#!/bin/bash

  # SPDX-License-Identifier: GPL-2.0

  #
  # Translate stack dump function offsets.
  #
  # addr2line doesn't work with KASLR addresses.  This works similarly to
  # addr2line, but instead takes the 'func+0x123' format as input:
  #
  #   $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568
  #   meminfo_proc_show+0x5/0x568:
  #   meminfo_proc_show at fs/proc/meminfo.c:27
  #
  # If the address is part of an inlined function, the full inline call chain is
  # printed:
  #
  #   $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27
  #   native_write_msr+0x6/0x27:
  #   arch_static_branch at arch/x86/include/asm/msr.h:121
  #    (inlined by) static_key_false at include/linux/jump_label.h:125
  #    (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125
  #
  # The function size after the '/' in the input is optional, but recommended.
  # It's used to help disambiguate any duplicate symbol names, which can occur
  # rarely.  If the size is omitted for a duplicate symbol then it's possible for
  # multiple code sites to be printed:
  #
  #   $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5
  #   raw_ioctl+0x5/0x20:
  #   raw_ioctl at drivers/char/raw.c:122
  #
  #   raw_ioctl+0x5/0xb1:
  #   raw_ioctl at net/ipv4/raw.c:876
  #
  # Multiple addresses can be specified on a single command line:
  #
  #   $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90
  #   type_show+0x10/0x2d:
  #   type_show at drivers/video/backlight/backlight.c:213
  #
  #   free_reserved_area+0x90/0x123:
  #   free_reserved_area at mm/page_alloc.c:6429 (discriminator 2)
  
  
  set -o errexit
  set -o nounset

  usage() {

  	echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2

  	exit 1
  }
  
  warn() {
  	echo "$1" >&2
  }
  
  die() {
  	echo "ERROR: $1" >&2
  	exit 1
  }

  READELF="${CROSS_COMPILE:-}readelf"
  ADDR2LINE="${CROSS_COMPILE:-}addr2line"
  AWK="awk"
  
  command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed"
  command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed"
  command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed"

  # Try to figure out the source directory prefix so we can remove it from the
  # addr2line output.  HACK ALERT: This assumes that start_kernel() is in

  # init/main.c!  This only works for vmlinux.  Otherwise it falls back to

  # printing the absolute path.
  find_dir_prefix() {
  	local objfile=$1

  	local start_kernel_addr=$(${READELF} --symbols --wide $objfile | ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}')

  	[[ -z $start_kernel_addr ]] && return

  	local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr)

  	[[ -z $file_line ]] && return
  
  	local prefix=${file_line%init/main.c:*}
  	if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then
  		return
  	fi
  
  	DIR_PREFIX=$prefix
  	return 0
  }
  
  __faddr2line() {
  	local objfile=$1
  	local func_addr=$2
  	local dir_prefix=$3
  	local print_warnings=$4

  	local sym_name=${func_addr%+*}

  	local func_offset=${func_addr#*+}
  	func_offset=${func_offset%/*}

  	local user_size=

  	local file_type
  	local is_vmlinux=0

  	[[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}

  	if [[ -z $sym_name ]] || [[ -z $func_offset ]] || [[ $sym_name = $func_addr ]]; then

  		warn "bad func+offset $func_addr"
  		DONE=1
  		return
  	fi

  	# vmlinux uses absolute addresses in the section table rather than
  	# section offsets.
  	local file_type=$(${READELF} --file-header $objfile |
  		${AWK} '$1 == "Type:" { print $2; exit }')

  	if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then
  		is_vmlinux=1
  	fi

  	# Go through each of the object's symbols which match the func name.

  	# In rare cases there might be duplicates, in which case we print all
  	# matches.
  	while read line; do
  		local fields=($line)
  		local sym_addr=0x${fields[1]}
  		local sym_elf_size=${fields[2]}
  		local sym_sec=${fields[6]}

  		local sec_size
  		local sec_name

  
  		# Get the section size:

  		sec_size=$(${READELF} --section-headers --wide $objfile |

  			sed 's/\[ /\[/' |
  			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')
  
  		if [[ -z $sec_size ]]; then
  			warn "bad section size: section: $sym_sec"
  			DONE=1
  			return
  		fi

  		# Get the section name:
  		sec_name=$(${READELF} --section-headers --wide $objfile |
  			sed 's/\[ /\[/' |
  			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print $2; exit }')
  
  		if [[ -z $sec_name ]]; then
  			warn "bad section name: section: $sym_sec"
  			DONE=1
  			return
  		fi

