Support domainname

crates/libcontainer/src/process/container_init_process.rs

@@ -129,6 +129,10 @@ fn apply_rest_namespaces(
             if let Some(hostname) = spec.hostname() {
                 syscall.set_hostname(hostname)?;
             }
+
+            if let Some(domainname) = spec.domainname() {
+                syscall.set_domainname(domainname)?;
+            }
         }
     }
     Ok(())
@@ -576,6 +580,14 @@ mod tests {
             .get_hostname_args();
         assert_eq!(1, got_hostnames.len());
         assert_eq!("youki".to_string(), got_hostnames[0]);
+
+        let got_domainnames = syscall
+            .as_ref()
+            .as_any()
+            .downcast_ref::<TestHelperSyscall>()
+            .unwrap()
+            .get_domainname_args();
+        assert_eq!(0, got_domainnames.len());
         Ok(())
     }
 

crates/libcontainer/src/syscall/linux.rs

@@ -8,7 +8,7 @@ use std::{any::Any, mem, path::Path, ptr};
 
 use anyhow::{anyhow, bail, Context, Result};
 use caps::{CapSet, CapsHashSet};
-use libc::{c_char, uid_t};
+use libc::{c_char, uid_t, setdomainname, EFAULT, EINVAL, EPERM};
 use nix::fcntl;
 use nix::{
     errno::Errno,
@@ -198,6 +198,25 @@ impl Syscall for LinuxSyscall {
         Ok(())
     }
 
+    /// Sets domainname for process (see
+    /// [setdomainname(2)](https://man7.org/linux/man-pages/man2/setdomainname.2.html)).
+    fn set_domainname(&self, domainname: &str) -> Result<()> {
+        let ptr = domainname.as_bytes().as_ptr() as *const c_char;
+        let len = domainname.len();
+        let res = unsafe { setdomainname(ptr, len) };
+        if res == EFAULT {
+            bail!("Failed to set {} as domainname. domainname pointed outside of user address space.", domainname)
+        }
+        if res == EINVAL {
+            bail!("Failed to set {} as domainname. domainname len was negative or too large.", domainname)
+        }
+        if res == EPERM {
+            bail!("Failed to set {} as domainname. the caller did not have the CAP_SYS_ADMIN capability.", domainname)
+        }
+
+        Ok(())
+    }
+
     /// Sets resource limit for process
     fn set_rlimit(&self, rlimit: &LinuxRlimit) -> Result<()> {
         let rlim = &libc::rlimit {

crates/libcontainer/src/syscall/syscall.rs

@@ -28,6 +28,7 @@ pub trait Syscall {
     fn unshare(&self, flags: CloneFlags) -> Result<()>;
     fn set_capability(&self, cset: CapSet, value: &CapsHashSet) -> Result<()>;
     fn set_hostname(&self, hostname: &str) -> Result<()>;
+    fn set_domainname(&self, domainname: &str) -> Result<()>;
     fn set_rlimit(&self, rlimit: &LinuxRlimit) -> Result<()>;
     fn get_pwuid(&self, uid: u32) -> Option<Arc<OsStr>>;
     fn mount(

crates/libcontainer/src/syscall/test.rs

@@ -59,6 +59,7 @@ pub enum ArgName {
     Mknod,
     Chown,
     Hostname,
+    Domainname,
     Groups,
     Capability,
 }
@@ -73,6 +74,7 @@ impl ArgName {
             ArgName::Mknod,
             ArgName::Chown,
             ArgName::Hostname,
+            ArgName::Domainname,
             ArgName::Groups,
             ArgName::Capability,
         ]
@@ -163,6 +165,11 @@ impl Syscall for TestHelperSyscall {
             .act(ArgName::Hostname, Box::new(hostname.to_owned()))
     }
 
+    fn set_domainname(&self, domainname: &str) -> anyhow::Result<()> {
+        self.mocks
+            .act(ArgName::Domainname, Box::new(domainname.to_owned()))
+    }
+
     fn set_rlimit(&self, _rlimit: &LinuxRlimit) -> anyhow::Result<()> {
         todo!()
     }
@@ -315,6 +322,15 @@ impl TestHelperSyscall {
             .collect::<Vec<String>>()
     }
 
+    pub fn get_domainname_args(&self) -> Vec<String> {
+        self.mocks
+            .fetch(ArgName::Domainname)
+            .values
+            .iter()
+            .map(|x| x.downcast_ref::<String>().unwrap().clone())
+            .collect::<Vec<String>>()
+    }
+
     pub fn get_groups_args(&self) -> Vec<Vec<Gid>> {
         self.mocks
             .fetch(ArgName::Groups)