problems debugging getopt function with gdb

Question

I'm building the dnstracer application from source with this script:

#!/bin/bash
#########
# FILES #
#########
PACKAGE_NAME=dnstracer-1.6
PACKAGE_TAR_FILE=${PACKAGE_NAME}.tar.gz    
PACKAGE_FTP_SITE=http://ftp.iij.ad.jp/pub/linux/momonga/1/PKGS/SOURCES/

####################################
# REMOVE OLD STUFF JUST TO BE SURE #
####################################
rm -rf build
rm -rf ${PACKAGE_NAME}
rm -rf ${PACKAGE_TAR_FILE}

#####################################
# Get source code for buggy package #
#####################################
wget ${PACKAGE_FTP_SITE}/${PACKAGE_TAR_FILE}

######################
# Unpack it here ... #
######################
tar xf ${PACKAGE_TAR_FILE}

##########################################
# Prepare an out of tree build directory #
##########################################
mkdir build

##############################
# Get inside build directory #
##############################
cd build

#################
# Configure ... #
#################
../${PACKAGE_NAME}/configure

###############
# Make it !!! #
###############
make -j

And I see it ships with its own getopt, which is good for me because I need to debug it:

$ ls -l ./dnstracer-1.6/getopt.*
./dnstracer-1.6/getopt.c
./dnstracer-1.6/getopt.h

However when I try to step inside getopt from gdb, I realize that it probably has some other getopt (maybe without debug symbols?) and it doesn't let me step inside:

$ cd build
$ gdb --args ./dnstracer -v aaaaaa
$ (gdb) break main
$ (gdb) run
$ (gdb) next
$ 1304 while ((ch=getopt(argc,argv,"coq:r:s:t:v"))!=-1) {
$ step
$ 1305 switch (ch) {

How can I configure the build process to use the shipped getopt version rather than some hidden default? Thanks!

What is your OS? Are you on Windows? Where are from did you get dnstracer sources? — ks1322, Mar 05 '18 at 11:51
Ubuntu 17.10 ... the entire building script with ftp site is inside the question — OrenIshShalom, Mar 05 '18 at 11:53

score 2 · Accepted Answer · answered Mar 05 '18 at 12:25

2

And I see it ships with its own getopt, which is good for me because I need to debug it:

Since you are on Ubuntu this is not the case for you, see in shipped getopt.h:

// Only used in the win32-version of dnstracer.
// Supplied by Mike Black <mblack@csihq.com>

Therefore you are using system getopt which is part of glibc. In order to step into getopt you need glibc debug symbols installed. See https://stackoverflow.com/a/48287761/72178 on how to debug glibc on Ubuntu.

answered Mar 05 '18 at 12:25

ks1322

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Thanks, I actually need to change getopt, but only want to do it ad hoc, for dnstracer. I've tried tricking the configure to think I'm on windows with: WIN32=1 ../${PACKAGE_NAME}/configure ... but still no go ... it uses the glibc getopt ... – OrenIshShalom Mar 05 '18 at 12:54

problems debugging getopt function with gdb

1 Answers1