
 177 #define RAM_SAVE_CONTROL_DELAYED  -2000
 178
 179 size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
 180                              ram_addr_t offset, size_t size,
 181                              uint64_t *bytes_sent);
 182
 183 void qemu_put_counted_string(QEMUFile *f, const char *name);
 184
 185 #endif