#!/bin/sh

echo "*** BUILD BUSYBOX BEGIN ***"

global SRC_DIR := $[pwd]

# Read the 'JOB_FACTOR' property from '.config'
global JOB_FACTOR := $[grep -i ^JOB_FACTOR .config | cut -f2 -d'=]

# Find the number of available CPU cores.
global NUM_CORES := $[grep ^processor /proc/cpuinfo | wc -l]

# Calculate the number of 'make' jobs to be used later.
global NUM_JOBS := $(NUM_CORES * JOB_FACTOR)

# Remember the glibc installation area.
global GLIBC_PREPARED := "$[pwd]/work/glibc/glibc_prepared"

cd work/busybox

# Remove the old BusyBox install area
rm -rf busybox_installed

# Change to the source directory ls finds, e.g. 'busybox-1.24.2'.
cd $[ls -d busybox-*]

# Remove previously generated artifacts.
echo "Preparing BusyBox work area. This may take a while..."
make distclean -j $NUM_JOBS

# Read the 'USE_PREDEFINED_BUSYBOX_CONFIG' property from '.config'
global USE_PREDEFINED_BUSYBOX_CONFIG := $[grep -i ^USE_PREDEFINED_BUSYBOX_CONFIG $SRC_DIR/.config | cut -f2 -d'=]

if test $USE_PREDEFINED_BUSYBOX_CONFIG = "true" -a ! -f $SRC_DIR/minimal_config/busybox.config  {
  echo "Config file $SRC_DIR/minimal_config/busybox.config does not exist."
  global USE_PREDEFINED_BUSYBOX_CONFIG := '"false'"
}

if test $USE_PREDEFINED_BUSYBOX_CONFIG = "true"  {
  # Use predefined configuration file for Busybox.
  echo "Using config file $SRC_DIR/minimal_config/busybox.config"  
  cp -f $SRC_DIR/minimal_config/busybox.config .config
} else {
  # Create default configuration file.
  echo "Generating default BusyBox configuration..."  
  make defconfig -j $NUM_JOBS
  
  # The 'inetd' applet fails to compile because we use the glibc installation area as
  # main pointer to the kernel headers (see 05_prepare_glibc.sh) and some headers are
  # not resolved. The easiest solution is to ignore this particular applet. 
  sed -i "s/.*CONFIG_INETD.*/CONFIG_INETD=n/" .config
}

# This variable holds the full path to the glibc installation area as quoted string.
# All back slashes are escaped (/ => \/) in order to keep the 'sed' command stable.
global GLIBC_PREPARED_ESCAPED := $[echo '"'$GLIBC_PREPARED'"' | sed 's/\//\\\//g]

# Now we tell BusyBox to use the glibc prepared area.
sed -i "s/.*CONFIG_SYSROOT.*/CONFIG_SYSROOT=$GLIBC_PREPARED_ESCAPED/" .config

# Compile busybox with optimization for "parallel jobs" = "number of processors".
echo "Building BusyBox..."
make \
  EXTRA_CFLAGS="-Os -s -fno-stack-protector -U_FORTIFY_SOURCE" \
  busybox -j $NUM_JOBS

# Create the symlinks for busybox. The file 'busybox.links' is used for this.
echo "Generating BusyBox based initramfs area..."
make \
  CONFIG_PREFIX="../busybox_installed" \
  install -j $NUM_JOBS

cd $SRC_DIR

echo "*** BUILD BUSYBOX END ***"

