5.1 file.h — File security
<peios/file.h> is the file surface of KACS. Where ordinary POSIX open() gives you a file descriptor governed by mode bits, peios_file_open performs a native KACS open — an NtCreateFile-shaped call carrying a desired access mask, a create disposition, create options, and an optional creator security descriptor — and hands back an ordinary Linux file fd whose granted access mask is fixed for the fd's lifetime. Because the grant is baked into the fd, it can be delegated safely by dup, SCM_RIGHTS, or across exec: whoever holds the fd holds exactly the access it was opened with, no more.
Alongside the open, this module reads and writes a file's security descriptor (by path or by fd) and governs how a superblock without native SD storage is treated.
The wire constants (KACS_DISPOSITION_*, KACS_CREATE_OPT_*, KACS_FILE_*, KACS_SECINFO_*, KACS_MOUNT_POLICY_*, KACS_STATUS_*) come from <pkm/file.h> and <pkm/sd.h>. The security descriptors these calls exchange are built and parsed with <peios/security.h>.
5.1.1 See also #
<peios/security.h>— building the creator SDs and parsing the SDs these calls return.<peios/access.h>— evaluating a file SD withpeios_file_generic_mapping.- File access and Mount policies — the operator-side model of native file security.