# HG changeset patch
# User Rob Landley <rob@landley.net>
# Date 1276983889 18000
# Node ID e5f9681a8b3c90d73aa76b227142e5d3dceddc5c
# Parent  1f51b4a0517b148be83f06f44d8d69e275108eda
Lots of comment updates.  Add a NO_HOST_TOOLS=1 config option, and a few "time" calls to stages that didn't have them.  Put native-compiler.sh after root-filesystem.sh in build so it's slightly easier to document.

diff -r 1f51b4a0517b -r e5f9681a8b3c build.sh
--- a/build.sh	Sat Jun 19 16:42:03 2010 -0500
+++ b/build.sh	Sat Jun 19 16:44:49 2010 -0500
@@ -2,31 +2,58 @@
 
 # Run all the steps needed to build a system image from scratch.
 
-# Simplest: download, simple-cross-compiler, simple-root-filesystem,
-# system-image.
+# The default set of stages run by this script is:
+#   download, host-tools, simple-cross-compiler, simple-root-filesystem,
+#   native-compiler, root-filesystem, system-image.
+
+# That sanitizes the host build environment and builds a cross compiler,
+# cross compiles a root filesystem and a native toolchain for the target,
+# and finally packages the root filesystem up into a system image bootable
+# by qemu.
 
-# More likely: download, host-tools, simple-cross-compiler, cross-compiler,
-# native-compiler, simple-root-filesystem, root-filesystem, system-image
+# The simplest set of stages is:
+#   download, simple-cross-compiler, simple-root-filesystem, system-image.
+#
+# That skips sanitizing the host environment, and skips building the native
+# compiler.  It builds a system image containing just enough code to boot to
+# a command prompt.  To invoke that, do:
+#
+#   NO_HOST_TOOLS=1 NO_NATIVE_COMPILER=1 ./build.sh $TARGET
 
-# If run with no arguments, list architectures.
+# The optional cross-compiler stage (after simple-cross-compiler but before
+# simple-root-filesystem) creates a more powerful and portable cross compiler
+# that can be used to cross compile more stuff (if you're into that sort of
+# thing).  To enable it, "export CROSS_HOST_ARCH=i686" (or whichever target
+# you want the new cross compiler to run on).
+
+# Start with some housekeeping stuff.  If this script was run with no
+# arguments, list available architectures out of sources/targets.
 
 if [ $# -ne 1 ]
 then
-  echo "Usage: $0 ARCH"
-  . sources/include.sh
-  read_arch_dir
+  echo "Usage: $0 TARGET"
+
+  echo "Supported architectures:"
+  cd sources/targets
+  ls
+
+  exit 1
 fi
 ARCH="$1"
 
+# Use environment variables persistently set in the config file.
+
 [ -e config ] && source config
 
+# Allow the output directory to be overridden.  This hasn't been tested in
+# forever and probably doesn't work.
+
 [ -z "$BUILD" ] && BUILD="build"
 
-# A function to skip stages that have already been done (because the
-# tarball they create is already there).  Stages delete the tarballs of
-# later stages as a simple form of dependency tracking.
+# Very simple dependency tracking: skip stages that have already been done
+# (because the tarball they create is already there).
 
-# If you need to rebuild a stage and everything after it, delete its
+# If you need to rebuild a stage (and everything after it), delete its
 # tarball out of "build" and re-run build.sh.
 
 not_already()
@@ -51,7 +78,10 @@
 # Build host tools.  This populates a single directory with every command the
 # build needs, so we can ditch the host's $PATH afterwards.
 
-time ./host-tools.sh || exit 1
+if [ -z "$NO_HOST_TOOLS" ]
+then
+  time ./host-tools.sh || exit 1
+fi
 
 # Do we need to build the simple cross compiler?
 
@@ -72,20 +102,10 @@
 then
   rm -rf "$BUILD/simple-root-filesystem-$ARCH.tar.bz2"
 
-  ./cross_compiler.sh "$ARCH" || exit 1
+  time ./cross_compiler.sh "$ARCH" || exit 1
 fi
 
-# Build a native compiler.  It's statically linked by default so it can
-# run on an arbitrary host system.
-
-if not_already native-compiler && [ -z "$NO_NATIVE_COMPILER" ]
-then
-  rm -rf "$BUILD/root-filesystem-$ARCH.tar.bz2"
-
-  ./native-compiler.sh "$ARCH" || exit 1
-fi
-
-# Do we need to build the root filesystem?
+# Build the basic root filesystem.
 
