LXR linux/scripts/decode

   1#!/bin/bash
   2# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
   3#set -x
   4
   5if [[ $# != 2 ]]; then
   6        echo "Usage:"
   7        echo "  $0 [vmlinux] [base path]"
   8        exit 1
   9fi
  10
  11vmlinux=$1
  12basepath=$2
  13declare -A cache
  14
  15parse_symbol() {
  16        # The structure of symbol at this point is:
  17        #   ([name]+[offset]/[total length])
  18        #
  19        # For example:
  20        #   do_basic_setup+0x9c/0xbf
  21
  22        # Remove the englobing parenthesis
  23        symbol=${symbol#\(}
  24        symbol=${symbol%\)}
  25
  26        # Strip the symbol name so that we could look it up
  27        local name=${symbol%+*}
  28
  29        # Use 'nm vmlinux' to figure out the base address of said symbol.
  30        # It's actually faster to call it every time than to load it
  31        # all into bash.
  32        if [[ "${cache[$name]+isset}" == "isset" ]]; then
  33                local base_addr=${cache[$name]}
  34        else
  35                local base_addr=$(nm "$vmlinux" | grep -i ' t ' | awk "/ $name\$/ {print \$1}" | head -n1)
  36                cache["$name"]="$base_addr"
  37        fi
  38        # Let's start doing the math to get the exact address into the
  39        # symbol. First, strip out the symbol total length.
  40        local expr=${symbol%/*}
  41
  42        # Now, replace the symbol name with the base address we found
  43        # before.
  44        expr=${expr/$name/0x$base_addr}
  45
  46        # Evaluate it to find the actual address
  47        expr=$((expr))
  48        local address=$(printf "%x\n" "$expr")
  49
  50        # Pass it to addr2line to get filename and line number
  51        # Could get more than one result
  52        if [[ "${cache[$address]+isset}" == "isset" ]]; then
  53                local code=${cache[$address]}
  54        else
  55                local code=$(addr2line -i -e "$vmlinux" "$address")
  56                cache[$address]=$code
  57        fi
  58
  59        # addr2line doesn't return a proper error code if it fails, so
  60        # we detect it using the value it prints so that we could preserve
  61        # the offset/size into the function and bail out
  62        if [[ $code == "??:0" ]]; then
  63                return
  64        fi
  65
  66        # Strip out the base of the path
  67        code=${code//$basepath/""}
  68
  69        # In the case of inlines, move everything to same line
  70        code=${code//$'\n'/' '}
  71
  72        # Replace old address with pretty line numbers
  73        symbol="$name ($code)"
  74}
  75
  76decode_code() {
  77        local scripts=`dirname "${BASH_SOURCE[0]}"`
  78
  79        echo "$1" | $scripts/decodecode
  80}
  81
  82handle_line() {
  83        local words
  84
  85        # Tokenize
  86        read -a words <<<"$1"
  87
  88        # Remove hex numbers. Do it ourselves until it happens in the
  89        # kernel
  90
  91        # We need to know the index of the last element before we
  92        # remove elements because arrays are sparse
  93        local last=$(( ${#words[@]} - 1 ))
  94
  95        for i in "${!words[@]}"; do
  96                # Remove the address
  97                if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
  98                        unset words[$i]
  99                fi
 100
 101                # Format timestamps with tabs
 102                if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
 103                        unset words[$i]
 104                        words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
 105                fi
 106        done
 107
 108        # The symbol is the last element, process it
 109        symbol=${words[$last]}
 110        unset words[$last]
 111        parse_symbol # modifies $symbol
 112
 113        # Add up the line number to the symbol
 114        echo "${words[@]}" "$symbol"
 115}
 116
 117while read line; do
 118        # Let's see if we have an address in the line
 119        if [[ $line =~ \[\<([^]]+)\>\]  ]]; then
 120                # Translate address to line numbers
 121                handle_line "$line"
 122        # Is it a code line?
 123        elif [[ $line == *Code:* ]]; then
 124                decode_code "$line"
 125        else
 126                # Nothing special in this line, show it as is
 127                echo "$line"
 128        fi
 129done
 130