### -*-makefile-*-
###
### Main maintenance script for chroots
###
### (c) 2018 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This file is part of the distorted.org.uk chroot maintenance tools.
###
### distorted-chroot is free software: you can redistribute it and/or
### modify it under the terms of the GNU General Public License as
### published by the Free Software Foundation; either version 2 of the
### License, or (at your option) any later version.
###
### distorted-chroot is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
### General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with distorted-chroot.  If not, write to the Free Software
### Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
### USA.

all::
clean::
.PHONY: all clean
.SECONDEXPANSION: #sorry

###--------------------------------------------------------------------------
### Configuration.

CONFIG_VARS		 =

## Volume group from which to allocate chroot volumes and snapshots.
CONFIG_VARS		+= VG LVPREFIX
VG			 = vg-$(shell hostname)
LVPREFIX		 =

## Logical volume size, as an LVM option.
CONFIG_VARS		+= LVSZ
LVSZ			 = -L8G

## Debian mirror.
CONFIG_VARS		+= DEBMIRROR
DEBMIRROR		 = http://deb.debian.org/debian/

## APT sources configurations.  (Also, $($d_APTSRC) for each $d in $(DISTS).)
CONFIG_VARS		+= APTSRC
APTSRC			 = etc/aptsrc.conf $(wildcard etc/aptsrc.local.conf)

## APT configuration fragment names.  These will be linked into
## `/etc/apt/apt.conf.d' in each chroot.  To put a fragment f in a surprising
## place, set $($f_APTCONFSRC).
CONFIG_VARS		+= APTCONF
APTCONF_DIR		 = etc/apt-conf.d
APTCONF			 = $(notdir $(wildcard $(APTCONF_DIR)/[0-9]*[!~]))

## Proxy setting.
CONFIG_VARS		+= PROXY
PROXY			:= $(shell \
	eval $$(apt-config $(foreach a,$(APTCONF), -c$(APTCONF_DIR)/$a) \
		shell proxy Acquire::http::proxy); \
	case $${proxy+t} in (t) echo "$$proxy" ;; (*) echo nil ;; esac)

## Debian distributions to support.
CONFIG_VARS		+= PRIMARY_DIST DISTS
PRIMARY_DIST		 = stretch
DISTS			 = $(PRIMARY_DIST) buster bullseye sid

## Host's native architecture(s).
CONFIG_VARS		+= MYARCH NATIVE_ARCHS
MYARCH			 = $(shell dpkg --print-architecture)
OTHERARCHS		 = $(shell dpkg --print-foreign-architectures)
NATIVE_ARCHS		 = $(MYARCH) $(OTHERARCHS)

## Foreign (emulated) architectures to support.
CONFIG_VARS		+= FOREIGN_ARCHS
FOREIGN_ARCHS		 =

## Master lists of chroots to build and maintain.
NATIVE_CHROOTS		 = $(foreach a,$(NATIVE_ARCHS), \
				$(foreach d,$(or $($a_DISTS) $(DISTS)), \
					$d-$a))
FOREIGN_CHROOTS		 = $(foreach a,$(FOREIGN_ARCHS), \
				$(foreach d,$(or $($a_DISTS) $(DISTS)), \
					$d-$a))

## Which host architecture to use for foreign architectures.  It turns out
## that it's best to use a Qemu with the same host bitness as the target
## architecture; otherwise it has to do a difficult job of converting
## arguments and results between kernel ABI flavours.
32BIT_QEMUHOST		 = $(or $(filter i386,$(NATIVE_ARCHS)),$(TOOLSARCH))
64BIT_QEMUHOST		 = $(or $(filter amd64,$(NATIVE_ARCHS)),$(TOOLSARCH))

CONFIG_VARS		+= $(foreach a,$(FOREIGN_ARCHS), $a_QEMUHOST)
armel_QEMUHOST		 = $(32BIT_QEMUHOST)
armhf_QEMUHOST		 = $(32BIT_QEMUHOST)
arm64_QEMUHOST		 = $(64BIT_QEMUHOST)
i386_QEMUHOST		 = $(32BIT_QEMUHOST)
amd64_QEMUHOST		 = $(64BIT_QEMUHOST)

## Qemu architecture names.  These tell us which Qemu binary to use for a
## particular Debian architecture.
CONFIG_VARS		+= $(foreach a,$(FOREIGN_ARCHS), $a_QEMUARCH)
armel_QEMUARCH		 = arm
armhf_QEMUARCH		 = arm
arm64_QEMUARCH		 = aarch64
i386_QEMUARCH		 = i386
amd64_QEMUARCH		 = x86_64

## Alias mapping for chroots.
CONFIG_VARS		+= $(foreach d,$(DISTS), $d_ALIASES)
stretch_ALIASES		 = oldstable
buster_ALIASES		 = stable
bullseye_ALIASE		 = testing
sid_ALIASES		 = unstable

