Fix diff link

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

ChangeLog.md

@@ -4,12 +4,37 @@ Change Log
 All relevant changes are documented in this file.
 
 
-[4.0][UNRELEASED] - 2021-03-xx
-------------------------------
+[4.1][UNRELEASED]
+-----------------
+
+Bug fix release.
+
+### Changes
+* Change behavior on SIGUSR1 to be compatible with sysvinit and systemd.
+  Previously SIGUSR1 caused Finit to halt, like BusyBox init.  This had
+  "interesting" side effects on Debian systems when coexisting with
+  sysvinit (upgrading/reinstalling causes scripts to `kill -USR1 1`)
+* Change how `contrib/debian/install.sh` sets up a Grub boot entry for
+  finit.  We now modify the $SUPPORTED_INITS variable in `10_linux`
+
+### Fixes
+* Stricter interface name validation in netlink plugin, modeled after
+  the kernel.  Suggested by Coverity Scan
+* The `contrib/*/install.sh` scripts failed to run from tarball
+* Fix #170: detect loss of default route when interfaces go down.  This
+  emulates the missing kernel netlink message to remove the condition
+  net/default/route to allow stopping dependent services
+* Fix #171: restore automatic mount of `/dev/shm`, `/dev/pts`, `/run`
+  and `/tmp`, unless mounted already by `/etc/fstab`.  This is what most
+  desktop systems expect PID 1 to do
+
+
+[4.0][] - 2021-04-26
+--------------------
 
 This release became v4.0, and not v3.2, because of incompatible changes
 to service conditions.  There are other significant changes as well, so
-make sure to read the whole changelog when upgrading.
+make sure to read the whole change log when upgrading.
 
 ### Changes
 * The stand-alone `reboot` tool has been replaced with a symlink to
@@ -24,28 +49,47 @@ make sure to read the whole changelog when upgrading.
 * Removed built-in inetd super server.  If you need this functionality,
   use an external inetd, like xinetd, instead.  A pull request for a
   stand-alone inetd, like watchdogd and getty, is most welcome!
-* Incompatible `configure` script changes, i.e., you must give proper
-  path arguments to the script, no more guessing just GNU defaults.
-  There are examples in the documentation and the `contrib/` section
-* Change service conditions from the non-obvious `<svc/path/to/foo>` to
-  `<pid/foo:id>`.  This to hopefully make it clear that one service's
-  'pid:!foo' pidfile is another service's `<pid/foo>` condition
-* Initial support for cgroups, every service now runs in its own cgroup
-  https://twitter.com/b0rk/status/1214341831049252870?s=20
+* Incompatible `configure` script changes, i.e., no guessing `--prefix`
+  and other paths.  Also, many options have been changed, renamed, or
+  flipped defaults, or even dropped altogether.  There are examples in
+  the documentation and the `contrib/` section
+* Service conditions change from the non-obvious `<svc/path/to/foo>` to
+  `<pid/foo:id>`.  Not only does this give simpler internal semantics,
+  it hopefully also makes it clear that one service's `pid:!foo` pidfile
+  is another service's `<pid/foo>` condition, issue #143
+* Initial support for cgroups v2:
+  - services runs in a cgroup named after their respective *.conf file
+  - top-level groups are; init, user, and system
+  - all top-level groups can be configured from finit *.conf files
+  - each service can tweak the cgroup settings
+  - Use `initctl [top|ps|cgroup]` commands to inspect runtime state
+  - https://twitter.com/b0rk/status/1214341831049252870?s=20
 * Major refactor of Finit's `main()` function to be able to start the
   event loop earlier.  This also facilitated factoring out functionality
   previously hard-coded in Finit, e.g., starting the bundled watchdogd,
   various distro packed udevd and other hotplugging tools
+* A proper rescue mode has been added.  It is started extremely early
+  and is protected with a bundled `suslogin`.  Exiting rescue mode now
+  brings up the system as a normal boot, as one expects
 * Support for `sysv` start/stop scripts as well as monitoring forking
   services, stared using `sysv` or `service` stanza
 * Support for custom `kill:DELAY`, default 3 sec.
 * Support for custom `halt:SIGNAL`, default SIGTERM
+* Support for `pre:script` and `post:script`, allows for setup and
+  teardown/cleanup before and after a service runs, issue #129
+* Support for `env:file` in `/etc/default/foo` or `/etc/conf.d/foo`, see
+  the contrib section for examples that utilize this feature.  Variables
+  expanded from env files, and the env files themselves, are tracked for
+  changes to see if a service .conf file is "dirty" and needs restart on
+  `initctl reload`
 * Support for tracking custom PID files, using `pid:!/path/to/foo.pid`,
   useful with new `sysv` or `service` which fork to background
 * Support starting run/task/services without absolute path, trust `$PATH`
 * Add support for `--disable-doc` and `--disable-contrib` to speed up
   builds and work around issue with massively parallel builds
-* Add support for `@console` also for external getty
+* Support for `@console` also for external getty
+* Support for `notty` option to built-in getty, for board bring-up
+* Support for `rescue` option to built-in getty, for rescue shells
 * Add `-b`, batch mode, for non-interactive use to `initctl`
 * Prefer udev to handle `/dev/` if mdev is also available
 * Redirect dbus daemon output to syslog
@@ -95,6 +139,8 @@ make sure to read the whole changelog when upgrading.
 * Always append `:ID` qualifier to conditions if set for a service
 * The IPC socket has moved from `/run/finit.sock` to `/run/finit/socket`
   officially only supported for use by the `initctl` tool
+* The IPC socket now uses `SOCK_SEQPACKET` instead of `SOCK_STREAM`.
+  Recommend using watchdogd v3.4, or later, which support this
 * Improved support for modern `/etc/network/interfaces`, which has
   include statements.  No more native `ifup` of individual interfaces,
   Finit now calls `ifup -a`, or `ifdown -a`, delegating all details to
@@ -112,16 +158,21 @@ make sure to read the whole changelog when upgrading.
   that do not have a watchdog
 * Fix #100: Early condition handling may not work if `/var/run` does
   not yet exist (symlink to `/run`).  Added compat layer for access
+* Fix #101: Built-in inetd removed
+* Fix #102: Start built-in watchdogd as a regular service
 * Fix #103: Register multiple getty if `@console` resolves to >1 TTY,
 * Fix #105: Only remove /etc/nologin when moving from runlevel 0, 1, 6
   Fixed by Jonas Johansson, Westermo
 * Fix #109: Support for PID files in sub-directories to `/var/run`
 * Handle rename of PID files, by Robert Andersson, Atlas Copco
+* Fix #110: automatic modprobe of RTC devices, built-in hwclock
 * Fix #120: Redirect `stdin` to `/dev/null` for services by default
 * Fix #122: Switch to `nanosleep()` to achieve "signal safe" sleep,
   fixed by Jacques de Laval, Westermo
 * Fix #124: Lingering processes in process group when session leader
   exits.  E.g., lingering `logit` processes when parent dies
+* Fix #127: Show all runparts scripts as they start, like rc.local, fixed
+  by Jacques de Laval, Westermo
 * Fix service name matching, e.g. for condition handling, may match with
   wrong service, by Jonas Holmberg, Westermo
 * Run all run-parts scripts using `/bin/sh -c foo` just like the standard
@@ -140,6 +191,8 @@ make sure to read the whole changelog when upgrading.
 * Provide service description for built-in watchdog daemon
 * Fix #138: Handle `SIGPWR` like `SIGSUR2`, i.e., power off the system
 * Drop the '%m' GNUism, for compat with older musl libc
+* Fix #139: call `tzset()` on `initctl reload` to activate system
+  timezone changes (for logging)
 
 
 [3.1][] - 2018-01-23
@@ -748,14 +801,14 @@ Major bug fix release.
 * Makefile fixes for installation, paths encoded wrong
 * Strip binaries + .so files, support for `$(CROSS)` toolchain strip
 * Default install is now to `/sbin/finit` and `/usr/`
-* Note change in `$PLUGIN_DIR` environemnt variable to `$plugindir`
+* Note change in `$PLUGIN_DIR` environment variable to `$plugindir`
 
 
 [1.2][] - 2012-09-27
 --------------------
 
 ### Changes
-* Update README with section on building and enviroment variables
+* Update README with section on building and environment variables
 
 ### Fixes
 * Fix installation paths encoded in finit binary
@@ -847,7 +900,7 @@ Major bug fix release.
 
 * Initial release
 
-[UNRELEASED]: https://github.com/troglobit/finit/compare/3.1...HEAD
+[UNRELEASED]: https://github.com/troglobit/finit/compare/4.0...HEAD
 [4.0]: https://github.com/troglobit/finit/compare/3.1...4.0
 [3.1]: https://github.com/troglobit/finit/compare/3.0...3.1
 [3.0]: https://github.com/troglobit/finit/compare/2.4...3.0
@@ -879,9 +932,3 @@ Major bug fix release.
 [0.2]: https://github.com/troglobit/finit/compare/0.1...0.2
 [libuEv]: https://github.com/troglobit/libuev
 [dea3ae8]: https://github.com/troglobit/finit/commit/dea3ae8
-
-<!--
-  -- Local Variables:
-  -- mode: markdown
-  -- End:
-  -->

README.md

@@ -44,6 +44,7 @@ Features include:
   * Built-in support for Debian/BusyBox `/etc/network/interfaces`
   * Cgroups v2, both configuration and monitoring in `initctl top`
   * Plugin support for customization
+  * Proper rescue mode with bundled `sulogin` for protected maintenance shell
 
