gdb debug mptcp kernel library with ns-3_dce

[Lawrence]

Hello friends,

I have successfully set up ns-3-dce with libos mptcp ( see here how : https://groups.google.com/forum/#!topic/ns-3-users/M3A5ydBLktY )

My aim is to debug the code at $HOME/net-next-nuse/net/mptcp/mptcp_sched.c

How do I do so ?

I have tried the following :


lawrence@lawrence:~/ns-3-dce$ ./waf --run dce-iperf-mptcp --command-template="gdb --args %s"
Waf: Entering directory `/home/lawrence/ns-3-dce/build'
[ 10/367] lib/pkgconfig/libns3-dev-netlink-debug.pc:  -> build/lib/pkgconfig/libns3-dev-netlink-debug.pc
[116/367] lib/pkgconfig/libns3-dev-dce-debug.pc:  -> build/lib/pkgconfig/libns3-dev-dce-debug.pc
Waf: Leaving directory `/home/lawrence/ns-3-dce/build'
'build' finished successfully (0.225s)
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Reading symbols from /home/lawrence/ns-3-dce/build/

bin/dce-iperf-mptcp...done.
(gdb) b write
Function "write" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (write) pending.
(gdb) run
Starting program: /home/lawrence/ns-3-dce/build/bin/dce-iperf-mptcp
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, write () at ../sysdeps/unix/syscall-template.S:81
81    ../sysdeps/unix/syscall-template.S: No such file or directory.
(gdb) step
ns3::ElfCache::CopyFile (this=0x7ffff7dd8f00 <ns3::CoojaLoader::Peek()::modules>, source="/home/lawrence/net-next-nuse/liblinux.so", destination="elf-cache/0/liblinux.so") at ../model/elf-cache.cc:65
65              bytes_written += written;
(gdb) step
62          while (bytes_written != bytes_read)
(gdb) step
67          bytes_read = read (src, buffer, 1024);
(gdb) step
read () at ../sysdeps/unix/syscall-template.S:81
81    ../sysdeps/unix/syscall-template.S: No such file or directory.
(gdb) step
ns3::ElfCache::CopyFile (this=0x7ffff7dd8f00 <ns3::CoojaLoader::Peek()::modules>, source="/home/lawrence/net-next-nuse/liblinux.so", destination="elf-cache/0/liblinux.so") at ../model/elf-cache.cc:59
59      while (bytes_read > 0)
(gdb)

I think I should enter and debug the library at $HOME/net-next-nuse/liblinux.so to get to the mptcp_sched.c file. However I don't know how as gdb doesn't seem to leave the file ../model/elf-cache.cc

What do I do ?

[Lawrence]

Sorry, I was being stupid. Was putting the wrong function name at the breakpoint :P