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#include "queue.h"
#include "signames.h"
#include <lua.h>
#include <lauxlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#define REG_TABLE "luasignal"
static lua_State* gL = NULL;
static lua_Hook old_hook = NULL;
static int old_mask = 0;
static int old_count = 0;
static queue q;
/* hardcoding 256 here is not great... is there a better way to get the highest
* numbered signal? */
static struct sigaction lua_handlers[256];
static void lua_signal_handler(lua_State* L, lua_Debug* D)
{
sigset_t sset, oldset;
int sig;
lua_sethook(gL, old_hook, old_mask, old_count);
sigfillset(&sset);
sigprocmask(SIG_BLOCK, &sset, &oldset);
while ((sig = dequeue(&q)) != -1) {
const char* signame;
signame = sig_to_name(sig);
lua_getfield(gL, LUA_REGISTRYINDEX, REG_TABLE);
lua_getfield(gL, -1, signame);
lua_pushstring(gL, signame);
lua_call(gL, 1, 0);
}
sigprocmask(SIG_SETMASK, &oldset, NULL);
}
static void signal_handler(int sig)
{
if (q.size == 0) {
old_hook = lua_gethook(gL);
old_mask = lua_gethookmask(gL);
old_count = lua_gethookcount(gL);
lua_sethook(gL, lua_signal_handler,
LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
}
enqueue(&q, sig);
}
static int l_signal(lua_State* L)
{
const char* signame;
int sig;
struct sigaction sa;
sigset_t sset;
void (*handler)(int) = NULL;
gL = L;
signame = luaL_checklstring(gL, 1, NULL);
sig = name_to_sig(signame);
if (sig == -1) {
lua_pushfstring(gL, "signal() called with invalid signal name: %s", signame);
lua_error(gL);
}
if (lua_isfunction(gL, 2)) {
handler = signal_handler;
lua_getfield(gL, LUA_REGISTRYINDEX, REG_TABLE);
lua_pushvalue(gL, 2);
lua_setfield(gL, -2, signame);
}
else if (lua_isstring(gL, 2)) {
const char* pseudo_handler;
pseudo_handler = lua_tostring(gL, 2);
if (strcmp(pseudo_handler, "ignore") == 0) {
handler = SIG_IGN;
}
else if (strcmp(pseudo_handler, "cdefault") == 0) {
handler = SIG_DFL;
}
else if (strcmp(pseudo_handler, "default") == 0) {
if (lua_handlers[sig].sa_handler != NULL) {
handler = lua_handlers[sig].sa_handler;
}
else {
return 0;
}
}
else {
lua_pushstring(gL, "Must pass a valid handler to signal()");
lua_error(gL);
}
}
else {
lua_pushstring(gL, "Must pass a handler to signal()");
lua_error(gL);
}
sa.sa_handler = handler;
sigfillset(&sset);
sa.sa_mask = sset;
if (lua_handlers[sig].sa_handler == NULL) {
sigaction(sig, &sa, &(lua_handlers[sig]));
}
else {
sigaction(sig, &sa, NULL);
}
return 0;
}
static int l_alarm(lua_State* L)
{
int time;
time = luaL_checkint(L, -1);
lua_pushinteger(L, alarm(time));
return 1;
}
const luaL_Reg reg[] = {
{ "signal", l_signal },
{ "alarm", l_alarm },
{ NULL, NULL },
};
int luaopen_signal(lua_State* L)
{
queue_init(&q, 4);
lua_newtable(L);
lua_setfield(L, LUA_REGISTRYINDEX, REG_TABLE);
luaL_register(L, "signal", reg);
return 1;
}
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