When Access Checks are Performed

Mandatory and discretionary access checks are performed on the path name at the time a file system object is opened. No further access checks are performed when the file descriptor is used in other system calls, except as follows:

• A file is opened for writing and the descriptor is later used with the fstat(2) system call for a read. In this case, there are access checks for the read and privilege may be required if the access is denied.

• A file is opened for reading and the descriptor is later used with the fchmod(2) system call for a write. In this case, there are access checks for the write access and privilege may be required if the access is denied.