/** Signal handler: write a crash message with a stack trace, and die. */
static void
crash_handler(int sig, siginfo_t *si, void *ctx_)
{
char buf[40];
int depth;
ucontext_t *ctx = (ucontext_t *) ctx_;
int n_fds, i;
const int *fds = NULL;
(void) si;
depth = backtrace(cb_buf, MAX_DEPTH);
/* Clean up the top stack frame so we get the real function
* name for the most recently failing function. */
clean_backtrace(cb_buf, depth, ctx);
format_dec_number_sigsafe((unsigned)sig, buf, sizeof(buf));
tor_log_err_sigsafe(bt_version, " died: Caught signal ", buf, "\n",
NULL);
n_fds = tor_log_get_sigsafe_err_fds(&fds);
for (i=0; i < n_fds; ++i)
backtrace_symbols_fd(cb_buf, depth, fds[i]);
abort();
}
/**
* Function called when a SIGSYS is caught by the application. It notifies the
* user that an error has occurred and either terminates or allows the
* application to continue execution, based on the DEBUGGING_CLOSE symbol.
*/
static void
sigsys_debugging(int nr, siginfo_t *info, void *void_context)
{
ucontext_t *ctx = (ucontext_t *) (void_context);
const char *syscall_name;
int syscall;
#ifdef USE_BACKTRACE
size_t depth;
int n_fds, i;
const int *fds = NULL;
#endif
(void) nr;
if (info->si_code != SYS_SECCOMP)
return;
if (!ctx)
return;
syscall = (int) ctx->uc_mcontext.M_SYSCALL;
#ifdef USE_BACKTRACE
depth = backtrace(syscall_cb_buf, MAX_DEPTH);
/* Clean up the top stack frame so we get the real function
* name for the most recently failing function. */
clean_backtrace(syscall_cb_buf, depth, ctx);
#endif
syscall_name = get_syscall_name(syscall);
tor_log_err_sigsafe("(Sandbox) Caught a bad syscall attempt (syscall ",
syscall_name,
")\n",
NULL);
#ifdef USE_BACKTRACE
n_fds = tor_log_get_sigsafe_err_fds(&fds);
for (i=0; i < n_fds; ++i)
backtrace_symbols_fd(syscall_cb_buf, (int)depth, fds[i]);
#endif
#if defined(DEBUGGING_CLOSE)
_exit(1);
#endif // DEBUGGING_CLOSE
}