cloud-hypervisor/vmm/src/migration.rs

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// Copyright © 2020 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0
use crate::config::VmConfig;
use crate::vm::{VmSnapshot, VM_SNAPSHOT_ID};
use anyhow::anyhow;
use std::fs::File;
use std::io::BufReader;
use std::path::PathBuf;
use std::sync::{Arc, Mutex};
use url::Url;
use vm_migration::{MigratableError, Snapshot};
pub const VM_SNAPSHOT_FILE: &str = "vm.json";
pub fn url_to_path(url: &Url) -> std::result::Result<PathBuf, MigratableError> {
match url.scheme() {
"file" => url
.to_file_path()
.map_err(|_| {
MigratableError::MigrateSend(anyhow!("Could not convert file URL to a file path"))
})
.and_then(|path| {
if !path.is_dir() {
return Err(MigratableError::MigrateSend(anyhow!(
"Destination is not a directory"
)));
}
Ok(path)
}),
_ => Err(MigratableError::MigrateSend(anyhow!(
"URL scheme is not file: {}",
url.scheme()
))),
}
}
pub fn recv_vm_snapshot(source_url: &str) -> std::result::Result<Snapshot, MigratableError> {
let url = Url::parse(source_url).map_err(|e| {
MigratableError::MigrateSend(anyhow!("Could not parse destination URL: {}", e))
})?;
match url.scheme() {
"file" => {
let mut vm_snapshot_path = url_to_path(&url)?;
vm_snapshot_path.push(VM_SNAPSHOT_FILE);
// Try opening the snapshot file
let vm_snapshot_file =
File::open(vm_snapshot_path).map_err(|e| MigratableError::MigrateSend(e.into()))?;
let vm_snapshot_reader = BufReader::new(vm_snapshot_file);
let vm_snapshot = serde_json::from_reader(vm_snapshot_reader)
.map_err(|e| MigratableError::MigrateReceive(e.into()))?;
Ok(vm_snapshot)
}
_ => Err(MigratableError::MigrateSend(anyhow!(
"Unsupported VM transport URL scheme: {}",
url.scheme()
))),
}
}
pub fn vm_config_from_snapshot(
snapshot: &Snapshot,
) -> std::result::Result<Arc<Mutex<VmConfig>>, MigratableError> {
if let Some(vm_section) = snapshot
.snapshot_data
.get(&format!("{}-section", VM_SNAPSHOT_ID))
{
let vm_snapshot: VmSnapshot =
serde_json::from_slice(&vm_section.snapshot).map_err(|e| {
MigratableError::Restore(anyhow!("Could not deserialize VM snapshot {}", e))
})?;
return Ok(vm_snapshot.config);
}
Err(MigratableError::Restore(anyhow!(
"Could not find VM config snapshot section"
)))
}