Add /proc/[pid]/cmdline support

kernel/aster-nix/src/fs/procfs/pid/cmdline.rs

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::*;
+
+/// Represents the inode at `/proc/[pid]/cmdline`.
+pub struct CmdlineFileOps(Arc<Process>);
+
+impl CmdlineFileOps {
+    pub fn new_inode(process_ref: Arc<Process>, parent: Weak<dyn Inode>) -> Arc<dyn Inode> {
+        ProcFileBuilder::new(Self(process_ref))
+            .parent(parent)
+            .build()
+            .unwrap()
+    }
+}
+
+impl FileOps for CmdlineFileOps {
+    fn data(&self) -> Result<Vec<u8>> {
+        let exe_path = self.0.executable_path();
+
+        let mut cmdline_output = exe_path.into_bytes();
+        cmdline_output.push(0); // Append a single NUL character at the end
+
+        Ok(cmdline_output)
+    }
+}

kernel/aster-nix/src/fs/procfs/pid/mod.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
-use self::{comm::CommFileOps, exe::ExeSymOps, fd::FdDirOps};
+use self::{cmdline::CmdlineFileOps, comm::CommFileOps, exe::ExeSymOps, fd::FdDirOps};
 use super::template::{
     DirOps, FileOps, ProcDir, ProcDirBuilder, ProcFileBuilder, ProcSymBuilder, SymOps,
 };
@@ -14,6 +14,7 @@ use crate::{
     process::Process,
 };
 
+mod cmdline;
 mod comm;
 mod exe;
 mod fd;
@@ -51,6 +52,7 @@ impl DirOps for PidDirOps {
             "exe" => ExeSymOps::new_inode(self.0.clone(), this_ptr.clone()),
             "comm" => CommFileOps::new_inode(self.0.clone(), this_ptr.clone()),
             "fd" => FdDirOps::new_inode(self.0.clone(), this_ptr.clone()),
+            "cmdline" => CmdlineFileOps::new_inode(self.0.clone(), this_ptr.clone()),
             _ => return_errno!(Errno::ENOENT),
         };
         Ok(inode)
@@ -70,6 +72,9 @@ impl DirOps for PidDirOps {
         });
         cached_children.put_entry_if_not_found("fd", || {
             FdDirOps::new_inode(self.0.clone(), this_ptr.clone())
-        })
+        });
+        cached_children.put_entry_if_not_found("cmdline", || {
+            CmdlineFileOps::new_inode(self.0.clone(), this_ptr.clone())
+        });
     }
 }