diff --git a/capsicum.go b/capsicum.go
new file mode 100644
index 0000000..f3d4826
--- /dev/null
+++ b/capsicum.go
@@ -0,0 +1,242 @@
+// This is an implementation of libbsm
+// Copyright johan@nosd.in 2023
+//
+//go:build freebsd
+// +build freebsd
+
+//
+
+package main
+
+
+const (
+	// From freeebsd-src/sys/sys/caprights.h :
+	/*
+	 * The top two bits in the first element of the cr_rights[] array contain
+	 * total number of elements in the array - 2. This means if those two bits are
+	 * equal to 0, we have 2 array elements.
+	 * The top two bits in all remaining array elements should be 0.
+	 * The next five bits contain array index. Only one bit is used and bit position
+	 * in this five-bits range defines array index. This means there can be at most
+	 * five array elements.
+	 */
+	// So, I lazily chose to include index bit in following values
+	/* INDEX 0 */
+	
+	/*
+	 * General file I/O.
+	 */
+	/* Allows for openat(O_RDONLY), read(2), readv(2). */
+	CAP_READ      = 0x0200000000000001
+	/* Allows for openat(O_WRONLY | O_APPEND), write(2), writev(2). */
+	CAP_WRITE     = 0x0200000000000002
+	/* Allows for lseek(fd, 0, SEEK_CUR). */
+	CAP_SEEK_TELL = 0x0200000000000004
+	/* Allows for lseek(2). */
+	CAP_SEEK      = CAP_SEEK_TELL | 0x0200000000000008
+	/* Allows for aio_read(2), pread(2), preadv(2). */
+	CAP_PREAD     = (CAP_SEEK | CAP_READ)
+	/*
+	 * Allows for aio_write(2), openat(O_WRONLY) (without O_APPEND), pwrite(2),
+	 * pwritev(2).
+	 */
+	CAP_PWRITE    = (CAP_SEEK | CAP_WRITE)
+	/* Allows for mmap(PROT_NONE). */
+	CAP_MMAP      = 0x0200000000000010
+	/* Allows for mmap(PROT_READ). */
+	CAP_MMAP_R    = (CAP_MMAP | CAP_SEEK | CAP_READ)
+	/* Allows for mmap(PROT_WRITE). */
+	CAP_MMAP_W    = (CAP_MMAP | CAP_SEEK | CAP_WRITE)
+	/* Allows for mmap(PROT_EXEC). */
+	CAP_MMAP_X    = (CAP_MMAP | CAP_SEEK | 0x0200000000000020)
+	/* Allows for mmap(PROT_READ | PROT_WRITE). */
+	CAP_MMAP_RW   = (CAP_MMAP_R | CAP_MMAP_W)
+	/* Allows for mmap(PROT_READ | PROT_EXEC). */
+	CAP_MMAP_RX   = (CAP_MMAP_R | CAP_MMAP_X)
+	/* Allows for mmap(PROT_WRITE | PROT_EXEC). */
+	CAP_MMAP_WX   = (CAP_MMAP_W | CAP_MMAP_X)
+	/* Allows for mmap(PROT_READ | PROT_WRITE | PROT_EXEC). */
+	CAP_MMAP_RWX  = (CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
+	/* Allows for openat(O_CREAT). */
+	CAP_CREATE    = 0x0200000000000040
+	/* Allows for openat(O_EXEC) and fexecve(2) in turn. */
+	CAP_FEXECVE   = 0x0200000000000080
+	/* Allows for openat(O_SYNC), openat(O_FSYNC), fsync(2), aio_fsync(2). */
+	CAP_FSYNC     = 0x0200000000000100
+	/* Allows for openat(O_TRUNC), ftruncate(2). */
+	CAP_FTRUNCATE = 0x0200000000000200
+	
+	/* Lookups - used to constrain *at() calls. */
+	CAP_LOOKUP    = 0x0200000000000400
+	
+	/* VFS methods. */
+	/* Allows for fchdir(2). */
+	CAP_FCHDIR    = 0x0200000000000800
+	/* Allows for fchflags(2). */
+	CAP_FCHFLAGS  = 0x0200000000001000
+	/* Allows for fchflags(2) and chflagsat(2). */
+	CAP_CHFLAGSAT = (CAP_FCHFLAGS | CAP_LOOKUP)
+	/* Allows for fchmod(2). */
+	CAP_FCHMOD    = 0x0200000000002000
+	/* Allows for fchmod(2) and fchmodat(2). */
+	CAP_FCHMODAT  = (CAP_FCHMOD | CAP_LOOKUP)
+	/* Allows for fchown(2). */
+	CAP_FCHOWN    = 0x0200000000004000
+	/* Allows for fchown(2) and fchownat(2). */
+	CAP_FCHOWNAT  = (CAP_FCHOWN | CAP_LOOKUP)
+	/* Allows for fcntl(2). */
+	CAP_FCNTL     = 0x0200000000008000
+	/*
+	 * Allows for flock(2), openat(O_SHLOCK), openat(O_EXLOCK),
+	 * fcntl(F_SETLK_REMOTE), fcntl(F_SETLKW), fcntl(F_SETLK), fcntl(F_GETLK).
