When installing packages from source, the function call order is
pkg_pretend (for EAPI=4 and later),
pkg_postinst. When installing packages
from a binary, the function call order is
As some phases haven't been introduced from the beginning, you can have a look at
EAPI Usage and Description for an overview, what have been introduced in which EAPI.
pkg_pretend function is to be used for performing various
early sanity checks, such as ensuring that certain kernel options are
enabled. It is important to keep in mind that
separately from the rest of the phase function sequence. Consequently,
there is no environment saving or propagation to the next
phase. Moreover, ebuild dependencies are not guaranteed to be
satisfied at this phase.
pkg_postrm functions are called when uninstalling a
pkg_config function is used for any special package
configuration — it is only run when explicitly requested by the user. The
pkg_nofetch function is used when a
RESTRICT="fetch" package needs to
Between the transition from
pkg_postinst, files are
copied over to the live filesystem from the sandboxed temporary installation
location, and Portage records digests of the files installed.
When testing or debugging, you can instruct Portage to execute a specific function
from an ebuild by using the
ebuild command, see the
page for further information.
Downloading a package's source happens before any of these phases, so
emerge --fetchonly should perform all the network access you
need (unless you're using live ebuilds). Network access outside of
this would not be cached locally (e.g. in
Predefined Read-Only Variables),
which makes it hard to have reproducible builds (see
Disadvantages of CVS Sources).
Avoid network access in any phase by using local files, extending
Ebuild-defined Variables), etc.