 Focus is on small and embedded systems, although Finit is fully usable
 on server and desktop systems as well.  For working examples, see the

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT(Finit, 4.0-rc4, https://github.com/troglobit/finit/issues, finit, https://troglobit.com/finit.html)
+AC_INIT(Finit, 4.1-rc1, https://github.com/troglobit/finit/issues, finit, https://troglobit.com/finit.html)
 AC_CONFIG_AUX_DIR(aux)
 AM_INIT_AUTOMAKE([1.11 foreign dist-xz subdir-objects])
 AM_SILENT_RULES([yes])
@@ -8,7 +8,7 @@ AC_CONFIG_HEADER([config.h])
 AC_CONFIG_FILES([Makefile
 	contrib/Makefile
 	contrib/alpine/Makefile contrib/alpine/finit.d/Makefile contrib/alpine/finit.d/available/Makefile
-	contrib/debian/Makefile contrib/debian/finit.d/Makefile contrib/debian/finit.d/available/Makefile contrib/debian/grub.d/Makefile
+	contrib/debian/Makefile contrib/debian/finit.d/Makefile contrib/debian/finit.d/available/Makefile
 	contrib/void/Makefile   contrib/void/finit.d/Makefile   contrib/void/finit.d/available/Makefile
 	doc/Makefile
 	plugins/Makefile
@@ -48,11 +48,6 @@ PKG_CHECK_MODULES([uev],  [libuev >= 2.2.0])
 PKG_CHECK_MODULES([lite], [libite >= 2.2.0])
 
 # Check for configured Finit features
-AC_ARG_ENABLE(emergency_shell,
-	AS_HELP_STRING([--enable-emergency-shell], [Experimental emergency fallback at boot.
-	                Use only for debugging very early boot problems with Finit]),,[
-	enable_emergency_shell=no])
-
 AC_ARG_ENABLE(auto_reload,
         AS_HELP_STRING([--enable-auto-reload], [Automatic reload on any .conf change]),,[
 	enable_auto_reload=no])
@@ -61,10 +56,6 @@ AC_ARG_ENABLE(redirect,
         AS_HELP_STRING([--disable-redirect], [Disable redirection of service output to /dev/null]),,[
 	enable_redirect=yes])
 
-AC_ARG_ENABLE(logit,
-     AS_HELP_STRING([--disable-logit], [Disable logit, used for log redirection, default: enable]),,[
-     enable_logit=yes])
-
 AC_ARG_ENABLE(logrotate,
         AS_HELP_STRING([--disable-logrotate], [Disable built-in rotation of /var/log/wtmp, default enabled]),,[
 	enable_logrotate=yes])
@@ -122,14 +113,11 @@ AC_ARG_WITH(random-seed,
 
 AC_ARG_WITH(watchdog,
         AS_HELP_STRING([--with-watchdog=[DEV]], [Enable built-in watchdog, default: /dev/watchdog]),
-	[watchdog=$withval],[watchdog=])
+	[watchdog=$withval], [with_watchdog=no watchdog=])
 
 ### Enable features ###########################################################################
 
 # Create config.h from selected features and fallback defaults
-AS_IF([test "x$enable_emergency_shell" = "xyes"], [
-        AC_DEFINE(EMERGENCY_SHELL,  1, [Fork off init and let PID 1 wait and start /bin/sh if init crashes.])])
-
 AS_IF([test "x$enable_auto_reload" = "xyes"], [
         AC_DEFINE(AUTO_RELOAD, 1, [Finit automatically does `initctl reload` on any .conf change])])
 
@@ -137,9 +125,6 @@ AS_IF([test "x$enable_redirect" = "xyes"], [
 	AC_DEFINE(REDIRECT_OUTPUT, 1, [Enable redirection of service output to /dev/null])])
 
 ### Disable features ###########################################################################
-AS_IF([test "x$enable_logit" != "xno"], [
-	AC_DEFINE(LOGIT_ENABLED,  1, [Enable logit tool, used for log redirection by Finit])])
-
 AS_IF([test "x$enable_logrotate" != "xno"], [
 	AC_DEFINE(LOGROTATE_ENABLED, 1, [Enable built-in rotation of /var/log/wtmp et al.])])
 
@@ -198,12 +183,12 @@ AS_IF([test "x$with_watchdog" != "xno"], [
 	AS_IF([test "x$watchdog" = "xyes"], [
 		watchdog=/dev/watchdog])
 	with_watchdog=yes
-        AC_DEFINE_UNQUOTED(WDT_DEVNODE, "$watchdog", [Built-in watchdog device node])])
+        AC_DEFINE_UNQUOTED(WDT_DEVNODE, "$watchdog", [Built-in watchdog device node])], [
+	watchdog=])
 
 # Control build with automake flags
 AM_CONDITIONAL(STATIC,    [test "x$enable_static" = "xyes"])
 AM_CONDITIONAL(WATCHDOGD, [test "x$with_watchdog" != "xno"])
-AM_CONDITIONAL(LOGIT,     [test "x$enable_logit" = "xyes"])
 AM_CONDITIONAL(DOC,       [test "x$enable_doc" = "xyes"])
 AM_CONDITIONAL(CONTRIB,   [test "x$enable_contrib" = "xyes"])
 
@@ -251,8 +236,6 @@ Optional features:
   Install contrib/......: $enable_contrib
   Built-in watchdogd....: $with_watchdog $watchdog
   Built-in logrotate....: $enable_logrotate
-  Scripting tool logit..: $enable_logit
-  Emergency shell.......: $enable_emergency_shell
   Redirect output.......: $enable_redirect
   Default hostname......: $hostname
   Default runlevel......: $runlevel

contrib/alpine/install.sh

@@ -10,7 +10,7 @@ fi
 # Adjust base directory
 if [ -e alpine-release ]; then
     cd ../..
-elif [ ! -e autogen.sh ]; then
+elif [ ! -e configure.ac ]; then
     echo "*** Please run this script from the Finit base directory."
     exit 1
 fi

contrib/debian/Makefile.am

@@ -1,4 +1,4 @@
-SUBDIRS    = finit.d grub.d
+SUBDIRS    = finit.d
 docsdir   := @docdir@/contrib/debian
 docs_DATA  = README.md finit.conf os-release build.sh install.sh
 EXTRA_DIST = $(docs_DATA)

contrib/debian/README.md

@@ -20,29 +20,41 @@ tools pre-systemd work as intended.
 
     root@debian:~# apt install initscripts console-setup
 
+> **Note:** as of Debian 11 (Bullseye), libuev and libite are part of
+> the main section of Debian.  So just install the -dev packages :)
+
 The following script can then be used to configure, build, install and
 set up your system to run Finit:
 
     user@debian:~/finit$ contrib/debian/build.sh
 
 However, since `/sbin/init` already exists on your system, the script
-creates another entry in your GRUB config, in `/etc/grub.d/40_custom`,
-where `init=/sbin/finit` is added to your kernel line.  It is of course
-also possible to change the default init to Finit, if you do you can
-remove the custom Grub entry:
+creates another entry in your GRUB config by updating `$SUPPORTED_INITS`
+in `/etc/grub.d/10_inux` and run `update-grub`.  On reboot you will find
+a (finit) entry in the "Advanced options for Debian GNU/Linux" section.
+It is of course also possible to change the default init to Finit:
 
     user@debian:~/finit# cd /sbin
-    user@debian:/sbin# sudo rm init
+    user@debian:/sbin# sudo mv init oldinit
     user@debian:/sbin# sudo ln -s finit init
 
 Before rebooting, check the default [/etc/finit.conf](finit.conf) and
 `/etc/finit.d/*.conf` files.  The build + install script above provides
-a few sample `.conf` files. See `initctl list` after boot for a list of
-enabled and available services.
+a few sample `.conf` files.  See `initctl ls` after boot for a list of
+enabled and available services, you can then use `enable` and `disable`
+comands to `initctl`, followed by `reload` to activate your changes.
 
 You can also use a standard [/etc/rc.local](rc.local) for one-shot tasks
 and initialization like keyboard language etc.
 
+If you want to use the X Window system, `sudo apt install elogind`
+(Bullseye and later).  Followed by `initctl reload` (enabled by default)
+and logout/login again.  The elogind daemon ensures a regular non-root
+user can start and interact with an X session, otherwise keyboard and
+mouse won't work.  When you're happy, you can enable the lightdm.conf,
+change the default runlevel to 3, and presto! you have a desktop again.
+
+
 Have fun!  
  /Joachim ツ
 

contrib/debian/finit.d/Makefile.am

@@ -1,7 +1,8 @@
 SUBDIRS    = available
 docsdir   := @docdir@/contrib/debian/finit.d
-d_LINKS    = console-setup.conf getty.conf keyboard-setup.conf	\
-	     modules.conf rsyslogd.conf sshd.conf
+d_LINKS    = console-setup.conf elogind.conf getty.conf 	\
+	     keyboard-setup.conf modules.conf rsyslogd.conf	\
+	     sshd.conf
 
 install-exec-hook:
 	@$(MKDIR_P) $(DESTDIR)$(docsdir)/available

contrib/debian/finit.d/available/Makefile.am

@@ -1,5 +1,5 @@
 docsdir   := @docdir@/contrib/debian/finit.d/available
-docs_DATA  = acpid.conf console-setup.conf getty.conf keyboard-setup.conf \
-	     lightdm.conf modules.conf rsyslogd.conf sntpd.conf		  \
-	     sshd.conf syslogd.conf xdm.conf
+docs_DATA  = acpid.conf console-setup.conf elogind.conf getty.conf	\
+	     keyboard-setup.conf lightdm.conf modules.conf sntpd.conf	\
+	     rsyslogd.conf sshd.conf syslogd.conf xdm.conf
 EXTRA_DIST = $(docs_DATA)

