# HG changeset patch
# User jbe
# Date 1517071695 -3600
# Node ID 930a43a0099a76102b288da043de6feec98131a4
# Parent  426848ae610825668af0c1f29766ce7c47547654
Bugfix/workaround: Do not call getpeername() when opening TCP connections in non-blocking mode

diff -r 426848ae6108 -r 930a43a0099a moonbridge_io.c
--- a/moonbridge_io.c	Fri Nov 24 01:32:23 2017 +0100
+++ b/moonbridge_io.c	Sat Jan 27 17:48:15 2018 +0100
@@ -873,10 +873,12 @@
 
 static int moonbr_io_pushhandle_impl(lua_State *L) {
   int *fd;
+  int skip_peeraddr;
   moonbr_io_handle_t *handle;
   struct sockaddr addr;
   socklen_t addrlen;
   fd = lua_touserdata(L, 1);
+  skip_peeraddr = lua_toboolean(L, 2);
   handle = lua_newuserdata(L, sizeof(moonbr_io_handle_t));
   handle->fd = -1;  /* avoid closing incomplete handle */
   addrlen = sizeof(addr);
@@ -928,6 +930,8 @@
     char addrstrbuf[INET6_ADDRSTRLEN];
     const char *addrstr;
     addrlen = sizeof(addr_in6);
+    /* NOTE: According to documentation, getsockname() may fail if connection
+     *       was reset. There seems to be no problem in practice though. */
     if (getsockname(*fd, (struct sockaddr *)&addr_in6, &addrlen)) {
       moonbr_io_prepare_errmsg();
       luaL_error(L, "Could not determine local IP address/port: %s", errmsg);
@@ -945,28 +949,34 @@
     }
     lua_pushinteger(L, ntohs(addr_in6.sin6_port));
     lua_setfield(L, -2, "local_tcpport");
-    if (getpeername(*fd, (struct sockaddr *)&addr_in6, &addrlen)) {
-      moonbr_io_prepare_errmsg();
-      luaL_error(L, "Could not determine remote IP address/port: %s", errmsg);
-    }
-    if (addrlen > sizeof(addr_in6)) {
-      luaL_error(L, "Could not determine remote IP address/port: buffer size exceeded");
+    if (!skip_peeraddr) {
+      /* NOTE: According to documentation, getpeername() may fail if connection
+       *       was reset. There seems to be no problem in practice though. */
+      if (getpeername(*fd, (struct sockaddr *)&addr_in6, &addrlen)) {
+        moonbr_io_prepare_errmsg();
+        luaL_error(L, "Could not determine remote IP address/port: %s", errmsg);
+      }
+      if (addrlen > sizeof(addr_in6)) {
+        luaL_error(L, "Could not determine remote IP address/port: buffer size exceeded");
+      }
+      addrstr = inet_ntop(AF_INET6, addr_in6.sin6_addr.s6_addr, addrstrbuf, sizeof(addrstrbuf));
+      if (!addrstr) {
+        moonbr_io_prepare_errmsg();
+        luaL_error(L, "Could not format remote IP address: %s", errmsg);
+      } else {
+        lua_pushstring(L, addrstr);
+        lua_setfield(L, -2, "remote_ip6");
+      }
+      lua_pushinteger(L, ntohs(addr_in6.sin6_port));
+      lua_setfield(L, -2, "remote_tcpport");
     }
-    addrstr = inet_ntop(AF_INET6, addr_in6.sin6_addr.s6_addr, addrstrbuf, sizeof(addrstrbuf));
-    if (!addrstr) {
-      moonbr_io_prepare_errmsg();
-      luaL_error(L, "Could not format remote IP address: %s", errmsg);
-    } else {
-      lua_pushstring(L, addrstr);
-      lua_setfield(L, -2, "remote_ip6");
-    }
-    lua_pushinteger(L, ntohs(addr_in6.sin6_port));
-    lua_setfield(L, -2, "remote_tcpport");
   } else if (handle->addrfam == AF_INET) {
     struct sockaddr_in addr_in;
     char addrstrbuf[INET_ADDRSTRLEN];
