Changeset 407 for trunk/kernel/fs/devfs.h

Timestamp:

Nov 7, 2017, 3:08:12 PM (7 years ago)

Author:

alain

Message:

First implementation of fork/exec.

Location:

trunk/kernel/fs

Files:

• . (moved) (moved from trunk/kernel/vfs)
• devfs.h (modified) (2 diffs)

trunk/kernel/fs/devfs.h

@@ -41 +41 @@
 //
 // The DEVFS extensions to the generic VFS are the following:
-// 1) The vfs_ctx_t "extend" field is a void* pointing on the devfs_ctx_t structure.
+// 1) The vfs_ctx_t "extend" void* field is pointing on the devfs_ctx_t structure.
 //    This structure contains two extended pointers on the DEVFS "dev" directory inode,
 //    and on the "external" directory inode.
-// 2) The vfs_inode_t "extend" field is a void*, pointing on the associated 
-//    chdev descriptor.
+// 2) The vfs_inode_t "extend" void* field is pointing on the chdev descriptor.
 //////////////////////////////////////////////////////////////////////////////////////////
 
@@ -119 +118 @@
                        xptr_t * devfs_internal_inode_xp );
                        
+/****************************************************************************************** 
+ * This function moves <size> bytes between a device, and a - possibly distributed - 
+ * user space <buffer>. It uses the <file_xp> and <to_buffer> arguments, to call the 
+ * relevant device access function.
+ * It is called by the sys_read() and sys_write() functions.
+ * The <size> argument cannot be larger than the CONFIG_TXT_KBUF_SIZE configuration
+ * parameter, as this function makes a copy between the user space buffer, and a local
+ * kernel buffer allocated in the kernel stack.
+ ******************************************************************************************
+ * @ to_buffer : device -> buffer if true / buffer -> device if false. 
+ * @ file_xp   : extended pointer on the remote file descriptor.
+ * @ u_buf     : user space buffer (virtual address).
+ * @ size      : requested number of bytes from offset.
+ * @ returns number of bytes actually moved if success / -1 if error.
+ *****************************************************************************************/
+int devfs_user_move( bool_t   to_buffer,
+                     xptr_t   file_xp, 
+                     void   * u_buf,
+                     uint32_t size );
+
+
 #endif  /* _DEVFS_H_ */