Add dgamelaunch docs to readme

(cherry picked from commit 1833ee1ae5e80d50b48e3d163f07cd8f4d68691f)

diff --git a/README.md b/README.md
index 7b52d1e9aafd9fb621a21369629faa6e8c876322..6483893f50b16851e2842a938903d75a3af2d9bd 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,3 +1,5 @@
+See far below for step by step usage!
+
 This repository is a fork of Crawl's version of dgamelaunch[^dgl-crawl], which
 was forked from Paxed's dgamlaunch after January 29th, 2011[^dgl-paxed-2011].
 Work by Paxed continued[^dgl-paxed] after Crawl's fork; this fork has been
@@ -41,6 +43,107 @@ chroot.
 * [suggestion - record terminal size info in ttyrec #17](https://github.com/paxed/dgamelaunch/issues/17)
 * [Allow importing NETHACKOPTIONS environment variable? #16](https://github.com/paxed/dgamelaunch/issues/16)
 
+# dgamelaunch documentation
+From paxed's excellent README
+```
+COMMANDLINE PARAMETERS
+======================
+
+ -a            Ignored.
+ -c            Shows error message and exits. (login shell command)
+ -e            Ignored.
+ -h            Ignored.
+ -i user       Autologin and run the register -command hook for "user"
+               (with password "user").
+ -p            Ignored.
+ -q            Be quiet, suppress errors.
+ -s            Show players currently playing.
+ -W user:msg   Send message "msg" to all players. The message seems
+               to come from "user".
+ -S            Free the shared memory block.
+ -D            Show contents of the shared memory block.
+
+
+ENVIRONMENT VARIABLES
+=====================
+
+ Linux telnetd allows importing the USER environment variables via telnet,
+ while FreeBSD does not.  FreeBSD, on the other hand, does allow the LOGNAME
+ environment variable.  Dgamelaunch will first check USER, then LOGNAME,
+ for "username:password", and tries autologin if either exists.
+ Dgamelaunch-specific DGLAUTH is checked before either of those.
+
+
+ERROR CODES
+===========
+
+   1   Could not terminate stale processes
+   2   Cannot chroot()
+   3   Cannot chdir()
+   4   Cannot setgroups()
+   5   Cannot setgid()
+   6   Cannot setuid()
+   7   Caught HUP
+   8   Cannot run as root: Config file has shed_user = "root"
+   9   Cannot run as root: Config file has shed_user set to UID 0 user.
+  10   Could not setup player
+  11   Cannot run as root: Config file has shed_uid = 0
+  12   Config file has an unrecognized token
+  13   Config file: Negative value not accepted
+  15   dgamelaunch called with -c (login shell command); exited
+  20   No menu defined, or no banner found for menu
+  60   Cannot create a new terminal, or no termcap files.
+  61   Cannot openpty()
+  62   Cannot open /dev/ptmx
+  65   Cannot open master ptsname
+  68   Cannot fcntl inprogress-lock
+  70   Cannot write to inprogress-lock
+  71   ftok() error for shm_key, no "dgamelaunch" file found?
+  72   ftok() error for shm_sem_key, no "dgamelaunch" file found?
+  73   shmget() error, cannot connect to shared memory
+  74   smat() error, cannot attach to shared memory
+  75   Nothing in shared memory?
+  76   sem_init() error, could not initialize shared memory
+  77   sem_wait() error
+  78   sem_post() error
+  95   Cannot fnctl lockfile
+  96   sqlite3_open() failed when checking user existence: could not open login database
+  97   sqlite3_open() failed in writefile()
+  98   sqlite3_exec() failed in writefile()
+  99   Could not open password file
+ 100   Username field too long in login file
+ 101   Email field too long in login file
+ 102   password field too long in login file
+ 103   env field too long in login file
+ 104   Cannot read config file
+ 105   Cannot read default config file
+ 106   Cannot open lockfile or password file
+ 107   fcntl failed on login database in writefile()
+ 108   sqlite3_exec() failed when checking user existence.
+ 109   Too many registered users. (see maxusers setting in config file)
+ 110   Login failed
+ 111   Two users trying to register at the same time
+ 112   Error changing password: cannot have ':' in password
+ 113   Error parsing configuration file
+ 114   exec-command fork failed
+ 115   could not read lock file in writefile()
+ 116   Too many registered users. (see maxusers setting in config file)
+ 117   wall error: no message to send
+ 118   wall error: no players
+ 119   User has a retarded terminal
+ 120   wall error: message too long
+ 121   wall error: "from" username is too short
+ 122   Error changing password: struct "me" does not exist
+ 123   chdir() failed in dgl commands.
+ 140   populate_games(): Cannot open inprogress-dir
+ 145   populate_games(): Inprogress-filename does not have ':' in it
+ 146   populate_games(): Inprogress-filename does not have ': in it (pt. 2)
+ 200   purge_stale_locks(): could not open inprogress-dir
+ 201   purge_stale_locks(): inprogress-file did not have ':' in it
+ 202   purge_stale_locks(): could not read inprogress-file
+ 203   purge_stale_locks(): could not get inprogress-file contents
+```
+
 # install-dgl-nh500 documentation
 ```bash
 #!/bin/bash