From 05d316d0bc3705e1e3c47ecdfbad4f4da3d9879d Mon Sep 17 00:00:00 2001
From: Rafal Mielniczuk <rafal.mielniczuk2@gmail.com>
Date: Mon, 27 May 2024 16:06:46 +0100
Subject: [PATCH] Fix memory leak on sys_exec

---
 cykusz-rs/src/arch/x86_64/task/mod.rs | 9 +++++++--
 cykusz-rs/src/kernel/fs/dirent.rs     | 5 ++++-
 cykusz-rs/src/kernel/task/mod.rs      | 7 +++++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/cykusz-rs/src/arch/x86_64/task/mod.rs b/cykusz-rs/src/arch/x86_64/task/mod.rs
index 1bcf1f04..6da81b57 100644
--- a/cykusz-rs/src/arch/x86_64/task/mod.rs
+++ b/cykusz-rs/src/arch/x86_64/task/mod.rs
@@ -1,4 +1,3 @@
-use alloc::string::String;
 use alloc::vec::Vec;
 use core::mem::size_of;
 use core::ptr::Unique;
@@ -19,6 +18,7 @@ use crate::arch::raw::segmentation::SegmentSelector;
 use crate::arch::syscall::SyscallFrame;
 use crate::arch::utils::StackHelper;
 use crate::drivers::elf::ElfHeader;
+use crate::kernel::fs::dirent::DirEntryItem;
 use crate::kernel::mm::virt::PageFlags;
 use crate::kernel::mm::{allocate, VirtAddr, PAGE_SIZE};
 use crate::kernel::mm::{Frame, PhysAddr};
@@ -450,12 +450,14 @@ impl Task {
         hdr: &ElfHeader,
         vm: &VM,
         tls_vm: Option<TlsVmInfo>,
-        path: String,
+        exe: DirEntryItem,
         args: Option<ExeArgs>,
         envs: Option<ExeArgs>,
     ) -> ! {
         logln!("entry point: {}", entry);
 
+        let path = exe.full_path();
+
         let args = args.map(|a| args::Args::new(a));
         let envs = envs.map(|e| args::Args::new(e));
 
@@ -538,9 +540,12 @@ impl Task {
             helper.write(argp.len()); // int argc
         }
 
+        // !!! Prevent memory leaks as we are not running destructors here!
         drop(envp);
         drop(argp);
         drop(tls_vm);
+        drop(path);
+        drop(exe);
 
         logln!("exec user stack: {:#x}", helper.current());
         assert_eq!(helper.current() % 16, 0);
diff --git a/cykusz-rs/src/kernel/fs/dirent.rs b/cykusz-rs/src/kernel/fs/dirent.rs
index cff5ede5..002c37c8 100644
--- a/cykusz-rs/src/kernel/fs/dirent.rs
+++ b/cykusz-rs/src/kernel/fs/dirent.rs
@@ -27,7 +27,10 @@ impl Cacheable<CacheKey> for DirEntry {
         data.parent = None;
     }
 
-    fn notify_used(&self) {}
+    fn notify_used(&self) {
+        let data = self.write();
+        logln!("mark used: {}", data.name);
+    }
 
     fn deallocate(&self, _me: &CacheItem<CacheKey, DirEntry>) {
         logln!("deallocate {}", _me.data.lock().name);
diff --git a/cykusz-rs/src/kernel/task/mod.rs b/cykusz-rs/src/kernel/task/mod.rs
index 11d2c386..eed0b2fa 100644
--- a/cykusz-rs/src/kernel/task/mod.rs
+++ b/cykusz-rs/src/kernel/task/mod.rs
@@ -210,6 +210,9 @@ impl Task {
         self.filetable().close_on_exec();
         self.filetable().debug();
 
+        // !!! Prevent memory leak as we are not running destructors here!
+        drop(vm);
+
         unsafe {
             // EXEC!
             self.arch_task_mut().exec(
@@ -218,7 +221,7 @@ impl Task {
                 &elf_hdr,
                 self.vm(),
                 tls_vm,
-                exe.full_path(),
+                exe,
                 Some(args),
                 envs,
             )
@@ -781,6 +784,6 @@ impl Task {
 
 impl Drop for Task {
     fn drop(&mut self) {
-        logln4!("drop task {}", self.tid());
+        logln!("drop task {}", self.tid());
     }
 }