Tribblix: manual page: moe.1

MOE(1) User Commands MOE(1)

NAME

moe - manifest the optimal expansion of a pathname

SYNOPSIS

moe [-c] [-32 | -64] [-s | -v] path

DESCRIPTION

The moe utility manifests the optimal expansion of a pathname
containing reserved runtime linker tokens. These tokens can be used
to define dependencies, filtees and runpaths within dynamic objects.
The expansion of these tokens at runtime, provides a flexible
mechanism for selecting objects and search paths that perform best on
this machine. See ld.so.1(1).

For example, the token $HWCAP can be employed to represent filters
and dependencies. The runtime interpretation of this token can result
in a family of objects that are analyzed to determine their
applicability for loading with a process. The objects are sorted
based on the hardware capabilities that each object requires to
execute. moe returns the name of the object optimally suited for
execution on the current platform.

moe analyzes a pathname by passing the supplied path to dlmopen(3C),
together with the RTLD_FIRST flag. Reserved token expansion is
therefore carried out by ld.so.1 as the expansion would occur in an
executing process. Although multiple objects can be analyzed as a
result of the dlmopen() call, the RTLD_FIRST flag insures only the
optimal object is processed.

By default, moe analyzes the specified path twice. The first analysis
looks for 32-bit objects. The second analysis, if applicable, looks
for 64-bit objects. Typically, 32-bit objects and 64-bit objects are
isolated to different directories. These directories are frequently
named to reflect the class of object the directory contains. The
multiple passes of moe catch any instances where 32-bit objects and
64-bit objects occupy the same directory. Multiple passes also
provide flexibility when the pathname that is specified does not
convey to the user the class of object the directory might contain.

For a complete description of the reserved token expansion carried
out by the runtime linker, refer to the Linker and Libraries Guide.

OPTIONS

The following options are supported:

-32
Only analyze 32-bit objects.

-64
Only analyze 64-bit objects.

-c
Prefix each pathname with the class of the object.

-s
Silent. No optimal name, or error diagnostics are displayed.
Only an error return is made available. This option is only
meaningful with the -32 and -64 options. The -s option can not
be used with the -v option.

-v
Verbose. If no optimal expansion name can be determined, an
error diagnostic is written to standard error. The -v option
can not be used with the -s option.

OPERANDS

The following operand is supported:

path
The pathname to be expanded.

EXAMPLES

The following example uses moe to display the optimal expansion of
objects in the directory /usr/lib/libc. This directory contains a
family of Intel objects that are built to use various hardware
capabilities.

% moe '/usr/lib/libc/$HWCAP'
/usr/lib/libc/libc_hwcap.so.1

The -c option can be used to clarify the class of the optimal object.

% moe -c '/usr/lib/libc/$HWCAP'
32-bit: /usr/lib/libc/libc_hwcap.so.1

The following example uses moe to display the optimal expansion of
objects under the /opt/ISV/cpu directory hierarchy. These directories
contain a family of SPARC objects that are built for various
platforms.

% moe -c -64 '/opt/ISV/$ISALIST/isa.so.1'
64-bit: /opt/ISV/sparcv9/isa.so.1

The -v can be used to diagnose the instance where an optimal name is
not returned. An attempt to inspect the previous pathname as a 32-bit
object, would result in the following diagnostic being produced.

% moe -c -v -32 '/opt/ISV/$ISALIST/isa.so.1'
32-bit: /opt/ISV/sparcv9/isa.so.1: wrong ELF class: ELFCLASS64

EXIT STATUS

When the -32 or -64 options are in effect, a successful optimal
expansion returns 0, otherwise non-zero. Without the -32 or -64
options in effect, the return value is always 0.

ATTRIBUTES