qemu/include/migration/qemu-file.h
Dr. David Alan Gilbert 548f52ea06 Make qemu_peek_buffer loop until it gets it's data
Make qemu_peek_buffer repeatedly call fill_buffer until it gets
all the data it requires, or until there is an error.

  At the moment, qemu_peek_buffer will try one qemu_fill_buffer if there
  isn't enough data waiting, however the kernel is entitled to return
  just a few bytes, and still leave qemu_peek_buffer with less bytes
  than it needed.  I've seen this fail in a dev world, and I think it
  could theoretically fail in the peeking of the subsection headers in
  the current world.

Comment qemu_peek_byte to point out it's not guaranteed to work for
  non-continuous peeks

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: ChenLiang <chenliang0016@icloud.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2014-05-05 22:15:03 +02:00

276 lines
7.9 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef QEMU_FILE_H
#define QEMU_FILE_H 1
#include "exec/cpu-common.h"
/* This function writes a chunk of data to a file at the given position.
* The pos argument can be ignored if the file is only being used for
* streaming. The handler should try to write all of the data it can.
*/
typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
int64_t pos, int size);
/* Read a chunk of data from a file at the given position. The pos argument
* can be ignored if the file is only be used for streaming. The number of
* bytes actually read should be returned.
*/
typedef int (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
int64_t pos, int size);
/* Close a file
*
* Return negative error number on error, 0 or positive value on success.
*
* The meaning of return value on success depends on the specific back-end being
* used.
*/
typedef int (QEMUFileCloseFunc)(void *opaque);
/* Called to return the OS file descriptor associated to the QEMUFile.
*/
typedef int (QEMUFileGetFD)(void *opaque);
/*
* This function writes an iovec to file.
*/
typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
int iovcnt, int64_t pos);
/*
* This function provides hooks around different
* stages of RAM migration.
*/
typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags);
/*
* Constants used by ram_control_* hooks
*/
#define RAM_CONTROL_SETUP 0
#define RAM_CONTROL_ROUND 1
#define RAM_CONTROL_HOOK 2
#define RAM_CONTROL_FINISH 3
/*
* This function allows override of where the RAM page
* is saved (such as RDMA, for example.)
*/
typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
ram_addr_t block_offset,
ram_addr_t offset,
size_t size,
int *bytes_sent);
typedef struct QEMUFileOps {
QEMUFilePutBufferFunc *put_buffer;
QEMUFileGetBufferFunc *get_buffer;
QEMUFileCloseFunc *close;
QEMUFileGetFD *get_fd;
QEMUFileWritevBufferFunc *writev_buffer;
QEMURamHookFunc *before_ram_iterate;
QEMURamHookFunc *after_ram_iterate;
QEMURamHookFunc *hook_ram_load;
QEMURamSaveFunc *save_page;
} QEMUFileOps;
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
QEMUFile *qemu_fopen(const char *filename, const char *mode);
QEMUFile *qemu_fdopen(int fd, const char *mode);
QEMUFile *qemu_fopen_socket(int fd, const char *mode);
QEMUFile *qemu_popen_cmd(const char *command, const char *mode);
int qemu_get_fd(QEMUFile *f);
int qemu_fclose(QEMUFile *f);
int64_t qemu_ftell(QEMUFile *f);
void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size);
void qemu_put_byte(QEMUFile *f, int v);
/*
* put_buffer without copying the buffer.
* The buffer should be available till it is sent asynchronously.
*/
void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size);
bool qemu_file_mode_is_not_valid(const char *mode);
