#!/bin/bash

#find-debuginfo.sh - automagically generate debug info and file list

#for inclusion in an rpm spec file.

#

# Usage: find-debuginfo.sh [--strict-build-id] [-g] [-r] [-m] [-i] [-n]

#			   [--keep-section SECTION] [--remove-section SECTION]

#	 		   [-j N] [--jobs N]

#	 		   [-o debugfiles.list]

#	 		   [-S debugsourcefiles.list]

#			   [--run-dwz] [--dwz-low-mem-die-limit N]

#			   [--dwz-max-die-limit N]

#			   [--build-id-seed SEED]

#			   [--unique-debug-suffix SUFFIX]

#			   [--unique-debug-src-base BASE]

#			   [[-l filelist]... [-p 'pattern'] -o debuginfo.list]

#			   [builddir]

#

# The -g flag says to use strip -g instead of full strip on DSOs or EXEs.

# The -r flag says to use eu-strip --reloc-debug-sections.

# Use --keep-section SECTION or --remove-section SECTION to explicitly

# keep a (non-allocated) section in the main executable or explicitly

# remove it into the .debug file. SECTION is an extended wildcard pattern.

# Both options can be given more than once.

#

# The --strict-build-id flag says to exit with failure status if

# any ELF binary processed fails to contain a build-id note.

# The -m flag says to include a .gnu_debugdata section in the main binary.

# The -i flag says to include a .gdb_index section in the .debug file.

# The -n flag says to not recompute the build-id.

#

# The -j, --jobs N option will spawn N processes to do the debuginfo

# extraction in parallel.

#

# A single -o switch before any -l or -p switches simply renames

# the primary output file from debugfiles.list to something else.

# A -o switch that follows a -p switch or some -l switches produces

# an additional output file with the debuginfo for the files in

# the -l filelist file, or whose names match the -p pattern.

# The -p argument is an grep -E -style regexp matching the a file name,

# and must not use anchors (^ or $).

#

# The --run-dwz flag instructs find-debuginfo.sh to run the dwz utility

# if available, and --dwz-low-mem-die-limit and --dwz-max-die-limit

# provide detailed limits.  See dwz(1) -l and -L option for details.

#

# If --build-id-seed SEED is given then debugedit is called to

# update the build-ids it finds adding the SEED as seed to recalculate

# the build-id hash.  This makes sure the build-ids in the ELF files

# are unique between versions and releases of the same package.

# (Use --build-id-seed "%{VERSION}-%{RELEASE}".)

#

# If --unique-debug-suffix SUFFIX is given then the debug files created

# for <FILE> will be named <FILE>-<SUFFIX>.debug.  This makes sure .debug

# are unique between package version, release and architecture.

# (Use --unique-debug-suffix "-%{VERSION}-%{RELEASE}.%{_arch}".)

#

# If --unique-debug-src-base BASE is given then the source directory

# will be called /usr/debug/src/<BASE>.  This makes sure the debug source

# directories are unique between package version, release and architecture.

# (Use --unique-debug-src-base "%{name}-%{VERSION}-%{RELEASE}.%{_arch}".)

#

# All file names in switches are relative to builddir (. if not given).

#

# Figure out where we are installed so we can call other helper scripts.

lib_rpm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# With -g arg, pass it to strip on libraries or executables.

strip_g=false

# with -r arg, pass --reloc-debug-sections to eu-strip.

strip_r=false

# keep or remove arguments to eu-strip.

keep_remove_args=

# with -m arg, add minimal debuginfo to binary.

include_minidebug=false

# with -i arg, add GDB index to .debug file.

include_gdb_index=false

# Barf on missing build IDs.

strict=false

# Do not recompute build IDs.

no_recompute_build_id=false

# DWZ parameters.

run_dwz=false

dwz_low_mem_die_limit=

dwz_max_die_limit=

# build id seed given by the --build-id-seed option

build_id_seed=

# Arch given by --unique-debug-arch

unique_debug_suffix=

# Base given by --unique-debug-src-base

unique_debug_src_base=

# Number of parallel jobs to spawn

n_jobs=1

BUILDDIR=.

out=debugfiles.list

srcout=

nout=0

while [ $# -gt 0 ]; do

  case "$1" in

  --strict-build-id)

    strict=true

    ;;

