#!/bin/bash

# Wrapper script for find-debuginfo.sh

#

# Usage:

#  wrap-find-debuginfo.sh SYSROOT-PATH SCRIPT-PATH SCRIPT-ARGS...

#

# The wrapper saves the original version of ld.so found in SYSROOT-PATH,

# invokes SCRIPT-PATH with SCRIPT-ARGS, and then restores the

# LDSO-PATH file, followed by note merging and DWZ compression.

# As a result, ld.so has (mostly) unchanged debuginfo even

# after debuginfo extraction.

#

# For libc.so.6 and other shared objects, a set of strategic symbols

# is preserved in .symtab that are frequently used in valgrind

# suppressions and elsewhere.

set -evx

tar_tmp="$(mktemp)"

declare -A libc_dlink_tmp_list

ldso_annobin_sym_tmp_list=""

# Prefer a separately installed debugedit over the RPM-integrated one.

if command -v debugedit >/dev/null ; then

    debugedit=debugedit

else

    debugedit=/usr/lib/rpm/debugedit

fi

cleanup () {

    rm -f "$tar_tmp" ${libc_dlink_tmp_list[@]} $ldso_annobin_sym_tmp_list

}

trap cleanup 0

sysroot_path="$1"

shift

script_path="$1"

shift

# See run_ldso setting in glibc.spec.

ldso_list=`cd "$sysroot_path"; find . -name 'ld-*.so' -type f`

libc_list=`cd "$sysroot_path"; find . -name 'libc-*.so' -type f`

libdl_list=`cd "$sysroot_path"; find . -name 'libdl-*.so' -type f`

libpthread_list=`cd "$sysroot_path"; find . -name 'libpthread-*.so' -type f`

librt_list=`cd "$sysroot_path"; find . -name 'librt-*.so' -type f`

full_list="$ldso_list $libc_list $libdl_list $libpthread_list $librt_list"

# Preserve the original files.

(cd "$sysroot_path"; ls -l $full_list)

(cd "$sysroot_path"; tar cvf "$tar_tmp" $full_list)

# Run the debuginfo extraction.

"$script_path" "$@"

# libc.so.6: Extract the .gnu_debuglink section

for f in $libc_list

do

  dlink_tmp="$(mktemp)"

  libc_dlink_tmp_list["$f"]="$dlink_tmp"

  objcopy -j.gnu_debuglink --set-section-flags .gnu_debuglink=alloc \

      -O binary "$sysroot_path/$f" "$dlink_tmp"

done

# Restore the original files.

(cd "$sysroot_path"; tar xf "$tar_tmp")

(cd "$sysroot_path"; ls -l $full_list)

# Reduce the size of notes.  Primarily for annobin.

for p in $full_list

do

    objcopy --merge-notes "$sysroot_path/$p"

done

# libc.so.6: Restore the .gnu_debuglink section

for f in ${!libc_dlink_tmp_list[@]}

do

  dlink_tmp="${libc_dlink_tmp_list[$f]}"

  objcopy --add-section .gnu_debuglink="$dlink_tmp" "$sysroot_path/$f"

done

# ld.so does not have separated debuginfo and so the debuginfo file

# generated by find-debuginfo is redundant.  Therefore, remove it.

for ldso_debug in `find "$sysroot_path" -name 'ld-*.so*.debug' -type f`

do

  rm -f "$ldso_debug"

done

# libc.so.6 and other shared objects: Reduce to valuable symbols.

# Eliminate file symbols, annobin symbols, and symbols used by the

# glibc build to implement hidden aliases (__EI_*).  We would also

# like to remove __GI_* symbols, but even listing them explicitly (as

# in -K __GI_strlen) still causes strip to remove them, so there is no

# filtering of __GI_* here.  (Debuginfo is gone after this, so no need

# to optimize it.)

for p in $libc_list $libdl_list $libpthread_list $librt_list ; do

    strip -w \

	  -K '*' \

	  -K '!*.c' \

	  -K '!*.os' \

	  -K '!.annobin_*' \

	  -K '!__EI_*' \

	  -K '!__PRETTY_FUNCTION__*' \

	  "$sysroot_path/$p"

done

# ld.so: Rewrite the source file paths to match the extracted

# locations.  First compute the arguments for invoking debugedit.

# See find-debuginfo.sh.

debug_dest_name="/usr/src/debug"

last_arg=

while true ; do

    arg="$1"

    shift || break

    case "$arg" in

	(--unique-debug-src-base)

	    debug_dest_name="/usr/src/debug/$1"

	    shift

	    ;;

	(-*)

	    ;;

	(*)

	    last_arg="$arg"

	    ;;

    esac

done

debug_base_name=${last_arg:-$RPM_BUILD_ROOT}

for p in $ldso_list

do

    $debugedit -b "$debug_base_name" -d "$debug_dest_name" -n "$sysroot_path/$p"

    # Remove the .annobin* symbols (and only them).

    ldso_annobin_sym_tmp="$(mktemp)"

    ldso_annobin_sym_tmp_list+=" $ldso_annobin_sym_tmp"

    if nm --format=posix "$sysroot_path/$p" | cut -d' ' -f1 \

        | grep '^\.annobin' > "$ldso_annobin_sym_tmp"; then

        objcopy --strip-symbols="$ldso_annobin_sym_tmp" "$sysroot_path/$p"

    fi

done

# Apply single-file DWARF optimization.

for ldso in $ldso_list

do

    dwz "$sysroot_path/$p"

done