CODEWITHSUNDEEP
debuggingstack-tracedebug-symbolsstracesystemtap
r.v
r.v

Reputation: 4877

Convert debugging symbols to files and line numbers

I am using strace and SystemTap to obtain stack traces at system calls. What I get currently shows the function name but not the file name and line number. A trace from strace on ls using -k option:

 > /usr/lib64/libc-2.22.so(_IO_file_close+0xb) [0x7890b]
 > /usr/lib64/libc-2.22.so(_IO_file_close_it+0x120) [0x79f40]
 > /usr/lib64/libc-2.22.so(fclose+0x183) [0x6db93]
 > /code/coreutils/src/ls(close_stream+0x1a) [0x1232a]
 > /code/coreutils/src/ls(close_stdout+0x12) [0x9d52]
 > /usr/lib64/libc-2.22.so(__run_exit_handlers+0xe8) [0x39658]
 > /usr/lib64/libc-2.22.so(exit+0x15) [0x396a5]
 > /usr/lib64/libc-2.22.so(__libc_start_main+0xf7) [0x20587]
 > /code/coreutils/src/ls(_start+0x29) [0x4629]

Another one from SystemTap again from ls with a slight modification of strace.stp in the examples:

 0x7f17e06eb607 : munmap+0x7/0x30 [/usr/lib64/libc-2.17.so]
 0x7f17e0672882 : _IO_setb+0x62/0x70 [/usr/lib64/libc-2.17.so]
 0x7f17e0671030 : _IO_file_close_it@@GLIBC_2.2.5+0xb0/0x180 [/usr/lib64/libc-2.17.so]
 0x7f17e0665020 : _IO_fclose@@GLIBC_2.2.5+0x180/0x210 [/usr/lib64/libc-2.17.so]
 0x4122ba : close_stream+0x1a/0x80 [/usr/bin/ls]
 0x40a8b5 : close_stdout+0x15/0xc0 [/usr/bin/ls]
 0x7f17e0632e69 : __run_exit_handlers+0xd9/0x110 [/usr/lib64/libc-2.17.so]
 0x7f17e0632eb5 : exit+0x15/0x20 [/usr/lib64/libc-2.17.so]
 0x40449c : main+0x1aec/0x2198 [/usr/bin/ls]
 0x7f17e061bb15 : __libc_start_main+0xf5/0x1c0 [/usr/lib64/libc-2.17.so]
 0x404b71 : _start+0x29/0x38 [/usr/bin/ls]

How do I convert the hexadecimal numbers to get the file names and line numbers?

Upvotes: 0

Views: 509

Answers (1)

fche
fche

Reputation: 2790

There are at least two possibilities

  1. ... manually filtering data through the addr2line program (part of binutils). This may be possible to automate, but clumsy; something like this, except one may have to split the hex addresses and process them one by one.
{ system(sprintf("addr2line -e /proc/self/exe %s", ubacktrace())) }
  1. ... through systemtap 2.7's [u]symfile and [u]symline functions. These functions work by uploading line-record parts of the debuginfo into the systemtap module, which these functions can use to map to kernel|userspace source file/lines.
{ hexaddr=tokenize(ubacktrace(), " ")
  ha=strtol(hexaddr,16)
  printf("%p %s:%s", ha, usymfile(ha), usymline(ha))
  while (1) {
      hexaddr=tokenize("", " ") // continue tokenizing
      if (hexaddr=="") break
      ha=strtol(hexaddr,16)
      printf("%p %s:%s", ha, usymfile(ha), usymline(ha))
  }
}

Upvotes: 2

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