  --run-dwz)

    run_dwz=true

    ;;

  --dwz-low-mem-die-limit)

    dwz_low_mem_die_limit=$2

    shift

    ;;

  --dwz-max-die-limit)

    dwz_max_die_limit=$2

    shift

    ;;

  --build-id-seed)

    build_id_seed=$2

    shift

    ;;

  --unique-debug-suffix)

    unique_debug_suffix=$2

    shift

    ;;

  --unique-debug-src-base)

    unique_debug_src_base=$2

    shift

    ;;

  -g)

    strip_g=true

    ;;

  -m)

    include_minidebug=true

    ;;

  -n)

    no_recompute_build_id=true

    ;;

  -i)

    include_gdb_index=true

    ;;

  -o)

    if [ -z "${lists[$nout]}" -a -z "${ptns[$nout]}" ]; then

      out=$2

    else

      outs[$nout]=$2

      ((nout++))

    fi

    shift

    ;;

  -l)

    lists[$nout]="${lists[$nout]} $2"

    shift

    ;;

  -p)

    ptns[$nout]=$2

    shift

    ;;

  -r)

    strip_r=true

    ;;

  --keep-section)

    keep_remove_args="${keep_remove_args} --keep-section $2"

    shift

    ;;

  --remove-section)

    keep_remove_args="${keep_remove_args} --remove-section $2"

    shift

    ;;

  -j)

    n_jobs=$2

    shift

    ;;

  -j*)

    n_jobs=${1#-j}

    ;;

  --jobs)

    n_jobs=$2

    shift

    ;;

  -S)

    srcout=$2

    shift

    ;;

  *)

    BUILDDIR=$1

    shift

    break

    ;;

  esac

  shift

done

if test -n "$build_id_seed" -a "$no_recompute_build_id" = "true"; then

  echo >&2 "*** ERROR: --build-id-seed (unique build-ids) and -n (do not recompute build-id) cannot be used together"

  exit 2

fi

i=0

while ((i < nout)); do

  outs[$i]="$BUILDDIR/${outs[$i]}"

  l=''

  for f in ${lists[$i]}; do

    l="$l $BUILDDIR/$f"

  done

  lists[$i]=$l

  ((++i))

done

LISTFILE="$BUILDDIR/$out"

SOURCEFILE="$BUILDDIR/debugsources.list"

LINKSFILE="$BUILDDIR/debuglinks.list"

ELFBINSFILE="$BUILDDIR/elfbins.list"

> "$SOURCEFILE"

> "$LISTFILE"

> "$LINKSFILE"

> "$ELFBINSFILE"

debugdir="${RPM_BUILD_ROOT}/usr/lib/debug"

strip_to_debug()

{

  local g=

  local r=

  $strip_r && r=--reloc-debug-sections

  $strip_g && case "$(file -bi "$2")" in

  application/x-sharedlib*) g=-g ;;

  application/x-executable*) g=-g ;;

  application/x-pie-executable*) g=-g ;;

  esac

  eu-strip --remove-comment $r $g ${keep_remove_args} -f "$1" "$2" || exit

  chmod 444 "$1" || exit

}

add_minidebug()

{

  local debuginfo="$1"

  local binary="$2"

  local dynsyms=`mktemp`

  local funcsyms=`mktemp`

  local keep_symbols=`mktemp`

  local mini_debuginfo=`mktemp`

  # In the minisymtab we don't need the .debug_ sections (already removed

  # by -S) but also not other non-allocated PROGBITS, NOTE or NOBITS sections.

  # List and remove them explicitly. We do want to keep the allocated,

  # symbol and NOBITS sections so cannot use --keep-only because that is

  # too aggressive. Field $2 is the section name, $3 is the section type

  # and $8 are the section flags.

  local remove_sections=`readelf -W -S "$debuginfo" \

	| awk '{ if (index($2,".debug_") != 1 \

		     && ($3 == "PROGBITS" || $3 == "NOTE" || $3 == "NOBITS") \

		     && index($8,"A") == 0) \

		   printf "--remove-section "$2" " }'`

  # Extract the dynamic symbols from the main binary, there is no need to also have these

  # in the normal symbol table

  nm -D "$binary" --format=posix --defined-only | awk '{ print $1 }' | sort > "$dynsyms"

