rm2fb: Use stream socket instead of dgram

Author: timower

apps/rocket/Launcher.cpp

@@ -71,6 +71,7 @@ waitForSleep() {
                            /* interactive */ 1);
   if (res < 0) {
     std::cerr << "Error suspending: " << strerror(-res) << "\n";
+    sd_bus_unref(bus);
     return res;
   }
   sd_bus_message_unref(reply);

libs/rm2fb/Client.cpp

@@ -11,24 +11,30 @@
 
 #include <dlfcn.h>
 
+#include <csignal>
 #include <cstring>
 #include <linux/limits.h>
 #include <unistd.h>
 
+#include "unistdpp/error.h"
+
 bool inXochitl = false;
 
 namespace {
 
-const unistdpp::Result<ControlSocket>&
+ControlSocket&
 getControlSocket() {
-  static auto socket = []() -> unistdpp::Result<ControlSocket> {
-    ControlSocket res;
-    TRY(res.init(nullptr));
-    TRY(res.connect(default_sock_addr.data()));
-    return res;
-  }();
-
-  return socket;
+  static ControlSocket res;
+  if (!res.sock.isValid()) {
+    res.init(nullptr)
+      .and_then([] { return res.connect(default_sock_addr.data()); })
+      .or_else([](auto err) {
+        std::cerr << "Failed connecting to rm2fb: " << unistdpp::to_string(err)
+                  << "\n";
+        res.sock.close();
+      });
+  }
+  return res;
 }
 
 int
@@ -53,29 +59,39 @@ setupHooks() {
 void
 waitForInit() {
   std::cerr << "Sending init check\n";
-  sendUpdate(UpdateParams{
-    .y1 = 0,
-    .x1 = 0,
-    .y2 = 0,
-    .x2 = 0,
-    .flags = 0,
-    .waveform = 0,
-    .temperatureOverride = 0,
-    .extraMode = 0,
-  });
+  if (!sendUpdate(UpdateParams{
+        .y1 = 0,
+        .x1 = 0,
+        .y2 = 0,
+        .x2 = 0,
+        .flags = 0,
+        .waveform = 0,
+        .temperatureOverride = 0,
+        .extraMode = 0,
+      })) {
+    std::cerr << "Init failed, no server running\n";
+    std::exit(EXIT_FAILURE);
+  }
 }
 
 } // namespace
 
 bool
 sendUpdate(const UpdateParams& params) {
-  const auto& clientSock = unistdpp::fatalOnError(getControlSocket());
+  auto& clientSock = getControlSocket();
+  if (!clientSock.sock.isValid()) {
+    return false;
+  }
 
   return clientSock.sendto(params)
     .and_then([&](auto _) {
       return clientSock.recvfrom<bool>().map(
         [](auto pair) { return pair.first; });
     })
+    .or_else([&](auto err) {
+      std::cerr << "Error sending: " << unistdpp::to_string(err) << "\n";
+      clientSock.sock.close();
+    })
     .value_or(false);
 }
 
@@ -206,14 +222,17 @@ __libc_start_main(int (*mainFn)(int, char**, char**), // NOLINT
   // We don't support waiting with semaphores yet
   setenv("RM2FB_NO_WAIT_IOCTL", "1", 1);
 
+  // Don't kill ourselves when SIGPIPE happens because rm2fb went down.
+  // It might come back up later!
+  std::signal(SIGPIPE, SIG_IGN);
+
   char pathBuffer[PATH_MAX];
   auto size = readlink("/proc/self/exe", pathBuffer, PATH_MAX);
 
   if (std::string_view(pathBuffer, size) == "/usr/bin/xochitl") {
     inXochitl = true;
 
     unistdpp::fatalOnError(SharedFB::getInstance(), "Error making shared FB");
-    unistdpp::fatalOnError(getControlSocket(), "Error creating control socket");
 
     if (setupHooks() != EXIT_SUCCESS) {
       std::cerr << "Seting up hooks failed\n";

libs/rm2fb/ControlSocket.cpp

@@ -9,13 +9,23 @@ using namespace unistdpp;
 
 Result<void>
 ControlSocket::init(const char* addr) {
-  sock = TRY(unistdpp::socket(AF_UNIX, SOCK_DGRAM, 0));
-  timeval tv{ .tv_sec = 5, .tv_usec = 0 };
-  TRY(unistdpp::setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)));
+  sock = TRY(unistdpp::socket(AF_UNIX, SOCK_STREAM, 0));
   return unistdpp::bind(sock, Address::fromUnixPath(addr));
 }
 
 Result<void>
-ControlSocket::connect(const char* addr) {
+ControlSocket::connect(const char* addr) const {
+  timeval tv{ .tv_sec = 5, .tv_usec = 0 };
+  TRY(unistdpp::setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)));
   return unistdpp::connect(sock, Address::fromUnixPath(addr));
 }
+
+Result<void>
+ControlSocket::listen(int n) const {
+  return unistdpp::listen(sock, n);
+}
+
+unistdpp::Result<unistdpp::FD>
+ControlSocket::accept() const {
+  return unistdpp::accept(sock, nullptr, nullptr);
+}

libs/rm2fb/ControlSocket.h

@@ -12,7 +12,10 @@ struct ControlSocket {
   unistdpp::FD sock;
 
   unistdpp::Result<void> init(const char* addr);
-  unistdpp::Result<void> connect(const char* addr);
+  unistdpp::Result<void> connect(const char* addr) const;
+
+  unistdpp::Result<unistdpp::FD> accept() const;
+  unistdpp::Result<void> listen(int n) const;
 
   template<typename T,
            typename = std::enable_if_t<std::is_trivially_copyable_v<T>>>