mirror of
https://github.com/tobast/libunwind-eh_elf.git
synced 2024-06-28 12:11:45 +02:00
26c99a3a3e
* Add `SA_SIGINFO` flag This is needed to guarantee the availability of the `ucontext` argument * Mark the `NULL` pointer load as `volatile` Further prevent any compiler optimization on the load.
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
#include "libunwind.h"
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
|
|
#include <stdlib.h>
|
|
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <assert.h>
|
|
|
|
int stepper(unw_cursor_t* c) {
|
|
int steps = 0;
|
|
int ret = 1;
|
|
while (ret) {
|
|
|
|
ret = unw_step(c);
|
|
if (!ret) {
|
|
break;
|
|
}
|
|
steps++;
|
|
}
|
|
return steps;
|
|
}
|
|
|
|
/* Verify that we can step from both ucontext, and from getcontext()
|
|
* roughly the same. This tests that the IP from ucontext is used
|
|
* correctly (see impl of unw_init_local2) */
|
|
void handler(int num, siginfo_t* info, void* ucontext) {
|
|
unw_cursor_t c;
|
|
unw_context_t context;
|
|
unw_getcontext(&context);
|
|
int ret = unw_init_local2(&c, ucontext, UNW_INIT_SIGNAL_FRAME);
|
|
assert(!ret);
|
|
int ucontext_steps = stepper(&c);
|
|
|
|
ret = unw_init_local(&c, &context);
|
|
(void)ret;
|
|
assert(!ret);
|
|
int getcontext_steps = stepper(&c);
|
|
if (ucontext_steps == getcontext_steps - 2) {
|
|
exit(0);
|
|
}
|
|
printf("unw_getcontext steps was %i, ucontext steps was %i, should be %i\n",
|
|
getcontext_steps, ucontext_steps, getcontext_steps - 2);
|
|
exit(-1);
|
|
}
|
|
|
|
int foo(volatile int* f);
|
|
|
|
int main(){
|
|
struct sigaction a;
|
|
memset(&a, 0, sizeof(struct sigaction));
|
|
a.sa_sigaction = &handler;
|
|
a.sa_flags = SA_SIGINFO;
|
|
sigaction(SIGSEGV, &a, NULL);
|
|
|
|
foo(NULL);
|
|
return 0;
|
|
}
|