## Which host architecture to use for commonly used tools in foreign chroots.
CONFIG_VARS		+= TOOLSARCH
TOOLSARCH		 = $(MYARCH)

## A directory in which we can maintain private files and state.
CONFIG_VARS		+= STATE
STATE			 = state

## A directory which will be spliced into chroots as `/usr/local.schroot/'.
## This will be our primary point of contact with the chroot.
CONFIG_VARS		+= LOCAL
LOCAL			 = local.schroot

## How to run a command as a privileged user.
ROOTLY			 = sudo

## Files to be copied into a chroot from the host.
SCHROOT_COPYFILES	 = /etc/resolv.conf
SCHROOT_NSSDATABASES	 = passwd shadow group gshadow

## Local configuration hook.
-include local.mk

## All chroot names.
CONFIG_VARS		+= ALL_CHROOTS
ALL_CHROOTS		 = $(NATIVE_CHROOTS) $(FOREIGN_CHROOTS)

###--------------------------------------------------------------------------
### Utilities.

##	$(call chroot-dist,D-A) -> D
##	$(call chroot-arch,D-A) -> A
##
## Parse chroot descriptions.
chroot-dist		 = $(patsubst %/,%,$(dir $(subst -,/,$1)))
chroot-arch		 = $(notdir $(subst -,/,$1))

##	$(call native-chroot-p,D-A) -> D | <empty>
##
## Answer whether D-A is a native chroot.
native-chroot-p		 = $(filter $(call chroot-arch,$1), $(NATIVE_ARCHS))

##	$(call chroot-qemuhost,D-A) -> AA
##
## Answer the apporopriate Qemu host architecture for foreign chroot D-A.
chroot-qemuhost		 = $($(call chroot-arch,$1)_QEMUHOST)

##	$(call chroot-deps,PRE,D-A) -> PRE/DD-AA ... | <empty>
##
## Answer a list of additional dependencies for the chroot D-A: specifically,
## if D-A is foreign then include PRE/DD-AA entries for the tools
## architecture, and Qemu host architecture (if that's different).
chroot-deps		 = $(if $(call native-chroot-p,$2),, \
				$(addprefix $1/$(call chroot-dist,$2)-,\
					$(sort $(call chroot-toolsarch,$2) \
					       $(call chroot-qemuhost,$2))))

## Substituting placeholders in files.
SUBSTITUTIONS		:= local=$(shell realpath $(LOCAL))
SUBSTITUTIONS		+= primary-dist=$(PRIMARY_DIST)
subst-file		 = { \
	echo "$1 GENERATED by distorted-chroot: do not edit"; \
	substs=""; \
	for v in $(SUBSTITUTIONS); do \
	  var=$${v%%=*} value=$${v\#*=}; \
	  substs="$$substs s@$$var@$$valueg;"; \
	done; \
	sed "$$substs"; \
}

## Silent-rules machinery.
V			 = 0
V_AT			 = $(V_AT_$V)
V_AT_0			 = @
v_print			 = $(call v_print_$V,$1,$2)
v_print_0		 = printf "  %-8s %s\n" "$1" "$2";
v_tag			 = $(V_AT)$(call v_print,$1,$@)
v_log			 = $(call v_log_$V,$1)
v_log_			 = $(call v_log_1,$1)
v_log_0			 = >$1.log 2>&1
v_log_1			 = 2>&1 | tee $1.log
CLEANFILES		+= *.log

###--------------------------------------------------------------------------
### APT configuration.

## In a chroot, `/etc/apt/sources.list' links to
## `/usr/local.schroot/etc/apt/sources.$d' for the appropriate distribution.
APT_SOURCES		 = $(foreach d,$(DISTS), $(LOCAL)/etc/apt/sources.$d)
CLEANFILES		+= $(APT_SOURCES)
all:: $(APT_SOURCES)

$(foreach d,$(DISTS), $(STATE)/etc/apt/aptsrc.$d): $(STATE)/etc/apt/aptsrc.%:
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,GEN){ \
	  echo "### -*-conf-*- GENERATED by distorted-chroot: do not edit"; \
	  echo "subscribe"; \
	  echo "	debian : $*"; \
	} >$@.new && mv $@.new $@

$(APT_SOURCES): $(LOCAL)/etc/apt/sources.%: \
		$$(APTSRC) $$($$*_APTSRC) $$(STATE)/etc/apt/aptsrc.$$*
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,GEN)bin/mkaptsrc \
		$(APTSRC) $($*_APTSRC) $(STATE)/etc/apt/aptsrc.$* \
		>$@.new && mv $@.new $@