contrib/debian/finit.d/available/elogind.conf

@@ -0,0 +1,4 @@
+# On some systems, bootstrap can be really quick and cause elogind
+# to not start before a user has managed to log in.  To prevent
+# this, add <pid/elogind> as condition to your TTYs in getty.conf
+service [2345] <pid/syslogd> /lib/elogind/elogind -- Login manager

contrib/debian/grub.d/40_custom

@@ -1,14 +0,0 @@
-#!/bin/sh
-exec tail -n +3 $0
-# This file provides an easy way to add custom menu entries.  Simply type the
-# menu entries you want to add after this comment.  Be careful not to change
-# the 'exec tail' line above.
-
-menuentry '$MENU with Finit' --class $TYPE --class gnu-linux --class gnu --class os --user {
-	insmod gzio
-	insmod part_msdos
-	insmod ext2
-	search --no-floppy --fs-uuid --set=root $BOOT
-	linux	/vmlinuz root=UUID=$ROOT ro quiet init=/sbin/finit
-	initrd	/initrd.img
-}

contrib/debian/grub.d/Makefile.am

@@ -1,3 +0,0 @@
-docsdir   := @docdir@/contrib/debian/grub.d
-docs_DATA  = 40_custom
-EXTRA_DIST = $(docs_DATA)

contrib/debian/install.sh

@@ -11,7 +11,7 @@ fi
 grep -q Debian os-release 2>/dev/null
 if [ $? -eq 0 ]; then
     cd ../..
-elif [ ! -e autogen.sh ]; then
+elif [ ! -e configure.ac ]; then
     echo "*** Please run this script from the Finit base directory."
     exit 1
 fi
@@ -23,7 +23,7 @@ echo "/sbin/finit           - PID 1"
 echo "/lib/finit/plugins/*  - All enabled Finit plugins"
 echo "/etc/finit.conf       - Finit configuration file"
 echo "/etc/finit.d/         - Finit services"
-echo "/etc/grub.d/40_custom - Add menu entry to the Grub boot loader"
+echo "/etc/grub.d/10_linux  - Add Finit to Grub's SUPPORTED_INITS"
 echo
 read -p "Do you want to continue (y/N)? " yorn
 echo
@@ -38,12 +38,18 @@ if [ "x$yorn" = "xy" -o "x$yorn" = "xY" ]; then
     cp -va finit.d /etc/
 
     echo "*** Setting up a GRUB boot entry ..."
-    MENU=`grep gnu-linux /boot/grub/grub.cfg |head -1 |sed "s/menuentry '\([^']*\).*/\1/"`
-    TYPE=`grep gnu-linux /boot/grub/grub.cfg |head -1 |sed "s/.*' --class \([a-z]*\).*/\1/"`
-    BOOT=`grep set=root /boot/grub/grub.cfg |head -1 |sed 's/.* \([a-f0-9]*-[a-f0-9]*-[a-f0-9]*-[a-f0-9]*-[a-f0-9]*\).*/\1/'`
-    ROOT=`grep root=UUID /boot/grub/grub.cfg |head -1 |sed 's/.*UUID=\([a-f0-9]*-[a-f0-9]*-[a-f0-9]*-[a-f0-9]*-[a-f0-9]*\).*/\1/'`
-    cat grub.d/40_custom | sed "s,\$BOOT,$BOOT,;s,\$ROOT,$ROOT,;s,\$TYPE,$TYPE,;s,\$MENU,$MENU," >/etc/grub.d/40_custom
-    update-grub
+    fn=/etc/grub.d/10_linux
+    if [ -e $fn ]; then
+	if `grep SUPPORTED_INITS $fn |head -1 |grep -q finit`; then
+	    echo "Already installed, done."
+	else
+	    echo "Adding Finit to list of SUPPORTED_INITS ..."
+	    sed -i 's/SUPPORTED_INITS="[^"]*/& finit:\/sbin\/finit/' $fn
+	    update-grub
+	fi
+    else
+	echo "Cannot find $fn, you'll have to set up your bootloader on your own."
+    fi
 
     echo
     echo "*** Done"

contrib/void/install.sh

@@ -10,7 +10,7 @@ fi
 # Adjust base directory
 if [ -e xbps ]; then
     cd ../..
-elif [ ! -e autogen.sh ]; then
+elif [ ! -e configure.ac ]; then
     echo "*** Please run this script from the Finit base directory."
     exit 1
 fi

doc/bootstrap.md

@@ -9,9 +9,11 @@ Bootstrap
 6. Load all `.so` plugins
 7. Call `fsck` on file systems listed in `/etc/fstab`
 8. Populate `/dev` using either udev or mdev, depending on system type
-9. Parse `/etc/finit.conf` and all `/etc/finit.d/*.conf` files
-10. Start built-in watchdog, if enabled
-11. Set hostname
+9. Parse `/etc/finit.conf`
+10. Start built-in watchdog, if enabled and `WDT_DEVNODE` exists.  This
+    means any WDT that requires a kernel module need to be either
+    compiled into the kernel, or insmod'ed in `/etc/finit.conf`
+11. Load all `/etc/finit.d/*.conf` files and set hostname
 12. Remount `/` read-write if `/` is listed in `/etc/fstab` without `ro`
 13. Call 1st level hooks, `HOOK_ROOTFS_UP`
 14. Mount all file systems listed in `/etc/fstab` and swap, if available

doc/cmdline.md

@@ -30,10 +30,12 @@ The `bool` setting is one of `on, off, true false, 1, 0`.
 * `quiet`: Suppress kernel logging to console, except for warnings and
   errors.
 
-* `rescue`: Start Finit rescue mode; no network, no `fsck` of file
-    systems in `/etc/fstab`, no `/etc/rc.local`, no `runparts`.  The
-    configuration is read from `/lib/finit/rescue.conf`, and can be
-    modified by the operator.
+* `rescue`: Start rescue/maintenance mode.  If your system comes with
+    the bundled `sulogin` program (Finit, or from util-linux/Busybox),
+    you will be given a root login to a maintenance shell.  However, if
+    `sulogin` is missing, the file `/lib/finit/rescue.conf` is read and
+    the system booted in a limited fallback mode.  See [config.md][]
+	for more information.
 
 * `single`, or `S`: Single user mode, runlevel 1, in Finit.  Useful to
     debug problems with the regular runlevel.  All services and TTYs in
@@ -42,5 +44,5 @@ The `bool` setting is one of `on, off, true false, 1, 0`.
 
 For more on kernel boot paramaters, see the man page [bootparam(7)][].
 
-
+[config.md][]:  config.md#rescue-mode
 [bootparam(7)]: https://www.man7.org/linux/man-pages/man7/bootparam.7.html

doc/config.md

@@ -21,9 +21,11 @@ Configuration
   * [TTYs and Consoles](#ttys-and-consoles)
   * [Non-privileged Services](#non-privileged-services)
   * [Redirecting Output](#redirecting-output)
+* [Rescue Mode](#rescue-mode)
 * [Limitations](#limitations)
   * [/etc/finit.conf](#etcfinitconf)
   * [/etc/finit.d](#etcfinitd)
+* [Watchdog](#watchdog)
 
 
 Introduction
@@ -37,8 +39,8 @@ Linux distributions -- each package can provide its own "script" file.
 - `/etc/finit.d/*.conf`: snippets, usually one service per file
 
 Not all configuration directives are available in `/etc/finit.d/*.conf`
-and some directives are only available at bootstrap, runlevel `S`, see
-the section [Limitations](#limitations) below for details.
+and some directives are only available at [bootstrap][], runlevel `S`,
+see the section [Limitations](#limitations) below for details.
 
 To add a new service, simply drop a `.conf` file in `/etc/finit.d` and
 run `initctl reload`.  (It is also possible to `SIGHUP` to PID 1, or
@@ -203,7 +205,7 @@ the contents of that file is used.
 
 Deprecated.  We recommend using `/etc/hostname` instead.
 
-> **Note:** only read and executed in runlevel S (bootstrap).
+> **Note:** only read and executed in runlevel S ([bootstrap][]).
 
 
 ### Kernel Modules
@@ -221,7 +223,7 @@ BusyBox mdev tool, add to `/etc/mdev.conf`:
 
     $MODALIAS=.*  root:root       0660    @modprobe -b "$MODALIAS"
 
-> **Note:** only read and executed in runlevel S (bootstrap).
+> **Note:** only read and executed in runlevel S ([bootstrap][]).
 
 
 ### Networking
@@ -234,7 +236,7 @@ Deprecated.  We recommend using dedicated task/run stanzas per runlevel,
 or `/etc/network/interfaces` if you have a system with `ifupdown`, like
 Debian, Ubuntu, Linux Mint, or an embedded BusyBox system.
 
-> **Note:** only read and executed in runlevel S (bootstrap).
+> **Note:** only read and executed in runlevel S ([bootstrap][]).
 
 
 ### Resource Limits
@@ -268,13 +270,13 @@ stanzas can share the same rlimits if they are in the same .conf.
 
 **Syntax:** `runlevel <N>`
 
-Defines the system runlevel to go to after bootstrap (S) has completed.
-N is the runlevel number 0-9, where 6 is reserved for reboot and 0 for
+The system runlevel to go to after [bootstrap][] (S) has completed.  `N`
+is the runlevel number 0-9, where 6 is reserved for reboot and 0 for
 halt.
 
