From a7eeb66a1b3ab5f4aea31798a384d7c5b886b3e1 Mon Sep 17 00:00:00 2001
From: Anton Kling <anton@kling.gg>
Date: Wed, 26 Jun 2024 20:37:16 +0200
Subject: Libc/Kernel: Add fcntl()

---
 include/fcntl.h               | 19 +++++++++++++++++++
 kernel/cpu/syscall.c          | 19 ++++++++++++++++++-
 kernel/fs/vfs.c               |  1 +
 kernel/fs/vfs.h               |  9 ---------
 userland/libc/include/fcntl.h | 14 --------------
 5 files changed, 38 insertions(+), 24 deletions(-)
 create mode 100644 include/fcntl.h
 delete mode 100644 userland/libc/include/fcntl.h

diff --git a/include/fcntl.h b/include/fcntl.h
new file mode 100644
index 0000000..af2a68f
--- /dev/null
+++ b/include/fcntl.h
@@ -0,0 +1,19 @@
+#define O_NONBLOCK (1 << 0)
+#define O_READ (1 << 1)
+#define O_WRITE (1 << 2)
+#define O_CREAT (1 << 3)
+#define O_TRUNC (1 << 4)
+#define O_APPEND (1 << 5)
+
+#define O_RDONLY O_READ
+#define O_WRONLY O_WRITE
+#define O_RDWR (O_WRITE | O_READ)
+
+#define F_GETFL 0
+#define F_SETFL 1
+
+#ifndef KERNEL
+int open(const char *file, int flags, ...);
+int open_process(int pid);
+int fcntl(int fd, int cmd, ...);
+#endif
diff --git a/kernel/cpu/syscall.c b/kernel/cpu/syscall.c
index adbb27a..4a446d5 100644
--- a/kernel/cpu/syscall.c
+++ b/kernel/cpu/syscall.c
@@ -4,6 +4,7 @@
 #include <cpu/syscall.h>
 #include <drivers/pst.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <fs/tmpfs.h>
 #include <fs/vfs.h>
 #include <interrupts.h>
@@ -169,6 +170,22 @@ int syscall_getpeername(int sockfd, struct sockaddr *restrict addr,
   return 0;
 }
 
+int syscall_fcntl(int fd, int cmd, int arg) {
+  vfs_fd_t *fd_ptr = get_vfs_fd(fd, NULL);
+  if (!fd_ptr) {
+    return -EBADF;
+  }
+  if (F_GETFL == cmd) {
+    return fd_ptr->flags;
+  } else if (F_SETFL == cmd) {
+    fd_ptr->flags = arg;
+    return 0;
+  } else {
+    return -EINVAL;
+  }
+  return 0;
+}
+
 int (*syscall_functions[])() = {
     (void(*))syscall_open,         (void(*))syscall_read,
     (void(*))syscall_write,        (void(*))syscall_pread,
@@ -190,7 +207,7 @@ int (*syscall_functions[])() = {
     (void(*))syscall_randomfill,   (void(*))syscall_munmap,
     (void(*))syscall_open_process, (void(*))syscall_lseek,
     (void(*))syscall_connect,      (void(*))syscall_setsockopt,
-    (void(*))syscall_getpeername,
+    (void(*))syscall_getpeername,  (void(*))syscall_fcntl,
 };
 
 void int_syscall(reg_t *r);
diff --git a/kernel/fs/vfs.c b/kernel/fs/vfs.c
index 21c98cf..dfdaf44 100644
--- a/kernel/fs/vfs.c
+++ b/kernel/fs/vfs.c
@@ -3,6 +3,7 @@
 #include <fs/vfs.h>
 #include <mmu.h>
 #include <poll.h>
+#include <fcntl.h>
 
 vfs_inode_t *root_dir;
 vfs_mounts_t mounts[10];
diff --git a/kernel/fs/vfs.h b/kernel/fs/vfs.h
index 64a7a80..080a663 100644
--- a/kernel/fs/vfs.h
+++ b/kernel/fs/vfs.h
@@ -13,15 +13,6 @@ typedef struct vfs_mounts vfs_mounts_t;
 #include <sys/stat.h>
 #include <typedefs.h>
 
-// FIXME: Is there some standard value for this?
-#define O_NONBLOCK (1 << 0)
-#define O_READ (1 << 1)
-#define O_WRITE (1 << 2)
-#define O_CREAT (1 << 3)
-#define O_RDONLY O_READ
-#define O_WRONLY O_WRITE
-#define O_RDWR (O_WRITE | O_READ)
-
 #define FS_TYPE_FILE 0
 #define FS_TYPE_UNIX_SOCKET 1
 #define FS_TYPE_CHAR_DEVICE 2
diff --git a/userland/libc/include/fcntl.h b/userland/libc/include/fcntl.h
deleted file mode 100644
index 57c968a..0000000
--- a/userland/libc/include/fcntl.h
+++ /dev/null
@@ -1,14 +0,0 @@
-// FIXME: Is there some standard value for this?
-#define O_NONBLOCK (1 << 0)
-#define O_READ (1 << 1)
-#define O_WRITE (1 << 2)
-#define O_CREAT (1 << 3)
-#define O_TRUNC (1 << 4)
-#define O_APPEND (1 << 5)
-
-#define O_RDONLY O_READ
-#define O_WRONLY O_WRITE
-#define O_RDWR (O_WRITE | O_READ)
-
-int open(const char *file, int flags, ...);
-int open_process(int pid);
-- 
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