critical impact:

mmap - some flags not available (CrUn216)

Problem description

The following mmap flags either do not exist on HP-UX or have different semantics than the those on Tru64 UNIX:

• MAP_UNALIGNED and MAP_INHERIT flags exist on Tru64 UNIX but not on HP-UX.

• MAP_FIXED has different syntax.

On Tru64 UNIX, the flags have the following meaning:

• MAP_UNALIGNED - Does not verify that the file offset is page aligned.

• MAP_INHERIT - Region is not mapped by an exec call.

• MAP_FIXED - Places a region at a fixed address.

On HP-UX, the MAP_FIXED flag means to interpret the addr parameter exactly.

Identifiers

MAP_FIXED

MAP_INHERIT

MAP_UNALIGNED

See also

• Background information on kernel impacts
• mmap(2)

Solution description

Review the source code and make the following modifications:

• If your code uses the MAP_UNALIGNED flag, you must ensure that the file offset is page aligned. On Tru64 UNIX, the mmapped region does not need to be page aligned.

• If your code uses the MAP_INHERIT flag, you must ensure that the exec application calls mmap to map the file.

• If your code uses the MAP_FIXED flag, you must supply a virtual address to which you will be mapped. On Tru64 UNIX, if you pass a NULL address, a virtual address is assigned by the system.

See also

• mmap(2)

Problem summary