fs/dup3: impletement dup3/nx_dup3_from_tcb function

refs: https://man7.org/linux/man-pages/man2/dup.2.html

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

include/nuttx/fs/fs.h

@@ -911,7 +911,7 @@ int file_allocate(FAR struct inode *inode, int oflags, off_t pos,
  *
  ****************************************************************************/
 
-int file_dup(FAR struct file *filep, int minfd, bool cloexec);
+int file_dup(FAR struct file *filep, int minfd, int flags);
 
 /****************************************************************************
  * Name: file_dup2
@@ -970,6 +970,24 @@ int nx_dup2_from_tcb(FAR struct tcb_s *tcb, int fd1, int fd2);
 
 int nx_dup2(int fd1, int fd2);
 
+/****************************************************************************
+ * Name: file_dup3
+ *
+ * Description:
+ *   Assign an inode to a specific files structure.  This is the heart of
+ *   dup3.
+ *
+ *   Equivalent to the non-standard dup3() function except that it
+ *   accepts struct file instances instead of file descriptors.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is return on
+ *   any failure.
+ *
+ ****************************************************************************/
+
+int file_dup3(FAR struct file *filep1, FAR struct file *filep2, int flags);
+
 /****************************************************************************
  * Name: file_open
  *

include/unistd.h

@@ -328,6 +328,7 @@ int     daemon(int nochdir, int noclose);
 int     close(int fd);
 int     dup(int fd);
 int     dup2(int fd1, int fd2);
+int     dup3(int fd1, int fd2, int flags);
 int     fsync(int fd);
 off_t   lseek(int fd, off_t offset, int whence);
 ssize_t read(int fd, FAR void *buf, size_t nbytes);