     const char *addrstr;
     addrlen = sizeof(addr_in);
+    /* NOTE: According to documentation, getsockname() may fail if connection
+     *       was reset. There seems to be no problem in practice though. */
     if (getsockname(*fd, (struct sockaddr *)&addr_in, &addrlen)) {
       moonbr_io_prepare_errmsg();
       luaL_error(L, "Could not determine local IP address/port: %s", errmsg);
@@ -984,23 +994,27 @@
     }
     lua_pushinteger(L, ntohs(addr_in.sin_port));
     lua_setfield(L, -2, "local_tcpport");
-    if (getpeername(*fd, (struct sockaddr *)&addr_in, &addrlen)) {
-      moonbr_io_prepare_errmsg();
-      luaL_error(L, "Could not determine remote IP address/port: %s", errmsg);
-    }
-    if (addrlen > sizeof(addr_in)) {
-      luaL_error(L, "Could not determine remote IP address/port: buffer size exceeded");
+    if (!skip_peeraddr) {
+      /* NOTE: According to documentation, getpeername() may fail if connection
+       *       was reset. There seems to be no problem in practice though. */
+      if (getpeername(*fd, (struct sockaddr *)&addr_in, &addrlen)) {
+        moonbr_io_prepare_errmsg();
+        luaL_error(L, "Could not determine remote IP address/port: %s", errmsg);
+      }
+      if (addrlen > sizeof(addr_in)) {
+        luaL_error(L, "Could not determine remote IP address/port: buffer size exceeded");
+      }
+      addrstr = inet_ntop(AF_INET, &addr_in.sin_addr.s_addr, addrstrbuf, sizeof(addrstrbuf));
+      if (!addrstr) {
+        moonbr_io_prepare_errmsg();
+        luaL_error(L, "Could not format remote IP address: %s", errmsg);
+      } else {
+        lua_pushstring(L, addrstr);
+        lua_setfield(L, -2, "remote_ip4");
+      }
+      lua_pushinteger(L, ntohs(addr_in.sin_port));
+      lua_setfield(L, -2, "remote_tcpport");
     }
-    addrstr = inet_ntop(AF_INET, &addr_in.sin_addr.s_addr, addrstrbuf, sizeof(addrstrbuf));
-    if (!addrstr) {
-      moonbr_io_prepare_errmsg();
-      luaL_error(L, "Could not format remote IP address: %s", errmsg);
-    } else {
-      lua_pushstring(L, addrstr);
-      lua_setfield(L, -2, "remote_ip4");
-    }
-    lua_pushinteger(L, ntohs(addr_in.sin_port));
-    lua_setfield(L, -2, "remote_tcpport");
   }
   luaL_setmetatable(L, MOONBR_IO_HANDLE_PUBLIC_MT_REGKEY);
   lua_setfield(L, -2, "public");
@@ -1019,6 +1033,16 @@
   }
 }
 
+void moonbr_io_pushhandle_skip_peeraddr(lua_State *L, int fd) {
+  lua_pushcfunction(L, moonbr_io_pushhandle_impl);
+  lua_pushlightuserdata(L, &fd);
+  lua_pushboolean(L, 1);
+  if (lua_pcall(L, 2, 1, 0)) {
+    if (fd != -1) close(fd);  // TODO: correct to close file descriptor here?
+    lua_error(L);
+  }
+}
+
 static int moonbr_io_handleindex(lua_State *L) {
   luaL_checkudata(L, 1, MOONBR_IO_HANDLE_MT_REGKEY);
   luaL_checkany(L, 2);
@@ -1129,7 +1153,16 @@
   } else {
     freeaddrinfo(res);
   }
-  moonbr_io_pushhandle(L, sock);
+  if (nonblocking) {
+    moonbr_io_pushhandle_skip_peeraddr(L, sock);
+    if (addrinfo->ai_family == AF_INET6) {
+      // TODO: fill remote_ip6 and remote_tcpport
+    } else if (addrinfo->ai_family == AF_INET) {
+      // TODO: fill remote_ip4 and remote_tcpport
+    }
+  } else {
+    moonbr_io_pushhandle(L, sock);
+  }
   return 1;
 }