pbot/applets/compiler_vm/guest/bin/guest-gdb

#!/usr/bin/perl

# SPDX-FileCopyrightText: 2021 Pragmatic Software <pragma78@gmail.com>
# SPDX-License-Identifier: MIT

# This script was thrown together quickly and sloppily. It will be
# rewritten "soon".

no warnings;
use strict;

my $cmdlineargs = '';
foreach my $arg (@ARGV) {
  $arg =~ s/'/'"'"'/g;
  $cmdlineargs .= "'$arg' ";
}

use IPC::Open2;

my $debug = $ENV{DEBUG} // 0;

#my $opening = "<";
#my $closing = ">\n";

my $opening = "\n";
my $closing = "\n\n";

my $watching = 0;
my $got_output = 0;
my $local_vars = "";
my $locals_start;
my $locals_end;
my $last_statement;
my ($main_start, $main_end);
sub flushall;
sub gdb;

my ($out, $in);

sub getlocals {
  print "getting locals\n" if $debug >= 5;
  gdb $in, "print \"Go.\"\ninfo locals\nprint \"~Ok.~\"\n";

  while(my $peep = <$out>) {
    chomp $peep;
    print "got peep: [$peep]\n" if $debug >= 5;
    last if $peep =~ m/\(gdb\) \$\d+ = "Go."/;

    next if $peep =~ m/Missing separate debug/;
    # fix this
    $peep =~ s/^\d+: (.*?) =/$1 =/;
    print "$opening$peep$closing";
    $got_output = 1;
  }

  my $result = {};

  while(my $line = <$out>) {
    chomp $line;
    print "got: [$line]\n" if $debug >= 5;
    last if $line =~ m/\(gdb\) \$\d+ = "~Ok.~"/;
    if($line =~ m/([^=]+)=\s+(.*)/) {
      my $var = $1;
      my $value = $2;
      $var =~ s/^\(gdb\)\s+//;
      $var =~ s/\s+$//;
      $result->{$var} = $value;
      print "  got local: $var = $value\n" if $debug >= 4;
    }
  }

  return $result;
}

sub execute {
  my ($cmdline) = @_;
  my ($ret, $result);

  open2($out, $in, "$cmdline 2>&1");

  while(my $line = <$out>) {
    chomp $line;
    print "--- got: [$line]\n" if $debug >= 1;

    my $ignore_response = 0;

    next if not length $line;
    <$out> and next if $line =~ m/^\(gdb\) No line \d+ in/;
    next if $line =~ m/No default breakpoint address/;
    next if $line =~ m/^\(gdb\) No symbol table/;
    next if $line =~ m/^\[Detaching after/;
    next if $line =~ m/^\[New Thread/;
    next if $line =~ m/^\(gdb\) Continuing/;
    next if $line =~ m/^\(gdb\) \$\d+ = "~Ok\.~"/;
    next if $line =~ m/^(\(gdb\) )*Breakpoint \d+ at 0x/;
    next if $line =~ m/^\(gdb\) Breakpoint \d+ at 0x/;
    next if $line =~ m/^\(gdb\) Note: breakpoint \d+ also set/;
    next if $line =~ m/^(\(gdb\) )*Starting program/;
    next if $line =~ m/PRETTY_FUNCTION__ =/;
    next if $line =~ m/libc_start_main/;
    next if $line =~ m/Thread debugging using libthread_db enabled/;
    next if $line =~ m/Using host libthread_db library/;
    next if $line =~ m/\s*Catchpoint \d+/;
    next if $line =~ m/Missing separate debuginfo/;
    next if $line =~ m/^Try: dnf/;

    if($line =~ m/^\d+: (.*? = .*)/) {
      print "$opening$1$closing";
      $got_output = 1;
      next;
    }

    if($line =~ m/^Reading symbols from/) {
      gdb $in, "break gdb\n";

