implement /proc/<pid>/exe

src/drivers/fs/proc/task/mod.rs

@@ -132,12 +132,18 @@ impl Inode for ProcTaskInode {
             FileType::File,
             8,
         ));
+        entries.push(Dirent::new(
+            "exe".to_string(),
+            InodeId::from_fsid_and_inodeid(PROCFS_ID, get_inode_id(&[&initial_str, "exe"])),
+            FileType::File,
+            9,
+        ));
         if self.desc.tid().value() == self.desc.tgid().value() && !self.is_task_dir {
             entries.push(Dirent::new(
                 "task".to_string(),
                 InodeId::from_fsid_and_inodeid(PROCFS_ID, get_inode_id(&[&initial_str, "task"])),
                 FileType::Directory,
-                9,
+                10,
             ));
         }
 

src/drivers/fs/proc/task/task_file.rs

@@ -18,6 +18,7 @@ pub enum TaskFileType {
     State,
     Stat,
     Maps,
+    Exe,
 }
 
 impl TryFrom<&str> for TaskFileType {
@@ -32,6 +33,7 @@ impl TryFrom<&str> for TaskFileType {
             "cwd" => Ok(TaskFileType::Cwd),
             "root" => Ok(TaskFileType::Root),
             "maps" => Ok(TaskFileType::Maps),
+            "exe" => Ok(TaskFileType::Exe),
             _ => Err(()),
         }
     }
@@ -56,7 +58,7 @@ impl ProcTaskFileInode {
                     | TaskFileType::State
                     | TaskFileType::Maps
                     | TaskFileType::Stat => FileType::File,
-                    TaskFileType::Cwd | TaskFileType::Root => FileType::Symlink,
+                    TaskFileType::Cwd | TaskFileType::Root | TaskFileType::Exe => FileType::Symlink,
                 },
                 permissions: FilePermissions::from_bits_retain(0o444),
                 ..FileAttr::default()
@@ -197,6 +199,14 @@ Threads:\t{tasks}\n",
 
                     output
                 }
+                TaskFileType::Exe => {
+                    if let Some(exe) = task.process.executable.lock_save_irq().clone() {
+                        // TODO: Check if exists
+                        exe.as_str().to_string()
+                    } else {
+                        "(deleted)".to_string()
+                    }
+                }
             }
         } else {
             "State:\tGone\n".to_string()
@@ -243,6 +253,28 @@ Threads:\t{tasks}\n",
             } else {
                 Err(FsError::NotFound.into())
             };
+        } else if let TaskFileType::Exe = self.file_type {
+            let tid = self.tid;
+            let task_list = TASK_LIST.lock_save_irq();
+            let id = task_list
+                .iter()
+                .find(|(desc, _)| desc.tid() == tid)
+                .map(|(desc, _)| *desc);
+            drop(task_list);
+            let task_details = if let Some(desc) = id {
+                find_task_by_descriptor(&desc)
+            } else {
+                None
+            };
+            return if let Some(task) = task_details {
+                if let Some(exe) = task.process.executable.lock_save_irq().clone() {
+                    Ok(exe.as_str().to_string().into())
+                } else {
+                    Err(FsError::NotFound.into())
+                }
+            } else {
+                Err(FsError::NotFound.into())
+            };
         }
         Err(KernelError::NotSupported)
     }

src/process/exec.rs

@@ -12,6 +12,7 @@ use crate::{
     process::{ctx::Context, thread_group::signal::SignalActionState},
     sched::current::current_task,
 };
+use alloc::borrow::ToOwned;
 use alloc::{string::String, vec};
 use alloc::{string::ToString, sync::Arc, vec::Vec};
 use auxv::{AT_BASE, AT_ENTRY, AT_NULL, AT_PAGESZ, AT_PHDR, AT_PHENT, AT_PHNUM, AT_RANDOM};
@@ -212,6 +213,7 @@ async fn exec_elf(
     let mut fd_table = current_task().fd_table.lock_save_irq().clone();
     fd_table.close_cloexec_entries().await;
     *current_task().fd_table.lock_save_irq() = fd_table;
+    *current_task().process.executable.lock_save_irq() = Some(path.to_owned());
 
     Ok(())
 }

src/process/thread_group.rs

@@ -10,6 +10,7 @@ use core::{
     fmt::Display,
     sync::atomic::{AtomicU32, Ordering},
 };
+use libkernel::fs::pathbuf::PathBuf;
 use pid::PidT;
 use rsrc_lim::ResourceLimits;
 use signal::{SigId, SigSet, SignalActionState};
@@ -104,6 +105,7 @@ pub struct ThreadGroup {
     pub utime: AtomicUsize,
     pub stime: AtomicUsize,
     pub last_account: AtomicUsize,
+    pub executable: SpinLock<Option<PathBuf>>,
     next_tid: AtomicU32,
 }
 

src/process/thread_group/builder.rs

@@ -90,6 +90,7 @@ impl ThreadGroupBuilder {
             next_tid: AtomicU32::new(1),
             state: SpinLock::new(ProcessState::Running),
             tasks: SpinLock::new(BTreeMap::new()),
+            executable: SpinLock::new(None),
         });
 
         TG_LIST