cmdline inode

Author: arihant2math

src/arch/arm64/mod.rs

@@ -2,6 +2,7 @@ use aarch64_cpu::{
     asm::wfi,
     registers::{DAIF, MPIDR_EL1, ReadWriteable, Readable},
 };
+use alloc::string::String;
 use alloc::sync::Arc;
 use cpu_ops::{local_irq_restore, local_irq_save};
 use exceptions::ExceptionState;
@@ -140,6 +141,10 @@ impl Arch for Aarch64 {
         Self::halt()
     }
 
+    fn get_cmdline() -> Option<String> {
+        fdt::get_cmdline()
+    }
+
     unsafe fn copy_from_user(
         src: UA,
         dst: *mut (),

src/arch/mod.rs

@@ -16,6 +16,7 @@ use crate::{
         thread_group::signal::{SigId, ksigaction::UserspaceSigAction},
     },
 };
+use alloc::string::String;
 use alloc::sync::Arc;
 use libkernel::{
     CpuOps, VirtualMemory,
@@ -54,6 +55,8 @@ pub trait Arch: CpuOps + VirtualMemory {
     /// Restarts the machine. Implementations must never return.
     fn restart() -> !;
 
+    fn get_cmdline() -> Option<String>;
+
     /// Call a user-specified signal handler in the current process.
     fn do_signal(
         sig: SigId,

src/drivers/fs/proc.rs

@@ -1,5 +1,6 @@
 #![allow(clippy::module_name_repetitions)]
 
+mod cmdline;
 mod meminfo;
 mod root;
 mod stat;

src/drivers/fs/proc/cmdline.rs

@@ -0,0 +1,40 @@
+use crate::arch::{Arch, ArchImpl};
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use async_trait::async_trait;
+use libkernel::fs::attr::FileAttr;
+use libkernel::fs::{InodeId, SimpleFile};
+
+pub struct ProcCmdlineInode {
+    id: InodeId,
+    attr: FileAttr,
+}
+
+impl ProcCmdlineInode {
+    pub fn new(id: InodeId) -> Self {
+        Self {
+            id,
+            attr: FileAttr {
+                file_type: libkernel::fs::FileType::File,
+                mode: libkernel::fs::attr::FilePermissions::from_bits_retain(0o444),
+                ..FileAttr::default()
+            },
+        }
+    }
+}
+
+#[async_trait]
+impl SimpleFile for ProcCmdlineInode {
+    fn id(&self) -> InodeId {
+        self.id
+    }
+
+    async fn getattr(&self) -> libkernel::error::Result<FileAttr> {
+        Ok(self.attr.clone())
+    }
+
+    async fn read(&self) -> libkernel::error::Result<Vec<u8>> {
+        let cmdline = ArchImpl::get_cmdline().unwrap_or_default();
+        Ok(cmdline.into_bytes())
+    }
+}

src/drivers/fs/proc/root.rs

@@ -1,3 +1,4 @@
+use crate::drivers::fs::proc::cmdline::ProcCmdlineInode;
 use crate::drivers::fs::proc::get_inode_id;
 use crate::drivers::fs::proc::meminfo::ProcMeminfoInode;
 use crate::drivers::fs::proc::stat::ProcStatInode;
@@ -54,6 +55,10 @@ impl Inode for ProcRootInode {
             return Ok(Arc::new(ProcMeminfoInode::new(
                 InodeId::from_fsid_and_inodeid(self.id.fs_id(), get_inode_id(&["meminfo"])),
             )));
+        } else if name == "cmdline" {
+            return Ok(Arc::new(ProcCmdlineInode::new(
+                InodeId::from_fsid_and_inodeid(self.id.fs_id(), get_inode_id(&["cmdline"])),
+            )));
         } else {
             let pid: u32 = name.parse().map_err(|_| FsError::NotFound)?;
             // Search for the task descriptor.
@@ -128,6 +133,12 @@ impl Inode for ProcRootInode {
             FileType::File,
             (entries.len() + 1) as u64,
         ));
+        entries.push(Dirent::new(
+            "cmdline".to_string(),
+            InodeId::from_fsid_and_inodeid(PROCFS_ID, get_inode_id(&["cmdline"])),
+            FileType::File,
+            (entries.len() + 1) as u64,
+        ));
 
         Ok(Box::new(SimpleDirStream::new(entries, start_offset)))
     }