  # Extract all the text (i.e. function) symbols from the debuginfo

  # Use format sysv to make sure we can match against the actual ELF FUNC

  # symbol type. The binutils nm posix format symbol type chars are

  # ambigous for architectures that might use function descriptors.

  nm "$debuginfo" --format=sysv --defined-only | awk -F \| '{ if ($4 ~ "FUNC") print $1 }' | sort > "$funcsyms"

  # Keep all the function symbols not already in the dynamic symbol table

  comm -13 "$dynsyms" "$funcsyms" > "$keep_symbols"

  # Copy the full debuginfo, keeping only a minumal set of symbols and removing some unnecessary sections

  objcopy -S $remove_sections --keep-symbols="$keep_symbols" "$debuginfo" "$mini_debuginfo" &> /dev/null

  #Inject the compressed data into the .gnu_debugdata section of the original binary

  xz "$mini_debuginfo"

  mini_debuginfo="${mini_debuginfo}.xz"

  objcopy --add-section .gnu_debugdata="$mini_debuginfo" "$binary"

  rm -f "$dynsyms" "$funcsyms" "$keep_symbols" "$mini_debuginfo"

}

# Make a relative symlink to $1 called $3$2

shopt -s extglob

link_relative()

{

  local t="$1" f="$2" pfx="$3"

  local fn="${f#/}" tn="${t#/}"

  local fd td d

  while fd="${fn%%/*}"; td="${tn%%/*}"; [ "$fd" = "$td" ]; do

    fn="${fn#*/}"

    tn="${tn#*/}"

  done

  d="${fn%/*}"

  if [ "$d" != "$fn" ]; then

    d="${d//+([!\/])/..}"

    tn="${d}/${tn}"

  fi

  mkdir -p "$(dirname "$pfx$f")" && ln -snf "$tn" "$pfx$f"

}

# Make a symlink in /usr/lib/debug/$2 to $1

debug_link()

{

  local l="/usr/lib/debug$2"

  local t="$1"

  echo >> "$LINKSFILE" "$l $t"

  link_relative "$t" "$l" "$RPM_BUILD_ROOT"

}

get_debugfn()

{

  dn=$(dirname "${1#$RPM_BUILD_ROOT}")

  bn=$(basename "$1" .debug)${unique_debug_suffix}.debug

  debugdn=${debugdir}${dn}

  debugfn=${debugdn}/${bn}

}

set -o pipefail

strict_error=ERROR

$strict || strict_error=WARNING

temp=$(mktemp -d ${TMPDIR:-/tmp}/find-debuginfo.XXXXXX)

trap 'rm -rf "$temp"' EXIT

# Build a list of unstripped ELF files and their hardlinks

touch "$temp/primary"

find "$RPM_BUILD_ROOT" ! -path "${debugdir}/*.debug" -type f \

     		     \( -perm -0100 -or -perm -0010 -or -perm -0001 \) \

		     -print |

file -N -f - | sed -n -e 's/^\(.*\):[ 	]*.*ELF.*, not stripped.*/\1/p' |

xargs --no-run-if-empty stat -c '%h %D_%i %n' |

while read nlinks inum f; do

  if [ $nlinks -gt 1 ]; then

    var=seen_$inum

    if test -n "${!var}"; then

      echo "$inum $f" >>"$temp/linked"

      continue

    else

      read "$var" < <(echo 1)

    fi

  fi

  echo "$nlinks $inum $f" >>"$temp/primary"

done

# Strip ELF binaries

do_file()

{

  local nlinks=$1 inum=$2 f=$3 id link linked

  get_debugfn "$f"

  [ -f "${debugfn}" ] && return

  echo "extracting debug info from $f"