static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
{
qemu_put_byte(f, (int)v);
}
#define qemu_put_sbyte qemu_put_byte
void qemu_put_be16(QEMUFile *f, unsigned int v);
void qemu_put_be32(QEMUFile *f, unsigned int v);
void qemu_put_be64(QEMUFile *f, uint64_t v);
int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset);
int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size);
/*
* Note that you can only peek continuous bytes from where the current pointer
* is; you aren't guaranteed to be able to peak to +n bytes unless you've
* previously peeked +n-1.
*/
int qemu_peek_byte(QEMUFile *f, int offset);
int qemu_get_byte(QEMUFile *f);
void qemu_file_skip(QEMUFile *f, int size);
void qemu_update_position(QEMUFile *f, size_t size);
static inline unsigned int qemu_get_ubyte(QEMUFile *f)
{
return (unsigned int)qemu_get_byte(f);
}
#define qemu_get_sbyte qemu_get_byte
unsigned int qemu_get_be16(QEMUFile *f);
unsigned int qemu_get_be32(QEMUFile *f);
uint64_t qemu_get_be64(QEMUFile *f);
int qemu_file_rate_limit(QEMUFile *f);
void qemu_file_reset_rate_limit(QEMUFile *f);
void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
int64_t qemu_file_get_rate_limit(QEMUFile *f);
int qemu_file_get_error(QEMUFile *f);
void qemu_file_set_error(QEMUFile *f, int ret);
void qemu_fflush(QEMUFile *f);
static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)
{
qemu_put_be64(f, *pv);
}
static inline void qemu_put_be32s(QEMUFile *f, const uint32_t *pv)
{
qemu_put_be32(f, *pv);
}
static inline void qemu_put_be16s(QEMUFile *f, const uint16_t *pv)
{
qemu_put_be16(f, *pv);
}
static inline void qemu_put_8s(QEMUFile *f, const uint8_t *pv)
{
qemu_put_byte(f, *pv);
}
static inline void qemu_get_be64s(QEMUFile *f, uint64_t *pv)
{
*pv = qemu_get_be64(f);
}
static inline void qemu_get_be32s(QEMUFile *f, uint32_t *pv)
{
*pv = qemu_get_be32(f);
}
static inline void qemu_get_be16s(QEMUFile *f, uint16_t *pv)
{
*pv = qemu_get_be16(f);
}
static inline void qemu_get_8s(QEMUFile *f, uint8_t *pv)
{
*pv = qemu_get_byte(f);
}
// Signed versions for type safety
static inline void qemu_put_sbuffer(QEMUFile *f, const int8_t *buf, int size)
{
qemu_put_buffer(f, (const uint8_t *)buf, size);
}
static inline void qemu_put_sbe16(QEMUFile *f, int v)
{
qemu_put_be16(f, (unsigned int)v);
}
static inline void qemu_put_sbe32(QEMUFile *f, int v)
{
qemu_put_be32(f, (unsigned int)v);
}
static inline void qemu_put_sbe64(QEMUFile *f, int64_t v)
{
qemu_put_be64(f, (uint64_t)v);
}
static inline size_t qemu_get_sbuffer(QEMUFile *f, int8_t *buf, int size)
{
return qemu_get_buffer(f, (uint8_t *)buf, size);
}
static inline int qemu_get_sbe16(QEMUFile *f)
{
return (int)qemu_get_be16(f);
}
static inline int qemu_get_sbe32(QEMUFile *f)
{
return (int)qemu_get_be32(f);
}
static inline int64_t qemu_get_sbe64(QEMUFile *f)
{
return (int64_t)qemu_get_be64(f);
}
static inline void qemu_put_s8s(QEMUFile *f, const int8_t *pv)
{
qemu_put_8s(f, (const uint8_t *)pv);
}
static inline void qemu_put_sbe16s(QEMUFile *f, const int16_t *pv)
{
qemu_put_be16s(f, (const uint16_t *)pv);
}
static inline void qemu_put_sbe32s(QEMUFile *f, const int32_t *pv)
{
qemu_put_be32s(f, (const uint32_t *)pv);
}
static inline void qemu_put_sbe64s(QEMUFile *f, const int64_t *pv)
{
qemu_put_be64s(f, (const uint64_t *)pv);
}
static inline void qemu_get_s8s(QEMUFile *f, int8_t *pv)
{
qemu_get_8s(f, (uint8_t *)pv);
}
static inline void qemu_get_sbe16s(QEMUFile *f, int16_t *pv)
{
qemu_get_be16s(f, (uint16_t *)pv);
}
static inline void qemu_get_sbe32s(QEMUFile *f, int32_t *pv)
{
qemu_get_be32s(f, (uint32_t *)pv);
}
static inline void qemu_get_sbe64s(QEMUFile *f, int64_t *pv)
{
qemu_get_be64s(f, (uint64_t *)pv);
}
#endif