util.signal: Add support for signalfd(2) on Linux
signalfd allows handling signal events using the same method as sockets,
via file descriptors. Thus all signal dispatch can go through the same
main event loop as everything else, removing need for thread-scary
signal handling where execution would just jump to the signal handler
regardless of the state of Lua, and needing to keep track of Lua
states/threads.
#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 200809L
#endif
#include <time.h>
#include <lua.h>
static lua_Number tv2number(struct timespec *tv) {
return tv->tv_sec + tv->tv_nsec * 1e-9;
}
static int lc_time_realtime(lua_State *L) {
struct timespec t;
clock_gettime(CLOCK_REALTIME, &t);
lua_pushnumber(L, tv2number(&t));
return 1;
}
static int lc_time_monotonic(lua_State *L) {
struct timespec t;
clock_gettime(CLOCK_MONOTONIC, &t);
lua_pushnumber(L, tv2number(&t));
return 1;
}
int luaopen_prosody_util_time(lua_State *L) {
lua_createtable(L, 0, 2);
{
lua_pushcfunction(L, lc_time_realtime);
lua_setfield(L, -2, "now");
lua_pushcfunction(L, lc_time_monotonic);
lua_setfield(L, -2, "monotonic");
}
return 1;
}
int luaopen_util_time(lua_State *L) {
return luaopen_prosody_util_time(L);
}