binutils-gdb/gdb/gcore-1.in

#!/usr/bin/env bash

#   Copyright (C) 2003-2025 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#
# Script to generate a core file of a running program.
# It starts up gdb, attaches to the given PID and invokes the gcore command.
#

PKGVERSION="@PKGVERSION@"
VERSION="@VERSION@"

# Need to check for -o option, but set default basename to "core".
prefix=core

# When the -a option is present, this may hold additional commands
# to ensure gdb dumps all mappings (OS dependent).
dump_all_cmds=()

data_directory_opt=()

# The GDB binary to run.
gdb_binary=

function print_usage() {
    prefix="Usage: $0"
    padding=$(printf '%*s' ${#prefix})

    echo "$prefix [-h|--help] [-v|--version]"
    echo "$padding [-a] [-o prefix] [-g gdb] [-d data-directory]"
    echo "$padding pid1 [pid2...pidN]"
}

function print_try_help() {
    echo "Try '$0 --help' for more information."
}

function print_help() {
    print_usage
    echo
    echo "Create a core file of a running program using GDB."
    echo
    echo "  -h, --help         Print this message then exit."
    echo "  -v, --version      Print version information then exit."
    echo "  -a                 Dump all memory mappings."
    echo "  -o prefix          Use 'prefix.pid' as the core file name."
    echo "                       The default prefix is 'core'."
    echo "  -g gdb             The GDB binary to run."
    echo "                       Defaults to GDB installed alongside gcore."
    echo "  -d dir             Pass '--data-directory dir' as an argument"
    echo "                       to GDB."
}

function print_version() {
    echo "GNU gcore (${PKGVERSION}) ${VERSION}"
}

while getopts vhao:g:d:-: OPT; do
    if [ "$OPT" = "-" ]; then
	OPT="${OPTARG%%=*}"
	OPTARG="${OPTARG#"$OPT"}"
	OPTARG="${OPTARG#=}"
    fi

    case "$OPT" in
        a)
            case "$OSTYPE" in
                linux*)
                    dump_all_cmds=("-ex" "set use-coredump-filter off")
                    dump_all_cmds+=("-ex" "set dump-excluded-mappings on")
                    ;;
            esac
            ;;
        o)
            prefix=$OPTARG
            ;;
        g)
            gdb_binary="$OPTARG"
            ;;
        d)
            data_directory_opt=("--data-directory" "$OPTARG")
            ;;
	h | help)
	    print_help
	    exit 0
	    ;;
	v | version)
	    print_version
	    exit 0
	    ;;
	\?)
	    # getopts has already output an error message.
	    print_try_help 1>&2
	    exit 2
	    ;;
        *)
	    # Unknown single character options are handled by the \?
	    # case above.  This is formatted to match the error
	    # getopts gives for an unknown single character option.
	    echo "$0: illegal option -- $OPT" 1>&2
	    print_try_help 1>&2
	    exit 2
            ;;
    esac
done

shift $((OPTIND-1))

if [ "$#" -eq "0" ]
then
    print_usage 1>&2
    exit 1
fi

# Attempt to fetch the absolute path to the gcore script that was
# called.
binary_path=$(dirname "$0")

if test "$binary_path" = . ; then
  # We got "." back as a path.  This means the user executed
  # the gcore script locally (i.e. ./gcore) or called the
  # script via a shell interpreter (i.e. sh gcore).
  binary_basename=$(basename "$0")

  # If the gcore script was called like "sh gcore" and the script
  # lives in the current directory, "which" will not give us "gcore".
  # So first we check if the script is in the current directory
  # before using the output of "which".
  if test -f "$binary_basename" ; then
    # We have a local gcore script in ".".  This covers the case of
    # doing "./gcore" or "sh gcore".
    binary_path="."
  else
    # The gcore script was not found in ".", which means the script
    # was called from somewhere else in $PATH by "sh gcore".
    # Extract the correct path now.
    binary_path_from_env=$(which "$0")
    binary_path=$(dirname "$binary_path_from_env")
  fi
fi

if [ -z "$gdb_binary" ]; then
   gdb_binary="$binary_path/@GDB_TRANSFORM_NAME@"
fi

gdb_binary_basename=$(basename "$gdb_binary")

# Check if the GDB binary is in the expected path.  If not, just
# quit with a message.
if [ ! -f "$gdb_binary" ]; then
  echo "gcore: GDB binary ($gdb_binary) not found"
  exit 1
fi

# Initialise return code.
rc=0

# Loop through pids
for pid in "$@"
do
	# `</dev/null' to avoid touching interactive terminal if it is
	# available but not accessible as GDB would get stopped on SIGTTIN.
	"$gdb_binary" </dev/null \
            "${data_directory_opt[@]}" \
	    --nx --batch --readnever -iex 'set debuginfod enabled off' \
	    -ex "set pagination off" -ex "set height 0" -ex "set width 0" \
	    "${dump_all_cmds[@]}" \
	    -ex "attach $pid" -ex "gcore $prefix.$pid" -ex detach -ex quit

	if [ -r "$prefix.$pid" ] ; then
	    rc=0
	else
	    echo "$gdb_binary_basename: failed to create $prefix.$pid"
	    rc=1
	    break
	fi


done

exit $rc