  # See also cpio SOURCEFILE copy. Directories must match up.

  debug_base_name="$RPM_BUILD_DIR"

  debug_dest_name="/usr/src/debug"

  if [ ! -z "$unique_debug_src_base" ]; then

    debug_base_name="$BUILDDIR"

    debug_dest_name="/usr/src/debug/${unique_debug_src_base}"

  fi

  no_recompute=

  if [ "$no_recompute_build_id" = "true" ]; then

    no_recompute="-n"

  fi

  id=$(${lib_rpm_dir}/debugedit -b "$debug_base_name" -d "$debug_dest_name" \

			      $no_recompute -i \

			      ${build_id_seed:+--build-id-seed="$build_id_seed"} \

			      -l "$SOURCEFILE" "$f") || exit

  if [ -z "$id" ]; then

    echo >&2 "*** ${strict_error}: No build ID note found in $f"

    $strict && exit 2

  fi

  # Add .gdb_index if requested.

  if $include_gdb_index; then

    if type gdb-add-index >/dev/null 2>&1; then

      gdb-add-index "$f"

    else

      echo >&2 "*** ERROR: GDB index requested, but no gdb-add-index installed"

      exit 2

    fi

  fi

  # A binary already copied into /usr/lib/debug doesn't get stripped,

  # just has its file names collected and adjusted.

  case "$dn" in

  /usr/lib/debug/*)

    return ;;

  esac

  mkdir -p "${debugdn}"

  if test -w "$f"; then

    strip_to_debug "${debugfn}" "$f"

  else

    chmod u+w "$f"

    strip_to_debug "${debugfn}" "$f"

    chmod u-w "$f"

  fi

  # strip -g implies we have full symtab, don't add mini symtab in that case.

  # It only makes sense to add a minisymtab for executables and shared

  # libraries. Other executable ELF files (like kernel modules) don't need it.

  if [ "$include_minidebug" = "true" -a "$strip_g" = "false" ]; then

    skip_mini=true

    case "$(file -bi "$f")" in

      application/x-sharedlib*) skip_mini=false ;;

      application/x-executable*) skip_mini=false ;;

    esac

    $skip_mini || add_minidebug "${debugfn}" "$f"

  fi

  echo "./${f#$RPM_BUILD_ROOT}" >> "$ELFBINSFILE"

  # If this file has multiple links, make the corresponding .debug files

  # all links to one file too.

  if [ $nlinks -gt 1 ]; then

    grep "^$inum " "$temp/linked" | while read inum linked; do

      link=$debugfn

      get_debugfn "$linked"

      echo "hard linked $link to $debugfn"

      mkdir -p "$(dirname "$debugfn")" && ln -nf "$link" "$debugfn"

    done

  fi

}

# 16^6 - 1 or about 16 million files

FILENUM_DIGITS=6

run_job()

{

  local jobid=$1 filenum

  local SOURCEFILE=$temp/debugsources.$jobid ELFBINSFILE=$temp/elfbins.$jobid

  >"$SOURCEFILE"

  >"$ELFBINSFILE"

  # can't use read -n <n>, because it reads bytes one by one, allowing for

  # races

  while :; do

    filenum=$(dd bs=$(( FILENUM_DIGITS + 1 )) count=1 status=none)

    if test -z "$filenum"; then

      break

    fi

    do_file $(sed -n "$(( 0x$filenum )) p" "$temp/primary")

  done

  echo 0 >"$temp/res.$jobid"

}

n_files=$(wc -l <"$temp/primary")

if [ $n_jobs -gt $n_files ]; then

  n_jobs=$n_files

fi

if [ $n_jobs -le 1 ]; then

  while read nlinks inum f; do

    do_file "$nlinks" "$inum" "$f"

  done <"$temp/primary"

else

  for ((i = 1; i <= n_files; i++)); do

    printf "%0${FILENUM_DIGITS}x\\n" $i

  done | (

    exec 3<&0

    for ((i = 0; i < n_jobs; i++)); do

      # The shell redirects stdin to /dev/null for background jobs. Work

      # around this by duplicating fd 0

      run_job $i <&3 &

    done

    wait

  )

  for f in "$temp"/res.*; do

    res=$(< "$f")

    if [ "$res" !=  "0" ]; then

      exit 1

    fi

  done

  cat "$temp"/debugsources.* >"$SOURCEFILE"

  cat "$temp"/elfbins.* >"$ELFBINSFILE"

fi

# Invoke the DWARF Compressor utility.

if $run_dwz \

   && [ -d "${RPM_BUILD_ROOT}/usr/lib/debug" ]; then

  readarray dwz_files < <(cd "${RPM_BUILD_ROOT}/usr/lib/debug"; find -type f -name \*.debug | LC_ALL=C sort)

