Trouble debugging functions in linked libraries with gdb - c

Question

I'm doing a bit of reading about gdb, and I'm having trouble getting gdb (I'm running 7.11.1) to debug a function from a library.
The sample code used to learn about the debugger is quite simple:
#include <stdio.h>
#include <string.h>
int main() {
char str_a[20];
strcpy(str_a, "Hello, world!\n");
printf(str_a);
}
I compiled it with debugging symbols enabled, fired up GDB, and set some breakpoints:
(gdb) list
1 #include <stdio.h>
2 #include <string.h>
3
4 int main() {
5 char str_a[20];
6
7 strcpy(str_a, "Hello, world!\n");
8 printf(str_a);
9 }
(gdb) break 7
Breakpoint 1 at 0x4005ad: file char_array2.c, line 7.
(gdb) break strcpy
Function "strcpy" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (strcpy) pending.
(gdb) break 8
Breakpoint 3 at 0x4005cf: file char_array2.c, line 8.
(gdb) run
Starting program: /home/david/hacking_the_art_of_exploitation/Chapter_2/char_array2
Breakpoint 1, main () at char_array2.c:7
7 strcpy(str_a, "Hello, world!\n");
(gdb) continue
Continuing.
Breakpoint 3, main () at char_array2.c:8
8 printf(str_a);
(gdb) continue
Continuing.
Hello, world!
[Inferior 1 (process 7061) exited normally]
As you can see, the debugger never descends into the strcpy function.
I've tried adding set stop-on-solib-events 1 to my .gdbinit. This leads to different but still undesirable results:
(gdb) run
Starting program: /home/david/hacking_the_art_of_exploitation/Chapter_2/char_array2
Stopped due to shared library event (no libraries added or removed)
I'm at a bit of a loss here. Thanks in advance for any help.

Answer 1

I believe you need the libc-dbg package and the libc source package for debugging a libc function. On Ubuntu you can install it via
sudo apt-get install libc6-dbg
mkdir ~/libc ; cd ~/libc
apt-get source libc6