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MENT-1098 Crash during update on 10.4.17 after upgrade from 10.4.10

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The reason for the crash was that there was not a write lock to
protect against file rotations in the server_audit plugin after an
audit plugin patch to changed audit mutexes to read & write locks.

The fixes are:
* Moving server_audit.c to use read & write locks (which improves
  performance).
* Added functionality in file_logger.c to not do file rotations until
  it is allowed by the caller (done without any interface changes for
  the logging service).
* Move checking of file size limit to server_audit.c and if it is time to
  do a rotation change the read lock to a write lock and tell file_logger
  that it is now allowed to rotate the log files.
This commit is contained in:
Monty 2021-02-25 11:55:08 +02:00
parent 4473d17430
commit 1d80e8e4f3
2 changed files with 97 additions and 62 deletions
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55
mysys/file_logger.c
View File

@ -150,23 +150,34 @@ exit:
}
/*
Return 1 if we should rotate the log
*/
my_bool logger_time_to_rotate(LOGGER_HANDLE *log)
{
my_off_t filesize;
if (log->rotations > 0 &&
(filesize= my_tell(log->file, MYF(0))) != (my_off_t) -1 &&
((ulonglong) filesize >= log->size_limit))
return 1;
return 0;
}
int logger_vprintf(LOGGER_HANDLE *log, const char* fmt, va_list ap)
{
int result;
my_off_t filesize;
char cvtbuf[1024];
size_t n_bytes;
flogger_mutex_lock(&log->lock);
if (log->rotations > 0)
if ((filesize= my_tell(log->file, MYF(0))) == (my_off_t) -1 ||
((unsigned long long)filesize >= log->size_limit &&
do_rotate(log)))
{
result= -1;
errno= my_errno;
goto exit; /* Log rotation needed but failed */
}
if (logger_time_to_rotate(log) && do_rotate(log))
{
result= -1;
errno= my_errno;
goto exit; /* Log rotation needed but failed */
}
n_bytes= my_vsnprintf(cvtbuf, sizeof(cvtbuf), fmt, ap);
if (n_bytes >= sizeof(cvtbuf))
@ -180,21 +191,18 @@ exit:
}
int logger_write(LOGGER_HANDLE *log, const char *buffer, size_t size)
static int logger_write_r(LOGGER_HANDLE *log, my_bool allow_rotations,
const char *buffer, size_t size)
{
int result;
my_off_t filesize;
flogger_mutex_lock(&log->lock);
if (log->rotations > 0)
if ((filesize= my_tell(log->file, MYF(0))) == (my_off_t) -1 ||
((unsigned long long)filesize >= log->size_limit &&
do_rotate(log)))
{
result= -1;
errno= my_errno;
goto exit; /* Log rotation needed but failed */
}
if (allow_rotations && logger_time_to_rotate(log) && do_rotate(log))
{
result= -1;
errno= my_errno;
goto exit; /* Log rotation needed but failed */
}
result= (int)my_write(log->file, (uchar *) buffer, size, MYF(0));
@ -204,6 +212,11 @@ exit:
}
int logger_write(LOGGER_HANDLE *log, const char *buffer, size_t size)
{
return logger_write_r(log, TRUE, buffer, size);
}
int logger_rotate(LOGGER_HANDLE *log)
{
int result;

