gpt4 book ai didi

c - 退出时出现段错误(EXIT_FAILURE)但没有错误(EXIT_FAILURE,...)

转载 作者:太空宇宙 更新时间:2023-11-04 08:48:25 25 4
gpt4 key购买 nike

我在程序中使用 getopt_long (source here),并且在给定无效长选项时测试其行为时 (--stack-overflow) ,然后我得到:

[marcoms@baguette16 btcwatch]$ ./btcwatch --stack-overflow
Segmentation fault (core dumped)

对于上下文,它在 getopt_long() 循环中,即:

while((opt = getopt_long(argc,
argv,
OPTSTRING,
long_options,
&longopt_i)) != -1)
{

...

default:
exit(EXIT_FAILURE);
break;

代替:

error(EXIT_FAILURE, 0, "unknown option !?");

(exit() 代码 SIGSEGV)

疯狂的是,默认不应该(根据gdb)不应该执行。强>

gdb 显示它在调用 getopt_long() 时立即崩溃,

(gdb) start --stack-overflow    
Temporary breakpoint 1, main (argc=2, argv=0x7fffffffe598) at src/main.c:96
96 btcdbg("main()");
(gdb) s
btcdbg (fmt=0x403260 "main()") at src/btcutil.c:50
50 }
(gdb)
main (argc=2, argv=0x7fffffffe598) at src/main.c:118
118 const struct option long_options[] = {
(gdb)
211 api_err.err = false;
(gdb)
212 colour = false;
(gdb)
213 found_path = false;
(gdb)
214 fp = NULL;
(gdb)
215 n = 1.0;
(gdb)
216 newlp = NULL;
(gdb)
217 pn = argv[0];
(gdb)
218 reverse = false;
(gdb)
219 verbose = false;
(gdb)
221 strcpy(currcy, "USD");
(gdb)
223 setlocale(LC_ALL, ""); // sets the locale to the system's default
(gdb)
225 while((opt = getopt_long(
(gdb)

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7643e2c in __strncmp_sse2 () from /usr/lib/libc.so.6

但是当它以 error() 而不是 exit() 运行时,它会正常进行:

(gdb) start --stack-overflow
Temporary breakpoint 1, main (argc=2, argv=0x7fffffffe598) at src/main.c:96
96 btcdbg("main()");
(gdb) s
btcdbg (fmt=0x4032a0 "main()") at src/btcutil.c:50
50 }
(gdb)
main (argc=2, argv=0x7fffffffe598) at src/main.c:118
118 const struct option long_options[] = {
(gdb)
211 api_err.err = false;
(gdb)
212 colour = false;
(gdb)
213 found_path = false;
(gdb)
214 fp = NULL;
(gdb)
215 n = 1.0;
(gdb)
216 newlp = NULL;
(gdb)
217 pn = argv[0];
(gdb)
218 reverse = false;
(gdb)
219 verbose = false;
(gdb)
221 strcpy(currcy, "USD");
(gdb)
223 setlocale(LC_ALL, ""); // sets the locale to the system's default
(gdb)
225 while((opt = getopt_long(
(gdb)
/home/marcoms/code/btcwatch/./btcwatch: unrecognized option '--stack-overflow'
232 btcdbg("got option '%c'", opt);
(gdb)
btcdbg (fmt=0x4032a8 "got option '%c'") at src/btcutil.c:50
50 }
(gdb)
main (argc=2, argv=0x7fffffffe598) at src/main.c:233
233 switch(opt) {
(gdb)
236 help(pn, optarg);
(gdb)
help (prog_nm=0x7fffffffe8d8 "/home/marcoms/code/btcwatch/./btcwatch", topic=0x0) at src/btcutil.c:69
69 btcdbg("help()");
(gdb)
btcdbg (fmt=0x403bfc "help()") at src/btcutil.c:50
50 }
(gdb)
help (prog_nm=0x7fffffffe8d8 "/home/marcoms/code/btcwatch/./btcwatch", topic=0x0) at src/btcutil.c:71
71 char currcies[][3 + 1] = {
(gdb)
101 char topics[][16] = {
(gdb)
117 if(!topic) {
(gdb)
118 bputs("Usage: "); bputs(prog_nm); bputs(" [OPTION]\n");
(gdb)
Usage: /home/marcoms/code/btcwatch/./btcwatch [OPTION]
119 bputs(
(gdb)
Get and monitor Bitcoin trade information

Options: Long options:
-C --compare comare current price with stored price
-S --store store current price
-a --all equivalent to -pbs
-b --buy print buy price
-c CURRENCY --currency=CURRENCY set conversion currency
-n AMOUNT --amount=AMOUNT set the amount to convert
-o --colour, --color enable use of colour
-p --ping check for a successful JSON response
-r --reverse convert currency to Bitcoin
-s --sell print sell price
-v --verbose increase verbosity

-h [topic] --help[=topic] print this help, or help designated by topic
use --help=topics for available topics
-V --version print version number

Report bugs to marco@scannadinari.co.uk
btcwatch home page: <https://github.com/marcoms/btcwatch>
142 exit(EXIT_SUCCESS);
(gdb)
[Inferior 1 (process 25752) exited normally]

说到这里,我真的被难住了。什么可能导致段错误?当然,我可以只使用 error() 而不是 exit,但这实在令人难以置信。

最佳答案

问题是您的选项数组没有正确终止:

    const struct option long_options[] = {
// ...
// This is the last element
{
.name = "verbose",
.has_arg = no_argument,
.flag = NULL,
.val = 'v'
}
};

getopt_long(3)要求选项数组以全零结尾,以便它知道数组有多大——请注意,您实际上从未将数组大小传递给 getopt_long。所以发生的事情是它走过数组的末尾,寻找终止符,然后它开始越界读取内存,Valgrind 正确地提示了这一点。未定义的行为结果。

修复很简单:

const struct option long_options[] = {
// ...
{
.name = "verbose",
.has_arg = no_argument,
.flag = NULL,
.val = 'v'
},

// Array terminator
{0, 0, 0, 0}
};

关于c - 退出时出现段错误(EXIT_FAILURE)但没有错误(EXIT_FAILURE,...),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20668530/

25 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com