PXC-4433: Create file with current MySQL state

https://perconadev.atlassian.net/browse/PXC-4433

server.state file containing current server state is being created
in data directory if the server is started with
create_server_state_file=ON option.
create_server_state_file default value is OFF.

mysys/my_init.cc

@@ -71,6 +71,8 @@
 #include "mysys/mysys_priv.h"
 #include "mysys_err.h"
 
+#include "sql/server_status_file.h"
+
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif

sql/CMakeLists.txt

@@ -480,6 +480,7 @@ SET(SQL_SHARED_SOURCES
   partition_info.cc
   partitioning/partition_handler.cc
   persisted_variable.cc
+  server_status_file.cc
   protocol_classic.cc
   psi_memory_key.cc
   psi_memory_resource.cc

sql/dd/impl/bootstrap/bootstrapper.cc

@@ -73,6 +73,7 @@
 #include "sql/sd_notify.h"  // sysd::notify
 #include "sql/sql_zip_dict.h"
 #include "sql/thd_raii.h"
+#include "sql/server_status_file.h"
 #include "storage/perfschema/pfs_dd_version.h"  // PFS_DD_VERSION
 
 using namespace dd;
@@ -1408,6 +1409,7 @@ bool initialize_dd_properties(THD *thd) {
     if (bootstrap::DD_bootstrap_ctx::instance().is_dd_upgrade()) {
       LogErr(SYSTEM_LEVEL, ER_DD_UPGRADE, actual_dd_version, dd::DD_VERSION);
       sysd::notify("STATUS=Data Dictionary upgrade in progress\n");
+      Server_status_file::set_status(Server_status_file::Status::UPGRADING);
     }
     if (bootstrap::DD_bootstrap_ctx::instance().is_server_upgrade()) {
       // This condition is hit only if upgrade has been skipped before

sql/dd/impl/upgrade/server.cc

@@ -64,6 +64,7 @@
 #include "sql/thd_raii.h"
 #include "sql/trigger.h"  // Trigger
 #include "sql/trigger_def.h"
+#include "sql/server_status_file.h"
 
 typedef ulonglong sql_mode_t;
 extern const char *mysql_sys_schema[];
@@ -977,11 +978,15 @@ bool upgrade_system_schemas(THD *thd) {
     LogErr(SYSTEM_LEVEL, ER_SERVER_DOWNGRADE_STATUS, server_version,
            MYSQL_VERSION_ID, "started");
     sysd::notify("STATUS=Server downgrade in progress\n");
+    Server_status_file::set_status(Server_status_file::Status::DOWNGRADING);
+
     /* purecov: end */
   } else {
     LogErr(SYSTEM_LEVEL, ER_SERVER_UPGRADE_STATUS, server_version,
            MYSQL_VERSION_ID, "started");
     sysd::notify("STATUS=Server upgrade in progress\n");
+    Server_status_file::set_status(Server_status_file::Status::UPGRADING);
+
   }
 
   bootstrap_error_handler.set_log_error(false);

sql/dd/upgrade_57/upgrade.cc

@@ -86,6 +86,7 @@
 #include "sql/table.h"
 #include "sql/thd_raii.h"
 #include "sql/transaction.h"  // trans_rollback
+#include "sql/server_status_file.h"
 
 namespace dd {
 
@@ -904,6 +905,7 @@ bool do_pre_checks_and_initialize_dd(THD *thd) {
     */
     LogErr(SYSTEM_LEVEL, ER_DD_UPGRADE_START);
     sysd::notify("STATUS=Data Dictionary upgrade from MySQL 5.7 in progress\n");
+    Server_status_file::set_status(Server_status_file::Status::UPGRADING);
   }
 
   /*

sql/mysqld.cc

@@ -809,6 +809,7 @@ MySQL clients support the protocol:
 #include "sql/options_mysqld.h"                  // OPT_THREAD_CACHE_SIZE
 #include "sql/partitioning/partition_handler.h"  // partitioning_init
 #include "sql/persisted_variable.h"              // Persisted_variables_cache
+#include "sql/server_status_file.h"
 #include "sql/plugin_table.h"
 #include "sql/protocol.h"
 #include "sql/psi_memory_key.h"  // key_memory_MYSQL_RELAY_LOG_index
@@ -1448,6 +1449,8 @@ bool avoid_temporal_upgrade;
 
 bool persisted_globals_load = true;
 
+bool create_server_state_file = false;
+
 bool opt_keyring_operations = true;
 
 bool opt_table_encryption_privilege_check = false;
@@ -2773,6 +2776,7 @@ static void unireg_abort(int exit_code) {
 #endif /* WITH_WSREP */
   DBUG_TRACE;
 
+  Server_status_file::set_status(Server_status_file::Status::STOPPING);
   if (errno) {
     sysd::notify("ERRNO=", errno, "\n");
   }
@@ -2899,6 +2903,8 @@ static void mysqld_exit(int exit_code) {
   close_service_status_pipe_in_mysqld();
 #endif  // _WIN32
 
+  Server_status_file::set_status(Server_status_file::Status::STOPPED);
+
   exit(exit_code); /* purecov: inspected */
 }
 
