-#! /usr/bin/perl
-$a2l = search_path ("i386-elf-addr2line") || search_path ("addr2line");
-$bin = shift @ARGV;
-open (A2L, "$a2l -fe $bin " . join (' ', @ARGV) . "|");
-while ($function = <A2L>) {
- $line = <A2L>;
- chomp $function;
- chomp $line;
- print "$function ($line)\n";
+#! /usr/bin/perl -w
+
+use strict;
+
+# Check command line.
+if (grep ($_ eq '-h' || $_ eq '--help', @ARGV)) {
+ print <<'EOF';
+backtrace, for converting raw addresses into symbolic backtraces
+usage: backtrace [BINARY] ADDRESS...
+where BINARY is the binary file from which to obtain symbols
+ and ADDRESS is a raw address to convert to a symbol name.
+
+If BINARY is unspecified, the default is the first of kernel.o or
+build/kernel.o that exists.
+
+The ADDRESS list should be taken from the "Call stack:" printed by the
+kernel. Read "Backtraces" in the "Debugging Tools" chapter of the
+Pintos documentation for more information.
+EOF
+ exit 0;
+}
+die "backtrace: at least one argument required (use --help for help)\n"
+ if @ARGV == 0;
+
+# Drop leading and trailing garbage inserted by kernel.
+shift while grep (/^(call|stack:?)$/i, $ARGV[0]);
+s/\.$// foreach @ARGV;
+
+# Find binary file.
+my ($bin) = $ARGV[0];
+if (-e $bin) {
+ shift @ARGV;
+} elsif ($bin !~ /^0/) {
+ die "backtrace: $bin: not found (use --help for help)\n";
+} elsif (-e 'kernel.o') {
+ $bin = 'kernel.o';
+} elsif (-e 'build/kernel.o') {
+ $bin = 'build/kernel.o';
+} else {
+ die "backtrace: can't find binary for backtrace (use --help for help)\n";
+}
+
+# Find addr2line.
+my ($a2l) = search_path ("i386-elf-addr2line") || search_path ("addr2line");
+if (!$a2l) {
+ die "backtrace: neither `i386-elf-addr2line' nor `addr2line' in PATH\n";
}
-
sub search_path {
my ($target) = @_;
- for $dir (split (':', $ENV{PATH})) {
- my ($file = "$dir/$target";
+ for my $dir (split (':', $ENV{PATH})) {
+ my ($file) = "$dir/$target";
return $file if -e $file;
}
- return 0;
+ return undef;
}
+
+# Do backtrace.
+open (A2L, "$a2l -fe $bin " . join (' ', @ARGV) . "|");
+while (<A2L>) {
+ my ($function, $line);
+ chomp ($function = $_);
+ chomp ($line = <A2L>);
+ $line = "..." . substr ($line, -25) if length ($line) > 28;
+ print shift (@ARGV), ": $function ($line)\n";
+}
+close (A2L);
+