104
plugin/server_audit/server_audit.c
View File

@ -15,7 +15,7 @@
#define PLUGIN_VERSION 0x104
#define PLUGIN_STR_VERSION "1.4.10"
#define PLUGIN_STR_VERSION "1.4.11"
#define _my_thread_var loc_thread_var
@ -139,6 +139,7 @@ static int loc_file_errno;
#define logger_write loc_logger_write
#define logger_rotate loc_logger_rotate
#define logger_init_mutexts loc_logger_init_mutexts
#define logger_time_to_rotate loc_logger_time_to_rotate
static size_t loc_write(File Filedes, const uchar *Buffer, size_t Count)
@ -553,22 +554,22 @@ static struct st_mysql_show_var audit_status[]=
{0,0,0}
};
#if defined(HAVE_PSI_INTERFACE) && !defined(FLOGGER_NO_PSI)
/* These belong to the service initialization */
#ifdef HAVE_PSI_INTERFACE
static PSI_mutex_key key_LOCK_operations;
static PSI_mutex_key key_LOCK_atomic;
static PSI_mutex_key key_LOCK_bigbuffer;
static PSI_mutex_info mutex_key_list[]=
{
{ &key_LOCK_operations, "SERVER_AUDIT_plugin::lock_operations",
PSI_FLAG_GLOBAL},
PSI_FLAG_GLOBAL}
#ifndef FLOGGER_NO_PSI
,
{ &key_LOCK_atomic, "SERVER_AUDIT_plugin::lock_atomic",
PSI_FLAG_GLOBAL},
{ &key_LOCK_bigbuffer, "SERVER_AUDIT_plugin::lock_bigbuffer",
PSI_FLAG_GLOBAL}
#endif /*FLOGGER_NO_PSI*/
};
#endif
static mysql_mutex_t lock_operations;
#endif /*HAVE_PSI_INTERFACE*/
static mysql_prlock_t lock_operations;
static mysql_mutex_t lock_atomic;
static mysql_mutex_t lock_bigbuffer;
@ -1319,19 +1320,41 @@ static void change_connection(struct connection_info *cn,
event->ip, event->ip_length);
}
/*
Write to the log
@param take_lock If set, take a read lock (or write lock on rotate).
If not set, the caller has a already taken a write lock
*/
static int write_log(const char *message, size_t len, int take_lock)
{
int result= 0;
if (take_lock)
flogger_mutex_lock(&lock_operations);
{
/* Start by taking a read lock */
mysql_prlock_rdlock(&lock_operations);
}
if (output_type == OUTPUT_FILE)
{
if (logfile &&
(is_active= (logger_write(logfile, message, len) == (int) len)))
goto exit;
++log_write_failures;
result= 1;
if (logfile)
{
my_bool allow_rotate= !take_lock; /* Allow rotate if caller write lock */
if (take_lock && logger_time_to_rotate(logfile))
{
/* We have to rotate the log, change above read lock to write lock */
mysql_prlock_unlock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
allow_rotate= 1;
}
if (!(is_active= (logger_write_r(logfile, allow_rotate, message, len) ==
(int) len)))
{
++log_write_failures;
result= 1;
}
}
}
else if (output_type == OUTPUT_SYSLOG)
{
@ -1339,9 +1362,8 @@ static int write_log(const char *message, size_t len, int take_lock)
syslog_priority_codes[syslog_priority],
"%s %.*s", syslog_info, (int) len, message);
}
exit:
if (take_lock)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
return result;
}
@ -1589,7 +1611,7 @@ static int do_log_user(const char *name, int len,
return 0;
if (take_lock)
flogger_mutex_lock(&lock_operations);
mysql_prlock_rdlock(&lock_operations);
if (incl_user_coll.n_users)
{
@ -1605,7 +1627,7 @@ static int do_log_user(const char *name, int len,
result= 1;
if (take_lock)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
return result;
}
@ -2496,11 +2518,11 @@ static int server_audit_init(void *p __attribute__((unused)))
servhost_len= (uint)strlen(servhost);
logger_init_mutexes();
#if defined(HAVE_PSI_INTERFACE) && !defined(FLOGGER_NO_PSI)
#ifdef HAVE_PSI_INTERFACE
if (PSI_server)
PSI_server->register_mutex("server_audit", mutex_key_list, 1);
#endif
flogger_mutex_init(key_LOCK_operations, &lock_operations, MY_MUTEX_INIT_FAST);
mysql_prlock_init(key_LOCK_operations, &lock_operations);
flogger_mutex_init(key_LOCK_operations, &lock_atomic, MY_MUTEX_INIT_FAST);
flogger_mutex_init(key_LOCK_operations, &lock_bigbuffer, MY_MUTEX_INIT_FAST);
@ -2588,7 +2610,7 @@ static int server_audit_deinit(void *p __attribute__((unused)))
closelog();
(void) free(big_buffer);
flogger_mutex_destroy(&lock_operations);
mysql_prlock_destroy(&lock_operations);
flogger_mutex_destroy(&lock_atomic);
flogger_mutex_destroy(&lock_bigbuffer);
@ -2699,7 +2721,7 @@ static void update_file_path(MYSQL_THD thd,
fprintf(stderr, "Log file name was changed to '%s'.\n", new_name);
if (!maria_55_started || !debug_server_started)
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
if (logging)
log_current_query(thd);