 Default: 2
 
-> **Note:** only read and executed in runlevel S (bootstrap).
+> **Note:** only read and executed in runlevel S ([bootstrap][]).
 
 
 ### One-shot Commands (sequence)
@@ -426,7 +428,7 @@ SIGKILLed, this can be adjusted using the above `kill:SEC` syntax.
 Call [run-parts(8)][] on `DIR` to run start scripts.  All executable
 files, or scripts, in the directory are called, in alphabetic order.
 The scripts in this directory are executed at the very end of runlevel
-`S`, bootstrap.
+`S`, [bootstrap][].
 
 It can be beneficial to use `S01name`, `S02othername`, etc. if there
 is a dependency order between the scripts.  Symlinks to existing
@@ -436,7 +438,9 @@ Similar to the `/etc/rc.local` shell script, make sure that all your
 services and programs either terminate or start in the background or
 you will block Finit.
 
-> **Note:** only read and executed in runlevel S (bootstrap).
+> **Note:** only read and executed in runlevel S ([bootstrap][]).
+
+[run-parts(8)]: http://manpages.debian.org/cgi-bin/man.cgi?query=run-parts
 
 
 ### Including Finit Configs
@@ -464,7 +468,8 @@ size limit is reached.
 ### TTYs and Consoles
 
 **Syntax:** `tty [LVLS] <COND> DEV [BAUD] [noclear] [nowait] [nologin] [TERM]`  
-  `tty [LVLS] <COND> CMD <ARGS> [noclear] [nowait]`
+  `tty [LVLS] <COND> CMD <ARGS> [noclear] [nowait]`  
+  `tty [LVLS] <COND> [notty] [rescue]`
 
 The first variant of this option uses the built-in getty on the given
 TTY device DEV, in the given runlevels.  The DEV may be the special
@@ -483,9 +488,18 @@ The default baud rate is 0, i.e., keep kernel default.
 
 The second `tty` syntax variant is for using an external getty, like
 agetty or the BusyBox getty.
-    
-By default both variants *clear* the TTY and *wait* for the user to
-press enter before starting getty.
+
+The third variant is for board bringup and the `rescue` boot mode.  No
+device node is required in this variant, the same output that the kernel
+uses is reused for stdio.  If the `rescue` option is omitted, a shell is
+started (`nologin`, `noclear`, and `nowait` are implied), if the rescue
+option is set the bundled `/libexec/finit/sulogin` is started to present
+a bare-bones root login prompt.  If the root (uid:0, gid:0) user does
+not have a password set, no rescue is possible.  For more information,
+see the [Rescue Mode](#rescue-mode) section.
+
+By default, the first two syntax variants *clear* the TTY and *wait* for
+the user to press enter before starting getty.
 
 **Example:**
 
@@ -522,10 +536,11 @@ can be omitted to keep the kernel default.
 
     tty [12345] @console noclear vt220
 
-On really bare bones systems Finit can give you a shell prompt as
-soon as bootstrap is done, without opening any device node:
+On really bare bones systems, or for board bringup, Finit can give you a
+shell prompt as soon as [bootstrap][] is done, without opening any
+device node:
 
-    tty [12345789] notty noclear
+    tty [12345789] notty
 
 This should of course not be enabled on production systems.  Because it
 may give a user root access without having to log in.  However, for
@@ -581,6 +596,59 @@ Log rotation is controlled using the global `log` setting.
     service log:prio:user.warn,tag:ntpd /sbin/ntpd pool.ntp.org -- NTP daemon
 
 
+Rescue Mode
+-----------
+
+Finit supports a rescue mode which is activated by the `rescue` option
+on the kernel command line.  See [cmdline docs](cmdline.md) for how to
+activate it.
+
+The rescue mode comes in two flavors; *traditional* and *fallback*.
+
+
+### Traditional
+
+This is what most users expect.  A very early maintenance login prompt,
+served by the bundled `/libexec/finit/sulogin` program, or the standard
+`sulogin` from util-linux or BusyBox is searched for in the UNIX default
+`$PATH`.  If a successful login is made, or the user exits (Ctrl-D), the
+rescue mode is ended and the system boots up normally.
+
+> **Note:** if the user (UID 0 and GID 0) does not have a password, or
+> __the account is locked__, the user is presented with a password-less
+> `"Press enter to enter maintenance mode."`, prompt which opens up a
+> root shell.
+
+
+### Fallback
+
+If no `sulogin` program is found, Finit tries to bring up as much of its
+own functionality as possible, yet limiting many aspects, meaning; no
+network, no `fsck` of file systems in `/etc/fstab`, no `/etc/rc.local`,
+no `runparts`, and most plugins are skipped (except those that provide
+functionality for the condition subsystem).
+
+Instead of reading `/etc/finit.conf` et al, system configuration is read
+from `/lib/finit/rescue.conf`, which can be freely modified by the
+system administrator.
+
+The bundled default `rescue.conf` contains nothing more than:
+
+    runlevel 1
+    tty [12345] rescue
+
+The `tty` has the `rescue` option set, which works similar to the board
+bring-up tty option `notty`.  The major difference being that `sulogin`
+is started to query for root/admin password.  If `sulogin` is not found,
+`rescue` behaves like `notty` and gives a plain root shell prompt.
+
+If Finit cannot find `/lib/finit/rescue.conf` it defaults to:
+
+    tty [12345] rescue
+
+There is no way to exit the *fallback* rescue mode.
+
+
 Limitations
 -----------
 
@@ -590,15 +658,49 @@ from `/etc/finit.conf`, since it is the first `.conf` file Finit reads.
 
 Originally, `/etc/finit.conf` was the only way to set up a Finit system.
 Today it is mainly used for bootstrap settings like system hostname,
-network bringup and system shutdown.  These can now also be set in any
-`.conf` file in `/etc/finit.d`.
+early module loading for watchdogd, network bringup and system shutdown.
+These can now also be set in any `.conf` file in `/etc/finit.d`.
 
 There is, however, nothing preventing you from having all configuration
 settings in `/etc/finit.conf`.
 
 > **Note:** The `/etc/finit.d` directory was previously the default
->          Finit `runparts` directory.  Finit no longer has a default
->          `runparts`, make sure to update your setup, or the finit
->          configuration, accordingly.
+>          Finit [runparts](#run-parts-scripts) directory.  Finit no
+>          longer has a default `runparts`, make sure to update your
+>          setup, or the finit configuration, accordingly.
 
-[run-parts(8)]: http://manpages.debian.org/cgi-bin/man.cgi?query=run-parts
+
+Watchdog
+--------
+
+When built `--with-watchdog` a separate service is built and installed
+in `/libexec/finit/watchdogd`.  If this exists at runtime, and the WDT
+device node exists, Finit will start it and treat it as the elected
+watchdog service to delegate its reboot to.  See [bootstrap][] for
+details.  This delegation is to ensure that the system is rebooted by a
+hardware watchdog timer -- on many embedded systems this is crucial to
+ensure all circuits on the board are properly reset for the next boot,
+in effect ensuring the system works the same after both a power-on and
+reboot event.
+
+The delegation is performed at the very last steps of system shutdown,
+if reboot has been selected and an elected watchdog is known, first a
+`SIGPWR` is sent to advise watchdogd of the pending reboot.  Then, when
+the necessary steps of preparing the system for shutdown (umount etc.)
+are completed, Finit sends `SIGTERM` to watchdogd and puts itself in a
+10 sec timeout loop waiting for the WDT to reset the board.  If a reset
+is not done before the timeout, Finit falls back to`reboot(RB_AUTOBOOT)`
+which tells the kernel to do the reboot.
+
+An external watchdog service can also be used.  The more advanced cousin
+[watchdogd](https://github.com/troglobit/watchdogd/) is the recommended
+option here.  It can register itself with Finit using the same IPC as
+`initctl`.  If the bundled watchdogd is running a hand-over takes place,
+so it's safe to have both services installed on a system.  For the
+hand-over to work it requires that the WDT driver supports the safe exit
+functionality where `"V"` is written to the device before closing the
+device descriptor.  If the kernel driver has been built without this,
+the only option is to remove `/libexec/finit/watchdogd` or build without
+it at configure time.
+
+[bootstrap]: bootstrap.md

doc/signals.md

@@ -12,28 +12,36 @@ have been adopted:
 Same effect as `finit q`, `init q`, or `initctl reload`, reloads all
 *.conf files in `/etc/finit.d/`
 
+This also restarts the API (initctl) socket, like SysV init and systemd
+does on USR1 with their FIFO/D-Bus.
+
+
 `SIGUSR1`
 ---------
 
-Calls shutdown hooks, including `HOOK_SHUTDOWN`, stopping all running
-processes, and unmounts all file systems.  Then tells kernel to halt.
-Most people these days want `SIGUSR2` though.
+Since Finit 4.1 this signal causes Finit to restart its API (initctl)
+socket, like SysV init and systemd does on USR1 with their FIFO/D-Bus.
+
+Finit <= 4.0 performed a system halt (like USR2 without power-off), but
+this caused compatibility problems with systemd and sysvinit on desktop
+systems.  Hence, since Finit 4.1 it is no longer possible to halt a
+system with a signal.
 
-SysV init and systemd use this to re-open their FIFO/D-Bus.
 
