These system calls provide a means to access a file given the file handle fhp. As this method bypasses directory access restrictions, these calls are restricted to the superuser.
The fhopen system call opens the file referenced by fhp for reading and/or writing as specified by the argument flags and returns the file descriptor to the calling process. The flags argument is specified by or ing together the flags used for the open(2) system call. All said flags are valid except for O_CREAT.
The fhstat and fhstatfs system calls provide the functionality of the fstat(2) and fstatfs(2) calls except that they return information for the file referred to by fhp rather than an open file.
Upon successful completion, fhopen returns the file descriptor for the opened file; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
.Rv -std fhstat fhstatfs
In addition to the errors returned by open(2), fstat(2), and fstatfs(2) respectively, fhopen, fhstat, and fhstatfs will return