1 files changed, 131 insertions, 0 deletions
diff --git a/src/signal.c b/src/signal.c
new file mode 100644
index 0000000..018ad63
--- /dev/null
+++ b/src/signal.c
@@ -0,0 +1,131 @@
+#include "queue.h"
+#include "signames.h"
+#include <lua.h>
+#include <lauxlib.h>
+#include <signal.h>
+#include <string.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;
+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, "default") == 0) {
+            handler = SIG_DFL;
+        }
+        else if (strcmp(pseudo_handler, "luadefault") == 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;
+}
+
+const luaL_Reg reg[] = {
+    { "signal", l_signal },
+    { 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;
+}