 if not_already simple-root-filesystem
 then
@@ -99,7 +119,17 @@
 
 fi
 
-# Install the native compiler into the root filesystem (if any).
+# Build a native compiler.  It's statically linked by default so it can
+# run on an arbitrary host system.
+
+if not_already native-compiler && [ -z "$NO_NATIVE_COMPILER" ]
+then
+  rm -rf "$BUILD/root-filesystem-$ARCH.tar.bz2"
+
+  time ./native-compiler.sh "$ARCH" || exit 1
+fi
+
+# Install the native compiler into the root filesystem, if necessary.
 
 if not_already root-filesystem && [ -z "$NO_NATIVE_COMPILER" ]
 then
@@ -108,6 +138,8 @@
   time ./root-filesystem.sh "$ARCH" || exit 1
 fi
 
+# Package it up into something qemu can boot.
+
 if not_already system-image
 then
   time ./system-image.sh $1 || exit 1
@@ -121,5 +153,6 @@
   mkdir -p "$BUILD/rw-system-image-$ARCH" &&
   cp "$BUILD/system-image-$ARCH"/zImage-* "$BUILD/rw-system-image-$ARCH"
 
-  STAGE_NAME=rw-system-image SYSIMAGE_TYPE=ext2 SYSIMAGE_HDA_MEGS=2048 time ./system-image.sh $1 || exit 1
+  STAGE_NAME=rw-system-image SYSIMAGE_TYPE=ext2 SYSIMAGE_HDA_MEGS=2048 \
+    time ./system-image.sh $1 || exit 1
 fi
diff -r 1f51b4a0517b -r e5f9681a8b3c config
--- a/config	Sat Jun 19 16:42:03 2010 -0500
+++ b/config	Sat Jun 19 16:44:49 2010 -0500
@@ -19,6 +19,13 @@
 
 # export ROOT_NODIRS=1
 
+# Setting this tells build.sh to use the existing $PATH commands to build
+# everything, which probably won't work out of the box.  Cross compiling is
+# an insanely delicate process which requires a carefully configured host
+# environment.  If we don't set up our own, you'll have to supply one.
+
+# export NO_HOST_TOOLS=1
+
 # Set this to a comma separated list of packages to build statically,
 # or "none" to build all packages dynamically.  Set to "all" to build all
 # packages statically (and not install static libraries on the target).
diff -r 1f51b4a0517b -r e5f9681a8b3c host-tools.sh
--- a/host-tools.sh	Sat Jun 19 16:42:03 2010 -0500
+++ b/host-tools.sh	Sat Jun 19 16:44:49 2010 -0500
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-# Set up a known host environment, providing known versions all required
+# Set up a known host environment, providing known versions of all required
 # prerequisites, built from source.
 
 # This script serves a similar purpose to the temporary chroot system in
diff -r 1f51b4a0517b -r e5f9681a8b3c root-filesystem.sh
--- a/root-filesystem.sh	Sat Jun 19 16:42:03 2010 -0500
+++ b/root-filesystem.sh	Sat Jun 19 16:44:49 2010 -0500
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-# Combine simple-root-filesystem and native-compiler.
+# Combine the output of simple-root-filesystem and native-compiler.
 
 . sources/include.sh || exit 1
 
@@ -14,6 +14,8 @@
   echo "No $BUILD/native-compiler-$ARCH" >&2 &&
   exit 1
 
+cp -a "$BUILD/simple-root-filesystem-$ARCH/." "$STAGE_DIR" || dienow
+
 # Remove shared libraries copied from cross compiler.
 
 rm -rf "$BUILD/root-filesystem-$ARCH/usr/lib" 2>/dev/null
diff -r 1f51b4a0517b -r e5f9681a8b3c simple-root-filesystem.sh
--- a/simple-root-filesystem.sh	Sat Jun 19 16:42:03 2010 -0500
+++ b/simple-root-filesystem.sh	Sat Jun 19 16:44:49 2010 -0500
@@ -2,6 +2,10 @@
 
 # Build a basic busybox+uClibc root filesystem for a given target.
 
+# Requires a cross-compiler (or simple-cross-compiler) in the $PATH or in
+# the build directory.  In theory you can supply your own as long as the
+# prefix- name is correct.
+
 source sources/include.sh || exit 1
 read_arch_dir "$1"
 check_for_base_arch || exit 0