debugging - How to read and load symbols selectively while attaching a process in gdb?

Question

My binary uses a number of different shared libraries. While attaching the process with gdb, it takes around 5 minutes to load and read symbols from all of these libraries.

Is there a way to read and load symbols selectively while attaching a process with gdb?

Answer 1

You can set auto-solib-add off and then use the sharedlibrary command to selectively load symbols. Example:

$ gdb -e ./a.out
(gdb) set auto-solib-add off
(gdb) file a.out
Reading symbols from a.out...done.
(gdb) start
Temporary breakpoint 1 at 0x4004ba: file sig.c, line 4.
Starting program: /home/a3f/a.out 

Temporary breakpoint 1, main () at sig.c:4
4       do();
(gdb) print environ
No symbol "environ" in current context.
(gdb) info shared
From                To                  Syms Read   Shared Object Library
0x00007ffff7ddcae0  0x00007ffff7df5130  No          /lib64/ld-linux-x86-64.so.2
                                        No          linux-vdso.so.1
0x00007ffff7a504a0  0x00007ffff7b7cc73  No          /lib/x86_64-linux-gnu/libc.so.6
(gdb) sharedlibrary libc
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libc-2.19.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6
(gdb) print environ
 $1 = (char **) 0x7fffffffe3b8
(gdb) print _dl_open
No symbol "_dl_open" in current context.
(gdb) sharedlibrary
Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/ld-2.19.so...done.
done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
(gdb) print _dl_open
$1 = {void *(const char *, int, const void *, Lmid_t, int, char **, char **)} 0x7ffff7dee350 <_dl_open>