/* * 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) { if (vmsd->load_state_old && version_id >= vmsd->minimum_version_id_old) { ret = vmsd->load_state_old(f, opaque, version_id); trace_vmstate_load_state_end(vmsd->name, "old path", ret); return ret; } 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++; } 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_ftell_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_ftell_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++; } 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; }