# HG changeset patch
# User jbe
# Date 1496772089 -7200
# Node ID d4c82c90d244ee575b27e63645f815607f519966
# Parent  4f965eda4c2fd400b749b351e907be95c53ddb4e
Make moonbridge_io.signalsocket(...) return a new socket each time it is called

diff -r 4f965eda4c2f -r d4c82c90d244 moonbridge_io.c
--- a/moonbridge_io.c	Tue Jun 06 18:00:30 2017 +0200
+++ b/moonbridge_io.c	Tue Jun 06 20:01:29 2017 +0200
@@ -55,16 +55,16 @@
     moonbr_io_return_prepared_errmsg(); \
   } while (0)
 
-static int moonbr_io_signalfds[2];
-#define moonbr_io_signalfd_read moonbr_io_signalfds[0]
-#define moonbr_io_signalfd_write moonbr_io_signalfds[1]
+#define MOONBR_IO_MAXSIGNUM 127
+static int moonbr_io_signalfds[2*(MOONBR_IO_MAXSIGNUM+1)];
+#define moonbr_io_signalfd_read(x) moonbr_io_signalfds[2*(x)+0]
+#define moonbr_io_signalfd_write(x) moonbr_io_signalfds[2*(x)+1]
 
 #define MOONBR_IO_HANDLE_MT_REGKEY "moonbridge_io_handle"
 #define MOONBR_IO_HANDLE_PUBLIC_MT_REGKEY "moonbridge_io_handle_public"
 #define MOONBR_IO_LISTENER_MT_REGKEY "moonbridge_io_listener"
 #define MOONBR_IO_CHILD_MT_REGKEY "moonbridge_io_child"
 #define MOONBR_IO_CHILD_PT_REGKEY "moonbridge_io_child_pt"
-#define MOONBR_IO_SIGNALSOCKET_REGKEY "moonbridge_io_signalsocket"
 #define MOONBR_IO_SIGNALS_REGKEY "moonbridge_io_signals"
 
 #ifdef MOONBR_IO_USE_TLS
@@ -1615,47 +1615,39 @@
 
 static void moonbr_io_signalhandler(int sig) {
   int errno2 = errno;
-  char buf[1] = {sig};
-  write(moonbr_io_signalfd_write, buf, 1);
+  char buf[1] = {'.'};
+  write(moonbr_io_signalfd_write(sig), buf, 1);
   errno = errno2;
 }
 
 static int moonbr_io_signalsocket(lua_State *L) {
-  int i, argc, sig;
-  if (moonbr_io_signalfd_read < 0) {
-    if (socketpair(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, moonbr_io_signalfds)) {
-      luaL_error(L, "Could not create socket pair for signal queueing");
+  int sig, fd;
+  if (lua_type(L, 1) == LUA_TSTRING) {
+    lua_getfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALS_REGKEY);
+    lua_pushvalue(L, 1);
+    lua_gettable(L, -2);
+    sig = lua_tointeger(L, -1);
+    if (!sig) {
+      lua_pushvalue(L, 1);
+      luaL_error(L, "Unknown signal \"%s\"", lua_tostring(L, 1));
     }
+  } else {
+    sig = luaL_checkinteger(L, 1);
   }
-  lua_getfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALS_REGKEY);
-  lua_insert(L, 1);
-  argc = lua_gettop(L);
-  for (i=2; i<=argc; i++) {
-    if (lua_type(L, i) == LUA_TSTRING) {
-      lua_pushvalue(L, i);
-      lua_gettable(L, 1);
-      sig = lua_tointeger(L, -1);
-      lua_pop(L, 1);
-      if (!sig) {
-        lua_pushvalue(L, i);
-        luaL_error(L, "Unknown signal \"%s\"", lua_tostring(L, i));
-      }
-    } else {
-      sig = luaL_checkinteger(L, i);
+  if (sig < 1 || sig > MOONBR_IO_MAXSIGNUM) {
+    luaL_error(L, "Signal number %i out of range", sig);
+  }
+  if (moonbr_io_signalfd_read(sig) < 0) {
+    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?)");
+    if (errno) luaL_error(L, "Could not install signal handler (invalid signal number %i?)", sig);
   }
-  lua_settop(L, 0);
-  lua_getfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALSOCKET_REGKEY);
-  if (lua_isnil(L, -1)) {
-    int fd = dup(moonbr_io_signalfd_read);  /* TODO: determine how mooonbr_io_pushhandle acts in case of error */
-    if (fd < 0) luaL_error(L, "Error in dup() system call");
-    moonbr_io_pushhandle(L, fd);
-    lua_pushvalue(L, -1);
-    lua_setfield(L, LUA_REGISTRYINDEX, MOONBR_IO_SIGNALSOCKET_REGKEY);
-  }
+  fd = dup(moonbr_io_signalfd_read(sig));
+  if (fd < 0) luaL_error(L, "Could not create duplicated file descriptor for signal socket");
+  moonbr_io_pushhandle(L, fd);
   return 1;
 }
 
@@ -2035,8 +2027,13 @@
 int luaopen_moonbridge_io(lua_State *L) {
 
   signal(SIGPIPE, SIG_IGN);  /* generate I/O errors instead of signal 13 */
-  moonbr_io_signalfd_read = -1;
-  moonbr_io_signalfd_write = -1;
+  {
+    int i;
+    for (i=0; i<=MOONBR_IO_MAXSIGNUM; i++) {
+      moonbr_io_signalfd_read(i) = -1;
+      moonbr_io_signalfd_write(i) = -1;
+    }
+  }
 
   lua_newtable(L);  // module
 
diff -r 4f965eda4c2f -r d4c82c90d244 reference.txt
--- a/reference.txt	Tue Jun 06 18:00:30 2017 +0200
+++ b/reference.txt	Tue Jun 06 20:01:29 2017 +0200
@@ -396,16 +396,18 @@
 number (e.g. 9 or 15, respectively).
 
 
-### moonbridge_io.signalsocket(signal1, signal2, ...)
+### 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").
 
-This function installs a signal handler for the signals with the numbers passed
-as arguments and returns a socket which receives a byte for each received
-signal. Optionally, a string may be used instead of the signal number (e.g.
-"KILL" instead of 9, or "TERM" instead of 15).
+The function returns a new socket object that receives a character (".") each
+time a signal is received.
 
-Subsequent calls of this function can extend the set of signals but will always
-return the same socket. If the socket is closed, it is no longer possible to
-detect signals until the process is terminated.
+Note that each socket object has an independent buffer. It is thus recommended
+to always read all bytes, e.g. by using the expression:
+
+#(assert(sigsock:read_nb())) > 0  -- true if signal occurred
 
 
 ### moonbridge_io.tcpconnect(hostname, port)