crosstools 脚本分析

 大致分析了一下crosstool的all.sh脚本，这个脚本是被demo-arm.sh调用的 ，由于在demo-arm.sh里面没有太多的工作，因此从这个脚本开始分析crosstool，这个脚本其实是crosstool的主引擎。

#!/bin/sh
# abort函数，可以打印参数，这个参数一般是出错提示信息,exec命令一般会替代当前的
# 进程，因此本shell就退出了.
abort() {
    echo $@
    exec false
}
# Script to download sources for, build, and test a gnu/linux toolchain
# Copyright (c) 2003 by Dan Kegel, Ixia Communications.
# Copyright (c) 2003-2005 by Dan Kegel, Google
# All rights reserved.  This script is provided under the terms of the GPL.
# For questions, comments or improvements see the crossgcc mailing
# list at http://sources.redhat.com/ml/crossgcc, but do your homework first.
# As Bill Gatliff says, "THINK!"
#
# Meant to be invoked from another shell script.
# Usage: six environment variables must be set, namely:

# test -z 和 -n 使用来检查字符串是否长度为0的
test -z "${TARGET}"           && abort "Please set TARGET to the Gnu target identifier (e.g. pentium-linux)"
test -z "${TARGET_CFLAGS}"    && abort "Please set TARGET_CFLAGS to any compiler flags needed when building glibc (-O recommended)"
test -z "${BINUTILS_DIR}"     && abort "Please set BINUTILS_DIR to the bare filename of the binutils tarball or directory"
test -z "${GCC_DIR}"          && abort "Please set GCC_DIR to the bare filename of the gcc tarball or directory"

# When building a cygwin target LINUX_DIR and GLIBC_DIR are not needed.
if test "${CYGWIN_DIR}" = ""; then
  if test -z "${LINUX_SANITIZED_HEADER_DIR}" ; then
    test -z "${LINUX_DIR}"        && abort "Please set either LINUX_DIR or LINUX_SANITIZED_HEADER_DIR to the bare filename of the tarball or directory containing the kernel headers"
  else
    test -n "${LINUX_DIR}"        && echo "You set both LINUX_DIR and LINUX_SANITIZED_HEADER_DIR - ignoring LINUX_DIR for the build"
  fi
  test -z "${GLIBC_DIR}"        && abort "Please set GLIBC_DIR to the bare filename of the glibc tarball or directory"
fi

# Five environment variables are optional, namely:
test -z "${DEJAGNU}"          && echo  "DEJAGNU not set, so not running any regression tests"
test -z "${GCC_EXTRA_CONFIG}" && echo  "GCC_EXTRA_CONFIG not set, so not passing any extra options to gcc's configure script"
test -z "${GLIBC_ADDON_OPTIONS}" && echo "GLIBC_ADDON_OPTIONS not set, so building all glibc add-on's"
test -z "${KERNELCONFIG}"     && echo  "KERNELCONFIG not set, so not configuring linux kernel"

# 要么KERNELCONFIG为空，要么不为空且能读，要么就 abort
test -z "${KERNELCONFIG}" || test -r "${KERNELCONFIG}"  || abort  "Can't read file KERNELCONFIG = $KERNELCONFIG, please fix."

# -e 使其在接下来的命令执行的结果如果不为0时就自动退出，-x使每条指令被扩展开后打印出来
set -ex

# 指定了一个临时目录
TOOLCOMBO=$GCC_DIR-$GLIBC_DIR
BUILD_DIR=`pwd`/build/$TARGET/$TOOLCOMBO

TOP_DIR=`pwd`

# SRC_DIR指定的是将压缩的工具连源码解药缩到的目的目录
# These environment variables are optional:
if test -z "${SRC_DIR}"; then
   SRC_DIR=$BUILD_DIR
   echo  "SRC_DIR not set, so source tarballs will be unpacked in the build directory"
fi

# 不能把$PREFIX设置成"/" 或者 “/usr”，因为处理完后，会删除$PREFIX的目录
# Sanity checks
case x$PREFIX in
x/) abort "Don't set PREFIX to /, as /$PREFIX gets deleted!" ;;
x/usr) abort "Don't set PREFIX to /usr, as /$PREFIX gets deleted!" ;;
*) ;;
esac

# 用户检查，不建议使用root用户
case x$USER in
xroot) abort "Don't run all.sh or crosstool.sh as root, it's dangerous" ;;
*) ;;
esac

# 检查是否有对/tmp的写权限
test -w /tmp || abort "Cannot write to /tmp.  This makes patch and configure scripts unhappy.  Please fix."

