Fix socket connection closed not detected (#2587)

esphome/components/api/api_connection.cpp

@@ -78,6 +78,8 @@ void APIConnection::loop() {
     on_fatal_error();
     if (err == APIError::SOCKET_READ_FAILED && errno == ECONNRESET) {
       ESP_LOGW(TAG, "%s: Connection reset", client_info_.c_str());
+    } else if (err == APIError::CONNECTION_CLOSED) {
+      ESP_LOGW(TAG, "%s: Connection closed", client_info_.c_str());
     } else {
       ESP_LOGW(TAG, "%s: Reading failed: %s errno=%d", client_info_.c_str(), api_error_to_str(err), errno);
     }

esphome/components/api/api_frame_helper.cpp

@@ -10,7 +10,7 @@ namespace api {
 
 static const char *const TAG = "api.socket";
 
-/// Is the given return value (from read/write syscalls) a wouldblock error?
+/// Is the given return value (from write syscalls) a wouldblock error?
 bool is_would_block(ssize_t ret) {
   if (ret == -1) {
     return errno == EWOULDBLOCK || errno == EAGAIN;
@@ -64,6 +64,8 @@ const char *api_error_to_str(APIError err) {
     return "HANDSHAKESTATE_SPLIT_FAILED";
   } else if (err == APIError::BAD_HANDSHAKE_ERROR_BYTE) {
     return "BAD_HANDSHAKE_ERROR_BYTE";
+  } else if (err == APIError::CONNECTION_CLOSED) {
+    return "CONNECTION_CLOSED";
   }
   return "UNKNOWN";
 }
@@ -185,12 +187,17 @@ APIError APINoiseFrameHelper::try_read_frame_(ParsedFrame *frame) {
     // no header information yet
     size_t to_read = 3 - rx_header_buf_len_;
     ssize_t received = socket_->read(&rx_header_buf_[rx_header_buf_len_], to_read);
-    if (is_would_block(received)) {
+    if (received == -1) {
+      if (errno == EWOULDBLOCK || errno == EAGAIN) {
         return APIError::WOULD_BLOCK;
-    } else if (received == -1) {
+      }
       state_ = State::FAILED;
       HELPER_LOG("Socket read failed with errno %d", errno);
       return APIError::SOCKET_READ_FAILED;
+    } else if (received == 0) {
+      state_ = State::FAILED;
+      HELPER_LOG("Connection closed");
+      return APIError::CONNECTION_CLOSED;
     }
     rx_header_buf_len_ += received;
     if (received != to_read) {
@@ -227,12 +234,17 @@ APIError APINoiseFrameHelper::try_read_frame_(ParsedFrame *frame) {
     // more data to read
     size_t to_read = msg_size - rx_buf_len_;
     ssize_t received = socket_->read(&rx_buf_[rx_buf_len_], to_read);
-    if (is_would_block(received)) {
+    if (received == -1) {
+      if (errno == EWOULDBLOCK || errno == EAGAIN) {
         return APIError::WOULD_BLOCK;
-    } else if (received == -1) {
+      }
       state_ = State::FAILED;
       HELPER_LOG("Socket read failed with errno %d", errno);
       return APIError::SOCKET_READ_FAILED;
+    } else if (received == 0) {
+      state_ = State::FAILED;
+      HELPER_LOG("Connection closed");
+      return APIError::CONNECTION_CLOSED;
     }
     rx_buf_len_ += received;
     if (received != to_read) {
@@ -778,12 +790,17 @@ APIError APIPlaintextFrameHelper::try_read_frame_(ParsedFrame *frame) {
   while (!rx_header_parsed_) {
     uint8_t data;
     ssize_t received = socket_->read(&data, 1);
-    if (is_would_block(received)) {
+    if (received == -1) {
+      if (errno == EWOULDBLOCK || errno == EAGAIN) {
         return APIError::WOULD_BLOCK;
-    } else if (received == -1) {
+      }
       state_ = State::FAILED;
       HELPER_LOG("Socket read failed with errno %d", errno);
       return APIError::SOCKET_READ_FAILED;
+    } else if (received == 0) {
+      state_ = State::FAILED;
+      HELPER_LOG("Connection closed");
+      return APIError::CONNECTION_CLOSED;
     }
     rx_header_buf_.push_back(data);
 
@@ -824,12 +841,17 @@ APIError APIPlaintextFrameHelper::try_read_frame_(ParsedFrame *frame) {
     // more data to read
     size_t to_read = rx_header_parsed_len_ - rx_buf_len_;
     ssize_t received = socket_->read(&rx_buf_[rx_buf_len_], to_read);
-    if (is_would_block(received)) {
+    if (received == -1) {
+      if (errno == EWOULDBLOCK || errno == EAGAIN) {
         return APIError::WOULD_BLOCK;
-    } else if (received == -1) {
+      }
       state_ = State::FAILED;
       HELPER_LOG("Socket read failed with errno %d", errno);
       return APIError::SOCKET_READ_FAILED;
+    } else if (received == 0) {
+      state_ = State::FAILED;
+      HELPER_LOG("Connection closed");
+      return APIError::CONNECTION_CLOSED;
     }
     rx_buf_len_ += received;
     if (received != to_read) {

esphome/components/api/api_frame_helper.h

@@ -53,6 +53,7 @@ enum class APIError : int {
   HANDSHAKESTATE_SETUP_FAILED = 1019,
   HANDSHAKESTATE_SPLIT_FAILED = 1020,
   BAD_HANDSHAKE_ERROR_BYTE = 1021,
+  CONNECTION_CLOSED = 1022,
 };
 
 const char *api_error_to_str(APIError err);

esphome/components/ota/ota_component.cpp

@@ -275,6 +275,12 @@ void OTAComponent::handle_() {
       }
       ESP_LOGW(TAG, "Error receiving data for update, errno: %d", errno);
       goto error;
+    } else if (read == 0) {
+      // $ man recv
+      // "When  a  stream socket peer has performed an orderly shutdown, the return value will
+      // be 0 (the traditional "end-of-file" return)."
+      ESP_LOGW(TAG, "Remote end closed connection");
+      goto error;
     }
 
     error_code = backend->write(buf, read);
@@ -362,6 +368,9 @@ bool OTAComponent::readall_(uint8_t *buf, size_t len) {
       }
       ESP_LOGW(TAG, "Failed to read %d bytes of data, errno: %d", len, errno);
       return false;
+    } else if (read == 0) {
+      ESP_LOGW(TAG, "Remote closed connection");
+      return false;
     } else {
       at += read;
     }

esphome/components/socket/lwip_raw_tcp_impl.cpp

@@ -320,8 +320,7 @@ class LWIPRawImpl : public Socket {
       return -1;
     }
     if (rx_closed_ && rx_buf_ == nullptr) {
-      errno = ECONNRESET;
+      return 0;
-      return -1;
     }
     if (len == 0) {
       return 0;
@@ -366,6 +365,11 @@ class LWIPRawImpl : public Socket {
       read += copysize;
     }
 
+    if (read == 0) {
+      errno = EWOULDBLOCK;
+      return -1;
+    }
+
     return read;
   }
   ssize_t readv(const struct iovec *iov, int iovcnt) override {