@ -2731,7 +2753,7 @@ static void update_file_path(MYSQL_THD thd,
file_path= path_buffer;
exit_func:
if (!maria_55_started || !debug_server_started)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
ADD_ATOMIC(internal_stop_logging, -1);
}
@ -2747,9 +2769,9 @@ static void update_file_rotations(MYSQL_THD thd __attribute__((unused)),
if (!logging || output_type != OUTPUT_FILE)
return;
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
logfile->rotations= rotations;
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
}
@ -2765,9 +2787,9 @@ static void update_file_rotate_size(MYSQL_THD thd __attribute__((unused)),
if (!logging || output_type != OUTPUT_FILE)
return;
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
logfile->size_limit= file_rotate_size;
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
}
@ -2812,7 +2834,7 @@ static void update_incl_users(MYSQL_THD thd,
char *new_users= (*(char **) save) ? *(char **) save : empty_str;
size_t new_len= strlen(new_users) + 1;
if (!maria_55_started || !debug_server_started)
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
mark_always_logged(thd);
if (new_len > sizeof(incl_user_buffer))
@ -2826,7 +2848,7 @@ static void update_incl_users(MYSQL_THD thd,
error_header();
fprintf(stderr, "server_audit_incl_users set to '%s'.\n", incl_users);
if (!maria_55_started || !debug_server_started)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
}
@ -2837,7 +2859,7 @@ static void update_excl_users(MYSQL_THD thd __attribute__((unused)),
char *new_users= (*(char **) save) ? *(char **) save : empty_str;
size_t new_len= strlen(new_users) + 1;
if (!maria_55_started || !debug_server_started)
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
mark_always_logged(thd);
if (new_len > sizeof(excl_user_buffer))
@ -2851,7 +2873,7 @@ static void update_excl_users(MYSQL_THD thd __attribute__((unused)),
error_header();
fprintf(stderr, "server_audit_excl_users set to '%s'.\n", excl_users);
if (!maria_55_started || !debug_server_started)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
}
@ -2864,7 +2886,7 @@ static void update_output_type(MYSQL_THD thd,
return;
ADD_ATOMIC(internal_stop_logging, 1);
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
if (logging)
{
log_current_query(thd);
@ -2878,7 +2900,7 @@ static void update_output_type(MYSQL_THD thd,
if (logging)
start_logging();
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
ADD_ATOMIC(internal_stop_logging, -1);
}
@ -2908,9 +2930,9 @@ static void update_syslog_priority(MYSQL_THD thd __attribute__((unused)),
if (syslog_priority == new_priority)
return;
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
mark_always_logged(thd);
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
error_header();
fprintf(stderr, "SysLog priority was changed from '%s' to '%s'.\n",
syslog_priority_names[syslog_priority],
@ -2929,7 +2951,7 @@ static void update_logging(MYSQL_THD thd,
ADD_ATOMIC(internal_stop_logging, 1);
if (!maria_55_started || !debug_server_started)
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
if ((logging= new_logging))
{
start_logging();
@ -2946,7 +2968,7 @@ static void update_logging(MYSQL_THD thd,
}
if (!maria_55_started || !debug_server_started)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
ADD_ATOMIC(internal_stop_logging, -1);
}
@ -2961,13 +2983,13 @@ static void update_mode(MYSQL_THD thd __attribute__((unused)),
ADD_ATOMIC(internal_stop_logging, 1);
if (!maria_55_started || !debug_server_started)
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
mark_always_logged(thd);
error_header();
fprintf(stderr, "Logging mode was changed from %d to %d.\n", mode, new_mode);
mode= new_mode;
if (!maria_55_started || !debug_server_started)
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
ADD_ATOMIC(internal_stop_logging, -1);
}
@ -2982,14 +3004,14 @@ static void update_syslog_ident(MYSQL_THD thd __attribute__((unused)),
syslog_ident= syslog_ident_buffer;
error_header();
fprintf(stderr, "SYSYLOG ident was changed to '%s'\n", syslog_ident);
flogger_mutex_lock(&lock_operations);
mysql_prlock_wrlock(&lock_operations);
mark_always_logged(thd);
if (logging && output_type == OUTPUT_SYSLOG)
{
stop_logging();
start_logging();
}
flogger_mutex_unlock(&lock_operations);
mysql_prlock_unlock(&lock_operations);
}