# Arbitrary locations for the input and output of the build.
# Change or override these to your taste.
TARBALLS_DIR=${TARBALLS_DIR-$TOP_DIR/tarballs}
RESULT_TOP=${RESULT_TOP-$TOP_DIR/result}
PREFIX=${PREFIX-$RESULT_TOP/$TOOLCOMBO/$TARGET}

export TOOLCOMBO
export PREFIX
export BUILD_DIR
export SRC_DIR
export TARBALLS_DIR
export TOP_DIR

# 下面依次处理传递给本脚本的参数,$#是参数个数，由于不断shift所以参数
# 个数也在不断减少
# Download/unpack/patch tarballs, if desired
while [ $# -gt 0 ]; do
    case "$1" in
    --nounpack|-nounpack)
       opt_no_unpack=1
       ;;
    --nobuild|-nobuild)
       opt_no_build=1
       ;;
    --builduserland|-builduserland)
       opt_builduserland=1
       ;;
    --notest|-notest)
       opt_no_test=1
       ;;
    --gdb|-gdb)
       opt_gdb=1
       ;;
    --testlinux|-testlinux)
       opt_testlinux=1
       ;;
    *)
        abort "Usage: all.sh [--nounpack|--nobuild|--testlinux|--gdb|--builduserland|--notest]"
    esac
    shift
done

if test "$opt_gdb" = "1"; then
    test -z "${GDB_DIR}"          && echo "Defaulting to GDB_DIR=gdb-6.3" && GDB_DIR=gdb-6.3 && export GDB_DIR
fi

if test "$opt_no_unpack" = ""; then
   if test "$opt_builduserland" = "1"; then
      # Ah, nobody would want to change this :-)
      PTXDIST_DIR=ptxdist-testing-20031113
      export PTXDIST_DIR
   fi
   # Download and patch
   if test -d "$BUILD_DIR"; then
    # Remove in background
       mv $BUILD_DIR $BUILD_DIR.del.$$
       rm -rf $BUILD_DIR.del.$$ &
   fi
# mkdir -p 使得如果被创建的目录的父目录不存在，也将他创建   
   mkdir -p $BUILD_DIR
# 新建一个shell去下载和 打补丁
   sh getandpatch.sh
fi

if test "$opt_no_build" = ""; then
    # Build
    if [ -d "$PREFIX" ]; then
    # Remove in background for speed
    mv "$PREFIX" "$PREFIX.del.$$"
    rm  -rf  "$PREFIX.del.$$" &
    fi
    mkdir -p $PREFIX
    mkdir -p $BUILD_DIR
    cd $BUILD_DIR
    if test "${CYGWIN_DIR}" = ""; then
        sh $TOP_DIR/crosstool.sh
    else
        sh ${TOP_DIR}/crosstool-cygwin.sh
    fi
    cd $TOP_DIR

    sh testhello.sh
fi
if test "$opt_gdb" = "1"; then
    # Build a debugger
    # kludge: don't abort if it doesn't build; we want to know if the kernel builds, too
    sh gdb.sh || test "$opt_testlinux" = "1"
fi

if test "$opt_testlinux" = "1"; then
    # Build a Linux kernel to see if we can
    sh testlinux.sh
fi

if test "$opt_builduserland" = "1"; then
    # Build /bin/sh and any other non-toolchain things configured in ptx.config
    # Only needed if you can't run the target's normal /bin/sh with the new toolchain
    cd $BUILD_DIR
    sh $TOP_DIR/ptx.sh
fi

if test "$opt_no_test" = ""; then
    # Beefy test that lasts for hours
    cd $BUILD_DIR
    sh $TOP_DIR/crosstest.sh
fi

    接下来会分析他调用的一些子脚本

转自：http://www.cublog.cn/u2/72383/showart_1077079.html