genode/tool/backtrace

#!/usr/bin/tclsh

#
# \brief  Decode 'Genode::backtrace()' output and other memory addresses
# \author Christian Prochaska
# \date   2024-01-25
#
# Credits: heavily inspired by the Fiasco.OC backtrace tool
#


if {$::argc == 0} {
	puts "Usage (in Genode debug directory):"
	puts ""
	puts {[KERNEL=...] backtrace [binary]}
	puts ""
	puts "then paste shared library info and backtrace addresses."
	puts ""
	puts "If the KERNEL environment variable is set, the file name "
	puts "'ld.lib.so' will be replaced by 'ld-KERNEL.lib.so'"
	puts ""
	exit 1
}


set genode_tools_dir "/usr/local/genode/tool/23.05/bin"

set arch {}

array set images {}
array set image_bases {}
array set sections {}
array set symbols {}

set sorted_symbols_keys {}


proc readelf {} {
	global genode_tools_dir
	return "$genode_tools_dir/genode-x86-readelf"
}


proc nm {} {
	global genode_tools_dir
	global arch
	return "$genode_tools_dir/genode-$arch-nm"
}


proc addr2line {} {
	global genode_tools_dir
	global arch
	return "$genode_tools_dir/genode-$arch-addr2line"
}


proc scan_image {img base} {

	global arch
	global images
	global image_bases
	global sections
	global symbols
	global sorted_symbols_keys

	if {$arch == ""} {
		set readelf_output [exec [readelf] -h $img]
		if {[regexp {AArch64} $readelf_output]} {
			set arch "aarch64"
		} elseif {[regexp {ARM} $readelf_output]} {
			set arch "arm"
		} elseif {[regexp {RISC-V} $readelf_output]} {
			set arch "riscv"
		} elseif {[regexp {80386} $readelf_output]} {
			set arch "x86"
		} elseif {[regexp {X86-64} $readelf_output]} {
			set arch "x86"
		} else {
			puts "Error: could not obtain architecture from image file"
			return
		}
	}

	# ignore base address of ld.lib.so
	if {$img == "ld.lib.so"} {
		set base 0
		if {[info exists ::env(KERNEL)]} {
			set img ld-$::env(KERNEL).lib.so
		}
	}

	set nm_output ""

	if {[catch { set nm_output [exec [nm] -C $img.debug] } msg]} {
		puts "Warning: $msg"
		return
	}

	set nm_lines [split $nm_output "\n"]

	foreach nm_line $nm_lines {

		if {[regexp {^([0-9a-fA-F]+)\s+(\S)\s+(.*)$} $nm_line -> addr section sym]} {
			set key "[format "0x%x" [expr $base + 0x$addr]]"
			set images($key) $img
			set image_bases($key) $base
			set sections($key) $section
			set symbols($key) $sym
		}
	}

	set sorted_symbols_keys [lsort -integer [array names symbols]]

	puts "Scanned image $img"
}


proc print_func {addr} {

	global images
	global image_bases
	global sections
	global symbols
	global sorted_symbols_keys

	set addr [format "0x%x" $addr]

	set symbol_start_addr 0

	foreach key $sorted_symbols_keys {
		if {[expr $key > $addr]} {
			break }
		set symbol_start_addr $key
	}

	if {$symbol_start_addr} {
		set img $images($symbol_start_addr)
		set local_addr [format "0x%x" [expr $addr - $image_bases($symbol_start_addr)]]
		set line [exec [addr2line] -e $img $local_addr]
		puts "$symbols($symbol_start_addr)"
		puts ""
		puts "    * $addr: $img:$local_addr $sections($symbol_start_addr)"
		puts "    * $line"
	} else {
		puts "<unknown>"
		puts "    * $addr"
	}

	puts ""
}


foreach arg $::argv { scan_image $arg 0 }

while {1} {

	gets stdin line

	# prevent mixing of pasted input and generated output
	after 10

	puts ""

	if {[regexp {^\[.*\]   (0x[0-9a-f]+).*?: (.*)$} $line -> base img]} {

		# shared library info

		# ignore linker area
		if {$img == "linker area"} {
			continue }

		# ignore stack area
		if {$img == "stack area"} {
			continue }

		scan_image $img $base

	} elseif {[regexp {^\[.*]\s+[0-9a-f]+\s+([0-9a-f]+)$} $line -> addr]} {

		# backtrace address

		print_func 0x$addr

	} elseif {[regexp {^(0x[0-9a-f]+)$} $line -> addr]} {

		# single hex address prefixed with 0x

		print_func $addr

	} elseif {[regexp {^([0-9a-f]+)$} $line -> addr]} {

		# single hex address not prefixed with 0x

		print_func 0x$addr

	}
}