## In a chroot, a link `/etc/apt/apt.conf.d/FOO' is created for each file in
## `/usr/local.schroot/etc/apt/apt.conf.d/FOO'.
APT_CONFIGS	       = $(addprefix $(LOCAL)/etc/apt/apt.conf.d/,$(APTCONF))
all:: $(APT_CONFIGS)
$(APT_CONFIGS): $(LOCAL)/etc/apt/apt.conf.d/%: \
		$$(or $$($$*_APTCONFSRC) $$(APTCONF_DIR)/$$*)
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,COPY)cp $< $@.new && mv $@.new $@

###--------------------------------------------------------------------------
### `schroot' and `sbuild' configuration.

all:: schroot-config
schroot-config::
.PHONY: schroot-config

%print-varlist		 = { \
	echo "\#\#\# -*-sh-*- GENERATED by distorted-chroot: do not edit"; \
	$(foreach v,$1, echo $v=\''$(subst ','\'\\\'\'',$($v))'\';) \
} #'
schroot-config_HASH	:= \
	$(shell $(call %print-varlist,$(CONFIG_VARS)) | \
		sha256sum | cut -c1-32)
schroot-config_FILE	 = $(STATE)/config.sh-$(schroot-config_HASH)
$(schroot-config_FILE):
	$(V_AT)mkdir -p $(STATE)
	$(V_AT)rm -f $(STATE)/config.sh-*
	$(call v_tag,STAMP)$(call %print-varlist,$(CONFIG_VARS)) \
		>$@.new && mv $@.new $@

schroot-config:: $(STATE)/config.sh
$(STATE)/config.sh: $(schroot-config_FILE)
	$(call v_tag,SYMLINK)ln -sf $(notdir $<) $@

schroot-config:: $(STATE)/etc/schroot/sbuild.schroot
$(STATE)/etc/schroot/sbuild.schroot: $(STATE)/config.sh bin/mkchrootconf
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,GEN)bin/mkchrootconf >$@.new && mv $@.new $@

schroot-config:: $(STATE)/etc/schroot/sbuild.profile/copyfiles
$(STATE)/etc/schroot/sbuild.profile/copyfiles: $(schroot-config_STAMP)
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,GEN){ \
	  echo "### -*-conf-*- GENERATED by distorted-chroot: do not edit"; \
	  for i in $(SCHROOT_COPYFILES); do echo "$$i"; done; \
	} >$@.new && mv $@.new $@

schroot-config:: $(STATE)/etc/schroot/sbuild.profile/nssdatabases
$(STATE)/etc/schroot/sbuild.profile/nssdatabases: $(schroot-config_STAMP)
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,GEN){ \
	  echo "### -*-conf-*- GENERATED by distorted-chroot: do not edit"; \
	  for i in $(SCHROOT_NSSDATABASES); do echo "$$i"; done; \
	} >$@.new && mv $@.new $@

schroot-config:: $(STATE)/etc/schroot/sbuild.profile/fstab
$(STATE)/etc/schroot/sbuild.profile/fstab: \
		etc/sbuild.fstab.in $(schroot-config_STAMP)
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,SUBST)$(call subst-file,### -*-conf-*-) \
		<$< >$@.new && mv $@.new $@

schroot-config:: $(STATE)/etc/sbuild.conf
$(STATE)/etc/sbuild.conf: etc/sbuild.conf.in $(schroot-config_STAMP)
	$(V_AT)mkdir -p $(dir $@)
	$(call v_tag,SUBST)$(call subst-file,### -*-perl-*-) \
		<$< >$@.new && mv $@.new $@

###--------------------------------------------------------------------------
### Constructing chroots.

BUILD_CHROOTS		 = $(addprefix chroot/,$(ALL_CHROOTS))
CHROOT_STAMPS		 = $(addprefix $(STATE)/stamp/chroot.,$(ALL_CHROOTS))
all:: setup-chroots
setup-chroots: $(BUILD_CHROOTS)
$(BUILD_CHROOTS): chroot/%: $(STATE)/stamp/chroot.%
.PHONY: setup-chroots $(BUILD_CHROOTS)

$(CHROOT_STAMPS): $(STATE)/stamp/chroot.%: $(STATE)/config.sh bin/mkbuildchroot
	$(call v_tag,CHROOT)bin/mkbuildchroot \
		$(call chroot-dist,$*) $(call chroot-arch,$*) \
		$(call v_log,setup-chroot.$*)

###--------------------------------------------------------------------------
### Installing basic custom software.



###--------------------------------------------------------------------------
### Other maintenance targets.

show:; : $x

clean::
	rm -f $(CLEANFILES)
	rm -rf $(STATE)

realclean:: clean
	rm -rf $(LOCAL)

###----- That's all, folks --------------------------------------------------