 `SIGUSR2`
 ---------
 
-Like SIGUSR1, but tell kernel to power-off the system, if ACPI or
-similar exists to actually do this.  If the kernel fails power-off,
-Finit falls back to halt.
- 
+Calls shutdown hooks, including `HOOK_SHUTDOWN`, stopping all running
+processes, and unmounts all file systems.  Then tells kernel to power
+off the system, if ACPI or similar exists to actually do this.  If the
+kernel fails power-off, Finit falls back to halt.
+
 SysV init N/A, systemd dumps its internal state to log.
 
 `SIGTERM`
 ---------
 
-Like `SIGUSR1`, but tell kernel to reboot the system when done.
+Like `SIGUSR2`, but tell kernel to reboot the system when done.
  
 SysV init N/A, systemd rexecutes itself.
 

plugins/alsa-utils.c

@@ -30,6 +30,11 @@
 
 static void save(void *arg)
 {
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	if (whichp(ALSACTL)) {
 		_d("Saving sound settings ...");
 		run_interactive(ALSACTL " -g store", "Saving sound settings");
@@ -38,6 +43,11 @@ static void save(void *arg)
 
 static void restore(void *arg)
 {
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	if (whichp(ALSACTL)) {
 		_d("Restoring sound settings ...");
 		run_interactive(ALSACTL " -g restore", "Restoring sound settings");

plugins/dbus.c

@@ -43,6 +43,11 @@ static void setup(void *arg)
 	mode_t prev;
 	char *cmd;
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	cmd = which(DAEMON);
 	if (!cmd) {
 		_d("Skipping plugin, %s is not installed.", DAEMON);

plugins/hotplug.c

@@ -34,6 +34,11 @@ static void setup(void *arg)
 	char cmd[256];
 	char *path;
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	/*
 	 * Populate /dev and prepare for runtime events from kernel.
 	 * Prefer udev if mdev is also available on the system.

plugins/netlink.c

@@ -31,6 +31,9 @@
 #include "helpers.h"
 #include "plugin.h"
 
+static int ifdown = 0;
+
+
 static int nlmsg_validate(struct nlmsghdr *nh, size_t len)
 {
 	if (!NLMSG_OK(nh, len))
@@ -51,10 +54,16 @@ static int nlmsg_validate(struct nlmsghdr *nh, size_t len)
 
 static void nl_route(struct nlmsghdr *nlmsg, ssize_t len)
 {
+	char daddr[INET_ADDRSTRLEN];
+	char gaddr[INET_ADDRSTRLEN];
+	struct in_addr ind, ing;
 	struct rtmsg *r;
 	struct rtattr *a;
+	int plen = 0;
+	int dst = 0;
+	int idx = 0;
+	int gw = 0;
 	int la;
-	int gw = 0, dst = 0, mask = 0, idx = 0;
 
 	if (nlmsg->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtmsg))) {
 		_e("Packet too small or truncated!");
@@ -80,8 +89,8 @@ static void nl_route(struct nlmsghdr *nlmsg, ssize_t len)
 
 		case RTA_DST:
 			dst = *((int *)data);
-			mask = r->rtm_dst_len;
-			//_d("MASK: 0x%04x", mask);
+			plen = r->rtm_dst_len;
+			//_d("Prefix LEN: 0x%04x", plen);
 			break;
 
 		case RTA_OIF:
@@ -93,7 +102,13 @@ static void nl_route(struct nlmsghdr *nlmsg, ssize_t len)
 		a = RTA_NEXT(a, la);
 	}
 
-	if ((!dst && !mask) && (gw || idx)) {
+	ind.s_addr = dst;
+	ing.s_addr = gw;
+	inet_ntop(AF_INET, &ind, daddr, sizeof(daddr));
+	inet_ntop(AF_INET, &ing, gaddr, sizeof(gaddr));
+	_d("Got gw %s dst/len %s/%d ifindex %d", gaddr, daddr, plen, idx);
+
+	if ((!dst && !plen) && (gw || idx)) {
 		if (nlmsg->nlmsg_type == RTM_DELROUTE)
 			cond_clear("net/route/default");
 		else
@@ -101,6 +116,36 @@ static void nl_route(struct nlmsghdr *nlmsg, ssize_t len)
 	}
 }
 
+static int nl_default(struct nlmsghdr *nlh, struct in_addr *dst, struct in_addr *gw)
+{
+	struct in_addr nil = { 0 };
+	struct rtattr *a;
+	struct rtmsg *r;
+	int len;
+
+	r = (struct rtmsg *)NLMSG_DATA(nlh);
+	if ((r->rtm_family != AF_INET) || (r->rtm_table != RT_TABLE_MAIN))
+		return -1;
+
+	len = RTM_PAYLOAD(nlh);
+	for (a = RTM_RTA(r); RTA_OK(a, len); a = RTA_NEXT(a, len)) {
+		switch (a->rta_type) {
+		case RTA_GATEWAY:
+			memcpy(gw, RTA_DATA(a), sizeof(*gw));
+			break;
+
+		case RTA_DST:
+			memcpy(dst, RTA_DATA(a), sizeof(*dst));
+			break;
+		}
+	}
+
+	if (!memcmp(dst, &nil, sizeof(nil)) && memcmp(gw, &nil, sizeof(nil)))
+		return 0;
+
+	return 1;
+}
+
 static void net_cond_set(char *ifname, char *cond, int set)
 {
 	char msg[MAX_ARG_LEN];
@@ -117,14 +162,14 @@ static int validate_ifname(const char *ifname)
 	if (!ifname || !ifname[0])
 		return 1;
 
-	if (strlen(ifname) >= IFNAMSIZ)
+	if (strnlen(ifname, IFNAMSIZ) == IFNAMSIZ)
 		return 1;
 
-	if (strstr(ifname, ".."))
+	if (!strcmp(ifname, ".") || !strcmp(ifname, ".."))
 		return 1;
 
 	while (*ifname) {
-		if (*ifname == '/' || isspace(*ifname))
+		if (*ifname == '/' || *ifname == ':' || isspace(*ifname))
 			return 1;
 		ifname++;
 	}
@@ -134,10 +179,10 @@ static int validate_ifname(const char *ifname)
 
 static void nl_link(struct nlmsghdr *nlmsg, ssize_t len)
 {
-	int la;
 	char ifname[IFNAMSIZ + 1];
-	struct rtattr *a;
 	struct ifinfomsg *i;
+	struct rtattr *a;
+	int la;
 
 	if (nlmsg->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg))) {
 		_e("Packet too small or truncated!");
@@ -172,6 +217,8 @@ static void nl_link(struct nlmsghdr *nlmsg, ssize_t len)
 			net_cond_set(ifname, "exist",   1);
 			net_cond_set(ifname, "up",      i->ifi_flags & IFF_UP);
 			net_cond_set(ifname, "running", i->ifi_flags & IFF_RUNNING);
+			if (!(i->ifi_flags & IFF_UP) || !(i->ifi_flags & IFF_RUNNING))
+				ifdown = 1;
 			break;
 
 		case RTM_DELLINK:
@@ -180,6 +227,7 @@ static void nl_link(struct nlmsghdr *nlmsg, ssize_t len)
 			net_cond_set(ifname, "exist",   0);
 			net_cond_set(ifname, "up",      0);
 			net_cond_set(ifname, "running", 0);
+			ifdown = 1;
 			break;
 
 		case RTM_NEWADDR:
@@ -211,6 +259,9 @@ static void nl_callback(void *arg, int sd, int events)
 		return;
 	}
 
+	/* check for interface changes -> loss of default route */
+	ifdown = 0;
+
 	for (nh = (struct nlmsghdr *)buf; !nlmsg_validate(nh, len); nh = NLMSG_NEXT(nh, len)) {
 		//_d("Well formed netlink message received. type %d ...", nh->nlmsg_type);
 		if (nh->nlmsg_type == RTM_NEWROUTE || nh->nlmsg_type == RTM_DELROUTE)
@@ -218,6 +269,53 @@ static void nl_callback(void *arg, int sd, int events)
 		else
 			nl_link(nh, len);
 	}
+
+	/*
+	 * Linux doesn't send route changes, when interfaces go down, so
+	 * we need to check ourselves, e.g. for loss of default route.
+	 */
+	if (ifdown) {
+		unsigned int seq = 0;
+		int found = 0;
+
+		sd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+		if (sd < 0) {
+			_pe("netlink socket");
+			return;
+		}
+
+		memset(buf, 0, sizeof(buf));
+		nh = (struct nlmsghdr *)buf;
+		nh->nlmsg_len   = NLMSG_LENGTH(sizeof(struct rtmsg));
+		nh->nlmsg_type  = RTM_GETROUTE;
+		nh->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
+		nh->nlmsg_seq   = seq++;
+		nh->nlmsg_pid   = 1;
+
+		if (send(sd, nh, nh->nlmsg_len, 0) < 0) {
+			_pe("Failed netlink route request");
+			close(sd);
+			return;
+		}
+
+		len = recv(sd, buf, sizeof(buf), 0);
+		close(sd);
+
+		for (; NLMSG_OK(nh, len); nh = NLMSG_NEXT(nh, len)) {
+			struct in_addr dst = { 0 };
+			struct in_addr gw = { 0 };
+
+			if (nl_default(nh, &dst, &gw))
+				continue;
+
+			_d("default via %s\n", inet_ntoa(gw));
+			found = 1;
+		}
+
+		/* We already get notification when adding default rt */
+		if (!found)
+			cond_clear("net/route/default");
+	}
 }
 
 static void nl_reconf(void *arg)
@@ -236,8 +334,8 @@ static plugin_t plugin = {
 
 PLUGIN_INIT(plugin_init)
 {
-	int sd;
 	struct sockaddr_nl sa;
+	int sd;
 
