/// This finalizer is called automatically as the auditor library
/// is being unmapped, but only if interception is on (aka active)
/// and only on "normal" exit as described in Interposer/exit.h.
/*static*/ void
interposed_finalize(void)
{
if (_auditor_isActiveByRequest()) {
pid_t pid;
// This is a really cute trick I got from a guy named Nate Eldredge.
// The exit status is not given to the library finalizer but we
// need it, so what can we do? This is the answer: do a meaningless
// fork. The child just returns so that the parent can wait for
// it and gets its exit status. There's a slight chance that
// the extra fork will cause non-beneficial side effects but
// that should be quite rare.
// IDEA Would it be better to use vfork() here? A big IDE
// like Eclipse might have a large memory footprint and forking
// it only to exit might be costly and/or have an OOM failure.
// Answer, no, vfork is not allowed to return. There could be
// an answer within posix_spawn but I haven't looked into it.
if ((pid = fork_real()) == -1) {
putil_syserr(0, "fork");
} else if (pid == 0) {
// The child just returns so the parent can wait for it.
} else {
int wstat, status = 7;
if (waitpid(pid, &wstat, 0) == pid) {
if (WIFEXITED(wstat)) {
status = WEXITSTATUS(wstat);
}
} else {
putil_syserr(0, "waitpid");
}
_audit_end("exit", EXITING, status);
// Do an explicit _exit( to abort any remaining library
// finalizers since they will have run in the child. I.e.
// any *previous* finalizers will have run in the
// original (now parent) copy and any *subsequent*
// ones will have run in the child, so continuing with
// exit processing here would run the latter set twice.
_exit_real(status);
}
} else if (_auditor_isActiveByDefault()) {
_audit_end("exit", EXITING, 0);
}
/*
* The cleanups below would be done by exit anyway but we try to
* free things explicitly so that leak detectors such as valgrind
* can more easily pinpoint real leaks. Perhaps we could have an
* optimized "production mode" which skips the explicit cleanup.
*/
code_fini();
prop_fini();
vb_fini();
}
void _exit(int status) {
static int loaded=0;
static void (*_exit_real)(int status);
if(!loaded) {
_exit_real=0;
_exit_real = (void (*)(int status))
dlsym(RTLD_NEXT, "_exit");
if(!dlerror()) loaded=1;
else {
IPMERR("Intercepting _exit(): load failed\n");
}
}
if( ipm_state==STATE_ACTIVE || ipm_state==STATE_NOTACTIVE )
ipm_finalize(0);
_exit_real(status);
}