      gdb $in, "list main,9001\n";
      gdb $in, "\nprint \"~Ok.~\"\n";
      my ($bracket, $main_ended) = (0);
      while(my $line = <$out>) {
        chomp $line;
        print "list got: [$line]\n" if $debug >= 4;
        my ($line_number) = $line =~ m/^(?:\(gdb\)\s+)?(\d+)/g;
        while($line =~ m/(.)/g) {
          my $char = $1;
          if($char eq '{' and not $main_ended) {
            if ($bracket == 0) {
              $main_start = $line_number;
            }
            $bracket++;
          } elsif($char eq '}') {
            $bracket--;

            if($bracket == 0 and not $main_ended) {
              $main_end = $line_number - 1;
              $main_ended = 1;
              last;
            }
          }
        }

        last if $line =~ m/^\(gdb\) \$\d+ = "~Ok.~"/;
      }

      gdb $in, "break $main_start\n";
      gdb $in, "break $main_end\n";
      gdb $in, "set width 0\n";
      gdb $in, "set height 0\n";
#      gdb $in, "set auto-solib-add off\n";
      gdb $in, "catch exec\n";
      gdb $in, "run $cmdlineargs < .input\n";
      next;
    }

    if($line =~ m/^Breakpoint \d+, main/) {
      my $line = <$out>;
      print "== got: $line\n" if $debug >= 5;
      if ($line =~ m/^\d+\s+return.*?;\s*$/ or $line =~ m/^\d+\s+}\s*$/) {
        if($got_output == 0) {
          $locals_end = getlocals();

          my $sep = '';
          foreach my $var (keys %$locals_end) {
            print "checking local $var...\n" if $debug >= 4;
            $locals_start->{$var} //= '';
            if ($locals_start->{$var} ne $locals_end->{$var}) {
              $local_vars .= "$sep$var = $locals_end->{$var}";
              $sep = '; ';
            }
          }
        }
      } elsif ($line =~ m/^$main_start\s+/) {
        $locals_start = getlocals();
      }

      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/Breakpoint \d+, gdb/) {
      gdb $in, "up\n";
      $line = <$out>;
      print "ignored $line\n" if $debug >= 2;
      $line = <$out>;
      print "ignored $line\n" if $debug >= 2;
      next;
    }

    if($line =~ m/^Breakpoint \d+, _(.*?) at/) {
      <$out>;
      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/^Breakpoint \d+, (.*?) at/) {
      my $func = $1;
      my $direction = "entered";
      my $return_value = "";
      my $nextline = <$out>;
      chomp $nextline;

      print "got bt nextline: <$nextline>\n" if $debug >= 5;

      if($nextline =~ m/^\d+\s+}$/) {
        $direction = "leaving";

        gdb $in, "finish\n";
        while(my $retval = <$out>) {
          chomp $retval;
          print "got retval line: <$retval>\n" if $debug >= 5;
          $retval =~ s/^\(gdb\)\s+//;

          if($retval =~ m/^Run till exit/) {
            <$out>;
            <$out>;
            next;
          }

          if($retval =~ m/Value returned is \$\d+ = (.*)/) {
            $return_value = ", returned $1";
            last;
          }

          next if not length $retval;
          next if $retval =~ m/^\$\d+ = 0/;

          print "$retval\n";
          $got_output = 1;
        }
      }

      flushall $in, $out;

      my $indent = 0;
      gdb $in, "bt\n";
      while(my $bt = <$out>) {
        chomp $bt;
        print "got bt: <$bt>\n" if $debug >= 5;
        $bt =~ s/^\(gdb\) //;
        if($bt =~ m/^#(\d+) .* main .* at prog/) {
          $indent = $1;
          last;
        }
      }