  if [ ${#dwz_files[@]} -gt 0 ]; then

    dwz_multifile_name="${RPM_PACKAGE_NAME}-${RPM_PACKAGE_VERSION}-${RPM_PACKAGE_RELEASE}.${RPM_ARCH}"

    dwz_multifile_suffix=

    dwz_multifile_idx=0

    while [ -f "${RPM_BUILD_ROOT}/usr/lib/debug/.dwz/${dwz_multifile_name}${dwz_multifile_suffix}" ]; do

      let ++dwz_multifile_idx

      dwz_multifile_suffix=".${dwz_multifile_idx}"

    done

    dwz_multifile_name="${dwz_multifile_name}${dwz_multifile_suffix}"

    dwz_opts="-h -q -r"

    [ ${#dwz_files[@]} -gt 1 ] \

      && dwz_opts="${dwz_opts} -m .dwz/${dwz_multifile_name}"

    mkdir -p "${RPM_BUILD_ROOT}/usr/lib/debug/.dwz"

    [ -n "${dwz_low_mem_die_limit}" ] \

      && dwz_opts="${dwz_opts} -l ${dwz_low_mem_die_limit}"

    [ -n "${dwz_max_die_limit}" ] \

      && dwz_opts="${dwz_opts} -L ${dwz_max_die_limit}"

    if type dwz >/dev/null 2>&1; then

      ( cd "${RPM_BUILD_ROOT}/usr/lib/debug" && dwz $dwz_opts ${dwz_files[@]} )

    else

      echo >&2 "*** ERROR: DWARF compression requested, but no dwz installed"

      exit 2

    fi

    # Remove .dwz directory if empty

    rmdir "${RPM_BUILD_ROOT}/usr/lib/debug/.dwz" 2>/dev/null

    if [ -f "${RPM_BUILD_ROOT}/usr/lib/debug/.dwz/${dwz_multifile_name}" ]; then

      id="`readelf -Wn "${RPM_BUILD_ROOT}/usr/lib/debug/.dwz/${dwz_multifile_name}" \

	     2>/dev/null | sed -n 's/^    Build ID: \([0-9a-f]\+\)/\1/p'`"

    fi

    # dwz invalidates .gnu_debuglink CRC32 in the main files.

    cat "$ELFBINSFILE" |

    (cd "$RPM_BUILD_ROOT"; \

     xargs -d '\n' ${lib_rpm_dir}/sepdebugcrcfix usr/lib/debug)

  fi

fi

# For each symlink whose target has a .debug file,

# make a .debug symlink to that file.

find "$RPM_BUILD_ROOT" ! -path "${debugdir}/*" -type l -print |

while read f

do

  t=$(readlink -m "$f").debug

  f=${f#$RPM_BUILD_ROOT}

  t=${t#$RPM_BUILD_ROOT}

  if [ -f "$debugdir$t" ]; then

    echo "symlinked /usr/lib/debug$t to /usr/lib/debug${f}.debug"

    debug_link "/usr/lib/debug$t" "${f}.debug"

  fi

done

if [ -s "$SOURCEFILE" ]; then

  # See also debugedit invocation. Directories must match up.

  debug_base_name="$RPM_BUILD_DIR"

  debug_dest_name="/usr/src/debug"

  if [ ! -z "$unique_debug_src_base" ]; then

    debug_base_name="$BUILDDIR"

    debug_dest_name="/usr/src/debug/${unique_debug_src_base}"

  fi

  mkdir -p "${RPM_BUILD_ROOT}${debug_dest_name}"

  # Filter out anything compiler generated which isn't a source file.

  # e.g. <internal>, <built-in>, <__thread_local_inner macros>.

  # Some compilers generate them as if they are part of the working

  # directory (which is why we match against ^ or /).

  LC_ALL=C sort -z -u "$SOURCEFILE" | grep -E -v -z '(^|/)<[a-z _-]+>$' |

  (cd "${debug_base_name}"; cpio -pd0mL "${RPM_BUILD_ROOT}${debug_dest_name}")