 	sd = socket(AF_NETLINK, SOCK_RAW | SOCK_NONBLOCK | SOCK_CLOEXEC, NETLINK_ROUTE);
 	if (sd < 0) {

plugins/procps.c

@@ -23,6 +23,9 @@
 
 #include <glob.h>
 #include <lite/lite.h>
+
+#include "finit.h"
+#include "helpers.h"
 #include "plugin.h"
 
 static void setup(void *arg)
@@ -31,6 +34,11 @@ static void setup(void *arg)
 	glob_t gl;
 	char buf[160];
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	glob("/run/sysctl.d/*.conf",           0, NULL, &gl);
 	glob("/etc/sysctl.d/*.conf",           GLOB_APPEND, NULL, &gl);
 	glob("/usr/local/lib/sysctl.d/*.conf", GLOB_APPEND, NULL, &gl);

plugins/rtc.c

@@ -84,6 +84,11 @@ static void rtc_save(void *arg)
 	int fd, rc = 0;
 	char tz[128];
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	fd = rtc_open();
 	if (fd < 0)
 		return;
@@ -121,6 +126,11 @@ static void rtc_restore(void *arg)
 	int fd, rc = 0;
 	char tz[128];
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	fd = rtc_open();
 	if (fd < 0)
 		return;

plugins/urandom.c

@@ -35,6 +35,11 @@
 static void setup(void *arg)
 {
 #ifdef RANDOMSEED
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	if (!fexist(RANDOMSEED)) {
 		int ret = 1;
 		mode_t prev;
@@ -71,6 +76,11 @@ static void save(void *arg)
 #ifdef RANDOMSEED
 	mode_t prev;
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	prev = umask(077);
 
 	print_desc("Saving random seed", NULL);

plugins/x11-common.c

@@ -39,6 +39,11 @@ static void setup(void *arg)
 	int fd;
 #endif
 
+	if (rescue) {
+		_d("Skipping %s plugin in rescue mode.", __FILE__);
+		return;
+	}
+
 	prev = umask(0);
 
 	makedir("/var/run/console", 01777);

src/.gitignore

@@ -3,6 +3,7 @@ finit
 initctl
 logit
 reboot
+sulogin
 watchdogd
 Makefile
 Makefile.in

src/Makefile.am

@@ -8,21 +8,22 @@ AM_LDFLAGS         = -export-dynamic
 endif
 
 sbin_PROGRAMS        = finit initctl
-pkglibexec_PROGRAMS  =
+pkglibexec_PROGRAMS  = logit sulogin
 finit_pkglibdir      = $(pkglibdir)
 finit_pkglib_SCRIPTS = rescue.conf sample.conf
 
+sulogin_SOURCES      = sulogin.c
+sulogin_CFLAGS       = -W -Wall -Wextra -std=gnu99
+sulogin_LDADD        = -lcrypt
+
 if WATCHDOGD
 pkglibexec_PROGRAMS += watchdogd
 endif
 
-if LOGIT
-pkglibexec_PROGRAMS += logit
 logit_SOURCES        = logit.c logrotate.c
 logit_CFLAGS         = -W -Wall -Wextra -Wno-unused-parameter -std=gnu99
 logit_CFLAGS        += $(lite_CFLAGS)
 logit_LDADD          = $(lite_LIBS)
-endif
 
 finit_SOURCES      = api.c	cgroup.c	cgroup.h	\
 		     cond.c	cond-w.c	cond.h		\
@@ -47,7 +48,7 @@ if LOGROTATE
 finit_SOURCES     += logrotate.c
 endif
 
-pkginclude_HEADERS = cond.h finit.h helpers.h log.h plugin.h svc.h
+pkginclude_HEADERS = cgroup.h cond.h finit.h helpers.h log.h plugin.h svc.h
 
 finit_CFLAGS       = -W -Wall -Wextra -Wno-unused-parameter -std=gnu99
 finit_CFLAGS      += $(lite_CFLAGS) $(uev_CFLAGS)

src/cgutil.c

@@ -580,7 +580,7 @@ static void key(uev_t *w, void *arg, int events)
 			break;
 
 		default:
-			warnx("Got char 0x%02x", ch);
+			dbg("Got char 0x%02x", ch);
 			break;
 		}
 	}

src/conf.c

@@ -672,7 +672,7 @@ int conf_reload(void)
 
 	if (rescue) {
 		int rc;
-		char line[80] = "tty [12345] @console noclear nologin";
+		char line[80] = "tty [12345] rescue";
 
 		/* If rescue.conf is missing, fall back to a root shell */
 		rc = parse_conf(RESCUE_CONF, 0);

src/finit.c

@@ -52,6 +52,7 @@
 #include "util.h"
 #include "utmp-api.h"
 #include "schedule.h"
+#include "watchdog.h"
 
 int   runlevel  = 0;		/* Bootstrap 'S' */
 int   cfglevel  = RUNLEVEL;	/* Fallback if no configured runlevel */
@@ -185,6 +186,44 @@ static void fs_remount_root(int fsckerr)
 }
 #endif	/* SYSROOT */
 
+/*
+ * Opinionated file system setup.  Checks for critical mount points and
+ * mounts them as most users expect.  All file systems are checked with
+ * /proc/mounts before mounting.
+ *
+ * Embedded systems, and other people who want full control, can set up
+ * their system with /etc/fstab, which is handled before this function
+ * is called.  For systems like Debian/Ubuntu, who only have / and swap
+ * in their /etc/fstab, this function does all the magic necessary.
+ */
+static void fs_finalize(void)
+{
+	/*
+	 * Some systems rely on us to both create /dev/shm and, to mount
+	 * a tmpfs there.  Any system with dbus needs shared memory, so
+	 * mount it, unless its already mounted, but not if listed in
+	 * the /etc/fstab file already.
+	 */
+	if (!fismnt("/dev/shm")) {
+		makedir("/dev/shm", 0777);
+		mount("shm", "/dev/shm", "tmpfs", 0, "mode=0777");
+	}
+
+	/* Modern systems use /dev/pts */
+	if (!fismnt("/dev/pts")) {
+		makedir("/dev/pts", 0755);
+		mount("devpts", "/dev/pts", "devpts", 0, "gid=5,mode=620,ptmxmode=0666");
+	}
+
+	/* Modern systems use tmpfs for /run */
+	if (!fismnt("/run"))
+		mount("tmpfs", "/run", "tmpfs", 0, "mode=0755,nosuid,nodev,noexec,relatime");
+
+	/* Modern systems use tmpfs for /tmp */
+	if (!fismnt("/tmp"))
+		mount("tmpfs", "/tmp", "tmpfs", 0, "mode=0755,nosuid,nodev");
+}
+
 static void fs_mount(void)
 {
 	if (!rescue)
@@ -200,6 +239,9 @@ static void fs_mount(void)
 	plugin_run_hooks(HOOK_MOUNT_POST);
 
 	run("swapon -ea");
+
+	_d("Finalize, ensure common file systems are available ...");
+	fs_finalize();
 }
 
 /*
@@ -234,48 +276,6 @@ static void fs_init(void)
 	}
 }
 
-/*
- * If everything goes south we can use this to give the operator an
- * emergency shell to debug the problem -- Finit should not crash!
- *
- * Note: Only use this for debugging a new Finit setup, don't use
- *       this in production since it gives a root shell to anyone
- *       if Finit crashes.
- *
- * This emergency shell steps in to prevent "Aieee, PID 1 crashed"
- * messages from the kernel, which usually results in a reboot, so
- * that the operator instead can debug the problem.
- */
-static void emergency_shell(void)
-{
-#ifdef EMERGENCY_SHELL
-	pid_t pid;
-
-	pid = fork();
-	if (pid) {
-		while (1) {
-			pid_t id;
-
-			/* Reap 'em (prevents Zombies) */
-			id = waitpid(-1, NULL, WNOHANG);
-			if (id == pid)
-				break;
-		}
-
-		fprintf(stderr, "\n=> Embarrassingly, Finit has crashed.  Check /dev/kmsg for details.\n");
-		fprintf(stderr,   "=> To debug, add 'debug' to the kernel command line.\n\n");
-
-		/*
-		 * Become session leader and set controlling TTY
-		 * to enable Ctrl-C and job control in shell.
-		 */
-		setsid();
-		ioctl(STDIN_FILENO, TIOCSCTTY, 1);
-
-		execl(_PATH_BSHELL, _PATH_BSHELL, NULL);
-	}
-#endif /* EMERGENCY_SHELL */
-}
 
 /*
  * Handle bootstrap transition to configured runlevel, start TTYs
@@ -504,13 +504,24 @@ int main(int argc, char *argv[])
 	if (chdir("/"))
 		_pe("Failed cd /");
 
-	/* Allow progress, if enabled */
-	enable_progress(1);
-
 	/*
 	 * In case of emergency.
 	 */
-	emergency_shell();
+	if (rescue) {
+		char *sulogin[] = {
+			_PATH_SULOGIN,
+			"sulogin",
+		};
+		size_t i;
+
+		for (i = 0; i < NELEMS(sulogin); i++) {
+			if (systemf(sulogin[i]))
+				continue;
+
+			rescue = 0;
+			break;
+		}
+	}
 
 	/*
 	 * Load plugins early, the first hook is in banner(), so we
@@ -521,6 +532,7 @@ int main(int argc, char *argv[])
 	/*
 	 * Hello world.
 	 */
+	enable_progress(1);	/* Allow progress, if enabled */
 	banner();
 