(CommandList
  children: [
    (C {(echo)} {(DQ ("*** BUILD BUSYBOX BEGIN ***"))})
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:SRC_DIR)
          op: Equal
          rhs: 
            {
              (CommandSubPart
                command_list: (CommandList children:[(C {(pwd)})])
                left_token: <Left_CommandSub "$(">
                spids: [12 14]
              )
            }
          spids: [11]
        )
      ]
      spids: [11]
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:JOB_FACTOR)
          op: Equal
          rhs: 
            {
              (DQ 
                (CommandSubPart
                  command_list: 
                    (CommandList
                      children: [
                        (Pipeline
                          children: [
                            (C {(grep)} {(-i)} {(Lit_Other "^") (JOB_FACTOR)} {(.config)})
                            (C {(cut)} {(-f2)} {(-d) (SQ <"=">)})
                          ]
                          negated: False
                        )
                      ]
                    )
                  left_token: <Left_CommandSub "$(">
                  spids: [22 42]
                )
              )
            }
          spids: [20]
        )
      ]
      spids: [20]
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:NUM_CORES)
          op: Equal
          rhs: 
            {
              (CommandSubPart
                command_list: 
                  (CommandList
                    children: [
                      (Pipeline
                        children: [
                          (C {(grep)} {(Lit_Other "^") (processor)} {(/proc/cpuinfo)})
                          (C {(wc)} {(-l)})
                        ]
                        negated: False
                      )
                    ]
                  )
                left_token: <Left_CommandSub "$(">
                spids: [50 63]
              )
            }
          spids: [49]
        )
      ]
      spids: [49]
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:NUM_JOBS)
          op: Equal
          rhs: 
            {
              (ArithSubPart
                anode: 
                  (ArithBinary
                    op_id: Arith_Star
                    left: (ArithVarRef name:NUM_CORES)
                    right: (ArithVarRef name:JOB_FACTOR)
                  )
                spids: [70 77]
              )
            }
          spids: [69]
        )
      ]
      spids: [69]
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:GLIBC_PREPARED)
          op: Equal
          rhs: 
            {
              (CommandSubPart
                command_list: (CommandList children:[(C {(pwd)})])
                left_token: <Left_CommandSub "$(">
                spids: [84 86]
              ) (/work/glibc/glibc_prepared)
            }
          spids: [83]
        )
      ]
      spids: [83]
    )
    (C {(cd)} {(work/busybox)})
    (C {(rm)} {(-rf)} {(busybox_installed)})
    (C {(cd)} 
      {
        (CommandSubPart
          command_list: (CommandList children:[(C {(ls)} {(-d)} {(busybox-) (Lit_Other "*")})])
          left_token: <Left_CommandSub "$(">
          spids: [110 117]
        )
      }
    )
    (C {(echo)} {(DQ ("Preparing BusyBox work area. This may take a while..."))})
    (C {(make)} {(distclean)} {(-j)} {($ VSub_Name "$NUM_JOBS")})
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:USE_PREDEFINED_BUSYBOX_CONFIG)
          op: Equal
          rhs: 
            {
              (DQ 
                (CommandSubPart
                  command_list: 
                    (CommandList
                      children: [
                        (Pipeline
                          children: [
                            (C {(grep)} {(-i)} {(Lit_Other "^") (USE_PREDEFINED_BUSYBOX_CONFIG)} 
                              {($ VSub_Name "$SRC_DIR") (/.config)}
                            )
                            (C {(cut)} {(-f2)} {(-d) (SQ <"=">)})
                          ]
                          negated: False
                        )
                      ]
                    )
                  left_token: <Left_CommandSub "$(">
                  spids: [143 164]
                )
              )
            }
          spids: [141]
        )
      ]
      spids: [141]
    )
    (If
      arms: [
        (if_arm
          cond: [
            (Sentence
              child: 
                (C {(Lit_Other "[")} {(DQ ($ VSub_Name "$USE_PREDEFINED_BUSYBOX_CONFIG"))} 
                  {(Lit_Other "=")} {(DQ (true))} {(-a)} {(KW_Bang "!")} {(-f)} {($ VSub_Name "$SRC_DIR") (/minimal_config/busybox.config)} 
                  {(Lit_Other "]")}
                )
              terminator: <Op_Semi ";">
            )
          ]
          action: [
            (C {(echo)} 
              {
                (DQ ("Config file ") ($ VSub_Name "$SRC_DIR") 
                  ("/minimal_config/busybox.config does not exist.")
                )
              }
            )
            (Assignment
              keyword: Assign_None
              pairs: [
                (assign_pair
                  lhs: (LhsName name:USE_PREDEFINED_BUSYBOX_CONFIG)
                  op: Equal
                  rhs: {(DQ (false))}
                  spids: [207]
                )
              ]
              spids: [207]
            )
          ]
          spids: [-1 195]
        )
      ]
      spids: [-1 212]
    )
    (If
      arms: [
        (if_arm
          cond: [
            (Sentence
              child: 
                (C {(Lit_Other "[")} {(DQ ($ VSub_Name "$USE_PREDEFINED_BUSYBOX_CONFIG"))} 
                  {(Lit_Other "=")} {(DQ (true))} {(Lit_Other "]")}
                )
              terminator: <Op_Semi ";">
            )
          ]
          action: [
            (C {(echo)} 
              {(DQ ("Using config file ") ($ VSub_Name "$SRC_DIR") (/minimal_config/busybox.config))}
            )
            (C {(cp)} {(-f)} {($ VSub_Name "$SRC_DIR") (/minimal_config/busybox.config)} {(.config)})
          ]
          spids: [-1 233]
        )
      ]
      else_action: [
        (C {(echo)} {(DQ ("Generating default BusyBox configuration..."))})
        (C {(make)} {(defconfig)} {(-j)} {($ VSub_Name "$NUM_JOBS")})
        (C {(sed)} {(-i)} {(DQ ("s/.*CONFIG_INETD.*/CONFIG_INETD=n/"))} {(.config)})
      ]
      spids: [259 307]
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:GLIBC_PREPARED_ESCAPED)
          op: Equal
          rhs: 
            {
              (CommandSubPart
                command_list: 
                  (CommandList
                    children: [
                      (Pipeline
                        children: [
                          (C {(echo)} 
                            {(EscapedLiteralPart token:<Lit_EscapedChar "\\\"">) 
                              ($ VSub_Name "$GLIBC_PREPARED") (EscapedLiteralPart token:<Lit_EscapedChar "\\\"">)
                            }
                          )
                          (C {(sed)} {(SQ <"s/\\//\\\\\\//g">)})
                        ]
                        negated: False
                      )
                    ]
                  )
                left_token: <Left_CommandSub "$(">
                spids: [317 331]
              )
            }
          spids: [316]
        )
      ]
      spids: [316]
    )
    (C {(sed)} {(-i)} 
      {(DQ ("s/.*CONFIG_SYSROOT.*/CONFIG_SYSROOT=") ($ VSub_Name "$GLIBC_PREPARED_ESCAPED") (/))} {(.config)}
    )
    (C {(echo)} {(DQ ("Building BusyBox..."))})
    (C {(make)} {(Lit_VarLike "EXTRA_CFLAGS=") (DQ ("-Os -s -fno-stack-protector -U_FORTIFY_SOURCE"))} 
      {(busybox)} {(-j)} {($ VSub_Name "$NUM_JOBS")}
    )
    (C {(echo)} {(DQ ("Generating BusyBox based initramfs area..."))})
    (C {(make)} {(Lit_VarLike "CONFIG_PREFIX=") (DQ (../busybox_installed))} {(install)} {(-j)} 
      {($ VSub_Name "$NUM_JOBS")}
    )
    (C {(cd)} {($ VSub_Name "$SRC_DIR")})
    (C {(echo)} {(DQ ("*** BUILD BUSYBOX END ***"))})
  ]
)