OpenE2K/qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity
cc37d98bfb
qemu-e2k/migration/vmstate.c
Dr. David Alan Gilbert 89c5684891 migration: Add canary to VMSTATE_END_OF_LIST 
We fairly regularly forget VMSTATE_END_OF_LIST markers off descriptions;
given that the current check is only for ->name being NULL, sometimes
we get unlucky and the code apparently works and no one spots the error.

Explicitly add a flag, VMS_END that should be set, and assert it is
set during the traversal.

Note: This can't go in until we update the copy of vmstate.h in slirp.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06 19:22:56 +01:00

539 lines
17 KiB
C
Raw Blame History

/*
* VMState interpreter
*
* Copyright (c) 2009-2017 Red Hat Inc
*
* Authors:
* Juan Quintela <quintela@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "migration.h"
#include "migration/vmstate.h"
#include "savevm.h"
#include "qapi/qmp/json-writer.h"
#include "qemu-file.h"
#include "qemu/bitops.h"
#include "qemu/error-report.h"
#include "trace.h"
static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, JSONWriter *vmdesc);
static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque);
static int vmstate_n_elems(void *opaque, const VMStateField *field)
{
int n_elems = 1;
if (field->flags & VMS_ARRAY) {
n_elems = field->num;
} else if (field->flags & VMS_VARRAY_INT32) {
n_elems = *(int32_t *)(opaque + field->num_offset);
} else if (field->flags & VMS_VARRAY_UINT32) {
n_elems = *(uint32_t *)(opaque + field->num_offset);
} else if (field->flags & VMS_VARRAY_UINT16) {
n_elems = *(uint16_t *)(opaque + field->num_offset);
} else if (field->flags & VMS_VARRAY_UINT8) {
n_elems = *(uint8_t *)(opaque + field->num_offset);
}
if (field->flags & VMS_MULTIPLY_ELEMENTS) {
n_elems *= field->num;
}
trace_vmstate_n_elems(field->name, n_elems);
return n_elems;
}
static int vmstate_size(void *opaque, const VMStateField *field)
{
int size = field->size;
if (field->flags & VMS_VBUFFER) {
size = *(int32_t *)(opaque + field->size_offset);
if (field->flags & VMS_MULTIPLY) {
size *= field->size;
}
}
return size;
}
static void vmstate_handle_alloc(void *ptr, const VMStateField *field,
void *opaque)
{
if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) {
gsize size = vmstate_size(opaque, field);
size *= vmstate_n_elems(opaque, field);
if (size) {
*(void **)ptr = g_malloc(size);
}
}
}
int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, int version_id)
{
const VMStateField *field = vmsd->fields;
int ret = 0;
trace_vmstate_load_state(vmsd->name, version_id);
if (version_id > vmsd->version_id) {
error_report("%s: incoming version_id %d is too new "
"for local version_id %d",
vmsd->name, version_id, vmsd->version_id);
trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL);
return -EINVAL;
}
if (version_id < vmsd->minimum_version_id) {
error_report("%s: incoming version_id %d is too old "
"for local minimum version_id %d",
vmsd->name, version_id, vmsd->minimum_version_id);
trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL);
return -EINVAL;
}
if (vmsd->pre_load) {
int ret = vmsd->pre_load(opaque);
if (ret) {
return ret;
}
}
while (field->name) {
trace_vmstate_load_state_field(vmsd->name, field->name);
if ((field->field_exists &&
field->field_exists(opaque, version_id)) ||
(!field->field_exists &&
field->version_id <= version_id)) {
void *first_elem = opaque + field->offset;
int i, n_elems = vmstate_n_elems(opaque, field);
int size = vmstate_size(opaque, field);
vmstate_handle_alloc(first_elem, field, opaque);
if (field->flags & VMS_POINTER) {
first_elem = *(void **)first_elem;
assert(first_elem || !n_elems || !size);
}
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
if (field->flags & VMS_ARRAY_OF_POINTER) {
curr_elem = *(void **)curr_elem;
}
if (!curr_elem && size) {
/* if null pointer check placeholder and do not follow */
assert(field->flags & VMS_ARRAY_OF_POINTER);
ret = vmstate_info_nullptr.get(f, curr_elem, size, NULL);
} else if (field->flags & VMS_STRUCT) {
ret = vmstate_load_state(f, field->vmsd, curr_elem,
field->vmsd->version_id);
} else if (field->flags & VMS_VSTRUCT) {
ret = vmstate_load_state(f, field->vmsd, curr_elem,
field->struct_version_id);
} else {
ret = field->info->get(f, curr_elem, size, field);
}
if (ret >= 0) {
ret = qemu_file_get_error(f);
}
if (ret < 0) {
qemu_file_set_error(f, ret);
