9fans/plan9port

Purpose and entry points

Plan 9 from User Space (plan9port) ports Plan 9 libraries, commands, protocols, and desktop tools to Unix hosts. Installation starts at ./INSTALL, with top-level build orchestration in Makefile and configure; it first bootstraps the Plan 9-style mk build tool, then builds the rest. User-facing launchers and compatibility commands are installed from bin/.

Build and portability layer

The repository supports Unix-family platforms through per-OS make fragments and C adaptation layers. The native Unix build path is represented by unix/make/Makefile.all, unix/make/Makefile.CMD, and OS files such as unix/make/Make.Linux. The internal mk implementation is a primary bootstrap/runtime dependency: src/cmd/mk/main.c, src/cmd/mk/graph.c, src/cmd/mk/job.c. Project-specific source-build scripts are centralized under src/mkfile, src/mkmk.sh, and src/mkcommon.

Core compatibility libraries

Most programs target Plan 9 interfaces rather than direct Unix APIs. src/lib9/ supplies the base runtime—process, filesystem, networking, error, formatting, and UTF behavior—anchored by src/lib9/mkfile, src/lib9/main.c, and src/lib9/rfork.c. Common API contracts are exposed through include/libc.h, include/u.h, and include/utf.h. Higher-level reusable libraries provide buffered I/O (src/libbio/), cooperative threading (src/libthread/), regular expressions (src/libregexp/), cryptography (src/libsec/), and IP utilities (src/libip/).

9P namespace and service boundary

9P is the central remote-filesystem/service protocol boundary. Server-side primitives live in src/lib9p/srv.c, src/lib9p/fid.c, and src/lib9p/req.c; client-side filesystem operations live in src/lib9pclient/fs.c, src/lib9pclient/walk.c, and src/lib9pclient/auth.c. Commands such as src/cmd/9p.c, src/cmd/9pserve.c, and src/cmd/9pfuse/main.c expose, inspect, or bridge 9P services to Unix/FUSE environments.

Graphics, windows, and interactive tools

The draw stack separates client graphics APIs from host display backends. src/libdraw/drawclient.c, src/libdraw/window.c, and src/libmemdraw/draw.c implement drawing and in-memory rendering; src/cmd/devdraw/devdraw.c bridges to macOS/X11 backends. Interactive applications build above this boundary: the Rio window system (src/cmd/rio/main.c, src/cmd/rio/manage.c), Acme editor (src/cmd/acme/acme.c, src/cmd/acme/fsys.c), Sam editor (src/cmd/sam/sam.c), and 9term terminal (src/cmd/9term/9term.c).

System services and persistent storage

Several substantial service implementations run as Unix processes while presenting Plan 9 interfaces. Fossil is a 9P archival filesystem with disk/cache logic (src/cmd/fossil/fossil.c, src/cmd/fossil/9p.c, src/cmd/fossil/fs.c). Venti is content-addressed block storage, split between client library (src/libventi/client.c, src/libventi/rpc.c) and server arena/index management (src/cmd/venti/srv/venti.c, src/cmd/venti/srv/arena.c, src/cmd/venti/srv/index.c). VAC and backup tools connect filesystem snapshots to Venti (src/cmd/vac/vac.c, src/cmd/vbackup/vbackup.c).

Network, authentication, and messaging

The distribution includes network-facing Unix services and clients: DNS/NDB (src/cmd/ndb/dnserver.c, src/libndb/dnsquery.c), authentication/key-agent functionality (src/cmd/auth/factotum/main.c, src/libauth/auth_rpc.c), and UPAS mail transport/storage (src/cmd/upas/smtp/smtpd.c, src/cmd/upas/send/main.c, src/cmd/upas/fs/fs.c). These components use external network services such as DNS, SMTP/IMAP/POP, SSH-compatible authentication, and 9P peers.

Distribution assets and command ecosystem

src/cmd/ is the broad command suite: Unix/Plan 9 shell and text tools, compilers/interpreters, document processing, image conversion, networking, and service daemons. Runtime resources are shipped beside binaries: fonts in font/, troff definitions in troff/ and postscript/, plumbing rules in plumb/, namespace/network data in ndb/, and executable wrappers in bin/. Man pages in man/ describe the installed interface; packaging/release assembly is under dist/.