+	 */
+	CAP_FLOCK           = 0x0200000000010000
+	/* Allows for fpathconf(2). */
+	CAP_FPATHCONF       = 0x0200000000020000
+	/* Allows for UFS background-fsck operations. */
+	CAP_FSCK            = 0x0200000000040000
+	/* Allows for fstat(2). */
+	CAP_FSTAT           = 0x0200000000080000
+	/* Allows for fstat(2), fstatat(2) and faccessat(2). */
+	CAP_FSTATAT         = (CAP_FSTAT | CAP_LOOKUP)
+	/* Allows for fstatfs(2). */
+	CAP_FSTATFS         = 0x0200000000100000
+	/* Allows for futimens(2) and futimes(2). */
+	CAP_FUTIMES         = 0x0200000000200000
+	/* Allows for futimens(2), futimes(2), futimesat(2) and utimensat(2). */
+	CAP_FUTIMESAT       = (CAP_FUTIMES | CAP_LOOKUP)
+	/* Allows for linkat(2) (target directory descriptor). */
+	CAP_LINKAT_TARGET   = (CAP_LOOKUP | 0x0200000000400000)
+	/* Allows for mkdirat(2). */
+	CAP_MKDIRAT         = (CAP_LOOKUP | 0x0200000000800000)
+	/* Allows for mkfifoat(2). */
+	CAP_MKFIFOAT        = (CAP_LOOKUP | 0x0200000001000000)
+	/* Allows for mknodat(2). */
+	CAP_MKNODAT         = (CAP_LOOKUP | 0x0200000002000000)
+	/* Allows for renameat(2) (source directory descriptor). */
+	CAP_RENAMEAT_SOURCE = (CAP_LOOKUP | 0x0200000004000000)
+	/* Allows for symlinkat(2). */
+	CAP_SYMLINKAT       = (CAP_LOOKUP | 0x0200000008000000)
+	/*
+	 * Allows for unlinkat(2) and renameat(2) if destination object exists and
+	 * will be removed.
+	 */
+	CAP_UNLINKAT    = (CAP_LOOKUP | 0x0200000010000000)
+	
+	/* Socket operations. */
+	/* Allows for accept(2) and accept4(2). */
+	CAP_ACCEPT      = 0x0200000020000000
+	/* Allows for bind(2). */
+	CAP_BIND        = 0x0200000040000000
+	/* Allows for connect(2). */
+	CAP_CONNECT     = 0x0200000080000000
+	/* Allows for getpeername(2). */
+	CAP_GETPEERNAME = 0x0200000100000000
+	/* Allows for getsockname(2). */
+	CAP_GETSOCKNAME = 0x0200000200000000
+	/* Allows for getsockopt(2). */
+	CAP_GETSOCKOPT  = 0x0200000400000000
+	/* Allows for listen(2). */
+	CAP_LISTEN      = 0x0200000800000000
+	/* Allows for sctp_peeloff(2). */
+	CAP_PEELOFF     = 0x0300001000000000
+	CAP_RECV        = CAP_READ
+	CAP_SEND        = CAP_WRITE
+	/* Allows for setsockopt(2). */
+	CAP_SETSOCKOPT  = 0x0200002000000000
+	/* Allows for shutdown(2). */
+	CAP_SHUTDOWN    = 0x0200004000000000
+	
+	/* Allows for bindat(2) on a directory descriptor. */
+	CAP_BINDAT        = (CAP_LOOKUP | 0x0200008000000000)
+	/* Allows for connectat(2) on a directory descriptor. */
+	CAP_CONNECTAT     = (CAP_LOOKUP | 0x0200010000000000)
+	
+	/* Allows for linkat(2) (source directory descriptor). */
+	CAP_LINKAT_SOURCE   = (CAP_LOOKUP | 0x0200020000000000)
+	/* Allows for renameat(2) (target directory descriptor). */
+	CAP_RENAMEAT_TARGET = (CAP_LOOKUP | 0x0200040000000000)
+	
