#include "cache.h"

#include "sigchain.h"

#define SIGCHAIN_MAX_SIGNALS 32

struct sigchain_signal {

	sigchain_fun *old;

	int n;

	int alloc;

};

static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];

static void check_signum(int sig)

{

	if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)

		BUG("signal out of range: %d", sig);

}

int sigchain_push(int sig, sigchain_fun f)

{

	struct sigchain_signal *s = signals + sig;

	check_signum(sig);

	ALLOC_GROW(s->old, s->n + 1, s->alloc);

	s->old[s->n] = signal(sig, f);

	if (s->old[s->n] == SIG_ERR)

		return -1;

	s->n++;

	return 0;

}

int sigchain_pop(int sig)

{

	struct sigchain_signal *s = signals + sig;

	check_signum(sig);

	if (s->n < 1)

		return 0;

	if (signal(sig, s->old[s->n - 1]) == SIG_ERR)

		return -1;

	s->n--;

	return 0;

}

void sigchain_push_common(sigchain_fun f)

{

	sigchain_push(SIGINT, f);

	sigchain_push(SIGHUP, f);

	sigchain_push(SIGTERM, f);

	sigchain_push(SIGQUIT, f);

	sigchain_push(SIGPIPE, f);

}

void sigchain_pop_common(void)

{

	sigchain_pop(SIGPIPE);

	sigchain_pop(SIGQUIT);

	sigchain_pop(SIGTERM);

	sigchain_pop(SIGHUP);

	sigchain_pop(SIGINT);

}