 	/*
@@ -552,7 +564,7 @@ int main(int argc, char *argv[])
 	/*
 	 * Start built-in watchdogd as soon as possible, if enabled
 	 */
-	if (which(FINIT_LIBPATH_ "/watchdogd")) {
+	if (whichp(FINIT_LIBPATH_ "/watchdogd") && fexist(WDT_DEVNODE)) {
 		service_register(SVC_TYPE_SERVICE, "[123456789] name:watchdog :finit " FINIT_LIBPATH_ "/watchdogd -- Finit watchdog daemon", global_rlimit, NULL);
 		wdog = svc_find_by_nameid("watchdog", "finit");
 	}

src/finit.h

@@ -50,7 +50,8 @@
 #define FINIT_CGPATH            "/sys/fs/cgroup"
 #endif
 
-#define LOGIT_PATH              FINIT_LIBPATH_ "/logit"
+#define _PATH_LOGIT             FINIT_LIBPATH_ "/logit"
+#define _PATH_SULOGIN           FINIT_LIBPATH_ "/sulogin"
 
 #define CMD_SIZE                256
 #define LINE_SIZE               1024

src/getty.c

@@ -189,8 +189,8 @@ static int do_login(char *name)
 	execl(_PATH_LOGIN, _PATH_LOGIN, name, NULL);
 
 	/*
-	 * Failed to exec login, should be impossible.  Try a starting a
-	 * fallback shell instead.
+	 * Failed to exec login, should not happen on normal systems.
+	 * Try a starting a rescue shell instead.
 	 *
 	 * Note: Add /etc/securetty handling.
 	 */

src/iwatch.c

@@ -94,8 +94,24 @@ int iwatch_add(struct iwatch *iw, char *file, uint32_t mask)
 
 	wd = inotify_add_watch(iw->fd, path, IWATCH_MASK | mask);
 	if (wd < 0) {
-		if (errno != EEXIST)
+		switch (errno) {
+		case EEXIST:
+			break;
+
+		case EINVAL:
+			/*
+			 * some older kernels, notably 4.19, don't like
+			 * inotify on top-level cgroups in cgroup v2
+			 */
+			if (!strncmp(path, "/sys/fs/cgroup", 14))
+				break;	/* ignore error */
+			/* fallthrough */
+
+		default:
 			_pe("Failed adding watcher for %s", path);
+			break;
+		}
+
 		free(path);
 		return -1;
 	}

src/reboot.c

@@ -206,7 +206,7 @@ int reboot_main(int argc, char *argv[])
 
 	case CMD_HALT:
 		if (do_halt(NULL))
-			do_kill(SIGUSR1, msg);
+			do_kill(SIGUSR2, msg);
 		break;
 
 	case CMD_POWEROFF:

src/rescue.conf

@@ -1,3 +1,2 @@
 runlevel 1
-hostname rescue
-tty [12345] @console noclear nologin
+tty [12345] rescue

src/service.c

@@ -206,8 +206,8 @@ static int lredirect(svc_t *svc)
 		/* Reset signals */
 		sig_unblock();
 
-		if (!whichp(LOGIT_PATH)) {
-			logit(LOG_INFO, LOGIT_PATH " missing, using syslog for %s instead", svc->name);
+		if (!whichp(_PATH_LOGIT)) {
+			logit(LOG_INFO, _PATH_LOGIT " missing, using syslog for %s instead", svc->name);
 			fallback_logger(tag, prio);
 			_exit(0);
 		}
@@ -218,7 +218,7 @@ static int lredirect(svc_t *svc)
 			snprintf(sz, sizeof(sz), "%d", logfile_size_max);
 			snprintf(num, sizeof(num), "%d", logfile_count_max);
 
-			execlp(LOGIT_PATH, "logit", "-f", svc->log.file, "-n", sz, "-r", num, NULL);
+			execlp(_PATH_LOGIT, "logit", "-f", svc->log.file, "-n", sz, "-r", num, NULL);
 			_exit(1);
 		}
 
@@ -227,7 +227,7 @@ static int lredirect(svc_t *svc)
 		if (svc->log.prio[0])
 			prio = svc->log.prio;
 
-		execlp(LOGIT_PATH, "logit", "-t", tag, "-p", prio, NULL);
+		execlp(_PATH_LOGIT, "logit", "-t", tag, "-p", prio, NULL);
 		_exit(1);
 	}
 
@@ -466,7 +466,7 @@ static int service_start(svc_t *svc)
 		return 1;
 	}
 
-	if (svc_is_tty(svc)) {
+	if (svc_is_tty(svc) && !svc->notty) {
 		char *dev = tty_canonicalize(svc->dev);
 
 		if (!dev || !tty_exists(dev)) {
@@ -1044,6 +1044,12 @@ static void parse_cmdline_args(svc_t *svc, char *cmd)
 		}
 	}
 
+	/*
+	 * Check also for changes to /etc/default/foo, because this
+	 * also constitutes changes to command line args.
+	 */
+	diff += conf_changed(svc_getenv(svc));
+
 	if (diff)
 		_d("Modified args for %s detected", cmd);
 	svc->args_dirty = (diff > 0);
@@ -1295,6 +1301,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 		svc->nowait  = tty.nowait;
 		svc->nologin = tty.nologin;
 		svc->notty   = tty.notty;
+		svc->rescue  = tty.rescue;
 
 		/* TTYs cannot be redirected */
 		log = NULL;

src/sig.c

@@ -31,21 +31,24 @@
  *      does on USR1 with their FIFO/D-Bus.
  *
  * SIGUSR1
- *      Calls shutdown hooks, including HOOK_SHUTDOWN, stops all running
- *      processes, and unmounts all file systems.  Then tells kernel to
- *      halt.  Most people these days want SIGUSR2 though.
+ *      Restarts API (initctl) socket, like SysV init and systemd does
+ *      on USR1 with their FIFO/D-Bus.
  *
- *      (SysV init and systemd use this to re-open their FIFO/D-Bus.)
+ *      Finit <= 4.0 used to perform a system halt on USR1.  This caused
+ *      some quite nasty problems on systems with both systemd/sysvinit
+ *      installed alongside finit.  For compatibility reasons Finit 4.1
+ *      changed to partial SIGHUP (api_exit/init).
  *
  * SIGUSR2
- *      Like SIGUSR1, but tell kernel to power-off the system, if ACPI
- *      or similar exists to actually do this.  If the kernel fails
- *      power-off, Finit falls back to halt.
+ *      Calls shutdown hooks, including HOOK_SHUTDOWN, stops all running
+ *      processes, and unmounts all file systems.  Then tells kernel to
+ *      power-off the system, if ACPI or similar exists to actually do
+ *      this.  If the kernel fails power-off, Finit falls back to halt.
  *
  *      (SysV init N/A, systemd dumps its internal state to log.)
  *
  * SIGTERM
- *      Like SIGUSR1, but tell kernel to reboot the system when done.
+ *      Like SIGUSR2, but tell kernel to reboot the system when done.
  *
  *      (SysV init N/A, systemd rexecutes itself.)
  *
@@ -323,7 +326,7 @@ static void sigint_cb(uev_t *w, void *arg, int events)
 }
 
 /*
- * SIGUSR1: BusyBox style halt
+ * SIGUSR1: SysV init/systemd API socket restart
  */
 static void sigusr1_cb(uev_t *w, void *arg, int events)
 {
@@ -333,8 +336,9 @@ static void sigusr1_cb(uev_t *w, void *arg, int events)
 		return;
 	}
 
-	halt = SHUT_HALT;
-	service_runlevel(0);
+	/* Restart initctl API domain socket, similar to systemd/SysV init */
+	api_exit();
+	api_init(w->ctx);
 }
 
 /*
@@ -520,7 +524,7 @@ void sig_setup(uev_ctx_t *ctx)
 	/* Standard SysV init calls ctrl-alt-delete handler */
 	uev_signal_init(ctx, &sigint_watcher, sigint_cb, NULL, SIGINT);
 
-	/* BusyBox init style signals for halt, power-off and reboot. */
+	/* BusyBox/SysV init style signals for halt, power-off and reboot. */
 	uev_signal_init(ctx, &sigusr1_watcher, sigusr1_cb, NULL, SIGUSR1);
 	uev_signal_init(ctx, &sigusr2_watcher, sigusr2_cb, NULL, SIGUSR2);
 	uev_signal_init(ctx, &sigpwr_watcher, sigusr2_cb, NULL, SIGPWR);