  # stupid cpio creates new directories in mode 0700,

  # and non-standard modes may be inherented from original directories, fixup

  find "${RPM_BUILD_ROOT}${debug_dest_name}" -type d -print0 |

  xargs --no-run-if-empty -0 chmod 0755

fi

if [ -d "${RPM_BUILD_ROOT}/usr/lib" -o -d "${RPM_BUILD_ROOT}/usr/src" ]; then

  ((nout > 0)) ||

  test ! -d "${RPM_BUILD_ROOT}/usr/lib" ||

  (cd "${RPM_BUILD_ROOT}/usr/lib"; find debug -type d) |

  sed 's,^,%dir /usr/lib/,' >> "$LISTFILE"

  (cd "${RPM_BUILD_ROOT}/usr"

   test ! -d lib/debug || find lib/debug ! -type d

   test ! -d src/debug -o -n "$srcout" || find src/debug -mindepth 1 -maxdepth 1

  ) | sed 's,^,/usr/,' >> "$LISTFILE"

fi

if [ -n "$srcout" ]; then

  srcout="$BUILDDIR/$srcout"

  > "$srcout"

  if [ -d "${RPM_BUILD_ROOT}/usr/src/debug" ]; then

    (cd "${RPM_BUILD_ROOT}/usr"

     find src/debug -mindepth 1 -maxdepth 1

    ) | sed 's,^,/usr/,' >> "$srcout"

  fi

fi

# Append to $1 only the lines from stdin not already in the file.

append_uniq()

{

  grep -F -f "$1" -x -v >> "$1"

}

# Helper to generate list of corresponding .debug files from a file list.

filelist_debugfiles()

{

  local extra="$1"

  shift

  sed 's/^%[a-z0-9_][a-z0-9_]*([^)]*) *//

s/^%[a-z0-9_][a-z0-9_]* *//

/^$/d

'"$extra" "$@"

}

# Write an output debuginfo file list based on given input file lists.

filtered_list()

{

  local out="$1"

  shift

  test $# -gt 0 || return

  grep -F -f <(filelist_debugfiles 's,^.*$,/usr/lib/debug&.debug,' "$@") \

  	-x $LISTFILE >> $out

  sed -n -f <(filelist_debugfiles 's/[\\.*+#]/\\&/g

h

s,^.*$,s# &$##p,p

g

s,^.*$,s# /usr/lib/debug&.debug$##p,p

' "$@") "$LINKSFILE" | append_uniq "$out"

}

# Write an output debuginfo file list based on an grep -E -style regexp.

pattern_list()

{

  local out="$1" ptn="$2"

  test -n "$ptn" || return

  grep -E -x -e "$ptn" "$LISTFILE" >> "$out"

  sed -n -r "\#^$ptn #s/ .*\$//p" "$LINKSFILE" | append_uniq "$out"

}

#

# When given multiple -o switches, split up the output as directed.

#

i=0

while ((i < nout)); do

  > ${outs[$i]}

  filtered_list ${outs[$i]} ${lists[$i]}

  pattern_list ${outs[$i]} "${ptns[$i]}"

  grep -Fvx -f ${outs[$i]} "$LISTFILE" > "${LISTFILE}.new"

  mv "${LISTFILE}.new" "$LISTFILE"

  ((++i))

done

if ((nout > 0)); then

  # Now add the right %dir lines to each output list.

  (cd "${RPM_BUILD_ROOT}"; find usr/lib/debug -type d) |

  sed 's#^.*$#\\@^/&/@{h;s@^.*$@%dir /&@;;g;}#' |

  LC_ALL=C sort -ur > "${LISTFILE}.dirs.sed"

  i=0

  while ((i < nout)); do

    sed -n -f "${LISTFILE}.dirs.sed" "${outs[$i]}" | sort -u > "${outs[$i]}.new"

    cat "${outs[$i]}" >> "${outs[$i]}.new"

    mv -f "${outs[$i]}.new" "${outs[$i]}"

    ((++i))

  done

  sed -n -f "${LISTFILE}.dirs.sed" "${LISTFILE}" | sort -u > "${LISTFILE}.new"

  cat "$LISTFILE" >> "${LISTFILE}.new"

  mv "${LISTFILE}.new" "$LISTFILE"

fi