# HG changeset patch
# User jbe
# Date 1496779106 -7200
# Node ID 1a4f89f4c712359281618c240c5a9d3d56295584
# Parent  dec24bd2592c49f10e7ebc64cdf0b6556d4013b5
Modified behavior of moonbridge_io.signalsocket(...); Fixed usage of moonbridge_io.signalsocket(...) in moonbridge_http module

diff -r dec24bd2592c -r 1a4f89f4c712 moonbridge_http.lua
--- a/moonbridge_http.lua	Tue Jun 06 20:19:09 2017 +0200
+++ b/moonbridge_http.lua	Tue Jun 06 21:58:26 2017 +0200
@@ -203,10 +203,10 @@
   local response_timeout       = default("response_timeout", 3600)
   local drain_timeout          = default("drain_timeout", 2)
   local poll = options.poll_function or moonbridge_io.poll
-  -- install SIGTERM handler:
-  local sigterm_socket = moonbridge_io.signalsocket("TERM")
   -- return socket handler:
   return function(socket)
+    -- install SIGTERM handler and initialize some variables:
+    local sigterm_socket = moonbridge_io.signalsocket("TERM")
     local socket_set = {[socket] = true}  -- used for poll function
     local socket_term_set = {             -- used for poll function
       [socket] = true,
diff -r dec24bd2592c -r 1a4f89f4c712 moonbridge_io.c
--- a/moonbridge_io.c	Tue Jun 06 20:19:09 2017 +0200
+++ b/moonbridge_io.c	Tue Jun 06 21:58:26 2017 +0200
@@ -66,6 +66,7 @@
 #define MOONBR_IO_CHILD_MT_REGKEY "moonbridge_io_child"
 #define MOONBR_IO_CHILD_PT_REGKEY "moonbridge_io_child_pt"
 #define MOONBR_IO_SIGNALS_REGKEY "moonbridge_io_signals"
+#define MOONBR_IO_SIGNALSOCKETS_REGKEY "moonbridge_io_signalsockets"
 
 #ifdef MOONBR_IO_USE_TLS
 
@@ -1641,13 +1642,20 @@
     if (socketpair(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, moonbr_io_signalfds+2*sig)) {
       luaL_error(L, "Could not create socket pair for signal queueing");
     }
-    errno = 0;
-    signal(sig, moonbr_io_signalhandler);
-    if (errno) luaL_error(L, "Could not install signal handler (invalid signal number %i?)", sig);
   }
-  fd = dup(moonbr_io_signalfd_read(sig));
+  errno = 0;
+  signal(sig, moonbr_io_signalhandler);
+  if (errno) luaL_error(L, "Could not install signal handler (invalid signal number %i?)", sig);
+  lua_getfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALSOCKETS_REGKEY);
+  lua_pushinteger(L, sig);
+  lua_gettable(L, -2);
+  if (!lua_isnil(L, -1)) return 1;
+  fd = dup(moonbr_io_signalfd_read(sig));  /* avoid close on Lua error */
   if (fd < 0) luaL_error(L, "Could not create duplicated file descriptor for signal socket");
   moonbr_io_pushhandle(L, fd);
+  lua_pushinteger(L, sig);
+  lua_pushvalue(L, -2);
+  lua_settable(L, -5);  /* store reference to signal socket in cache table */
   return 1;
 }
 
@@ -2110,6 +2118,9 @@
   lua_pushvalue(L, -1);
   lua_setfield(L, -3, "signals");
   lua_setfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALS_REGKEY);
+
+  lua_newtable(L);  // signal sockets
+  lua_setfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALSOCKETS_REGKEY);
   
   luaL_setfuncs(L, moonbr_io_module_funcs, 0);
   return 1;
diff -r dec24bd2592c -r 1a4f89f4c712 reference.txt
--- a/reference.txt	Tue Jun 06 20:19:09 2017 +0200
+++ b/reference.txt	Tue Jun 06 21:58:26 2017 +0200
@@ -399,15 +399,14 @@
 ### moonbridge_io.signalsocket(signal)
 
 This function installs a signal handler. As argument, either the signal number
-is passed (e.g. 15) or a name (e.g. "TERM").
-
-The function returns a new socket object that receives a character (".") each
-time a signal is received.
+is passed (e.g. 15) or a name (e.g. "TERM"). The function returns a socket
+object that receives a character (".") each time a signal is received.
 
-Note that each socket object has an independent buffer. It is thus recommended
-to always read all bytes, e.g. by using the expression:
+The function can be called multiple times, in which case the same socket object
+is returned. The returned socket should never be closed by the caller.
 
-#(assert(sigsock:read_nb())) > 0  -- true if signal occurred
+The process should not be forked after calling this function (except for
+replacing the process with another program).
 
 
 ### moonbridge_io.tcpconnect(hostname, port)