src/config/network.rs: implement network reload, set "changes" attribute

src/api2/config/network.rs

@@ -27,7 +27,7 @@ use crate::api2::types::*;
 pub fn list_network_devices(
     _param: Value,
     _info: &ApiMethod,
-    _rpcenv: &mut dyn RpcEnvironment,
+    rpcenv: &mut dyn RpcEnvironment,
 ) -> Result<Value, Error> {
 
     let (config, digest) = network::config()?;
@@ -41,6 +41,11 @@ pub fn list_network_devices(
         list.push(item);
     }
 
+    let diff = network::changes()?;
+    if !diff.is_empty() {
+        rpcenv.set_result_attrib("changes",  diff.into());
+    }
+
     Ok(list.into())
 }
 
@@ -312,6 +317,23 @@ pub fn delete_interface(name: String, digest: Option<String>) -> Result<(), Erro
     Ok(())
 }
 
+#[api(
+    access: {
+        permission: &Permission::Privilege(&[], PRIV_SYS_MODIFY, false),
+    },
+)]
+/// Reload network configuration (requires ifupdown2).
+pub fn reload_network_config() -> Result<(), Error> {
+
+    network::assert_ifupdown2_installed()?;
+
+    let _ = std::fs::rename(network::NETWORK_INTERFACES_NEW_FILENAME, network::NETWORK_INTERFACES_FILENAME);
+
+    network::network_reload()?;
+
+    Ok(())
+}
+
 const ITEM_ROUTER: Router = Router::new()
     .get(&API_METHOD_READ_INTERFACE)
     .put(&API_METHOD_UPDATE_INTERFACE)
@@ -319,4 +341,5 @@ const ITEM_ROUTER: Router = Router::new()
 
 pub const ROUTER: Router = Router::new()
     .get(&API_METHOD_LIST_NETWORK_DEVICES)
+    .put(&API_METHOD_RELOAD_NETWORK_CONFIG)
     .match_all("name", &ITEM_ROUTER);

src/bin/proxmox-backup-manager.rs

@@ -254,6 +254,12 @@ fn list_network_devices(param: Value, rpcenv: &mut dyn RpcEnvironment) -> Result
         _ => unreachable!(),
     };
 
+    if let Some(changes) = rpcenv.get_result_attrib("changes") {
+        if let Some(diff) = changes.as_str() {
+            eprintln!("pending changes:\n{}\n", diff);
+        }
+    }
+
     fn render_address(_value: &Value, record: &Value) -> Result<String, Error> {
         let mut text = String::new();
 
@@ -300,15 +306,21 @@ fn network_commands() -> CommandLineInterface {
 
     let cmd_def = CliCommandMap::new()
         .insert("list", CliCommand::new(&API_METHOD_LIST_NETWORK_DEVICES))
-        .insert("update",
-                CliCommand::new(&api2::config::network::API_METHOD_UPDATE_INTERFACE)
+        .insert(
+            "update",
+            CliCommand::new(&api2::config::network::API_METHOD_UPDATE_INTERFACE)
                 .arg_param(&["name"])
                 .completion_cb("name", config::network::complete_interface_name)
         )
-        .insert("remove",
-                CliCommand::new(&api2::config::network::API_METHOD_DELETE_INTERFACE)
+        .insert(
+            "remove",
+            CliCommand::new(&api2::config::network::API_METHOD_DELETE_INTERFACE)
                 .arg_param(&["name"])
                 .completion_cb("name", config::network::complete_interface_name)
+        )
+        .insert(
+            "reload",
+            CliCommand::new(&api2::config::network::API_METHOD_RELOAD_NETWORK_CONFIG)
         );
 
     cmd_def.into()

src/config/network.rs

@@ -387,6 +387,15 @@ pub fn config() -> Result<(NetworkConfig, [u8;32]), Error> {
     Ok((data, digest))
 }
 
+pub fn changes() -> Result<String, Error> {
+
+    if !std::path::Path::new(NETWORK_INTERFACES_NEW_FILENAME).exists() {
+        return Ok(String::new());
+    }
+
+    compute_file_diff(NETWORK_INTERFACES_FILENAME, NETWORK_INTERFACES_NEW_FILENAME)
+}
+
 pub fn save_config(config: &NetworkConfig) -> Result<(), Error> {
 
     let mut raw = Vec::new();

src/config/network/helper.rs

@@ -1,3 +1,5 @@
+use std::path::Path;
+use std::process::Command;
 use std::collections::HashMap;
 
 use anyhow::{Error, bail, format_err};
@@ -136,3 +138,59 @@ pub fn get_network_interfaces() -> Result<HashMap<String, bool>, Error> {
 
     Ok(interface_list)
 }
+
+pub fn compute_file_diff(filename: &str, shadow: &str) -> Result<String, Error> {
+
+    let output = Command::new("/usr/bin/diff")
+        .arg("-b")
+        .arg("-u")
+        .arg(filename)
+        .arg(shadow)
+        .output()
+        .map_err(|err| format_err!("failed to execute diff - {}", err))?;
+
+    if !output.status.success() {
+        match output.status.code() {
+            Some(code) => {
+                if code == 0 { return Ok(String::new()); }
+                if code != 1 {
+                    let msg = String::from_utf8(output.stderr)
+                        .map(|m| if m.is_empty() { String::from("no error message") } else { m })
+                        .unwrap_or_else(|_| String::from("non utf8 error message (suppressed)"));
+
+                   bail!("diff failed with status code: {} - {}", code, msg);
+                }
+            }
+            None => bail!("diff terminated by signal"),
+        }
+    }
+
+    let diff = String::from_utf8(output.stdout)?;
+
+    Ok(diff)
+}
+
+pub fn assert_ifupdown2_installed() -> Result<(), Error> {
+    if !Path::new("/usr/share/ifupdown2").exists() {
+        bail!("ifupdown2 is not installed.");
+    }
+
+    Ok(())
+}
+
+pub fn network_reload() -> Result<(), Error> {
+
+    let status = Command::new("/sbin/ifreload")
+        .arg("-a")
+        .status()
+        .map_err(|err| format_err!("failed to execute ifreload: - {}", err))?;
+
+    if !status.success() {
+        match status.code() {
+            Some(code) => bail!("ifreload failed with status code: {}", code),
+            None => bail!("ifreload terminated by signal")
+        }
+    }
+
+    Ok(())
+}