@@ -8424,6 +8430,9 @@ int mysqld_main(int argc, char **argv)
   strmake(mysql_real_data_home, get_relative_path(MYSQL_DATADIR),
           sizeof(mysql_real_data_home) - 1);
 
+  Server_status_file::init(&argc, &argv);
+  Server_status_file::set_status(Server_status_file::Status::INITIALIZING);
+
   /* Must be initialized early for comparison of options name */
   system_charset_info = &my_charset_utf8mb3_general_ci;
 
@@ -9468,9 +9477,12 @@ int mysqld_main(int argc, char **argv)
   }
 
   mysqld_socket_acceptor->check_and_spawn_admin_connection_handler_thread();
-  mysqld_socket_acceptor->connection_event_loop();
+  Server_status_file::set_status(Server_status_file::Status::READY);
+  mysqld_socket_acceptor->connection_event_loop();  // KH: end of limbo state
 #endif /* _WIN32 */
   server_operational_state = SERVER_SHUTTING_DOWN;
+  Server_status_file::set_status(Server_status_file::Status::STOPPING);
+
   sysd::notify("STOPPING=1\nSTATUS=Server shutdown in progress\n");
 
   DBUG_PRINT("info", ("No longer listening for incoming connections"));

sql/mysqld.h

@@ -441,6 +441,7 @@ extern ulonglong utility_user_privileges;
 extern char *utility_user_dynamic_privileges;
 
 extern bool persisted_globals_load;
+extern bool create_server_state_file;
 extern bool opt_keyring_operations;
 extern bool opt_table_encryption_privilege_check;
 extern char *opt_keyring_migration_user;

sql/signal_handler.cc

@@ -43,6 +43,7 @@
 #include "sql/mysqld.h"
 #include "sql/sql_class.h"
 #include "sql/sql_const.h"
+#include "sql/server_status_file.h"
 
 #ifdef WITH_WSREP
 #include "wsrep_mysqld.h"
@@ -227,9 +228,11 @@ void print_fatal_signal(int sig) {
 extern "C" void handle_fatal_signal(int sig) {
   if (s_handler_being_processed) {
     my_safe_printf_stderr("Fatal " SIGNAL_FMT " while backtracing\n", sig);
+    Server_status_file::set_status(Server_status_file::Status::STOPPED);
     _exit(MYSQLD_FAILURE_EXIT); /* Quit without running destructors */
   }
 
+  Server_status_file::set_status(Server_status_file::Status::STOPPING);
   s_handler_being_processed = true;
 
 #ifdef WITH_WSREP
@@ -246,6 +249,10 @@ extern "C" void handle_fatal_signal(int sig) {
 
   buffered_error_log.write_to_disk();
 
+  // This is the last chance to report in the file.
+  // Below coredump will exit the process
+  Server_status_file::set_status(Server_status_file::Status::STOPPED);
+
   if ((test_flags & TEST_CORE_ON_SIGNAL) != 0) {
 #if HAVE_LIBCOREDUMPER
     if (opt_libcoredumper) {
@@ -290,6 +297,9 @@ void my_server_abort() {
   static std::atomic_bool abort_processing{false};
   /* Broadcast that this thread wants to print the signal info. */
   aborts_pending++;
+
+  Server_status_file::set_status(Server_status_file::Status::STOPPING);
+
   /*
     Wait for the exclusive right to print the signal info. This assures the
     output is not interleaved.
@@ -319,6 +329,8 @@ void my_server_abort() {
     while (abort_processing.exchange(true)) {
       std::this_thread::sleep_for(std::chrono::milliseconds(1));
     }
+
+    Server_status_file::set_status(Server_status_file::Status::STOPPED);
     abort();
   }
   /*

sql/sys_vars.cc

@@ -7868,6 +7868,14 @@ static Sys_var_bool Sys_persisted_globals_load(
     DEFAULT(true), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(nullptr),
     ON_UPDATE(nullptr));
 
+static Sys_var_bool Sys_create_server_state_file(
+    "create_server_state_file",
+    "When this option is enabled, server reports its state in server.state "
+    "file located in datadir.",
+    READ_ONLY NON_PERSIST GLOBAL_VAR(create_server_state_file), CMD_LINE(OPT_ARG),
+    DEFAULT(false), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(nullptr),
+    ON_UPDATE(nullptr));
+
 static bool sysvar_check_authid_string(sys_var *, THD *thd, set_var *var) {
   /*
     Since mandatory_roles is similar to a GRANT role statement without a

storage/innobase/ut/ut0dbg.cc

@@ -41,6 +41,7 @@ this program; if not, write to the Free Software Foundation, Inc.,
 #endif /* !UNIV_HOTBACKUP */
 
 #include "ut0dbg.h"
+#include "sql/server_status_file.h"
 
 static std::function<void()> assert_callback;
 
@@ -78,6 +79,7 @@ void ut_set_assert_callback(std::function<void()> &callback) {
           to_string(std::this_thread::get_id()).c_str());
 #endif /* !UNIV_HOTBACKUP */
 
+  Server_status_file::set_status(Server_status_file::Status::STOPPING);
   fputs(
       "InnoDB: We intentionally generate a memory trap.\n"
       "InnoDB: Submit a detailed bug report"