src/bin/proxmox-backup-manager.rs: add dns sub command

Also improved the DNS api, added a --delete option.

src/api2/node/dns.rs

@@ -5,6 +5,7 @@ use lazy_static::lazy_static;
 use openssl::sha;
 use regex::Regex;
 use serde_json::{json, Value};
+use ::serde::{Deserialize, Serialize};
 
 use proxmox::api::{api, ApiMethod, Router, RpcEnvironment, Permission};
 use proxmox::tools::fs::{file_get_contents, replace_file, CreateOptions};
@@ -15,6 +16,19 @@ use crate::config::acl::{PRIV_SYS_AUDIT, PRIV_SYS_MODIFY};
 
 static RESOLV_CONF_FN: &str = "/etc/resolv.conf";
 
+#[api()]
+#[derive(Serialize, Deserialize)]
+#[allow(non_camel_case_types)]
+/// Deletable property name
+pub enum DeletableProperty {
+    /// Delete first nameserver entry
+    dns1,
+    /// Delete second nameserver entry
+    dns2,
+    /// Delete third nameserver entry
+    dns3,
+}
+
 pub fn read_etc_resolv_conf() -> Result<Value, Error> {
 
     let mut result = json!({});
@@ -33,6 +47,8 @@ pub fn read_etc_resolv_conf() -> Result<Value, Error> {
             concat!(r"^\s*nameserver\s+(", IPRE!(),  r")\s*")).unwrap();
     }
 
+    let mut options = String::new();
+
     for line in data.lines() {
 
         if let Some(caps) = DOMAIN_REGEX.captures(&line) {
@@ -43,9 +59,16 @@ pub fn read_etc_resolv_conf() -> Result<Value, Error> {
             let nameserver = &caps[1];
             let id = format!("dns{}", nscount);
             result[id] = Value::from(nameserver);
+        } else {
+            if !options.is_empty() { options.push('\n'); }
+            options.push_str(line);
         }
     }
 
+    if !options.is_empty() {
+        result["options"] = options.into();
+    }
+
     Ok(result)
 }
 
@@ -59,6 +82,7 @@ pub fn read_etc_resolv_conf() -> Result<Value, Error> {
             },
             search: {
                 schema: SEARCH_DOMAIN_SCHEMA,
+                optional: true,
             },
             dns1: {
                 optional: true,
@@ -72,6 +96,14 @@ pub fn read_etc_resolv_conf() -> Result<Value, Error> {
                 optional: true,
                 schema: THIRD_DNS_SERVER_SCHEMA,
             },
+            delete: {
+                description: "List of properties to delete.",
+                type: Array,
+                optional: true,
+                items: {
+                    type: DeletableProperty,
+                }
+            },
             digest: {
                 optional: true,
                 schema: PROXMOX_CONFIG_DIGEST_SCHEMA,
@@ -83,10 +115,13 @@ pub fn read_etc_resolv_conf() -> Result<Value, Error> {
     }
 )]
 /// Update DNS settings
-fn update_dns(
-    param: Value,
-    _info: &ApiMethod,
-    _rpcenv: &mut dyn RpcEnvironment,
+pub fn update_dns(
+    search: Option<String>,
+    dns1: Option<String>,
+    dns2: Option<String>,
+    dns3: Option<String>,
+    delete: Option<Vec<DeletableProperty>>,
+    digest: Option<String>,
 ) -> Result<Value, Error> {
 
     lazy_static! {
@@ -95,33 +130,41 @@ fn update_dns(
 
     let _guard = MUTEX.lock();
 
-    let search = crate::tools::required_string_param(&param, "search")?;
+    let mut config = read_etc_resolv_conf()?;
+    let old_digest = config["digest"].as_str().unwrap();
 
-    let raw = file_get_contents(RESOLV_CONF_FN)?;
-    let old_digest = proxmox::tools::digest_to_hex(&sha::sha256(&raw));
-
-    if let Some(digest) = param["digest"].as_str() {
-        crate::tools::assert_if_modified(&old_digest, &digest)?;
+    if let Some(digest) = digest {
+        crate::tools::assert_if_modified(old_digest, &digest)?;
     }
 
-    let old_data = String::from_utf8(raw)?;
-
-    let mut data = format!("search {}\n", search);
-
-    for opt in &["dns1", "dns2", "dns3"] {
-        if let Some(server) = param[opt].as_str() {
-            data.push_str(&format!("nameserver {}\n", server));
+    if let Some(delete) = delete {
+        for delete_prop in delete {
+            let config = config.as_object_mut().unwrap();
+            match delete_prop {
+                DeletableProperty::dns1 => { config.remove("dns1"); },
+                DeletableProperty::dns2 => { config.remove("dns2"); },
+                DeletableProperty::dns3 => { config.remove("dns3"); },
+            }
         }
     }
 
-    // append other data
-    lazy_static! {
-        static ref SKIP_REGEX: Regex = Regex::new(r"^(search|domain|nameserver)\s+").unwrap();
+    if let Some(search) = search { config["search"] = search.into(); }
+    if let Some(dns1) = dns1 { config["dns1"] = dns1.into(); }
+    if let Some(dns2) = dns2 { config["dns2"] = dns2.into(); }
+    if let Some(dns3) = dns3 { config["dns3"] = dns3.into(); }
+
+    let mut data = String::new();
+
+    if let Some(search) = config["search"].as_str() {
+        data.push_str(&format!("search {}\n", search));
     }
-    for line in old_data.lines() {
-        if SKIP_REGEX.is_match(line) { continue; }
-        data.push_str(line);
-        data.push('\n');
+    for opt in &["dns1", "dns2", "dns3"] {
+        if let Some(server) = config[opt].as_str() {
+            data.push_str(&format!("nameserver {}\n", server));
+        }
+    }
+    if let Some(options) = config["options"].as_str() {
+        data.push_str(options);
     }
 
     replace_file(RESOLV_CONF_FN, data.as_bytes(), CreateOptions::new())?;
@@ -167,7 +210,7 @@ fn update_dns(
     }
 )]
 /// Read DNS settings.
-fn get_dns(
+pub fn get_dns(
     _param: Value,
     _info: &ApiMethod,
     _rpcenv: &mut dyn RpcEnvironment,