  		# Calculate the symbol size.
  		#
  		# Unfortunately we can't use the ELF size, because kallsyms
  		# also includes the padding bytes in its size calculation.  For
  		# kallsyms, the size calculation is the distance between the
  		# symbol and the next symbol in a sorted list.
  		local sym_size
  		local cur_sym_addr
  		local found=0
  		while read line; do
  			local fields=($line)
  			cur_sym_addr=0x${fields[1]}
  			local cur_sym_elf_size=${fields[2]}
  			local cur_sym_name=${fields[7]:-}
  
  			if [[ $cur_sym_addr = $sym_addr ]] &&
  			   [[ $cur_sym_elf_size = $sym_elf_size ]] &&
  			   [[ $cur_sym_name = $sym_name ]]; then
  				found=1
  				continue
  			fi
  
  			if [[ $found = 1 ]]; then
  				sym_size=$(($cur_sym_addr - $sym_addr))
  				[[ $sym_size -lt $sym_elf_size ]] && continue;
  				found=2
  				break
  			fi
  		done < <(${READELF} --symbols --wide $objfile | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)
  
  		if [[ $found = 0 ]]; then
  			warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
  			DONE=1
  			return
  		fi
  
  		# If nothing was found after the symbol, assume it's the last
  		# symbol in the section.
  		[[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr))

  		if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then

  			warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr"

  			DONE=1
  			return
  		fi

  		sym_size=0x$(printf %x $sym_size)

  		# Calculate the address from user-supplied offset:
  		local addr=$(($sym_addr + $func_offset))

  		if [[ -z $addr ]] || [[ $addr = 0 ]]; then

  			warn "bad address: $sym_addr + $func_offset"

  			DONE=1
  			return
  		fi

  		addr=0x$(printf %x $addr)

  		# If the user provided a size, make sure it matches the symbol's size:
  		if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then

  			[[ $print_warnings = 1 ]] &&

  				echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)"

  			continue;
  		fi

  		# Make sure the provided offset is within the symbol's range:

  		if [[ $func_offset -gt $sym_size ]]; then

  			[[ $print_warnings = 1 ]] &&

  				echo "skipping $sym_name address at $addr due to size mismatch ($func_offset > $sym_size)"

  			continue
  		fi

  		# In case of duplicates or multiple addresses specified on the
  		# cmdline, separate multiple entries with a blank line:

  		[[ $FIRST = 0 ]] && echo
  		FIRST=0

  		echo "$sym_name+$func_offset/$sym_size:"

  		# Pass section address to addr2line and strip absolute paths
  		# from the output:

  		local args="--functions --pretty-print --inlines --exe=$objfile"
  		[[ $is_vmlinux = 0 ]] && args="$args --section=$sec_name"
  		local output=$(${ADDR2LINE} $args $addr | sed "s; $dir_prefix\(\./\)*; ;")

  		[[ -z $output ]] && continue
  
  		# Default output (non --list):

  		if [[ $LIST = 0 ]]; then

  			echo "$output" | while read -r line

  			do
  				echo $line
  			done
  			DONE=1;

  			continue

  		fi

  		# For --list, show each line with its corresponding source code:
  		echo "$output" | while read -r line

  		do

  			echo

  			echo $line

  			n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
  			n1=$[$n-5]
  			n2=$[$n+5]
  			f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')

  			${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s
  ", $0)}' $f

  		done

  		DONE=1

  	done < <(${READELF} --symbols --wide $objfile | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')

  }
  
  [[ $# -lt 2 ]] && usage
  
  objfile=$1

  
  LIST=0
  [[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1

  [[ ! -f $objfile ]] && die "can't find objfile $objfile"
  shift
  
  DIR_PREFIX=supercalifragilisticexpialidocious
  find_dir_prefix $objfile
  
  FIRST=1
  while [[ $# -gt 0 ]]; do
  	func_addr=$1
  	shift
  
  	# print any matches found
  	DONE=0
  	__faddr2line $objfile $func_addr $DIR_PREFIX 0
  
  	# if no match was found, print warnings
  	if [[ $DONE = 0 ]]; then
  		__faddr2line $objfile $func_addr $DIR_PREFIX 1
  		warn "no match for $func_addr"
  	fi
  done