From a8c9d04b0c138942ee1da6a5f543f0cc388d28cf Mon Sep 17 00:00:00 2001
From: Terr <git@terr.nl>
Date: Tue, 2 Jan 2024 15:14:43 +0100
Subject: [PATCH] Add some more mounts that the OCI describes as required

See https://github.com/opencontainers/runtime-spec/blob/main/config-linux.md#default-filesystems
---
 crates/libcarton/src/container.rs         | 43 ++++++++++++++++++-----
 crates/libcarton/src/container_builder.rs |  5 ++-
 crates/libcarton/src/error.rs             |  8 +++++
 3 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/crates/libcarton/src/container.rs b/crates/libcarton/src/container.rs
index 146925a..1040d30 100644
--- a/crates/libcarton/src/container.rs
+++ b/crates/libcarton/src/container.rs
@@ -150,6 +150,16 @@ pub struct Mount {
 }
 
 impl Mount {
+    pub(crate) fn rootfs(source: PathBuf) -> Self {
+        Mount {
+            source: Some(source),
+            relative_target: "".into(),
+            fstype: None,
+            flags: mount::MsFlags::MS_BIND | mount::MsFlags::MS_PRIVATE,
+            data: None,
+        }
+    }
+
     /// Defines a "bind" mount which can be used to share a directory from outside the container
     /// with the container.
     pub(crate) fn bind(
@@ -169,22 +179,22 @@ impl Mount {
 
     /// When the container runs in a separate PID namespace it also needs a separate /proc mount that
     /// will contain only this PID namespace's processes.
-    pub(crate) fn procfs(relative_target: PathBuf) -> Self {
+    pub(crate) fn procfs() -> Self {
         Mount {
             source: None::<PathBuf>,
-            relative_target,
+            relative_target: "proc".into(),
             fstype: Some("proc".into()),
             flags: mount::MsFlags::empty(),
             data: None,
         }
     }
 
-    pub(crate) fn rootfs(source: PathBuf) -> Self {
+    pub(crate) fn sysfs() -> Self {
         Mount {
-            source: Some(source),
-            relative_target: "".into(),
-            fstype: None,
-            flags: mount::MsFlags::MS_BIND | mount::MsFlags::MS_PRIVATE,
+            source: None::<PathBuf>,
+            relative_target: "sys".into(),
+            fstype: Some("sysfs".into()),
+            flags: mount::MsFlags::empty(),
             data: None,
         }
     }
@@ -199,18 +209,33 @@ impl Mount {
         }
     }
 
+    pub(crate) fn devpts() -> Self {
+        Mount {
+            source: None::<PathBuf>,
+            relative_target: "dev/pts".into(),
+            fstype: Some("devpts".into()),
+            flags: mount::MsFlags::empty(),
+            data: None,
+        }
+    }
+
     /// Returns the absolute path where the mount has been mounted
     pub(crate) fn mount(&self, rootfs_path: &Path) -> Result<PathBuf, CartonError> {
         let mount_path = rootfs_path.join(&self.relative_target);
 
+        if !mount_path.exists() {
+            info!("creating {}", mount_path.display());
+            std::fs::create_dir_all(&mount_path)?;
+        }
+
         info!(
-            "mount {} ({}) at {}",
+            "mounting {} ({}) at {}",
             &self
                 .source
                 .as_ref()
                 .map_or("(no source)", |p| p.to_str().unwrap()),
             self.fstype.as_ref().map_or("bind mount", |f| f.as_str()),
-            &mount_path.display()
+            mount_path.display()
         );
 
         mount::mount(
diff --git a/crates/libcarton/src/container_builder.rs b/crates/libcarton/src/container_builder.rs
index c7bb2ce..de06319 100644
--- a/crates/libcarton/src/container_builder.rs
+++ b/crates/libcarton/src/container_builder.rs
@@ -40,9 +40,12 @@ impl ContainerBuilder {
     /// Adds mounting configuration for some important mounts, in the correct order.
     pub fn add_default_mounts(mut self) -> Self {
         self.config.mounts.extend(vec![
-            Mount::procfs("proc".into()),
+            Mount::procfs(),
+            Mount::sysfs(),
             Mount::tmpfs("tmp".into()),
             Mount::tmpfs("dev".into()),
+            Mount::devpts(),
+            Mount::tmpfs("dev/shm".into()),
         ]);
 
         self
diff --git a/crates/libcarton/src/error.rs b/crates/libcarton/src/error.rs
index e4fa64b..1547d06 100644
--- a/crates/libcarton/src/error.rs
+++ b/crates/libcarton/src/error.rs
@@ -16,6 +16,14 @@ pub enum CartonError {
     SysCallFailed(String),
     #[error("namespace error: {0}")]
     NamespaceError(String),
+    #[error("I/O error: {0}")]
+    IOError(String),
+}
+
+impl From<std::io::Error> for CartonError {
+    fn from(error: std::io::Error) -> Self {
+        CartonError::IOError(format!("{}", error))
+    }
 }
 
 impl From<nix::Error> for CartonError {