1. #!/bin/bash
  2. # This is an update version of the script found at
  3. # http://forum.xda-developers.com/wiki/index.php?title=Extract_initramfs_from_zImage
  4. #
  5. # The problem with that script is that the gzip magic number occasionally occur
  6. # naturally, meaning that some non-compressed files get uncompressed.
  8. #GET CURRENT DIR
  9. CURRENT_DIR=`pwd`
  10. TEMP_DIR=$CURRENT_DIR/out
  11. KERNEL_FILE=kernel
  12. KERNEL_GZIP_FILE=kernel.gz
  13. KERNEL_LZMA_FILE=kernel.lzma
  14. KERNEL_XZ_FILE=kernel.xz
  15. KERNEL_LZO_FILE=kernel.lzo
  16. INITRAMFS_FILE=initramfs.cpio
  17. INITRAMFS_DIR=initramfs_root
  19. # DO NOT MODIFY BELOW THIS LINE
  20. [ -z $1 ] && exit 1 || boot_img=$1
  21. [ ! -e $1 ] && exit 1
  23. zImage=$TEMP_DIR/zImage
  25. C_H1="\033[1;36m" # highlight text 1
  26. C_ERR="\033[1;31m"
  27. C_CLEAR="\033[1;0m"
  29. printhl() {
  30. printf "${C_H1}[I] ${1}${C_CLEAR} \n"
  31. }
  33. printerr() {
  34. printf "${C_ERR}[E] ${1}${C_CLEAR} \n"
  35. }
  37. function pre_clean()
  38. {
  39. [ -e $TEMP_DIR ] && rm -rf $TEMP_DIR
  40. mkdir $TEMP_DIR
  41. }
  42. function unpack_kernel()
  43. {
  44. # test Compressed format
  45. pos1=`grep -P -a -b -m 1 --only-matching '\x1F\x8B\x08' $zImage | \
  46. cut -f 1 -d : | awk '(int($0)<50000){print $0;exit}'`
  47. pos2=`grep -P -a -b -m 1 --only-matching '\x{5D}\x{00}\x..\x{FF}\x{FF}\x{FF}\x{FF}\x{FF}\x{FF}' \
  48. $zImage | cut -f 1 -d : | awk '(int($0)<50000){print $0;exit}'`
  49. pos3=`grep -P -a -b -m 1 --only-matching '\xFD\x37\x7A\x58\x5A' $zImage | \
  50. cut -f 1 -d : | tail -1 | awk '(int($0)<50000){print $0;exit}'`
  51. pos4=`grep -P -a -b --only-matching '\211\114\132' $zImage | head -2 | \
  52. tail -1 | cut -f 1 -d : | awk '(int($0)<50000){print $0;exit}'`
  54. zImagesize=$(stat -c "%s" $zImage)
  55. [ -z $pos1 ] && pos1=$zImagesize
  56. [ -z $pos2 ] && pos2=$zImagesize
  57. [ -z $pos3 ] && pos3=$zImagesize
  58. [ -z $pos4 ] && pos4=$zImagesize
  59. minpos=`echo -e "$pos1\n$pos2\n$pos3\n$pos4" | sort -n | head -1`
  60. if [ $minpos -eq $zImagesize ]; then
  61. printerr "not found kernel from $zImage!"
  62. exit 1
  63. elif [ $minpos -eq $pos1 ]; then
  64. ungzip_kernel
  65. elif [ $minpos -eq $pos2 ]; then
  66. unlzma_kernel
  67. elif [ $minpos -eq $pos3 ]; then
  68. unxz_kernel
  69. elif [ $minpos -eq $pos4 ]; then
  70. unlzo_kernel
  71. fi
  72. }
  74. function ungzip_kernel()
  75. {
  76. printhl "Extracting gzip'd kernel image from file: $zImage (start = $pos1)"
  77. dd if=$zImage of=$TEMP_DIR/$KERNEL_GZIP_FILE bs=$pos1 skip=1 2>/dev/null >/dev/null
  78. gunzip -qf $TEMP_DIR/$KERNEL_GZIP_FILE
  79. }
  81. function unlzma_kernel()
  82. {
  83. printhl "Extracting lzma'd kernel image from file: $zImage (start = $pos2)"
  84. dd if=$zImage of=$TEMP_DIR/$KERNEL_LZMA_FILE bs=$pos2 skip=1 2>/dev/null >/dev/null
  85. unlzma -qf $TEMP_DIR/$KERNEL_LZMA_FILE
  86. }
  88. function unxz_kernel()
  89. {
  90. printhl "Extracting xz'd kernel image from file: $zImage (start = $pos3)"
  91. dd status=noxfer if=$zImage bs=$pos3 skip=1 2>/dev/null | unxz -qf > $TEMP_DIR/$KERNEL_FILE 2>/dev/null
  92. }
  94. function unlzo_kernel()
  95. {
  96. printhl "Extracting lzo'd kernel image from file: $zImage (start = $pos4)"
  97. dd if=$zImage of=$TEMP_DIR/$KERNEL_LZO_FILE bs=$pos4 skip=1 2>/dev/null >/dev/null
  98. lzop -d $TEMP_DIR/$KERNEL_LZO_FILE 2>/dev/null >/dev/null
  99. }
  101. function clean_up()
  102. {
  103. #rm -Rf initrd.img
  104. echo end
  105. }
  106. function extract_boot_img()
  107. {
  108. cp $boot_img $TEMP_DIR
  109. cd $TEMP_DIR
  110. abootimg -x $boot_img
  111. cd $CURRENT_DIR
  112. }
  114. pre_clean
  115. extract_boot_img
  116. unpack_kernel
  117. [ -z $3 ] && clean_up

extract_boot_img