GSoC: Separation of Ports Build Process from Local Installation

[Theron Tarigo]

Hello all,

This project aims to decouple the build process of the ports framework 
from the local installation.  To work around the assumptions made by 
ports about dependency file locations, a userspace tool to remap 
processes' filesystem namespaces is under development: 
freebsd-user-namespace, provided as port devel/userns.

This past week, I investigated the problems of incompatibilities between 
port Makefile special cases and the new mode of ports building.  Right 
now, usage of a modified environment as required by the approach is 
handled for standard do-configure, do-build, etc. targets but not for 
port-defined targets.  Furthermore, usage of absolute paths in Make 
targets must be handled specially since a constraint of this project has 
been to not require anything from ports to be installed system-wide.  
Several approaches or prototypes and experiments thereof have been tried:
  1. For each known BUILD_DEPENDS which is a command, make that command 
available in a special PATH.
  2. Use Make's .SHELL feature to intercept all Make target commands in 
a wrapper shell which sets up the environment.
  3. Set environment directly from Make
  5. Rewrite _ALL_ ports which define targets to use a Make variable 
which may set the required environment.
  7. Run entire top-level Make command under the required environment.

Each of these is not appropriate as a general solution.  Instead, 
bsd.port.mk will be modified to run all targets (do-configure, do-build, 
do-install, etc.) in a sub-make with modified environment, while all 
scripts (do-depends.sh etc.) will continue to be run as they are currently.

What I am working on next:

- Implement the planned sub-make fix described above.  Test ports and debug.
- Compare the packages built by separated-build method to either 
official packages or ports built by original FreeBSD method.  Any 
differences should be attributable to built times and hostnames.
- Debug the ports which fail by segfaut or buserror; this implicates 
userns library.
- Provide more thorough documentation of PORTS_SEPARATED_BUILD, in 
particular its usage and its limitations, so that users and devs 
interested in this project can more easily test it for themselves.

Project goals and status are kept at 
https://wiki.freebsd.org/SummerOfCode2019Projects/PortsSeparatedBuild .

Source of the userspace filesystem namespace tool is shared at 
https://github.com/therontarigo/freebsd-user-namespace .
Changes to ports framework are shared at 
https://github.com/freebsd/freebsd-ports/compare/master...therontarigo:separated 
.

Theron Tarigo