      $indent++ if $direction eq "leaving";

      print "$opening$direction [$indent]", ' ' x $indent, "$func$return_value$closing";
      gdb $in, "cont\n";
      next;
    }

    if ($line =~ m/^\d+\s+.*\bprint_last_statement\((.*)\)/) {
      my $stmt = $1;

      if ($stmt =~ m/^\s*(print|trace|watch|print|ptype|whatis|gdb)\b/) {
        $line = "1 $stmt";
      } else {
        $line = "1 gdb(\"print_last_statement $stmt\");";
      }
    }


    if ($line =~ m/^\d+\s+.*\btrace\((.*)\)/) {
      $line = "1 gdb(\"break $1\");";
    }

    if ($line =~ m/^\d+\s+.*\bwatch\((.*)\)/) {
      $line = "1 gdb(\"watch $1\");";
    }

    if ($line =~ m/^\d+\s+.*\bdump\((.*)\)/) {
      $line = "1 gdb(\"print $1\");";
    }

    if ($line =~ m/^\d+\s+.*\bprint\((.*)\)/) {
      $line = "1 gdb(\"print $1\");";
    }

    if ($line =~ m/^\d+\s+.*\bptype\((.*)\)/) {
      $line = "1 gdb(\"ptype $1\");";
    }

    if ($line =~ m/^\d+\s+.*\bwhatis\((.*)\)/) {
      $line = "1 gdb(\"whatis $1\");";
    }

    if($line =~ m/^\d+\s+.*\bgdb\("(.*)"\)/) {
      my $command = $1;
      my ($cmd, $args) = split / /, $command, 2;
      $args = "" if not defined $args;

      print "got command [$command][$cmd][$args]\n" if $debug >= 10;

      flushall $in, $out;

      if ($cmd eq "print_last_statement") {
        $command =~ s/;$//;
        gdb $in, "print $args\nprint \"~Ok.~\"\n";

        while ($line = <$out>) {
          chomp $line;
          print "got last output line: [$line]\n" if $debug >= 10;
          $line =~ s/^\(gdb\)\s*//;
          if ($line =~ m/^\$\d+ = "~Ok.~"/) {
            last;
          } elsif ($line =~ s/\$\d+ = (.*)$//) {
            unless ($1 eq 'void' || $args eq $1) {
              $last_statement = "$args = $1";
              print "got last statement [$last_statement]\n" if $debug;
            }
            if (length $line) {
              print "$line\n";
              $got_output = 1;
            }
          } else {
            if ($line =~ m/Program received signal/) {
              print "GOT SIGNAL!\n" if $debug;
              goto SIGNAL;
              last;
            }

            $line =~ s/\$\d+ = \d+$//;
            print "$line\n";
            $got_output = 1;
          }
        }
        gdb $in, "cont\n";
        next;
      }

      if($cmd eq "break") {
        $ignore_response = 1;

        gdb $in, "list $args,9001\n";
        gdb $in, "print \"~Ok.~\"\n";
        my $break = 0;
        my $bracket = 0;
        my $func_ended = 0;
        while(my $line = <$out>) {
          chomp $line;
          print "list break got: [$line]\n" if $debug >= 4;
          my ($line_number) = $line =~ m/^(\d+)/g;
          while($line =~ m/(.)/g) {
            my $char = $1;
            if($char eq '{') {
              $bracket++;
            } elsif($char eq '}') {
              $bracket--;

              if($bracket == 0 and not $func_ended) {
                gdb $in, "break $line_number\n";
                print "func ended, breaking at $line_number\n" if $debug >= 5;
                $func_ended = 1;
                last;
              }
            }
          }

          last if $line =~ m/^\(gdb\) \$\d+ = "~Ok.~"/;
        }
      }

      if($cmd eq "watch") {
        gdb $in, "display $args\n";
        <$out>;
        $watching++;
        $ignore_response = 1;
      }

      my $final_closing = "";
      gdb $in, "$command\nprint \"~Ok.~\"\n";
      while(my $next_line = <$out>) {
        chomp $next_line;
        print "nextline: $next_line\n" if $debug >= 1;

