Add session(5).

login/login.8

@@ -26,6 +26,15 @@ exists.
 The process remains running in the background and takes over again when the user
 session exits.
 .Pp
+The user's
+.Xr session 5
+is created upon login by running the user's
+.Pa ~/.session
+script if it exists and is executable, otherwise attempting
+.Pa /etc/session ,
+and ultimately falling back on the user's shell from
+.Xr passwd 5 .
+.Pp
 Type a special username to perform special options:
 .Pp
 .Bl -tag -width "poweroff" -compact -offset indent
@@ -57,12 +66,18 @@ shell
 username
 .El
 .Sh FILES
-.Bl -tag -width "/etc/passwd" -compact
+.Bl -tag -width "/etc/login.conf.textual" -compact
+.It Pa ~/.session
+user session script run upon login (see
+.Xr session 5 )
+.It Pa /etc/login.conf.textual
+textual interface is forced if this file exists
 .It Pa /etc/passwd
 user database (see
 .Xr passwd 5 )
-.It Pa /etc/login.conf.textual
-textual interface is forced if this file exists
+.It Pa /etc/session
+fallback session script run upon login (see
+.Xr session 5 )
 .El
 .Sh EXIT STATUS
 .Nm login
@@ -72,6 +87,7 @@ reboot, or exits 2 on fatal failure and the boot should halt.
 .Xr passwd 1 ,
 .Xr crypt_checkpass 3 ,
 .Xr passwd 5 ,
+.Xr session 5 ,
 .Xr init 8 ,
 .Xr login 8
 .Sh BUGS

login/login.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2015, 2018 Jonas 'Sortie' Termansen.
+ * Copyright (c) 2014, 2015, 2018, 2022 Jonas 'Sortie' Termansen.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -249,6 +249,10 @@ bool login(const char* username)
 		tcsetpgrp(0, getpgid(0)) ||
 		sigprocmask(SIG_SETMASK, &oldset, NULL) < 0 ||
 		settermmode(0, TERMMODE_NORMAL) < 0 ||
+		(execlp("./.session", "./.session", (const char*) NULL) < 0 &&
+		 errno != ENOENT && errno != EACCES) ||
+		(execlp("/etc/session", "/etc/session", (const char*) NULL) < 0 &&
+		 errno != ENOENT && errno != EACCES) ||
 		execlp(pwd->pw_shell, pwd->pw_shell, (const char*) NULL));
 		write(pipe_fds[1], &errno, sizeof(errno));
 		_exit(127);

share/man/man5/session.5

@@ -0,0 +1,51 @@
+.Dd September 18, 2022
+.Dt SESSION 5
+.Os
+.Sh NAME
+.Nm session
+.Nd user login ession
+.Sh SYNOPSIS
+.Nm ~/.session
+.Nm /etc/session
+.Sh DESCRIPTION
+.Xr login 8
+creates the user's session by running the user's
+.Nm
+script, which normally
+executes a command line or graphical user environment.
+The session concludes once the session script exits and
+.Xr login 8
+reclaims control.
+.Pp
+The session script is found by searching for an executable script in the
+following paths:
+.Bl -bullet -compact
+.It
+.Pa ~/.session
+.It
+.Pa /etc/session
+.El
+.Pp
+The user's shell from
+.Xr passwd 5
+is used as a fallback session.
+.Sh EXAMPLES
+The user's
+.Pa ~/.session
+file can be created in any text editor and then made executable:
+.Bd -literal -offset indent
+editor ~/.session
+chmod +x ~/.session
+.Ed
+.Ss Trianglix
+.Xr trianglix 1
+can be selected as the user's triangle environment with this executable
+.Pa ~/.session
+script:
+.Bd -literal -offset indent
+#!/bin/sh
+exec trianglix
+.Ed
+.Sh SEE ALSO
+.Xr passwd 5 ,
+.Xr login 8