mirror of
https://github.com/tobast/libunwind-eh_elf.git
synced 2024-12-01 02:37:39 +01:00
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.
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
#include "libunwind.h"
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#include <sys/types.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <stdio.h>
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#include <assert.h>
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int stepper(unw_cursor_t* c) {
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int steps = 0;
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int ret = 1;
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while (ret) {
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ret = unw_step(c);
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if (!ret) {
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break;
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}
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steps++;
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}
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return steps;
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}
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/* Verify that we can step from both ucontext, and from getcontext()
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* roughly the same. This tests that the IP from ucontext is used
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* correctly (see impl of unw_init_local2) */
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void handler(int num, siginfo_t* info, void* ucontext) {
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unw_cursor_t c;
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unw_context_t context;
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unw_getcontext(&context);
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int ret = unw_init_local2(&c, ucontext, UNW_INIT_SIGNAL_FRAME);
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assert(!ret);
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int ucontext_steps = stepper(&c);
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ret = unw_init_local(&c, &context);
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(void)ret;
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assert(!ret);
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int getcontext_steps = stepper(&c);
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if (ucontext_steps == getcontext_steps - 2) {
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exit(0);
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}
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printf("unw_getcontext steps was %i, ucontext steps was %i, should be %i\n",
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getcontext_steps, ucontext_steps, getcontext_steps - 2);
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exit(-1);
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}
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int foo(volatile int* f);
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int main(){
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struct sigaction a;
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memset(&a, 0, sizeof(struct sigaction));
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a.sa_sigaction = &handler;
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a.sa_flags = SA_SIGINFO;
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sigaction(SIGSEGV, &a, NULL);
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foo(NULL);
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return 0;
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}
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