        print $final_closing and last if $next_line =~ m/\$\d+ = "~Ok.~"/;
        $next_line =~ s/^\(gdb\)\s*\(gdb\)\s+\$\d+ = "~Ok.~"//;
        $next_line =~ s/^\(gdb\)\s+\$\d+//;
        $next_line =~ s/^\(gdb\)\s+type//;
        $next_line =~ s/^\(gdb\)\s*//;

        next if not length $next_line;

        if(not $ignore_response) {
          if($next_line =~ m/=/) { # ptype
            $got_output = 1;
            print "$opening$args$next_line";
            $final_closing = $closing;
          } else {
            $got_output = 1;
            $next_line =~ s/^\s+//;
            print "\n$next_line";
          }
        }
      }

      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/^Watchpoint \d+: (.*)/) {
      my $var = $1;

      my $ignore = <$out>;
      print "ignored $ignore\n" if $debug >= 5;
      my $old = <$out>;
      my $new = <$out>;
      $ignore = <$out>;
      print "ignored $ignore\n" if $debug >= 5;
      $ignore = <$out>;
      print "ignored $ignore\n" if $debug >= 5;

      my ($val1) = $old =~ m/Old value = (.*)/;
      my ($val2) = $new =~ m/New value = (.*)/;

      $got_output = 1;
      print "$opening$var = $val2$closing";
      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/^Hardware watchpoint \d+: (.*)/) {
      my $var = $1;

      my $ignore = <$out>;
      my $old = <$out>;
      my $new = <$out>;
      $ignore = <$out>;
      $ignore = <$out>;

      my ($val1) = $old =~ m/Old value = (.*)/;
      my ($val2) = $new =~ m/New value = (.*)/;

      $got_output = 1;
      my $output = "$opening$var changed: $val1 => $val2$closing";
      flushall $in, $out;
      print $output;
      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/^Watchpoint \d+ deleted/) {
      my $ignore = <$out>;
      print "ignored $ignore\n" if $debug >= 5;
      gdb $in, "cont\n";
      next;
    }

    if($line =~ m/^Program exited/) {
      if (not $got_output and (length $local_vars or defined $last_statement)) {
        print $opening . "no output:";
        print " $last_statement" if defined $last_statement;
        print ";" if defined $last_statement and length $local_vars;
        print " $local_vars" if length $local_vars;
        print $closing . "\n";
      }
      exit 0;
    }

    if($line =~ s/\[Inferior .* exited with code (\d+)\]//) {
      print "$line\n" if length $line;
      print $opening . "Exit " . (oct $1) . $closing;
      if (not $got_output and (length $local_vars or defined $last_statement)) {
        print $opening . "no output:";
        print " $last_statement" if defined $last_statement;
        print ";" if defined $last_statement and length $local_vars;
        print " $local_vars" if length $local_vars;
        print $closing . "\n";
      }
      exit 0;
    }

    if($line =~ s/\[Inferior .* exited normally\]//) {
      print "$line\n" if length $line;
      $got_output = 1 if length $line;
      if (not $got_output and (length $local_vars or defined $last_statement)) {
        print $opening . "no output:";
        print " $last_statement" if defined $last_statement;
        print ";" if defined $last_statement and length $local_vars;
        print " $local_vars" if length $local_vars;
        print $closing . "\n";
      }
      exit 0;
    }

    if($line =~ m/Program terminated with signal SIGKILL/) {
      print "[Killed]\n";
      return 0;
    }

    if($line =~ m/Program received signal SIGTRAP/) {
      my $output = "";
      my $line = <$out>;
      print "ignored $line\n" if $debug >= 5;
      $line = <$out>;
      print "ignored $line\n" if $debug >= 5;
      for(my $i = 0; $i < $watching; $i++) {
        $line = <$out>;
        chomp $line;
        $line =~ s/^\d+:\s//;
        $got_output = 1;
        $output .= "$opening$line$closing";
      }
      flushall $in, $out;
      print $output;
      gdb $in, "cont\n";
      next;
    }

