From 3021fffb079c1db895e1f30f321482477622f27d Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Thu, 3 Aug 2023 17:46:45 +0200
Subject: [PATCH] kernel: Store FD_CLOEXEC in the file descriptor itself

Closes #39.
---
 kernel/src/sys/exec.cpp    |  2 +-
 kernel/src/sys/file.cpp    | 18 +++++++++---------
 kernel/src/sys/open.cpp    |  5 +++--
 kernel/src/thread/Thread.h |  3 ++-
 4 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/kernel/src/sys/exec.cpp b/kernel/src/sys/exec.cpp
index 038f4b30..280ce407 100644
--- a/kernel/src/sys/exec.cpp
+++ b/kernel/src/sys/exec.cpp
@@ -100,7 +100,7 @@ Result<u64> sys_execve(Registers* regs, SyscallArgs args)
     {
         auto& descriptor = current->fd_table[i];
         if (!descriptor.has_value()) continue;
-        if (descriptor->description->flags & O_CLOEXEC) { descriptor = {}; }
+        if (descriptor->flags & O_CLOEXEC) { descriptor = {}; }
     }
 
     if (VFS::is_setuid(inode)) current->auth.euid = current->auth.suid = inode->metadata().uid;
diff --git a/kernel/src/sys/file.cpp b/kernel/src/sys/file.cpp
index 66c22c83..85fa7691 100644
--- a/kernel/src/sys/file.cpp
+++ b/kernel/src/sys/file.cpp
@@ -124,28 +124,28 @@ Result<u64> sys_fcntl(Registers*, SyscallArgs args)
 
         current->fd_table[new_fd] = descriptor;
 
-        if (is_cloexec) current->fd_table[new_fd]->flags() |= O_CLOEXEC;
+        if (is_cloexec) current->fd_table[new_fd]->flags |= O_CLOEXEC;
         else
-            current->fd_table[new_fd]->flags() &= ~O_CLOEXEC;
+            current->fd_table[new_fd]->flags &= ~O_CLOEXEC;
 
         return (u64)new_fd;
     }
-    case F_GETFD: return (u64) !!(descriptor.flags() & O_CLOEXEC);
+    case F_GETFD: return (u64) !!(descriptor.flags & O_CLOEXEC);
     case F_SETFD: {
         int arg = (int)args[2];
-        if (arg == FD_CLOEXEC) descriptor.flags() |= O_CLOEXEC;
+        if (arg == FD_CLOEXEC) descriptor.flags |= O_CLOEXEC;
         else
-            descriptor.flags() &= ~O_CLOEXEC;
+            descriptor.flags &= ~O_CLOEXEC;
         return 0;
     }
-    case F_GETFL: return (u64)(descriptor.flags() & ~O_CLOEXEC);
+    case F_GETFL: return (u64)descriptor.status_flags();
     case F_SETFL: {
         int arg = (int)args[2];
 
-        descriptor.flags() &= ~(O_APPEND | O_NONBLOCK);
+        descriptor.status_flags() &= ~(O_APPEND | O_NONBLOCK);
         arg &= (O_APPEND | O_NONBLOCK);
 
-        descriptor.flags() |= arg;
+        descriptor.status_flags() |= arg;
 
         return 0;
     }
@@ -189,7 +189,7 @@ Result<u64> sys_dup2(Registers*, SyscallArgs args)
     if (newfd == oldfd) return (u64)newfd;
 
     current->fd_table[newfd] = descriptor;
-    current->fd_table[newfd]->flags() &= ~O_CLOEXEC;
+    current->fd_table[newfd]->flags &= ~O_CLOEXEC;
 
     return (u64)newfd;
 }
diff --git a/kernel/src/sys/open.cpp b/kernel/src/sys/open.cpp
index 48a78596..cec57de4 100644
--- a/kernel/src/sys/open.cpp
+++ b/kernel/src/sys/open.cpp
@@ -7,7 +7,7 @@
 #include <bits/open-flags.h>
 
 // These flags are needed after open(), the rest only affect open().
-constexpr int FLAGS_TO_KEEP = O_RDWR | O_APPEND | O_NONBLOCK | O_CLOEXEC;
+constexpr int FLAGS_TO_KEEP = O_RDWR | O_APPEND | O_NONBLOCK;
 
 Result<u64> sys_openat(Registers*, SyscallArgs args)
 {
@@ -87,7 +87,8 @@ Result<u64> sys_openat(Registers*, SyscallArgs args)
     kdbgln("openat: opening file %s from dirfd %d, flags %d, mode %#o = fd %d", path.chars(), dirfd, flags, mode, fd);
 #endif
 
-    current->fd_table[fd] = FileDescriptor { TRY(make_shared<OpenFileDescription>(inode, flags & FLAGS_TO_KEEP)), 0 };
+    current->fd_table[fd] =
+        FileDescriptor { TRY(make_shared<OpenFileDescription>(inode, flags & FLAGS_TO_KEEP)), 0, flags & O_CLOEXEC };
 
     return (u64)fd;
 }
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
index 98014448..d73e498e 100644
--- a/kernel/src/thread/Thread.h
+++ b/kernel/src/thread/Thread.h
@@ -41,6 +41,7 @@ struct FileDescriptor
 {
     SharedPtr<OpenFileDescription> description;
     usize offset { 0 };
+    int flags { 0 };
 
     bool should_append();
     bool should_block();
@@ -52,7 +53,7 @@ struct FileDescriptor
         return description->inode;
     }
 
-    int& flags()
+    int& status_flags()
     {
         return description->flags;
     }