how to check the source code of musl in gdb

Question

First of all, I don't speak English very well. Please forgive me. I want to check the source code of musl in gdb. This is what i have done.

1. apt install musl-tools

2. git://git.musl-libc.org/musl ，i have put it into ~

3. set the path for gdb,below is what in my '/~/.gdbinit':

   layout src
   directory ~/musl/src                        
   

4. i create a c program:

   #include <stdio.h>
   
   int main(){
     printf("hello\n");
   
     return 0;
   }
   

5. i compile it with 'musl-gcc -O1 -g3 -static test.c'

6. then i run it with gdb.But when i use 's' to try to step into the source code of printf,it just skip it.

i have tried to ask chatgpt,but still can't solve it. can anybody tell me why this happen and how can i sovle it.

Answer 1

1. Build musl with debug symbols:

   $ (cd musl; configure --enable-debug; make)
   

2. Build you program against library with debug symbols:

   $ musl-gcc -g3 -static -Lmusl/lib test.c
   

3. Kick back and enjoy the sweet success:

   $ gdb ./a.out
   (gdb) start
   Temporary breakpoint 1 at 0x40113d: file test.c, line 4.
   Starting program: /home/allan/a.out 
   
   Temporary breakpoint 1, main () at test.c:4
   4               printf("hello\n");
   (gdb) s
   puts (s=0x402000 "hello") at src/stdio/puts.c:6
   6       FLOCK(stdout);