+	CAP_SOCK_CLIENT   = (CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT |
+		CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
+	CAP_SOCK_SERVER   = (CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME |
+		CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND |
+		CAP_SETSOCKOPT | CAP_SHUTDOWN)
+	
+	/* All used bits for index 0. */
+	CAP_ALL0       = 0x020007FFFFFFFFFF
+	
+	/* Available bits for index 0. */
+	CAP_UNUSED0_44 = 0x0200080000000000
+	/* ... */
+	CAP_UNUSED0_57 = 0x0300000000000000
+	
+	/* INDEX 1 */
+	
+	/* Mandatory Access Control. */
+	/* Allows for mac_get_fd(3). */
+	CAP_MAC_GET      = 0x0400000000000001
+	/* Allows for mac_set_fd(3). */
+	CAP_MAC_SET      = 0x0400000000000002
+	
+	/* Methods on semaphores. */
+	CAP_SEM_GETVALUE = 0x0400000000000004
+	CAP_SEM_POST     = 0x0400000000000008
+	CAP_SEM_WAIT     = 0x0400000000000010
+	
+	/* Allows select(2) and poll(2) on descriptor. */
+	CAP_EVENT        = 0x0400000000000020
+	/* Allows for kevent(2) on kqueue descriptor with eventlist != NULL. */
+	CAP_KQUEUE_EVENT = 0x0400000000000040
+	
+	/* Strange and powerful rights that should not be given lightly. */
+	/* Allows for ioctl(2). */
+	CAP_IOCTL        = 0x0400000000000080
+	CAP_TTYHOOK      = 0x0400000000000100
+	
+	/* Process management via process descriptors. */
+	/* Allows for pdgetpid(2). */
+	CAP_PDGETPID     = 0x0400000000000200
+	/*
+	 * Allows for pdwait4(2).
+	 *
+	 * XXX: this constant was imported unused, but is targeted to be implemented
+	 *      in the future (bug 235871).
+	 */
+	CAP_PDWAIT         = 0x0400000000000400
+	/* Allows for pdkill(2). */
+	CAP_PDKILL         = 0x0400000000000800
+	
+	/* Extended attributes. */
+	/* Allows for extattr_delete_fd(2). */
+	CAP_EXTATTR_DELETE = 0x0400000000001000
+	/* Allows for extattr_get_fd(2). */
+	CAP_EXTATTR_GET    = 0x0400000000002000
+	/* Allows for extattr_list_fd(2). */
+	CAP_EXTATTR_LIST   = 0x0400000000004000
+	/* Allows for extattr_set_fd(2). */
+	CAP_EXTATTR_SET    = 0x0400000000008000
+	
+	/* Access Control Lists. */
+	/* Allows for acl_valid_fd_np(3). */
+	CAP_ACL_CHECK      = 0x0400000000010000
+	/* Allows for acl_delete_fd_np(3). */
+	CAP_ACL_DELETE     = 0x0400000000020000
+	/* Allows for acl_get_fd(3) and acl_get_fd_np(3). */
+	CAP_ACL_GET        = 0x0400000000040000
+	/* Allows for acl_set_fd(3) and acl_set_fd_np(3). */
+	CAP_ACL_SET        = 0x0400000000080000
+	
+	/* Allows for kevent(2) on kqueue descriptor with changelist != NULL. */
+	CAP_KQUEUE_CHANGE  = 0x0400000000100000
+	
+	CAP_KQUEUE         = (CAP_KQUEUE_EVENT | CAP_KQUEUE_CHANGE)
+	
+	/* All used bits for index 1. */
+	CAP_ALL1           = 0x04000000001FFFFF
+	
+	/* Available bits for index 1. */
+	CAP_UNUSED1_22     = 0x0400000000200000
+	/* ... */
+	CAP_UNUSED1_57     = 0x0500000000000000
+)