指令堆里逆向出来的代码有歧义，有三处返回，有嵌套IF语句，故推断出是个函数；

    #if 0/*27ec:	48 8d 3d 58 39 00 00 	lea    0x3958(%rip),%rdi        # 614b <_IO_stdin_used@@Base+0x14b> // rdi="COLUMNS"27f3:	e8 e8 fb ff ff       	callq  23e0 <getenv@plt>*/	// getenv(rdi)char *ptr_strtol;struct winsize p_0xa8;/*struct winsize{unsigned short ws_row; // 窗口字符行数。unsigned short ws_col; // 窗口字符列数。unsigned short ws_xpixel; // 窗口宽度，象素值。unsigned short ws_ypixel; // 窗口高度，象素值。};*/char *p_getenv = getenv("COLUMNS");/*27f8:	48 85 c0             	test   %rax,%rax			// rax="113"27fb:	74 09                	je     2806 <__sprintf_chk@plt+0x96>	// no27fd:	80 38 00             	cmpb   $0x0,(%rax)			// 0-0x31, so zf=02800:	0f 85 1e 07 00 00    	jne    2f24 <__sprintf_chk@plt+0x7b4>*/	// if zf=0 than jumpif ((p_getenv != NULL) && (*p_getenv != 0)) {// goto 2f24 --> 283acol = strtol(p_getenv, &ptr_strtol, 0);printf("col = %d\n", col);if ( (!*ptr_strtol) && (col > 0) && (col < 0x7ffffffd))} else {/*2806:	48 8d 94 24 a8 00 00 	lea    0xa8(%rsp),%rdx  // rdx=(rsp+0xa8)=struct winsize p_0xa8280d:	00 280e:	be 13 54 00 00       	mov    $0x5413,%esi2813:	bf 01 00 00 00       	mov    $0x1,%edi2818:	31 c0                	xor    %eax,%eax281a:	e8 51 fd ff ff       	callq  2570 <ioctl@plt>281f:	41 89 c0             	mov    %eax,%r8d*/          // r8d=ret，把返回值存起来, 此处有可能是一个函数调用的返回。// include/uapi/asm-generic/ioctls.h:38:#define TIOCGWINSZ 0x5413ret = ioctl(1, 0x5413, &p_0xa8);printf("ret = %d, 0x%x\n", ret, p_0xa8.ws_row);    col = 0x84;/*2822:	b8 84 00 00 00       	mov    $0x84,%eax   // 0x84=1322827:	45 85 c0             	test   %r8d,%r8d    // r8d=ret282a:	78 0e                	js     283a <__sprintf_chk@plt+0xca>    SF = 1 负数, jump282c:	0f b7 8c 24 aa 00 00 	movzwl 0xaa(%rsp),%ecx  // (rsp+0xaa)=p_0xa8.ws_col，通过查看内存值可以判断结构的成员及大小2833:	00 2834:	66 85 c9             	test   %cx,%cx          // cx=cx&0xff2837:	0f 45 c1             	cmovne %ecx,%eax */     // cmovne 不等传送if (ret >= 0) {if (p_0xa8.ws_col != 0) {col = p_0xa8.ws_col;}}}#endifcol = get_ws_col();/*283a:	48 8d 35 2b 3a 00 00 	lea    0x3a2b(%rip),%rsi        # 626c <_IO_stdin_used@@Base+0x26c> // ""2841:	bf 06 00 00 00       	mov    $0x6,%edi2846:	89 05 78 6a 00 00    	mov    %eax,0x6a78(%rip)        # 92c4 <_IO_stdin_used@@Base+0x32c4> // 0x55555555684c+0x6a78=0x55555555d2c4=113284c:	e8 4f fe ff ff       	callq  26a0 <setlocale@plt>*/

int get_ws_col()
{
    char *ptr_strtol;
    struct winsize p_0xa8 = {0};
    int col = 0;

    char *p_getenv = getenv("COLUMNS");

    if ((p_getenv != NULL) && (*p_getenv != 0)) {
        col = strtol(p_getenv, &ptr_strtol, 0);
        printf("col = %d\n", col);

        if ( (!*ptr_strtol) && (col > 0) && (col < 0x7ffffffd)) {
            return col;
        }
    }

    if (ioctl(1, 0x5413, &p_0xa8) >= 0) {
        if (p_0xa8.ws_col != 0) {
            return p_0xa8.ws_col;
        }
    }

    reutrn 0x84;
}