agent: agent.proto: Add AddSwap

Add new fuction AddSwap.  When agent get AddSwap, it will get the device
name from PCIPath and set the device as the swap device.

Fixes: #2201

Signed-off-by: Hui Zhu <teawater@antfin.com>

src/agent/protocols/protos/agent.proto

@@ -66,6 +66,7 @@ service AgentService {
 	rpc SetGuestDateTime(SetGuestDateTimeRequest) returns (google.protobuf.Empty);
 	rpc CopyFile(CopyFileRequest) returns (google.protobuf.Empty);
 	rpc GetOOMEvent(GetOOMEventRequest) returns (OOMEvent);
+	rpc AddSwap(AddSwapRequest) returns (google.protobuf.Empty);
 }
 
 message CreateContainerRequest {
@@ -503,6 +504,10 @@ message OOMEvent {
 	string container_id = 1;
 }
 
+message AddSwapRequest {
+	repeated uint32 PCIPath = 1;
+}
+
 message GetMetricsRequest {}
 
 message Metrics {

src/agent/src/device.rs

@@ -62,7 +62,7 @@ pub fn online_device(path: &str) -> Result<()> {
 // the sysfs path for the PCI host bridge, based on the PCI path
 // provided.
 #[instrument]
-fn pcipath_to_sysfs(root_bus_sysfs: &str, pcipath: &pci::Path) -> Result<String> {
+pub fn pcipath_to_sysfs(root_bus_sysfs: &str, pcipath: &pci::Path) -> Result<String> {
     let mut bus = "0000:00".to_string();
     let mut relpath = String::new();
 

src/agent/src/rpc.rs

@@ -3,11 +3,14 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
+use crate::pci;
 use async_trait::async_trait;
 use rustjail::{pipestream::PipeStream, process::StreamType};
 use tokio::io::{AsyncReadExt, AsyncWriteExt, ReadHalf};
 use tokio::sync::Mutex;
 
+use std::ffi::CString;
+use std::io;
 use std::path::Path;
 use std::sync::Arc;
 use ttrpc::{
@@ -20,8 +23,9 @@ use anyhow::{anyhow, Context, Result};
 use oci::{LinuxNamespace, Root, Spec};
 use protobuf::{RepeatedField, SingularPtrField};
 use protocols::agent::{
-    AgentDetails, CopyFileRequest, GuestDetailsResponse, Interfaces, Metrics, OOMEvent,
-    ReadStreamResponse, Routes, StatsContainerResponse, WaitProcessResponse, WriteStreamResponse,
+    AddSwapRequest, AgentDetails, CopyFileRequest, GuestDetailsResponse, Interfaces, Metrics,
+    OOMEvent, ReadStreamResponse, Routes, StatsContainerResponse, WaitProcessResponse,
+    WriteStreamResponse,
 };
 use protocols::empty::Empty;
 use protocols::health::{
@@ -40,7 +44,7 @@ use nix::sys::stat;
 use nix::unistd::{self, Pid};
 use rustjail::process::ProcessOperations;
 
-use crate::device::{add_devices, rescan_pci_bus, update_device_cgroup};
+use crate::device::{add_devices, pcipath_to_sysfs, rescan_pci_bus, update_device_cgroup};
 use crate::linux_abi::*;
 use crate::metrics::get_metrics;
 use crate::mount::{add_storages, remove_mounts, BareMount, STORAGE_HANDLER_LIST};
@@ -59,7 +63,7 @@ use tracing_opentelemetry::OpenTelemetrySpanExt;
 
 use tracing::instrument;
 
-use libc::{self, c_ushort, pid_t, winsize, TIOCSWINSZ};
+use libc::{self, c_char, c_ushort, pid_t, winsize, TIOCSWINSZ};
 use std::convert::TryFrom;
 use std::fs;
 use std::os::unix::prelude::PermissionsExt;
@@ -1192,6 +1196,18 @@ impl protocols::agent_ttrpc::AgentService for AgentService {
 
         Err(ttrpc_error(ttrpc::Code::INTERNAL, ""))
     }
+
+    async fn add_swap(
+        &self,
+        ctx: &TtrpcContext,
+        req: protocols::agent::AddSwapRequest,
+    ) -> ttrpc::Result<Empty> {
+        trace_rpc_call!(ctx, "add_swap", req);
+
+        do_add_swap(&req).map_err(|e| ttrpc_error(ttrpc::Code::INTERNAL, e.to_string()))?;
+
+        Ok(Empty::new())
+    }
 }
 
 #[derive(Clone)]
@@ -1541,6 +1557,56 @@ fn do_copy_file(req: &CopyFileRequest) -> Result<()> {
     Ok(())
 }
 
+pub fn path_name_lookup<P: std::clone::Clone + AsRef<Path> + std::fmt::Debug>(
+    path: P,
+    lookup: &str,
+) -> Result<(PathBuf, String)> {
+    for entry in fs::read_dir(path.clone())? {
+        let entry = entry?;
+        if let Some(name) = entry.path().file_name() {
+            if let Some(name) = name.to_str() {
+                if Some(0) == name.find(lookup) {
+                    return Ok((entry.path(), name.to_string()));
+                }
+            }
+        }
+    }
+    Err(anyhow!("cannot get {} dir in {:?}", lookup, path))
+}
+
+fn do_add_swap(req: &AddSwapRequest) -> Result<()> {
+    // re-scan PCI bus
+    // looking for hidden devices
+    rescan_pci_bus().context("Could not rescan PCI bus")?;
+
+    let mut slots = Vec::new();
+    for slot in &req.PCIPath {
+        slots.push(pci::Slot::new(*slot as u8)?);
+    }
+    let pcipath = pci::Path::new(slots)?;
+    let root_bus_sysfs = format!("{}{}", SYSFS_DIR, create_pci_root_bus_path());
+    let sysfs_rel_path = format!(
+        "{}{}",
+        root_bus_sysfs,
+        pcipath_to_sysfs(&root_bus_sysfs, &pcipath)?
+    );
+    let (mut virtio_path, _) = path_name_lookup(sysfs_rel_path, "virtio")?;
+    virtio_path.push("block");
+    let (_, dev_name) = path_name_lookup(virtio_path, "vd")?;
+    let dev_name = format!("/dev/{}", dev_name);
+
+    let c_str = CString::new(dev_name)?;
+    let ret = unsafe { libc::swapon(c_str.as_ptr() as *const c_char, 0) };
+    if ret != 0 {
+        return Err(anyhow!(
+            "libc::swapon get error {}",
+            io::Error::last_os_error()
+        ));
+    }
+
+    Ok(())
+}
+
 // Setup container bundle under CONTAINER_BASE, which is cleaned up
 // before removing a container.
 // - bundle path is /<CONTAINER_BASE>/<cid>/