gdb/gstack-1.in

   1 #!/usr/bin/env bash
   2
   3 # Copyright (C) 2024 Free Software Foundation, Inc.
   4
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 # Print a stack trace of a running process.
  19 # Similar to the gcore command, but instead of creating a core file,
  20 # we simply have gdb print out the stack backtrace to the terminal.
  21
  22 GDB=${GDB:-$(command -v gdb)}
  23 GDBARGS=${GDBARGS:-}
  24 AWK=${AWK:-}
  25 PKGVERSION=@PKGVERSION@
  26 VERSION=@VERSION@
  27
  28 # Find an appropriate awk interpreter if one was not specified
  29 # via the environment.
  30 awk_prog=""
  31 if [ -z "$AWK" ]; then
  32     for prog in gawk mawk nawk awk; do
  33         awk_prog=$(command -v $prog)
  34         test -n "$awk_prog" && break
  35     done
  36     AWK="$awk_prog"
  37 fi
  38 if [ ! -x "$AWK" ]; then
  39     echo "$0: could not find usable awk interpreter" 1>&2
  40     exit 2
  41 fi
  42
  43 function print_usage() {
  44     echo "Usage: $0 [-h|--help] [-v|--version] PID"
  45 }
  46
  47 function print_try_help() {
  48     echo "Try '$0 --help' for more information."
  49 }
  50
  51 function print_help() {
  52     print_usage
  53     echo "Print a stack trace of a running program"
  54     echo
  55     echo "  -h, --help         Print this message then exit."
  56     echo "  -v, --version      Print version information then exit."
  57 }
  58
  59 function print_version() {
  60     echo "GNU gstack (${PKGVERSION}) ${VERSION}"
  61 }
  62
  63 # Parse options.
  64 while getopts hv-: OPT; do
  65     if [ "$OPT" = "-" ]; then
  66         OPT="${OPTARG%%=*}"
  67         OPTARG="${OPTARG#'$OPT'}"
  68         OPTARG="${OPTARG#=}"
  69     fi
  70
  71     case "$OPT" in
  72         h | help)
  73             print_help
  74             exit 0
  75             ;;
  76         v | version)
  77             print_version
  78             exit 0
  79             ;;
  80         \?)
  81             # getopts has already output an error message.
  82             print_try_help 1>&2
  83             exit 2 ;;
  84         *)
  85             echo "$0: unrecognized option '--$OPT'" 1>&2
  86             print_try_help 1>&2
  87             exit 2
  88             ;;
  89     esac
  90 done
  91 shift $((OPTIND-1))
  92
  93 # The sole remaining argument should be the PID of the process
  94 # whose backtrace is desired.
  95 if [ $# -ne 1 ]; then
  96     print_usage 1>&2
  97     exit 1
  98 fi
  99
 100 PID=$1
 101
 102 awk_script=$(cat << EOF
 103 BEGIN {
 104   first=1
 105   attach_okay=0
 106 }
 107
 108 /ATTACHED/ {
 109   attach_okay=1
 110 }
 111
 112 /^#/ {
 113   if (attach_okay) {
 114     print \$0
 115   }
 116 }
 117
 118 /^Thread/ {
 119   if (attach_okay) {
 120     if (first == 0)
 121        print ""
 122     first=0
 123     print \$0
 124   }
 125 }
 126
 127 END {
 128 if (attach_okay == 0)
 129   exit 2
 130 }
 131 EOF
 132           )
 133
 134 # Run GDB and remove some unwanted noise.
 135 "$GDB" --quiet -nx --readnever $GDBARGS <<EOF |
 136 set width 0
 137 set height 0
 138 set pagination no
 139 set debuginfod enabled off
 140 define attach-bt
 141 attach \$arg0
 142 echo "ATTACHED"
 143 thread apply all bt
 144 end
 145 attach-bt $PID
 146 EOF
 147 $AWK -- "$awk_script"