c-为什么我在这个信号处理程序的代码中出现分段错误

Question

我在程序中编写了一个信号处理程序，但在这个文件结构中，我遇到了分段错误。但是，如果所有内容都在一个文件中，那么所有内容都可以正常工作。据我所知，它无法访问返回地址。我该怎么修？

"test.h">

#ifndef TEST_H
#define TEST_H
#include <string.h>
#include <setjmp.h>
#include <signal.h>
static jmp_buf g_env;
void sig_handler(int sig);
endif TEST_H

"test.c">

#include "test.h"
void sig_handler(int sig) {
psignal(sig, "Signal");
siglongjmp(g_env, 1);
}

"main.c">

#include "test.h"
int main(void) {
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = sig_handler;
sigemptyset(&act.sa_mask);
sigaddset(&act.sa_mask, SIGSEGV);
sigaction(SIGSEGV, &act, 0);
if (!sigsetjmp(g_env, 1)) {
raise(SIGSEGV);
}
return (1);
}

"结果：">

Signal: Segmentation fault
Segmentation fault (core dumped)

"Valgrind：">

==44698== Command: ./a.out
==44698==
Signal: Segmentation fault
==44698== Warning: client switching stacks?  SP change: 0x1ffeffee08 --> 0xf7c1f413060a2966
==44698==          to suppress, use: --max-stackframe=593925450715481250 or greater
==44698== Jump to the invalid address stated on the next line
==44698==    at 0xF7C1F413060A2966: ???
==44698==  Address 0xf7c1f413060a2966 is not stack'd, malloc'd or (recently) free'd
==44698==
==44698==
==44698== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==44698==  Bad permissions for mapped region at address 0xF7C1F413060A2966
==44698==    at 0xF7C1F413060A2966: ???
==44698== Invalid write of size 8
==44698==    at 0x482F120: _vgnU_freeres (vg_preloaded.c:59)
==44698==  Address 0xf7c1f413060a295e is not stack'd, malloc'd or (recently) free'd
==44698==
==44698==
==44698== Process terminating with default action of signal 11 (SIGSEGV)
==44698==  General Protection Fault
==44698==    at 0x482F120: _vgnU_freeres (vg_preloaded.c:59)

Answer 1

这是因为您有不同的g_env实例-每个翻译单元都得到不同的g_env。因此，sigsetjmp中使用的g_env缓冲区与siglongjmp中使用的缓冲区不同。

只需从中删除static

static jmp_buf g_env;

现在，只有一个g_env的全局实例。