1 Parameter Info Block (PIB), all offsets in pointer-length words
3 buffer_size 0 Size of the destination buffer
5 The total number of bytes in all of the segments that require a
6 buffer to be created in the destination address space. This is
7 specified so that the kernel can allocate one large buffer for all
8 segments before traversing the segment list. When returning from a
9 method, the buffer size only includes buffers allocated by the
10 caller; "inout" segments where the caller specified a non-NULL ptr,
11 and the callee did not increase the length, are not included
12 (because the kernel does not need to allocate a caller-side buffer
15 objlist_ptr 1 Pointer to the object list
16 objlist_len 2 Length of the object list
18 The object list is a list of pointers into segment data describing
19 where object IDs can be found. When copying a segment to the
20 destination address space, it will convert all IDs (allocating a new
21 ID if necessary). The object list must be in order (first by
22 segment, then by address); an exception may be thrown if it is out
23 of order or if it contains invalid entries. Segments with object
24 IDs cannot have the Shared flag. Unmarshalling code should always
25 verify that any ID it expects is actually in the object list.
27 ptrlist_ptr 3 Pointer to the pointer list
28 ptrlist_len 4 Length of the pointer list
30 The pointer list, like the object list, is a list of pointers to
31 segment data. Each pointer pointed to must also point within
32 segment data, and will be modified by the ORB when copied to point
33 to the equivalent location in the destination address space. The
34 pointer list must be in order (first by segment, then by address);
35 an exception may be thrown if it is out of order of if it contains
36 invalid entries. Segments with internal pointers cannot have the
37 Shared flag (shared segments can still be pointed to, of course).
38 Unmarshalling code should always verify that any internal pointer it
39 expects actually points within a valid segment.
41 num_segments 5 Number of data segments
42 segment.ptr 6+n*3 Pointer to data segment
43 segment.len 7+n*3 Length of data segment in bytes
44 segment.flags 8+n*3 Attributes of data segment
46 Each segment describes data being transmitted to and/or from the
47 callee. For out segments, the caller may designate a buffer to hold
48 the data, or it may leave the ptr field NULL. The caller may
49 replace an out segment pointer with its own (it must do this if it
50 was NULL), and it may change the length of the segment. Except when
51 flags such as Push or Shared force the kernel to map, rather than
52 copy, the data, it will choose which method to use based on the
53 size, page-alignment, and overmap status of the segment.
55 Segment Flags (see doc/orb/memory-management for more details):
56 In 0x01 Data is copied/mapped from caller to callee
57 Out 0x02 Data is copied/mapped from callee to caller
58 Shared 0x04 A permanent shared mapping is created
59 Push 0x08 The region is unmapped from the source and
60 transferred to the destination.
61 Inline 0x10 The callee cannot change the length of an
62 Out segment. Ignored for In segments.
63 Immutable 0x20 The segment is to be mapped read-only in
65 Copy 0x8000 The segment is permanently copied into the
66 destination address space, with read/write
67 access (unless Immutable is set).