From ec63247ae0a480348cdef8ae00d9a73b78bd5f20 Mon Sep 17 00:00:00 2001 From: "J. Nick Koston" Date: Tue, 7 Oct 2025 18:19:29 -1000 Subject: [PATCH] [mdns] Fix delete/malloc bug and store string constants in flash (#11105) --- esphome/components/mdns/__init__.py | 8 ++-- esphome/components/mdns/mdns_component.cpp | 43 +++++++++----------- esphome/components/mdns/mdns_component.h | 19 +++++++-- esphome/components/mdns/mdns_esp32.cpp | 14 +++---- esphome/components/mdns/mdns_esp8266.cpp | 12 +++--- esphome/components/mdns/mdns_libretiny.cpp | 6 +-- esphome/components/mdns/mdns_rp2040.cpp | 6 +-- esphome/components/openthread/openthread.cpp | 4 +- 8 files changed, 61 insertions(+), 51 deletions(-) diff --git a/esphome/components/mdns/__init__.py b/esphome/components/mdns/__init__.py index ce0241677d..3fa4d2ebef 100644 --- a/esphome/components/mdns/__init__.py +++ b/esphome/components/mdns/__init__.py @@ -61,7 +61,7 @@ CONFIG_SCHEMA = cv.All( def mdns_txt_record(key: str, value: str): return cg.StructInitializer( MDNSTXTRecord, - ("key", key), + ("key", cg.RawExpression(f"MDNS_STR({cg.safe_exp(key)})")), ("value", value), ) @@ -71,8 +71,8 @@ def mdns_service( ): return cg.StructInitializer( MDNSService, - ("service_type", service), - ("proto", proto), + ("service_type", cg.RawExpression(f"MDNS_STR({cg.safe_exp(service)})")), + ("proto", cg.RawExpression(f"MDNS_STR({cg.safe_exp(proto)})")), ("port", port), ("txt_records", txt_records), ) @@ -114,7 +114,7 @@ async def to_code(config): txt = [ cg.StructInitializer( MDNSTXTRecord, - ("key", txt_key), + ("key", cg.RawExpression(f"MDNS_STR({cg.safe_exp(txt_key)})")), ("value", await cg.templatable(txt_value, [], cg.std_string)), ) for txt_key, txt_value in service[CONF_TXT].items() diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp index eed2516c6a..8945053b7d 100644 --- a/esphome/components/mdns/mdns_component.cpp +++ b/esphome/components/mdns/mdns_component.cpp @@ -9,24 +9,21 @@ #include // Macro to define strings in PROGMEM on ESP8266, regular memory on other platforms #define MDNS_STATIC_CONST_CHAR(name, value) static const char name[] PROGMEM = value -// Helper to get string from PROGMEM - returns a temporary std::string +// Helper to convert PROGMEM string to std::string for TemplatableValue // Only define this function if we have services that will use it #if defined(USE_API) || defined(USE_PROMETHEUS) || defined(USE_WEBSERVER) || defined(USE_MDNS_EXTRA_SERVICES) -static std::string mdns_string_p(const char *src) { +static std::string mdns_str_value(PGM_P str) { char buf[64]; - strncpy_P(buf, src, sizeof(buf) - 1); + strncpy_P(buf, str, sizeof(buf) - 1); buf[sizeof(buf) - 1] = '\0'; return std::string(buf); } -#define MDNS_STR(name) mdns_string_p(name) -#else -// If no services are configured, we still need the fallback service but it uses string literals -#define MDNS_STR(name) std::string(name) +#define MDNS_STR_VALUE(name) mdns_str_value(name) #endif #else // On non-ESP8266 platforms, use regular const char* -#define MDNS_STATIC_CONST_CHAR(name, value) static constexpr const char *name = value -#define MDNS_STR(name) name +#define MDNS_STATIC_CONST_CHAR(name, value) static constexpr const char name[] = value +#define MDNS_STR_VALUE(name) std::string(name) #endif #ifdef USE_API @@ -118,31 +115,31 @@ void MDNSComponent::compile_records_() { txt_records.push_back({MDNS_STR(TXT_MAC), get_mac_address()}); #ifdef USE_ESP8266 - txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR(PLATFORM_ESP8266)}); + txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR_VALUE(PLATFORM_ESP8266)}); #elif defined(USE_ESP32) - txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR(PLATFORM_ESP32)}); + txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR_VALUE(PLATFORM_ESP32)}); #elif defined(USE_RP2040) - txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR(PLATFORM_RP2040)}); + txt_records.push_back({MDNS_STR(TXT_PLATFORM), MDNS_STR_VALUE(PLATFORM_RP2040)}); #elif defined(USE_LIBRETINY) - txt_records.emplace_back(MDNSTXTRecord{"platform", lt_cpu_get_model_name()}); + txt_records.push_back({MDNS_STR(TXT_PLATFORM), lt_cpu_get_model_name()}); #endif txt_records.push_back({MDNS_STR(TXT_BOARD), ESPHOME_BOARD}); #if defined(USE_WIFI) - txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR(NETWORK_WIFI)}); + txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR_VALUE(NETWORK_WIFI)}); #elif defined(USE_ETHERNET) - txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR(NETWORK_ETHERNET)}); + txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR_VALUE(NETWORK_ETHERNET)}); #elif defined(USE_OPENTHREAD) - txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR(NETWORK_THREAD)}); + txt_records.push_back({MDNS_STR(TXT_NETWORK), MDNS_STR_VALUE(NETWORK_THREAD)}); #endif #ifdef USE_API_NOISE MDNS_STATIC_CONST_CHAR(NOISE_ENCRYPTION, "Noise_NNpsk0_25519_ChaChaPoly_SHA256"); if (api::global_api_server->get_noise_ctx()->has_psk()) { - txt_records.push_back({MDNS_STR(TXT_API_ENCRYPTION), MDNS_STR(NOISE_ENCRYPTION)}); + txt_records.push_back({MDNS_STR(TXT_API_ENCRYPTION), MDNS_STR_VALUE(NOISE_ENCRYPTION)}); } else { - txt_records.push_back({MDNS_STR(TXT_API_ENCRYPTION_SUPPORTED), MDNS_STR(NOISE_ENCRYPTION)}); + txt_records.push_back({MDNS_STR(TXT_API_ENCRYPTION_SUPPORTED), MDNS_STR_VALUE(NOISE_ENCRYPTION)}); } #endif @@ -175,10 +172,10 @@ void MDNSComponent::compile_records_() { // Publish "http" service if not using native API or any other services // This is just to have *some* mDNS service so that .local resolution works auto &fallback_service = this->services_.emplace_next(); - fallback_service.service_type = "_http"; - fallback_service.proto = "_tcp"; + fallback_service.service_type = MDNS_STR(SERVICE_HTTP); + fallback_service.proto = MDNS_STR(SERVICE_TCP); fallback_service.port = USE_WEBSERVER_PORT; - fallback_service.txt_records.emplace_back(MDNSTXTRecord{"version", ESPHOME_VERSION}); + fallback_service.txt_records.push_back({MDNS_STR(TXT_VERSION), ESPHOME_VERSION}); #endif } @@ -190,10 +187,10 @@ void MDNSComponent::dump_config() { #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE ESP_LOGV(TAG, " Services:"); for (const auto &service : this->services_) { - ESP_LOGV(TAG, " - %s, %s, %d", service.service_type.c_str(), service.proto.c_str(), + ESP_LOGV(TAG, " - %s, %s, %d", MDNS_STR_ARG(service.service_type), MDNS_STR_ARG(service.proto), const_cast &>(service.port).value()); for (const auto &record : service.txt_records) { - ESP_LOGV(TAG, " TXT: %s = %s", record.key.c_str(), + ESP_LOGV(TAG, " TXT: %s = %s", MDNS_STR_ARG(record.key), const_cast &>(record.value).value().c_str()); } } diff --git a/esphome/components/mdns/mdns_component.h b/esphome/components/mdns/mdns_component.h index e0e268c914..b1f73fbb32 100644 --- a/esphome/components/mdns/mdns_component.h +++ b/esphome/components/mdns/mdns_component.h @@ -9,21 +9,34 @@ namespace esphome { namespace mdns { +// Helper struct that identifies strings that may be stored in flash storage (similar to LogString) +struct MDNSString; + +// Macro to cast string literals to MDNSString* (works on all platforms) +#define MDNS_STR(name) (reinterpret_cast(name)) + +#ifdef USE_ESP8266 +#include +#define MDNS_STR_ARG(s) ((PGM_P) (s)) +#else +#define MDNS_STR_ARG(s) (reinterpret_cast(s)) +#endif + // Service count is calculated at compile time by Python codegen // MDNS_SERVICE_COUNT will always be defined struct MDNSTXTRecord { - std::string key; + const MDNSString *key; TemplatableValue value; }; struct MDNSService { // service name _including_ underscore character prefix // as defined in RFC6763 Section 7 - std::string service_type; + const MDNSString *service_type; // second label indicating protocol _including_ underscore character prefix // as defined in RFC6763 Section 7, like "_tcp" or "_udp" - std::string proto; + const MDNSString *proto; TemplatableValue port; std::vector txt_records; }; diff --git a/esphome/components/mdns/mdns_esp32.cpp b/esphome/components/mdns/mdns_esp32.cpp index ffd86afec1..40d305a1e6 100644 --- a/esphome/components/mdns/mdns_esp32.cpp +++ b/esphome/components/mdns/mdns_esp32.cpp @@ -29,23 +29,23 @@ void MDNSComponent::setup() { std::vector txt_records; for (const auto &record : service.txt_records) { mdns_txt_item_t it{}; - // dup strings to ensure the pointer is valid even after the record loop - it.key = strdup(record.key.c_str()); + // key is a compile-time string literal in flash, no need to strdup + it.key = MDNS_STR_ARG(record.key); + // value is a temporary from TemplatableValue, must strdup to keep it alive it.value = strdup(const_cast &>(record.value).value().c_str()); txt_records.push_back(it); } uint16_t port = const_cast &>(service.port).value(); - err = mdns_service_add(nullptr, service.service_type.c_str(), service.proto.c_str(), port, txt_records.data(), - txt_records.size()); + err = mdns_service_add(nullptr, MDNS_STR_ARG(service.service_type), MDNS_STR_ARG(service.proto), port, + txt_records.data(), txt_records.size()); // free records for (const auto &it : txt_records) { - delete it.key; // NOLINT(cppcoreguidelines-owning-memory) - delete it.value; // NOLINT(cppcoreguidelines-owning-memory) + free((void *) it.value); // NOLINT(cppcoreguidelines-no-malloc) } if (err != ESP_OK) { - ESP_LOGW(TAG, "Failed to register service %s: %s", service.service_type.c_str(), esp_err_to_name(err)); + ESP_LOGW(TAG, "Failed to register service %s: %s", MDNS_STR_ARG(service.service_type), esp_err_to_name(err)); } } } diff --git a/esphome/components/mdns/mdns_esp8266.cpp b/esphome/components/mdns/mdns_esp8266.cpp index 2c90d57021..f1c8909807 100644 --- a/esphome/components/mdns/mdns_esp8266.cpp +++ b/esphome/components/mdns/mdns_esp8266.cpp @@ -21,18 +21,18 @@ void MDNSComponent::setup() { // part of the wire protocol to have an underscore, and for example ESP-IDF // expects the underscore to be there, the ESP8266 implementation always adds // the underscore itself. - auto *proto = service.proto.c_str(); - while (*proto == '_') { + auto *proto = MDNS_STR_ARG(service.proto); + while (progmem_read_byte((const uint8_t *) proto) == '_') { proto++; } - auto *service_type = service.service_type.c_str(); - while (*service_type == '_') { + auto *service_type = MDNS_STR_ARG(service.service_type); + while (progmem_read_byte((const uint8_t *) service_type) == '_') { service_type++; } uint16_t port = const_cast &>(service.port).value(); - MDNS.addService(service_type, proto, port); + MDNS.addService(FPSTR(service_type), FPSTR(proto), port); for (const auto &record : service.txt_records) { - MDNS.addServiceTxt(service_type, proto, record.key.c_str(), + MDNS.addServiceTxt(FPSTR(service_type), FPSTR(proto), FPSTR(MDNS_STR_ARG(record.key)), const_cast &>(record.value).value().c_str()); } } diff --git a/esphome/components/mdns/mdns_libretiny.cpp b/esphome/components/mdns/mdns_libretiny.cpp index 7a41ec9dce..9010ca2bc6 100644 --- a/esphome/components/mdns/mdns_libretiny.cpp +++ b/esphome/components/mdns/mdns_libretiny.cpp @@ -21,18 +21,18 @@ void MDNSComponent::setup() { // part of the wire protocol to have an underscore, and for example ESP-IDF // expects the underscore to be there, the ESP8266 implementation always adds // the underscore itself. - auto *proto = service.proto.c_str(); + auto *proto = MDNS_STR_ARG(service.proto); while (*proto == '_') { proto++; } - auto *service_type = service.service_type.c_str(); + auto *service_type = MDNS_STR_ARG(service.service_type); while (*service_type == '_') { service_type++; } uint16_t port_ = const_cast &>(service.port).value(); MDNS.addService(service_type, proto, port_); for (const auto &record : service.txt_records) { - MDNS.addServiceTxt(service_type, proto, record.key.c_str(), + MDNS.addServiceTxt(service_type, proto, MDNS_STR_ARG(record.key), const_cast &>(record.value).value().c_str()); } } diff --git a/esphome/components/mdns/mdns_rp2040.cpp b/esphome/components/mdns/mdns_rp2040.cpp index 95894323f4..039453f501 100644 --- a/esphome/components/mdns/mdns_rp2040.cpp +++ b/esphome/components/mdns/mdns_rp2040.cpp @@ -21,18 +21,18 @@ void MDNSComponent::setup() { // part of the wire protocol to have an underscore, and for example ESP-IDF // expects the underscore to be there, the ESP8266 implementation always adds // the underscore itself. - auto *proto = service.proto.c_str(); + auto *proto = MDNS_STR_ARG(service.proto); while (*proto == '_') { proto++; } - auto *service_type = service.service_type.c_str(); + auto *service_type = MDNS_STR_ARG(service.service_type); while (*service_type == '_') { service_type++; } uint16_t port = const_cast &>(service.port).value(); MDNS.addService(service_type, proto, port); for (const auto &record : service.txt_records) { - MDNS.addServiceTxt(service_type, proto, record.key.c_str(), + MDNS.addServiceTxt(service_type, proto, MDNS_STR_ARG(record.key), const_cast &>(record.value).value().c_str()); } } diff --git a/esphome/components/openthread/openthread.cpp b/esphome/components/openthread/openthread.cpp index 57b972d195..bc5dcadef6 100644 --- a/esphome/components/openthread/openthread.cpp +++ b/esphome/components/openthread/openthread.cpp @@ -155,7 +155,7 @@ void OpenThreadSrpComponent::setup() { // Set service name char *string = otSrpClientBuffersGetServiceEntryServiceNameString(entry, &size); - std::string full_service = service.service_type + "." + service.proto; + std::string full_service = std::string(MDNS_STR_ARG(service.service_type)) + "." + MDNS_STR_ARG(service.proto); if (full_service.size() > size) { ESP_LOGW(TAG, "Service name too long: %s", full_service.c_str()); continue; @@ -181,7 +181,7 @@ void OpenThreadSrpComponent::setup() { for (size_t i = 0; i < service.txt_records.size(); i++) { const auto &txt = service.txt_records[i]; auto value = const_cast &>(txt.value).value(); - txt_entries[i].mKey = strdup(txt.key.c_str()); + txt_entries[i].mKey = MDNS_STR_ARG(txt.key); txt_entries[i].mValue = reinterpret_cast(strdup(value.c_str())); txt_entries[i].mValueLength = value.size(); }