remove do_exec now that default executor is used.

Signed-off-by: yihuaf <yihuaf@unkies.org>

crates/libcontainer/src/utils.rs

@@ -1,16 +1,14 @@
 //! Utility functionality
 
 use std::collections::HashMap;
-use std::ffi::CString;
 use std::fs::{self, DirBuilder, File};
 use std::os::linux::fs::MetadataExt;
 use std::os::unix::fs::DirBuilderExt;
-use std::os::unix::prelude::{AsRawFd, OsStrExt};
+use std::os::unix::prelude::AsRawFd;
 use std::path::{Component, Path, PathBuf};
 
 use nix::sys::stat::Mode;
 use nix::sys::statfs;
-use nix::unistd;
 use nix::unistd::{Uid, User};
 
 #[derive(Debug, thiserror::Error)]
@@ -145,33 +143,6 @@ pub fn get_user_home(uid: u32) -> Option<PathBuf> {
     }
 }
 
-#[derive(Debug, thiserror::Error)]
-pub enum DoExecError {
-    #[error("failed to convert path to cstring")]
-    PathToCString {
-        source: std::ffi::NulError,
-        path: PathBuf,
-    },
-    #[error("failed to execvp")]
-    Execvp { source: nix::Error },
-}
-
-pub fn do_exec(path: impl AsRef<Path>, args: &[String]) -> Result<(), DoExecError> {
-    let p = CString::new(path.as_ref().as_os_str().as_bytes()).map_err(|e| {
-        DoExecError::PathToCString {
-            source: e,
-            path: path.as_ref().to_path_buf(),
-        }
-    })?;
-    let c_args: Vec<CString> = args
-        .iter()
-        .map(|s| CString::new(s.as_bytes()).unwrap_or_default())
-        .collect();
-    unistd::execvp(&p, &c_args).map_err(|err| DoExecError::Execvp { source: err })?;
-
-    Ok(())
-}
-
 /// If None, it will generate a default path for cgroups.
 pub fn get_cgroup_path(
     cgroups_path: &Option<PathBuf>,

crates/libcontainer/src/workload/default.rs

@@ -38,7 +38,7 @@ impl Executor for DefaultExecutor {
             ExecutorError::Execution(err.into())
         })?;
 
-        // After do_exec is called, the process is replaced with the container
+        // After execvp is called, the process is replaced with the container
         // payload through execvp, so it should never reach here.
         unreachable!();
     }

docs/src/user/libcontainer.md

@@ -32,4 +32,4 @@ This exposes several modules, each dealing with a specific aspect of working wit
 
 - `tty` : this deals with setting up the tty for the container process.
 
-- `utils` : provides various utility functions, such as `parse_env` to parse the env variables, `do_exec` to do an exec syscall and execute a binary in the container process, `get_cgroups_path`, `create_dir_all_with_mode` etc.
+- `utils` : provides various utility functions, such as `parse_env` to parse the env variables, `get_cgroups_path`, `create_dir_all_with_mode` etc.