error_report("Failed to load %s:%s", vmsd->name,
field->name);
trace_vmstate_load_field_error(field->name, ret);
return ret;
}
}
} else if (field->flags & VMS_MUST_EXIST) {
error_report("Input validation failed: %s/%s",
vmsd->name, field->name);
return -1;
}
field++;
}
assert(field->flags == VMS_END);
ret = vmstate_subsection_load(f, vmsd, opaque);
if (ret != 0) {
return ret;
}
if (vmsd->post_load) {
ret = vmsd->post_load(opaque, version_id);
}
trace_vmstate_load_state_end(vmsd->name, "end", ret);
return ret;
}
static int vmfield_name_num(const VMStateField *start,
const VMStateField *search)
{
const VMStateField *field;
int found = 0;
for (field = start; field->name; field++) {
if (!strcmp(field->name, search->name)) {
if (field == search) {
return found;
}
found++;
}
}
return -1;
}
static bool vmfield_name_is_unique(const VMStateField *start,
const VMStateField *search)
{
const VMStateField *field;
int found = 0;
for (field = start; field->name; field++) {
if (!strcmp(field->name, search->name)) {
found++;
/* name found more than once, so it's not unique */
if (found > 1) {
return false;
}
}
}
return true;
}
static const char *vmfield_get_type_name(const VMStateField *field)
{
const char *type = "unknown";
if (field->flags & VMS_STRUCT) {
type = "struct";
} else if (field->flags & VMS_VSTRUCT) {
type = "vstruct";
} else if (field->info->name) {
type = field->info->name;
}
return type;
}
static bool vmsd_can_compress(const VMStateField *field)
{
if (field->field_exists) {
/* Dynamically existing fields mess up compression */
return false;
}
if (field->flags & VMS_STRUCT) {
const VMStateField *sfield = field->vmsd->fields;
while (sfield->name) {
if (!vmsd_can_compress(sfield)) {
/* Child elements can't compress, so can't we */
return false;
}
sfield++;
}
if (field->vmsd->subsections) {
/* Subsections may come and go, better don't compress */
return false;
}
}
return true;
}
static void vmsd_desc_field_start(const VMStateDescription *vmsd,
JSONWriter *vmdesc,
const VMStateField *field, int i, int max)
{
char *name, *old_name;
bool is_array = max > 1;
bool can_compress = vmsd_can_compress(field);
if (!vmdesc) {
return;
}
name = g_strdup(field->name);
/* Field name is not unique, need to make it unique */
if (!vmfield_name_is_unique(vmsd->fields, field)) {
int num = vmfield_name_num(vmsd->fields, field);
old_name = name;
name = g_strdup_printf("%s[%d]", name, num);
g_free(old_name);
}
json_writer_start_object(vmdesc, NULL);
json_writer_str(vmdesc, "name", name);
if (is_array) {
if (can_compress) {
json_writer_int64(vmdesc, "array_len", max);
} else {
json_writer_int64(vmdesc, "index", i);
}
}
json_writer_str(vmdesc, "type", vmfield_get_type_name(field));
if (field->flags & VMS_STRUCT) {
json_writer_start_object(vmdesc, "struct");
}
g_free(name);
}
static void vmsd_desc_field_end(const VMStateDescription *vmsd,
JSONWriter *vmdesc,
const VMStateField *field, size_t size, int i)
{
if (!vmdesc) {
return;
}
if (field->flags & VMS_STRUCT) {
/* We printed a struct in between, close its child object */
json_writer_end_object(vmdesc);
}
json_writer_int64(vmdesc, "size", size);
json_writer_end_object(vmdesc);
}
bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque)
{
if (vmsd->needed && !vmsd->needed(opaque)) {
/* optional section not needed */
return false;
}
return true;
}
int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, JSONWriter *vmdesc_id)
{
return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id);
}
int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, JSONWriter *vmdesc, int version_id)
{
int ret = 0;
const VMStateField *field = vmsd->fields;
trace_vmstate_save_state_top(vmsd->name);
if (vmsd->pre_save) {
ret = vmsd->pre_save(opaque);
trace_vmstate_save_state_pre_save_res(vmsd->name, ret);
if (ret) {
error_report("pre-save failed: %s", vmsd->name);
return ret;
}
}
if (vmdesc) {
json_writer_str(vmdesc, "vmsd_name", vmsd->name);
json_writer_int64(vmdesc, "version", version_id);
json_writer_start_array(vmdesc, "fields");
}
while (field->name) {
if ((field->field_exists &&
field->field_exists(opaque, version_id)) ||
(!field->field_exists &&
field->version_id <= version_id)) {
void *first_elem = opaque + field->offset;
int i, n_elems = vmstate_n_elems(opaque, field);
int size = vmstate_size(opaque, field);
int64_t old_offset, written_bytes;
JSONWriter *vmdesc_loop = vmdesc;
trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems);
if (field->flags & VMS_POINTER) {
first_elem = *(void **)first_elem;
assert(first_elem || !n_elems || !size);
}
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems);
old_offset = qemu_file_total_transferred_fast(f);
if (field->flags & VMS_ARRAY_OF_POINTER) {
assert(curr_elem);
curr_elem = *(void **)curr_elem;
}
if (!curr_elem && size) {
/* if null pointer write placeholder and do not follow */
assert(field->flags & VMS_ARRAY_OF_POINTER);
ret = vmstate_info_nullptr.put(f, curr_elem, size, NULL,
NULL);
} else if (field->flags & VMS_STRUCT) {
ret = vmstate_save_state(f, field->vmsd, curr_elem,
vmdesc_loop);
} else if (field->flags & VMS_VSTRUCT) {
ret = vmstate_save_state_v(f, field->vmsd, curr_elem,
vmdesc_loop,
field->struct_version_id);
} else {
ret = field->info->put(f, curr_elem, size, field,
vmdesc_loop);
}
if (ret) {
error_report("Save of field %s/%s failed",
vmsd->name, field->name);
if (vmsd->post_save) {
vmsd->post_save(opaque);
}
return ret;
}
written_bytes = qemu_file_total_transferred_fast(f) -
old_offset;
vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i);
/* Compressed arrays only care about the first element */
if (vmdesc_loop && vmsd_can_compress(field)) {
vmdesc_loop = NULL;
}
}
} else {
if (field->flags & VMS_MUST_EXIST) {
error_report("Output state validation failed: %s/%s",
vmsd->name, field->name);
assert(!(field->flags & VMS_MUST_EXIST));
}
}
field++;
}
assert(field->flags == VMS_END);
if (vmdesc) {
json_writer_end_array(vmdesc);
}
ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc);
if (vmsd->post_save) {
int ps_ret = vmsd->post_save(opaque);
if (!ret) {
ret = ps_ret;
}
}
return ret;
}
static const VMStateDescription *
vmstate_get_subsection(const VMStateDescription **sub, char *idstr)
{
while (sub && *sub) {
if (strcmp(idstr, (*sub)->name) == 0) {
return *sub;
}
sub++;
}
return NULL;
}
static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque)
{
trace_vmstate_subsection_load(vmsd->name);
while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) {
char idstr[256], *idstr_ret;
int ret;
uint8_t version_id, len, size;
const VMStateDescription *sub_vmsd;
len = qemu_peek_byte(f, 1);
if (len < strlen(vmsd->name) + 1) {
/* subsection name has be be "section_name/a" */
trace_vmstate_subsection_load_bad(vmsd->name, "(short)", "");
return 0;
}
size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2);
if (size != len) {
trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", "");
return 0;
}
memcpy(idstr, idstr_ret, size);
idstr[size] = 0;
if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) {
trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)");
/* it doesn't have a valid subsection name */
return 0;
}
sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr);
if (sub_vmsd == NULL) {
trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)");
return -ENOENT;
}
qemu_file_skip(f, 1); /* subsection */
qemu_file_skip(f, 1); /* len */
qemu_file_skip(f, len); /* idstr */
version_id = qemu_get_be32(f);
ret = vmstate_load_state(f, sub_vmsd, opaque, version_id);
if (ret) {
trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)");
return ret;
}
}
trace_vmstate_subsection_load_good(vmsd->name);
return 0;
}
static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, JSONWriter *vmdesc)
{
const VMStateDescription **sub = vmsd->subsections;
bool vmdesc_has_subsections = false;
int ret = 0;
trace_vmstate_subsection_save_top(vmsd->name);
while (sub && *sub) {
if (vmstate_save_needed(*sub, opaque)) {
const VMStateDescription *vmsdsub = *sub;
uint8_t len;
trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name);
if (vmdesc) {
/* Only create subsection array when we have any */
if (!vmdesc_has_subsections) {
json_writer_start_array(vmdesc, "subsections");
vmdesc_has_subsections = true;
}
json_writer_start_object(vmdesc, NULL);
}
qemu_put_byte(f, QEMU_VM_SUBSECTION);
len = strlen(vmsdsub->name);
qemu_put_byte(f, len);
qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len);
qemu_put_be32(f, vmsdsub->version_id);
ret = vmstate_save_state(f, vmsdsub, opaque, vmdesc);
if (ret) {
return ret;
}
if (vmdesc) {
json_writer_end_object(vmdesc);
}
}
sub++;
}
if (vmdesc_has_subsections) {
json_writer_end_array(vmdesc);
}
return ret;
}
Reference in New Issue View Git Blame Copy Permalink