    SIGNAL:
    #print "SIGNAL - testing line [$line]\n" if $debug;
    if($line =~ m/Program received signal/) {
      my $result = "";
      my $vars = "";
      my $varsep = "";

      $line =~ s/\.$//;
      $got_output = 1;
      print "$line ";

      while(my $line = <$out>) {
        chomp $line;
        $line =~ s/^\(gdb\)\s+//;
        $line =~ s/main \(.*?\)/main ()/g;

        print "signal got: [$line]\n" if $debug >= 5;

        next if $line =~ m/__PRETTY_FUNCTION__ =/;
        gdb $in, "up\n" and next if $line =~ m{^\#\d+\s+<function called from gdb>};
        <$out> and gdb $in, "up\n" and next if $line =~ m/^\#\d+\s+gdb \(\)/;

        if($line =~ s/^(#\d+\s+)?0x[0-9A-Fa-f]+\s// || $line =~ m/\w+ \(\) (at|in) /) {
          $line =~ s/\s+at .*:\d+//;
          $line =~ s/\s+from \/lib.*//;

          gdb $in, "up\n" and next if $line =~ m{in \?\?};
          gdb $in, "up\n" and next if $line =~ m{/usr/lib/};
          gdb $in, "up\n" and next if $line =~ m{^_};

          if($line =~ s/^\s*in\s+//) {
            if(not length $result) {
              $result .= "in $line ";
            } else {
              $result .= "called by $line ";
            }
            gdb $in, "info locals\n";
          } else {
            $result = "in $line from ";
            gdb $in, "info locals\n";
          }
        }
        elsif($line =~ m/^No symbol table info available/ || $line =~ m/^No locals/) {
          gdb $in, "up\n";
        }
        elsif($line =~ s/^\d+\s+//) {
          next if $line =~ /No such file/;

          $line = $1 if $line =~ m/print_last_statement\((.*)\)/;

          $result .= "at statement: $line ";
          gdb $in, "up\n";
        }
        elsif($line =~ m/([^=]+)=\s+(.*)/) {
          unless ($2 =~ m/~Ok\.~/) {
            $vars .= "$varsep$1= $2";
            $varsep = "; ";
          }
        }
        elsif($line =~ m/^Initial frame selected; you cannot go up/) {
          last;
        }
      }

      $result =~ s/^\s+//;
      $result =~ s/\s+$//;
      $result =~ s/in main \(\) //;

      $vars = " <local variables: $vars>" if length $vars;

      print "$result$vars\n";
      exit 0;
    }

    if($line =~ s/^\(gdb\)\s*//) {
      $got_output = 1;
      print "$opening$line$closing";
      next;
    }

    next if $line =~ m/^\d+\s+void gdb\(\) \{\}/;

    next if not length $line;

    $got_output = 1;
    print "$line\n";
  }
}

sub gdb {
  my ($in, $command) = @_;

  chomp $command;
  print "+++ gdb command [$command]\n" if $debug >= 2;
  print $in "$command\n";
}

sub flushall {
  my ($in, $out) = @_;

  gdb $in, "call (int(*)(FILE *)) fflush(0)\nprint \"~Ok.~\"\n";
  while(my $line = <$out>) {
    chomp $line;
    $line =~ s/^\(gdb\)\s*//;
    $line =~ s/\$\d+ = \Q(int (*)(FILE *)) 0x0\E$//;
    last if $line =~ m/\$\d+ = "~Ok.~"/;
    next unless length $line;
    $got_output = 1;
    print "$line\n";
  }
}

$SIG{ALRM} = sub { print "\n"; exit 1; };
alarm 8;

execute("LIBC_FATAL_STDERR=1 MALLOC_CHECK_=1 gdb -silent -q -nx -iex 'set auto-load safe-path /' ./prog");