Move euid check back to Server.cpp.

Use getpwnam_r instead of getpwnam.
Fix style.

dbms/programs/server/Server.cpp

@@ -2,7 +2,11 @@
 
 #include <memory>
 #include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <errno.h>
+#include <pwd.h>
+#include <unistd.h>
 #include <Poco/Version.h>
 #include <Poco/DirectoryIterator.h>
 #include <Poco/Net/HTTPServer.h>
@@ -70,6 +74,9 @@ namespace ErrorCodes
     extern const int EXCESSIVE_ELEMENT_IN_CONFIG;
     extern const int INVALID_CONFIG_PARAMETER;
     extern const int SYSTEM_ERROR;
+    extern const int FAILED_TO_STAT_DATA;
+    extern const int FAILED_TO_GETPWUID;
+    extern const int MISMATCHING_USERS_FOR_PROCESS_AND_DATA;
 }
 
 
@@ -83,6 +90,25 @@ static std::string getCanonicalPath(std::string && path)
     return std::move(path);
 }
 
+static std::string getUserName(uid_t user_id) {
+    /// Try to convert user id into user name.
+    auto buffer_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+    if (buffer_size <= 0)
+        buffer_size = 32;
+    std::string buffer;
+    buffer.reserve(buffer_size);
+
+    struct passwd passwd_entry;
+    struct passwd * result = nullptr;
+    const auto error = getpwuid_r(user_id, &passwd_entry, buffer.data(), buffer_size, &result);
+
+    if (error)
+        throwFromErrno("Failed to find user name for " + toString(user_id), ErrorCodes::FAILED_TO_GETPWUID, error);
+    else if (result)
+        return result->pw_name;
+    return toString(user_id);
+}
+
 void Server::uninitialize()
 {
     logger().information("shutting down");
@@ -166,6 +192,22 @@ int Server::main(const std::vector<std::string> & /*args*/)
     std::string path = getCanonicalPath(config().getString("path", DBMS_DEFAULT_PATH));
     std::string default_database = config().getString("default_database", "default");
 
+    /// Check that the process' user id matches the owner of the data.
+    const auto effective_user_id = geteuid();
+    struct stat statbuf;
+    const auto effective_user = getUserName(effective_user_id);
+    LOG_INFO(log, "effective_user = " + effective_user);
+    if (stat(path.c_str(), &statbuf) == 0 && effective_user_id != statbuf.st_uid)
+    {
+        const auto effective_user = getUserName(effective_user_id);
+        const auto data_owner = getUserName(statbuf.st_uid);
+        std::string message = "Effective user of the process (" + effective_user +
+            ") does not match the owner of the data (" + data_owner + ").";
+        if (effective_user_id == 0)
+            message += " Run under 'sudo -u " + data_owner + "'.";
+        throw Exception(message, ErrorCodes::MISMATCHING_USERS_FOR_PROCESS_AND_DATA);
+    }
+
     global_context->setPath(path);
 
     /// Create directories for 'path' and for default database, if not exist.
@@ -376,8 +418,6 @@ int Server::main(const std::vector<std::string> & /*args*/)
     format_schema_path.createDirectories();
 
     LOG_INFO(log, "Loading metadata.");
-    try
-    {
     loadMetadataSystem(*global_context);
     /// After attaching system databases we can initialize system log.
     global_context->initializeSystemLogs();
@@ -385,12 +425,6 @@ int Server::main(const std::vector<std::string> & /*args*/)
     attachSystemTablesServer(*global_context->getDatabase("system"), has_zookeeper);
     /// Then, load remaining databases
     loadMetadata(*global_context);
-    }
-    catch (...)
-    {
-        tryLogCurrentException(log, "Caught exception while loading metadata");
-        throw;
-    }
     LOG_DEBUG(log, "Loaded metadata.");
 
     global_context->setCurrentDatabase(default_database);

dbms/src/Common/ErrorCodes.cpp

@@ -402,6 +402,9 @@ namespace ErrorCodes
     extern const int SYSTEM_ERROR = 425;
     extern const int NULL_POINTER_DEREFERENCE = 426;
     extern const int CANNOT_COMPILE_REGEXP = 427;
+    extern const int FAILED_TO_STAT_DATA = 428;
+    extern const int FAILED_TO_GETPWUID = 429;
+    extern const int MISMATCHING_USERS_FOR_PROCESS_AND_DATA = 430;
 
     extern const int KEEPER_EXCEPTION = 999;
     extern const int POCO_EXCEPTION = 1000;

libs/libdaemon/src/BaseDaemon.cpp

@@ -14,7 +14,6 @@
 #include <signal.h>
 #include <cxxabi.h>
 #include <execinfo.h>
-#include <pwd.h>
 #include <unistd.h>
 
 #if USE_UNWIND
@@ -578,17 +577,6 @@ static bool tryCreateDirectories(Poco::Logger * logger, const std::string & path
 }
 
 
-static std::string getUserName(uid_t userId) {
-    /// Try to convert user id into user name.
-    const struct passwd * result = getpwuid(userId);
-    if (errno)
-        throw Poco::SystemException("Failed to get user name for " + DB::toString(userId));
-    else if (result)
-        return result->pw_name;
-    return DB::toString(userId);
-}
-
-
 void BaseDaemon::reloadConfiguration()
 {
     /** If the program is not run in daemon mode and 'config-file' is not specified,
@@ -910,28 +898,6 @@ void BaseDaemon::initialize(Application & self)
         umask(umask_num);
     }
 
-    std::string path = config().getString("path", DBMS_DEFAULT_PATH);
-
-    /// Check that the process' user id matches the owner of the data.
-    const auto effectiveUserId = geteuid();
-    struct stat statbuf;
-    if (stat(path.c_str(), &statbuf)) {
-        const auto parent = Poco::Path(path).parent().toString();
-        if (stat(parent.c_str(), &statbuf)) {
-            throw Poco::SystemException("Failed to stat data path " + parent);
-        }
-    }
-    if (effectiveUserId != statbuf.st_uid)
-    {
-        const auto effectiveUser = getUserName(effectiveUserId);
-        const auto dataOwner = getUserName(statbuf.st_uid);
-        std::string message = "Effective user of the process (" + effectiveUser +
-            ") does not match the owner of the data (" + dataOwner + ").";
-        if (effectiveUserId == 0)
-            message += " Run under 'sudo -u " + dataOwner + "'.";
-        throw Poco::SystemException(message);
-    }
-
     DB::ConfigProcessor(config_path).savePreprocessedConfig(loaded_config, "");
 
     /// Write core dump on crash.