fixup! rename to (dds_)network_adapter_watcher

third-party/rsutils/src/network-adapter-watcher.cpp

@@ -20,6 +20,7 @@
 #include <linux/rtnetlink.h>
 #include <sys/eventfd.h>
 #include <unistd.h>
+#include <errno.h>
 #include <poll.h>
 
 #endif
@@ -39,8 +40,8 @@ class network_adapter_watcher_singleton
 #ifdef _WIN32
     HANDLE _done;
 #else
-    int _socket;
     int _done;
+    int _socket;
 #endif
     std::thread _th;
 
@@ -98,80 +99,89 @@ class network_adapter_watcher_singleton
         // https://stackoverflow.com/questions/27008067/how-to-get-notified-about-network-interface-changes-with-netlist-and-rtmgrp-link
         : _socket( open_netlink() )
         , _done( eventfd( 0, 0 ) )
-        , _th(
-              [this]
-              {
-                  // We're going to wait on the following handles:
-                  LOG_DEBUG( "starting network adapter watcher" );
-
-                  int const timeout = -1;  // negative value = infinite
-                  int const nfds = 2;
-                  pollfd fds[nfds];
-                  memset( fds, 0, sizeof( fds ) );
-                  fds[0].fd = _done;
-                  fds[0].events = POLLIN;
-                  fds[1].fd = _socket;
-                  fds[1].events = POLLIN;
-
-                  while( true )
-                  {
-                      fds[0].revents = 0;
-                      fds[1].revents = 0;
-                      auto rv = poll( fds, nfds, timeout );
-                      if( rv <= 0 )
-                      {
-                          LOG_ERROR( "poll failed: " << rv );
-                          break;
-                      }
-
-                      if( fds[0].revents != 0 )
-                          break;  // we're done
-
-                      LOG_DEBUG( "network adapter changes detected!" );
-
-                      char buf[4096];
-                      struct sockaddr_nl snl;
-                      iovec iov = { buf, sizeof( buf ) };
-                      msghdr msg = { (void *)&snl, sizeof snl, &iov, 1, NULL, 0, 0 };
-                      int status = recvmsg( _socket, &msg, 0 );
-                      if( status < 0 )
-                      {
-                          // Socket non-blocking so bail out once we have read everything
-                          if( errno == EWOULDBLOCK || errno == EAGAIN )
-                              continue;
-
-                          // Anything else is an error
-                          LOG_DEBUG( "read_netlink: Error recvmsg: " << status );
-                          break;
-                      }
-                      if( status == 0 )
-                          LOG_DEBUG( "read_netlink: EOF" );
-
-                      // We need to handle more than one message per recvmsg
-                      for( auto h = (struct nlmsghdr *)buf; NLMSG_OK( h, (unsigned int)status );
-                           h = NLMSG_NEXT( h, status ) )
-                      {
-                          // Finish reading
-                          if( h->nlmsg_type == NLMSG_DONE )
-                              continue;
-
-                          // Message is some kind of error
-                          if( h->nlmsg_type == NLMSG_ERROR )
-                          {
-                              LOG_DEBUG( "read_netlink: got NLMSG_ERROR" );
-                              continue;
-                          }
-                      }
-
-                      // Call our clients once for all the messages... outside the loop
-                      callbacks.raise();
-                  }
-
-                  LOG_DEBUG( "exiting network adapter watcher" );
-              } )
 #endif
     {
-        LOG_DEBUG( "network adapter watcher singleton is up" );
+#ifndef _WIN32
+        if( _socket < 0 )
+        {
+            auto const error = errno;
+            LOG_ERROR( "Failed to start network adapter watcher (errno= " << error << ")" );
+        }
+        else
+        {
+            _th = std::thread(
+                [this]
+                {
+                    // We're going to wait on the following handles:
+                    LOG_DEBUG( "starting network adapter watcher" );
+
+                    int const timeout = -1;  // negative value = infinite
+                    int const nfds = 2;
+                    pollfd fds[nfds];
+                    memset( fds, 0, sizeof( fds ) );
+                    fds[0].fd = _done;
+                    fds[0].events = POLLIN;
+                    fds[1].fd = _socket;
+                    fds[1].events = POLLIN;
+
+                    while( true )
+                    {
+                        fds[0].revents = 0;
+                        fds[1].revents = 0;
+                        auto rv = poll( fds, nfds, timeout );
+                        if( rv <= 0 )
+                        {
+                            LOG_ERROR( "poll failed: " << rv );
+                            break;
+                        }
+
+                        if( fds[0].revents != 0 )
+                            break;  // we're done
+
+                        LOG_DEBUG( "network adapter changes detected!" );
+
+                        char buf[4096];
+                        struct sockaddr_nl snl;
+                        iovec iov = { buf, sizeof( buf ) };
+                        msghdr msg = { (void *)&snl, sizeof snl, &iov, 1, NULL, 0, 0 };
+                        int status = recvmsg( _socket, &msg, 0 );
+                        if( status < 0 )
+                        {
+                            // Socket non-blocking so bail out once we have read everything
+                            if( errno == EWOULDBLOCK || errno == EAGAIN )
+                                continue;
+
+                            // Anything else is an error
+                            LOG_DEBUG( "read_netlink: Error recvmsg: " << status );
+                            break;
+                        }
+                        if( status == 0 )
+                            LOG_DEBUG( "read_netlink: EOF" );
+
+                        // We need to handle more than one message per recvmsg
+                        for( auto h = (struct nlmsghdr *)buf; NLMSG_OK( h, (unsigned int)status );
+                             h = NLMSG_NEXT( h, status ) )
+                        {
+                            // Finish reading
+                            if( h->nlmsg_type == NLMSG_DONE )
+                                continue;
+
+                            // Message is some kind of error
+                            if( h->nlmsg_type == NLMSG_ERROR )
+                            {
+                                LOG_DEBUG( "read_netlink: got NLMSG_ERROR" );
+                                continue;
+                            }
+                        }
+
+                        // Call our clients once for all the messages... outside the loop
+                        callbacks.raise();
+                    }
+
+                    LOG_DEBUG( "exiting network adapter watcher" );
+                } );
+        }
+#endif
     }
 
     ~network_adapter_watcher_singleton()
@@ -204,7 +214,7 @@ class network_adapter_watcher_singleton
         // https://manpages.ubuntu.com/manpages/oracular/en/man7/netlink.7.html
         int sock = socket( AF_NETLINK, SOCK_RAW, NETLINK_ROUTE );
         if( sock < 0 )
-            return sock;
+            return -1;
 
         struct sockaddr_nl addr;
         memset( (void *)&addr, 0, sizeof( addr ) );