src/sulogin.c

@@ -0,0 +1,213 @@
+/* poor man's sulogin, may be statically linked
+ *
+ * Copyright (c) 2021  Joachim Wiberg <troglobit@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <crypt.h>
+#include <err.h>
+#include <paths.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+
+/* getpwnam() cannot be used when statically linked */
+static int get_passwd(struct passwd *pw)
+{
+	char *ptr, *tmp;
+	char buf[256];
+	FILE *fp;
+
+	fp = fopen("/etc/passwd", "r");
+	if (!fp)
+		return 1;
+
+	while ((tmp = fgets(buf, sizeof(buf), fp))) {
+		if (!strstr(buf, ":0:0:"))
+			continue;	/* not uid 0 */
+
+		ptr = strsep(&tmp, ":");
+		if (!ptr)
+			break;
+		pw->pw_name = strdup(ptr);
+
+		ptr = strsep(&tmp, ":");
+		if (!ptr)
+			break;
+
+		/* x : password in /etc/shadow, see passwd(5) */
+		if (ptr[0] != 'x')
+			pw->pw_passwd = strdup(ptr);
+
+		break;			/* done, check it */
+	}
+	fclose(fp);
+
+	if (!pw->pw_name)
+		return 1;		/* no uid 0 here */
+	if (pw->pw_passwd)
+		return 0;		/* passwd in passwd */
+
+	fp = fopen("/etc/shadow", "r");
+	if (!fp) {
+		if (pw->pw_name)
+			free(pw->pw_name);
+		return 1;
+	}
+
+	while ((tmp = fgets(buf, sizeof(buf), fp))) {
+		ptr = strsep(&tmp, ":");
+		if (!ptr)
+			break;
+
+		if (!strcmp(tmp, pw->pw_name))
+			continue;
+
+		ptr = strsep(&tmp, ":");
+		if (!ptr)
+			break;
+
+		pw->pw_passwd = strdup(ptr);
+		break;
+	}
+	fclose(fp);
+
+	if (!pw->pw_passwd) {
+		if (pw->pw_name)
+			free(pw->pw_name);
+		return 1;		/* nopass => nologin */
+	}
+
+	return 0;			/* passwd in shadow */
+}
+
+static void freepw(struct passwd *pw)
+{
+	if (pw->pw_passwd) {
+		free(pw->pw_passwd);
+		pw->pw_passwd = NULL;
+	}
+	free(pw->pw_name);
+}
+
+static int sh(void)
+{
+	/*
+	 * Become session leader and set controlling TTY
+	 * to enable Ctrl-C and job control in shell.
+	 */
+	setsid();
+	ioctl(STDIN_FILENO, TIOCSCTTY, 1);
+	setenv("PS1", "# ", 1);
+
+	return execl(_PATH_BSHELL, "-sh", NULL);
+}
+
+int main(void)
+{
+	struct termios old, raw;
+	struct passwd pw = { 0 };
+	int rc = 1, ch;
+
+	if (get_passwd(&pw))
+		err(1, "reading credentials for UID 0");
+
+	switch (pw.pw_passwd[0]) {
+	case '*': case '!':	/* login disabled, allow */
+		printf("The %s account is locked, allowing entry.\n", pw.pw_name);
+		/* fallthrough */
+	case 0:			/* no password at all? */
+		printf("Press enter for maintenance (Ctrl-D to continue) ");
+		fflush(stdout);
+		ch = getchar();
+		if (ch == 4 || ch == EOF) { /* Ctrl-D */
+			rc = 0;
+			goto done;
+		}
+		goto nopass;
+
+	case '$': /* md5/shaN or similar, original DES not supported */
+		break;
+	default:
+		break;
+	}
+
+	if (tcgetattr(1, &old) < 0)
+		goto done;		/* failed reading tty */
+
+	raw = old;
+	raw.c_lflag &= ~ICANON;
+	raw.c_lflag &= ~ECHO;
+	raw.c_cc[VMIN] = 1;
+	raw.c_cc[VTIME] = 0;
+	if (tcsetattr(1, TCSANOW, &raw) < 0) {
+                tcsetattr(1, TCSANOW, &old);
+		goto done;		/* failed setting raw/pw mode */
+	}
+
+	while (1) {
+		char pwd[256];		/* reasonable max? */
+		size_t i = 0;
+		char *passwd;
+
+		printf("Give %s password for maintenance (Ctrl-D to continue): ", pw.pw_name);
+		fflush(stdout);
+		do {
+			ch = getchar();
+			if (ch == '\n' || ch == '\r')
+				break;
+			if (ch == 4 || ch == EOF) { /* Ctrl-D */
+				rc = 0;
+				goto exit;
+			}
+
+			pwd[i++] = ch;
+		} while (i + 1 < sizeof(pwd));
+		pwd[i] = 0;
+		puts("");
+
+		passwd = crypt(pwd, pw.pw_passwd);
+		if (passwd && !strcmp(passwd, pw.pw_passwd)) {
+			tcsetattr(1, TCSANOW, &old);	/* restore tty */
+		nopass:
+			freepw(&pw);
+
+			return sh();
+		}
+	}
+
+exit:
+	tcsetattr(1, TCSANOW, &old);	/* restore tty */
+	puts("");
+done:
+	freepw(&pw);
+	return rc;
+}
+
+/**
+ * Local Variables:
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */

src/svc.c

@@ -433,7 +433,7 @@ svc_t *svc_find_by_tty(char *dev)
 {
 	svc_t *svc, *iter = NULL;
 
-	/* this is valid for fallback (notty) shells */
+	/* rescue (notty) shells have no device node */
 	if (!dev)
 		return NULL;
 

src/svc.h

@@ -149,6 +149,7 @@ typedef struct svc {
 			char  nowait;
 			char  nologin;
 			char  notty;
+			char  rescue;
 		};
 	};
 

src/tty.c

@@ -158,7 +158,9 @@ int tty_parse_args(char *cmd, struct tty *tty)
 		else if (!strcmp(cmd, "nologin"))
 			tty->nologin = 1;
 		else if (!strcmp(cmd, "notty"))
-			tty->notty = 1;	/* for fallback shell */
+			tty->notty = 1;		/* for board bringup */
+		else if (!strcmp(cmd, "rescue"))
+			tty->rescue = 1;	/* for rescue shells */
 		else if (!access(cmd, X_OK))
 			tty->cmd = cmd;
 		else
@@ -167,6 +169,10 @@ int tty_parse_args(char *cmd, struct tty *tty)
 		cmd = strtok(NULL, " \t");
 	} while (cmd && tty->num < NELEMS(tty->args));
 
+	/* rescue shells are always notty */
+	if (tty->rescue)
+		tty->notty = 1;
+
 	/* skip /dev probe, we just want a bríngup shell */
 	if (tty->notty)
 		return 0;
@@ -220,27 +226,38 @@ int tty_parse_args(char *cmd, struct tty *tty)
 
 int tty_exists(char *dev)
 {
-	int fd, result;
 	struct termios c;
+	int fd, rc;
 
 	fd = open(dev, O_RDWR);
 	if (-1 == fd)
 		return 0;
 
 	/* XXX: Add check for errno == EIO? */
-	result = tcgetattr(fd, &c);
+	rc = tcgetattr(fd, &c);
 	close(fd);
 
-	return result == 0;
+	return rc == 0;
 }
 
-int tty_exec(svc_t *tty)
+int tty_exec(svc_t *svc)
 {
 	char *args[MAX_NUM_SVC_ARGS];
 	char *dev;
 	int i, j;
 
-	if (tty->notty) {
+	/* try to protect system with sulogin, fall back to root shell */
+	if (svc->notty) {
+		if (svc->rescue) {
+			/* check if bundled one is available */
+			if (whichp(_PATH_SULOGIN))
+				return execl(_PATH_SULOGIN, _PATH_SULOGIN, NULL);
+
+			/* util-linux or busybox, no args for compat */
+			if (whichp("sulogin"))
+				return execlp("sulogin", "sulogin", NULL);
+		}
+
 		/*
 		 * Become session leader and set controlling TTY
 		 * to enable Ctrl-C and job control in shell.
@@ -249,12 +266,12 @@ int tty_exec(svc_t *tty)
 		ioctl(STDIN_FILENO, TIOCSCTTY, 1);
 
 		prctl(PR_SET_NAME, "finitsh", 0, 0, 0);
-		return execl(_PATH_BSHELL, _PATH_BSHELL, NULL);
+		return execl(_PATH_BSHELL, "-sh", NULL);
 	}
 
-	dev = tty_canonicalize(tty->dev);
+	dev = tty_canonicalize(svc->dev);
 	if (!dev) {
-		_d("%s: Cannot find TTY device: %s", tty->dev, strerror(errno));
+		_d("%s: Cannot find TTY device: %s", svc->dev, strerror(errno));
 		return EX_CONFIG;
 	}
 
@@ -263,24 +280,24 @@ int tty_exec(svc_t *tty)
 		return EX_OSFILE;
 	}
 
-	if (tty->nologin) {
+	if (svc->nologin) {
 		_d("%s: Starting /bin/sh ...", dev);
-		return run_sh(dev, tty->noclear, tty->nowait, tty->rlimit);
+		return run_sh(dev, svc->noclear, svc->nowait, svc->rlimit);
 	}
 
-	_d("%s: Starting %sgetty ...", dev, !tty->cmd ? "built-in " : "");
-	if (!strcmp(tty->cmd, "tty"))
-		return run_getty(dev, tty->baud, tty->term, tty->noclear, tty->nowait, tty->rlimit);
+	_d("%s: Starting %sgetty ...", dev, !svc->cmd ? "built-in " : "");
+	if (!strcmp(svc->cmd, "tty"))
+		return run_getty(dev, svc->baud, svc->term, svc->noclear, svc->nowait, svc->rlimit);
 
 	for (i = 1, j = 0; i < MAX_NUM_SVC_ARGS; i++) {
-		if (!tty->args[i][0])
+		if (!svc->args[i][0])
 			break;
 
-		args[j++] = tty->args[i];
+		args[j++] = svc->args[i];
 	}
 	args[j++] = NULL;
 
-	return run_getty2(dev, tty->cmd, args, tty->noclear, tty->nowait, tty->rlimit);
+	return run_getty2(dev, svc->cmd, args, svc->noclear, svc->nowait, svc->rlimit);
 }
 
 /**

src/tty.h

@@ -40,6 +40,7 @@ struct tty {
 	char	 nowait;
 	char	 nologin;
 	char	 notty;
+	char	 rescue;
 };
 
 char	*tty_canonicalize (char *dev);