How to map function address to function in *.so files

Question

backtrace function give set of backtrace how to map it with function name/file name/line number?

for ex:-
backtrace() returned 8 addresses
./libtst.so(myfunc5+0x2b) [0xb7767767]
./libtst.so(fun4+0x4a) [0xb7767831]
./libtst.so(fun3+0x48) [0xb776787f]
./libtst.so(fun2+0x35) [0xb77678ba]
./libtst.so(fun1+0x35) [0xb77678f5]
./a.out() [0x80485b9]
/lib/libc.so.6(__libc_start_main+0xe5) [0xb75e9be5]
./a.out() [0x80484f1]

From the above stack how can I get the file name and line number? I did following things, but no luck. Correct me if I am wrong :)

for ex:-
./libtst.so(fun2+0x35) [0xb77dc887]

0xb77dc887(fun2 addr+offset)-0xb77b6000 (lib starting addr) = 0x26887 (result)
result is no way related to function in nm output.

I used addr2line command:-
addr2line -f -e libtst.so 0xb77dc887
??
??:0

So, how can I resolve either at runtime or post runtime? Thanks in advance...

nm:-
00000574 T _init
00000680 t __do_global_dtors_aux
00000700 t frame_dummy
00000737 t __i686.get_pc_thunk.bx
0000073c T myfunc5
000007e7 T fun4
00000837 T fun3
00000885 T fun2
000008c0 T fun1
00000900 t __do_global_ctors_aux
00000938 T _fini
000009b4 r __FRAME_END__
00001efc d __CTOR_LIST__
00001f00 d __CTOR_END__
00001f04 d __DTOR_LIST__
00001f08 d __DTOR_END__
00001f0c d __JCR_END__
00001f0c d __JCR_LIST__
00001f10 a _DYNAMIC
00001ff4 a _GLOBAL_OFFSET_TABLE_
00002030 d __dso_handle
00002034 A __bss_start
00002034 A _edata
00002034 b completed.5773
00002038 b dtor_idx.5775
0000203c B funptr
00002040 A _end
     U backtrace@@GLIBC_2.1
     U backtrace_symbols@@GLIBC_2.1
     U free@@GLIBC_2.0
     U __isoc99_scanf@@GLIBC_2.7
     U perror@@GLIBC_2.0
     U printf@@GLIBC_2.0
     U puts@@GLIBC_2.0
     w __cxa_finalize@@GLIBC_2.1.3
     w __gmon_start__
     w _Jv_RegisterClasses

pmap:-
START       SIZE     RSS     PSS   DIRTY    SWAP PERM MAPPING
08048000      4K      4K      4K      0K      0K r-xp /home/test/libtofun/a.out
08049000      4K      4K      4K      4K      0K r--p /home/test/libtofun/a.out
0804a000      4K      4K      4K      4K      0K rw-p /home/test/libtofun/a.out
...
b7767000      4K      4K      4K      0K      0K r-xp /home/test/libtofun/libtst.so
b7768000      4K      4K      4K      4K      0K r--p /home/test/libtofun/libtst.so
b7769000      4K      4K      4K      4K      0K rw-p /home/test/libtofun/libtst.so
....
Total:     1688K    376K     82K     72K      0K

128K writable-private, 1560K readonly-private, 0K shared, and 376K referenced

libtst.c:-

void myfunc5(void){
int j, nptrs;
#define SIZE 100
void *buffer[100];
char **strings;

nptrs = backtrace(buffer, SIZE);
printf("backtrace() returned %d addresses\n", nptrs);

strings = backtrace_symbols(buffer, nptrs);
if (strings == NULL) {
    perror("backtrace_symbols");
}

for (j = 0; j < nptrs; j++)
    printf("%s\n", strings[j]);

free(strings);
}

void fun4(){
char ip;
char *fun = "fun4\0";
printf("Fun name %s\n",fun);
scanf("%c",&ip);
myfunc5();
}


void fun3(){
char *fun = "fun3\0";
printf("Fun name %s\n",fun);
funptr = fun4;
funptr();
}


void fun2(){
char *fun = "fun2\0";
printf("Fun name %s\n",fun);
fun3();
}


void fun1(){
char *fun = "fun1\0";
printf("Fun name %s\n",fun);
fun2();
}

main.c:-

int main(){
char ip;
funptr = &fun1;
scanf("%c",&ip);
funptr();
return 0;
}

Let me know if need more information...

Answer 1

Try giving the offset to addr2line, along with the section name. Like this:

addr2line -j .text -e libtst.so 0x26887

Edit: By the way, if it wasn't clear, the 0x26887 comes from what you provided:

0xb77dc887(fun2 addr+offset)-0xb77b6000 (lib starting addr) = 0x26887 (result)