#!/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]

#	 		   [-o debugfiles.list]

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

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

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

#

# 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 $).

#

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

#

# 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

# Barf on missing build IDs.

strict=false

BUILDDIR=.

out=debugfiles.list

nout=0

while [ $# -gt 0 ]; do

  case "$1" in

  --strict-build-id)

    strict=true

    ;;

  -g)

    strip_g=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

    ;;

  *)

    BUILDDIR=$1

    shift

    break

    ;;

  esac

  shift

done

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"

> "$SOURCEFILE"

> "$LISTFILE"

> "$LINKSFILE"

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 ;;

  esac

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

  chmod 444 "$1" || exit

}

# 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"

}

# Provide .2, .3, ... symlinks to all filename instances of this build-id.

make_id_dup_link()

{

  local id="$1" file="$2" idfile

  local n=1

  while true; do

    idfile=".build-id/${id:0:2}/${id:2}.$n"

    [ $# -eq 3 ] && idfile="${idfile}$3"

    if [ ! -L "$RPM_BUILD_ROOT/usr/lib/debug/$idfile" ]; then

      break

    fi

    n=$[$n+1]

  done

  debug_link "$file" "/$idfile"

}

# Make a build-id symlink for id $1 with suffix $3 to file $2.

make_id_link()

{

  local id="$1" file="$2"

  local idfile=".build-id/${id:0:2}/${id:2}"

  [ $# -eq 3 ] && idfile="${idfile}$3"

  local root_idfile="$RPM_BUILD_ROOT/usr/lib/debug/$idfile"

  if [ ! -L "$root_idfile" ]; then

    debug_link "$file" "/$idfile"

    return

  fi

  make_id_dup_link "$@"

  [ $# -eq 3 ] && return 0

  local other=$(readlink -m "$root_idfile")

  other=${other#$RPM_BUILD_ROOT}

  if cmp -s "$root_idfile" "$RPM_BUILD_ROOT$file" ||

     eu-elfcmp -q "$root_idfile" "$RPM_BUILD_ROOT$file" 2> /dev/null; then

    # Two copies.  Maybe one has to be setuid or something.

    echo >&2 "*** WARNING: identical binaries are copied, not linked:"

    echo >&2 "        $file"

    echo >&2 "   and  $other"

  else

    # This is pathological, break the build.

    echo >&2 "*** ERROR: same build ID in nonidentical files!"

    echo >&2 "        $file"

    echo >&2 "   and  $other"

    exit 2

  fi

}

get_debugfn()

{

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

  [ "$dn" == "." ] && dn=""

  bn=$(basename "$1" .so).debug

  bn=$(basename "$bn" .debug).debug

  debugdn=${debugdir}${dn}

  debugfn=${debugdn}/${bn}

  [ -n "$2" ] && shadowfn=$(basename "$2")

}

set -o pipefail

strict_error=ERROR

$strict || strict_error=WARNING

handle_single_file()

{

  nlinks=$1 && shift

  inum=$1 && shift

  f=$1 && shift

  shadow=$1 && shift

  zf="$f"

  [ -n "${shadowfn}" ] && zf="${shadowfn}"

  get_debugfn "$f" "$shadow"

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

  # If this file has multiple links, keep track and make

  # the corresponding .debug files all links to one file too.

  if [ $nlinks -gt 1 ]; then

    eval linked=\$linked_$inum

    if [ -n "$linked" ]; then

      eval id=\$linkedid_$inum

      make_id_dup_link "$id" "$dn/$(basename ${zf})"

      make_id_dup_link "$id" "/usr/lib/debug$dn/$bn" .debug

      link=$debugfn

      get_debugfn "$linked"

      echo "hard linked $link to $debugfn"

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

      return

    else

      eval linked_$inum=\$f

      echo "file $f has $[$nlinks - 1] other hard links"

    fi

  fi

  echo "extracting debug info from $f"

  echo /usr/lib/rpm/debugedit -b "$RPM_BUILD_DIR" -d /usr/src/debug \

			      -i -l "$SOURCEFILE" "$f"

  id=$(/usr/lib/rpm/debugedit -b "$RPM_BUILD_DIR" -d /usr/src/debug \

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

  if [ $nlinks -gt 1 ]; then

    eval linkedid_$inum=\$id

  fi

  if [ -z "$id" ]; then

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

    $strict && exit 2

  fi

  [ -x /usr/bin/gdb-add-index ] && /usr/bin/gdb-add-index "$zf" > /dev/null 2>&1

  # 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/*)

    [ -z "$id" ] || make_id_link "$id" "$dn/$(basename $zf)"

    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

  if [ -n "$id" ]; then

    make_id_link "$id" "$dn/$(basename ${zf})"

    make_id_link "$id" "/usr/lib/debug$dn/$bn" .debug

  fi

}

# Strip ELF binaries

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

    handle_single_file $nlinks $inum $f

done || exit

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

                     -iname '*.efi' -print |

file -N -f - | sed -n -e 's/^\(.*\):[ 	]*.*PE32.*EFI .*/\1/p' |

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

while read nlinks inum f; do

    [ -f "$f" ] || continue

    [ -f "${f%%.efi}.so" ] || continue

    handle_single_file $nlinks $inum ${f%%.efi}.so $f

done || exit

# On Aarch64 file tells us "MS-DOS" instead of PE32+.  Why not.

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

                     -iname '*.efi' -print |

file -N -f - | sed -n -e 's/^\(.*\):[ 	]MS-DOS.*/\1/p' |

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

while read nlinks inum f; do

    [ -f "$f" ] || continue

    [ -f "${f%%.efi}.so" ] || continue

    handle_single_file $nlinks $inum ${f%%.efi}.so $f

done || exit

# 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

  mkdir -p "${RPM_BUILD_ROOT}/usr/src/debug"

  LC_ALL=C sort -z -u "$SOURCEFILE" | grep -E -v -z '(<internal>|<built-in>)$' |

  (cd "$RPM_BUILD_DIR"; cpio -pd0mL "${RPM_BUILD_ROOT}/usr/src/debug")

  # stupid cpio creates new directories in mode 0700, fixup

  find "${RPM_BUILD_ROOT}/usr/src/debug" -type d -print0 |

  xargs --no-run-if-empty -0 chmod a+rx

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 || find src/debug -mindepth 1 -maxdepth 1

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

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