fix(utils): report runtime config probe errors

libs/linglong/tests/ll-tests/src/linglong/utils/runtime_config_test.cpp

@@ -10,9 +10,10 @@
 #include "linglong/utils/log/log.h"
 #include "linglong/utils/runtime_config.h"
 
 #include <filesystem>
 #include <fstream>
 #include <string>
+#include <system_error>
 
 namespace fs = std::filesystem;
 using namespace linglong::api::types::v1;
@@ -443,3 +444,54 @@
     EXPECT_EQ(loadedConfig.devices->at(1), "vendor.com/device=10");
     EXPECT_EQ(loadedConfig.devices->at(2), "vendor.com/device=20");
 }
+
+TEST(RuntimeConfigTest, LoadRuntimeConfigWithSymlinkLoop)
+{
+    TempDir tempDir;
+
+    // A config.json pointing at itself makes the exists() probe fail with
+    // ELOOP, which must be reported as an error.
+    fs::path configDir = tempDir.path() / "linglong" / "apps" / "test-app";
+    fs::create_directories(configDir);
+
+    fs::path configFile = configDir / "config.json";
+    std::error_code ec;
+    fs::create_symlink(configFile, configFile, ec);
+    ASSERT_EQ(ec.value(), 0);
+
+    std::vector<std::filesystem::path> configDirs = { tempDir.path() / "linglong" };
+    auto result = linglong::utils::loadRuntimeConfig(configDirs, "test-app", "");
+    EXPECT_FALSE(result);
+}
+
+TEST(RuntimeConfigTest, LoadRuntimeConfigWithoutConfig)
+{
+    TempDir tempDir;
+
+    fs::path configDir = tempDir.path() / "linglong";
+    fs::create_directories(configDir);
+
+    std::vector<std::filesystem::path> configDirs = { configDir };
+    auto result = linglong::utils::loadRuntimeConfig(configDirs, "test-app", "");
+    ASSERT_TRUE(result.has_value());
+    EXPECT_FALSE(result->has_value());
+}
+
+TEST(RuntimeConfigTest, LoadRuntimeConfigWithConfigDSymlinkLoop)
+{
+    TempDir tempDir;
+
+    // A config.d pointing at itself makes the is_directory() probe fail with
+    // ELOOP, which must be reported as an error.
+    fs::path configDir = tempDir.path() / "linglong";
+    fs::create_directories(configDir);
+
+    fs::path configDPath = configDir / "config.d";
+    std::error_code ec;
+    fs::create_symlink(configDPath, configDPath, ec);
+    ASSERT_EQ(ec.value(), 0);
+
+    std::vector<std::filesystem::path> configDirs = { configDir };
+    auto result = linglong::utils::loadRuntimeConfig(configDirs, "", "");
+    EXPECT_FALSE(result);
+}

libs/utils/src/linglong/utils/runtime_config.cpp

@@ -7,10 +7,12 @@
 #include "runtime_config.h"
 
 #include "linglong/common/dir.h"
 #include "linglong/utils/error/error.h"
 #include "linglong/utils/serialize/json.h"
 
+#include <fmt/format.h>
+
 #include <algorithm>
 #include <filesystem>
 #include <fstream>
 
@@ -38,7 +40,14 @@
     std::vector<RuntimeConfigure> configs;
     auto configPath = configBaseDir / "config.json";
     std::error_code ec;
-    if (std::filesystem::exists(configPath, ec)) {
+    // file_type::none means the status itself could not be determined (e.g. ELOOP/EACCES);
+    // not_found with a set error_code is the regular "absent" case on POSIX.
+    auto configStatus = std::filesystem::status(configPath, ec);
+    if (configStatus.type() == std::filesystem::file_type::none) {
+        return LINGLONG_ERR(
+          fmt::format("failed to check runtime config {}: {}", configPath.string(), ec.message()));
+    }
+    if (std::filesystem::exists(configStatus)) {
         auto config = linglong::utils::loadRuntimeConfig(configPath);
         if (!config) {
             return LINGLONG_ERR(config);
@@ -47,7 +56,13 @@
     }
 
     auto configDPath = configBaseDir / "config.d";
-    if (std::filesystem::is_directory(configDPath, ec)) {
+    auto configDStatus = std::filesystem::status(configDPath, ec);
+    if (configDStatus.type() == std::filesystem::file_type::none) {
+        return LINGLONG_ERR(fmt::format("failed to check runtime config drop-in dir {}: {}",
+                                        configDPath.string(),
+                                        ec.message()));
+    }
+    if (std::filesystem::is_directory(configDStatus)) {
         std::vector<std::filesystem::path> paths;
         for (const auto &entry : std::filesystem::directory_iterator(
                configDPath,