From ce10fb574366d420faf4d581cbd2d08b06200d1c Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Mon, 17 Oct 2022 17:01:22 +0200
Subject: [PATCH] fcntl(F_DUPFD): Allocate any file descriptor greater than or
 equal to arg

---
 kernel/src/sys/stdio.cpp | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/src/sys/stdio.cpp b/kernel/src/sys/stdio.cpp
index a32e8d55..9ad01b8f 100644
--- a/kernel/src/sys/stdio.cpp
+++ b/kernel/src/sys/stdio.cpp
@@ -20,7 +20,7 @@
 
 #define FNCTL_DUPFD 0
 
-void sys_fcntl(Context* context, int fd, int command, [[maybe_unused]] uintptr_t arg)
+void sys_fcntl(Context* context, int fd, int command, uintptr_t arg)
 {
     if (fd >= TASK_MAX_FDS || fd < 0)
     {
@@ -34,10 +34,14 @@ void sys_fcntl(Context* context, int fd, int command, [[maybe_unused]] uintptr_t
         return;
     }
     Descriptor& file = current_task->files[fd];
-    if (command == FNCTL_DUPFD) // FIXME: If arg is greater than 0, return the lowest numbered available file descriptor
-                                // greater than or equal to arg.
+    if (command == FNCTL_DUPFD)
     {
-        int dupfd = current_task->alloc_fd();
+        if ((int)arg < 0 || (int)arg >= TASK_MAX_FDS)
+        {
+            context->rax = -EINVAL;
+            return;
+        }
+        int dupfd = current_task->alloc_fd_greater_than_or_equal((int)arg);
         if (dupfd < 0)
         {
             context->rax = -EMFILE;