It works great. Thank you.
From: Joe Damato [mailto:[email protected]] Sent: Wednesday, March 31, 2010 2:35 PM To: Rodrigo Dominguez Cc: [email protected] Subject: Re: [Ltrace-devel] Tracing dependent libraries Hi - Sorry for the delayed response. Very busy few days. You need to specify on the command line the name of the symbol you want to trace. I'm actually not sure if -c works with libdl symbols, but I THINK it does. Please let me know. If not, I can fix it. You name the symbol on the command line with -x, so for example I usually use ltrace like this: ltrace -ttTgx functionB -x functionC -x functionD tt - prefix line with time of day in microsecs T - amount of time spent in the call g - an option I added to tell ltrace NOT to trace libc -- tracing libc can be noisy and annoying x - the symbol name I want to trace x will look for the symbol name in the binary and all currently linked libraries (i.e. if you ltrace attached after dlsym, it'll pick it up just fine) and if nothing is found it'll listen and attach when the symbol is dlsym'd later (i.e. if you start your application with ltrace and dlsym hasnt happened yet). let me know if it works for you -- joe On Tue, Mar 30, 2010 at 1:13 PM, Rodrigo Dominguez <[email protected]> wrote: Joe, Option 2 below compiles on my system. However, I am not sure I am getting the libdl features you added. I wrote a small test program that uses dlopen to load a library file I created (libB.so): #include <dlfcn.h> int main(void) { void *handle; int (*myFunctionB)(void); handle = dlopen("./libB.so", RTLD_LAZY); myFunctionB = dlsym(handle, "functionB"); (*myFunctionB)(); return 0; } Neither the system ltrace nor your ltrace show the call to functionB. This is the output: $ ltrace -c ./a.out Inside libB::functionB % time seconds usecs/call calls function ------ ----------- ----------- --------- -------------------- 99.36 0.003254 3254 1 dlopen 0.64 0.000021 21 1 dlsym ------ ----------- ----------- --------- -------------------- 100.00 0.003275 2 total Am I missing something? Or am I misunderstanding the libdl support you added? Thank you. _____ Date: Tue, 30 Mar 2010 11:53:02 -0700 Subject: Re: [Ltrace-devel] Tracing dependent libraries From: [email protected] To: [email protected]; [email protected] Replying to this on-list just incase other people have this problem. Not sure if I ever submit this patch back to the list, but I added support for backtraces so you can see the function call stack for traced functions. The problem with this feature is that I didn't take the time to fix the configure script so that it would disable that code if you don't have libunwind on your system. There are two solutions: 1.) The simplest solution (until I or some one else fixes the configure script) is to install libunwind library and header files on your system and try building my branch again. or 2.) Rewind the source tree in git to before that commit was made. To do this you can just: git checkout a95f1 -b before_unwind That will create a local branch called "before_unwind" (the first byte of the sha before the libunwind commit are a95f1). The downside is that if you do this you lose some of the man page cleanup and a small bugfix. Sorry for the pain. joe On Tue, Mar 30, 2010 at 11:11 AM, Rodrigo Dominguez <[email protected]> wrote: Thanks. I was able to checkout your code. I am getting the following errors after ./configure && make make -C sysdeps/linux-gnu make[1]: Entering directory `/home/rdomingu/ltrace/sysdeps/linux-gnu' gcc -Wall -g -O2 -iquote /home/rdomingu/ltrace -iquote /home/rdomingu/ltrace/sysdeps/linux-gnu -DSYSCONFDIR=\"/usr/local/etc\" -I /usr/include/libelf -I/home/rdomingu/ltrace/sysdeps/linux-gnu/x86_64 -c -o events.o events.c In file included from events.c:12: /home/rdomingu/ltrace/common.h:1:23: error: libunwind.h: No such file or directory In file included from /home/rdomingu/ltrace/common.h:11, from events.c:12: /home/rdomingu/ltrace/elf.h:4:18: error: gelf.h: No such file or directory In file included from /home/rdomingu/ltrace/common.h:11, from events.c:12: /home/rdomingu/ltrace/elf.h:9: error: expected specifier-qualifier-list before âElfâ /home/rdomingu/ltrace/elf.h:50: error: expected â=â, â,â, â;â, âasmâ or â__attribute__â before âarch_plt_sym_valâ In file included from events.c:12: /home/rdomingu/ltrace/common.h:193: error: expected specifier-qualifier-list before âunw_addr_space_tâ In file included from events.c:12: /home/rdomingu/ltrace/common.h:234: error: expected declaration specifiers or â...â before âGElf_Symâ /home/rdomingu/ltrace/common.h:236: error: expected â)â before âaddrâ make[1]: *** [events.o] Error 1 make[1]: Leaving directory `/home/rdomingu/ltrace/sysdeps/linux-gnu' make: *** [sysdeps/sysdep.o] Error 2 From: Joe Damato [mailto:[email protected]] Sent: Tuesday, March 30, 2010 1:12 PM To: Rodrigo Dominguez Cc: [email protected] Subject: Re: [Ltrace-devel] Tracing dependent libraries Not a dumb question at all. My code isn't part of the official repository, but it is on github at: git://github.com/ice799/ltrace.git My code is in the branch "libdl" So you should: git clone git://github.com/ice799/ltrace.git git checkout -b libdl origin/libdl and you will be sitting in the libdl branch. You can take a look at the commits on that branch by doing git log. If a particular commit interests you, you can git show <sha> to look at the diff. If you have any other questions/issues getting my code or getting it to build feel free to email me off list. joe On Tue, Mar 30, 2010 at 9:35 AM, Rodrigo Dominguez <[email protected]> wrote: Joe, I am sorry for the dumb question but how do you checkout a branch from github. I am not familiar with git. I ran: git clone git://git.debian.org/git/collab-maint/ltrace.git but this only gets me the master branch. Thank you. From: Joe Damato [mailto:[email protected]] Sent: Tuesday, March 09, 2010 5:20 PM To: Rodrigo Dominguez Cc: [email protected] Subject: Re: [Ltrace-devel] Tracing dependent libraries I implemented support for libdl and you can get that tree from github: http://github.com/ice799/ltrace/tree/libdl I have *not* implemented tracing calls from libraries to other libraries, though. doing that should be pretty straightforward. i don't really have the cycles right now to implement that in the near term but I am willing to point people in the right direction if they are interested in implementing it. otherwise as soon as i have time to do it (probably later this month), i can implement it. joe On Tue, Mar 9, 2010 at 2:13 PM, Rodrigo Dominguez <[email protected]> wrote: How can I get ltrace to trace dependent libraries (libraries called from within libraries)? All I was able to find was this old post: http://sourceware.org/ml/binutils/2006-09/msg00009.html Has this been implemented since then? 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