Requests validation of user access to a virtual node (v-node).
int vn_access (vp, mode, who, crp) struct vnode *vp; int mode; int who; struct ucred *crp;
The vn_access entry point is used by the logical volume file system to validate access to a v-node. This entry point is used to implement the access subroutine. The v-node is held for the duration of the vn_access entry point. The v-node count is unchanged by this entry point.
In addition, the vn_access entry point is used for permissions checks from within the file system implementation. The valid types of access are listed in the /usr/include/sys/access.h file. Current modes are read, write, execute, and existence check.
Note: The vn_access entry point must ensure that write access is not requested on a read-only file system.
The vn_access entry point can be called from the process environment only.
0 | Indicates success. |
Nonzero return values are returned from the /usr/include/sys/errno.h file to indicate failure. A typical value includes:
EACCESS | Indicates no access is allowed. |
The access subroutine.
Virtual File System Overview, Virtual File System Kernel Extensions Overview, Logical File System Overview, Understanding Virtual Nodes (V-nodes) in AIX Kernel Extensions and Device Support Programming Concepts.
List of Virtual File System Operations.