MXS-1141: maxbinlogcheck to replace an event with ignorable event

maxbinlogcheck utility can replace an event at pos with an ignorable
event

New option is -R, —replace

-R $pos

The -R needs -f as file will be modified

server/modules/routing/binlogrouter/blr.c

@@ -111,7 +111,6 @@ static int blr_handler_config(void *userdata, const char *section, const char *n
 static int blr_handle_config_item(const char *name, const char *value, ROUTER_INSTANCE *inst);
 static int blr_load_dbusers(const ROUTER_INSTANCE *router);
 static int blr_check_binlog(ROUTER_INSTANCE *router);
-int blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug);
 void blr_master_close(ROUTER_INSTANCE *);
 void blr_free_ssl_data(ROUTER_INSTANCE *inst);
 static void destroyInstance(MXS_ROUTER *instance);
@@ -2304,7 +2303,7 @@ static int blr_check_binlog(ROUTER_INSTANCE *router)
      * router->current_pos is the last event found.
      */
 
-    n = blr_read_events_all_events(router, 0, 0);
+    n = blr_read_events_all_events(router, NULL, 0);
 
     MXS_DEBUG("blr_read_events_all_events() ret = %i\n", n);
 

server/modules/routing/binlogrouter/blr.h

@@ -73,6 +73,7 @@ MXS_BEGIN_DECLS
 /* BINLOG_EVENT_LEN_OFFSET points to event_size in event_header */
 #define BINLOG_EVENT_LEN_OFFSET     9
 #define BINLOG_FATAL_ERROR_READING  1236
+#define BINLOG_DATA_TRUNCATED       2032
 
 /* Binlog Encryption */
 #define BINLOG_ENC_ALGO_NAME_LEN        13
@@ -638,6 +639,23 @@ typedef struct binlog_encryption_ctx
     char     *binlog_file;           /**< Current binlog file being encrypted */
 } BINLOG_ENCRYPTION_CTX;
 
+/**
+ * Holds information about:
+ * truncating a corrupted file
+ * or replace an event at specified pos
+ * or replace a transaction that start
+ * at specified pos
+ */
+
+typedef struct binlog_pos_fix
+{
+    bool        fix;            /**< Truncate file to last safe pos */
+    uint64_t    pos;            /**< Position of the event to be replaced
+                                 * by an Ignorable Event */
+    bool        replace_trx;    /**< Replace all events belonging to
+                                 * a transaction starting at pos */
+} BINLOG_FILE_FIX;
+
 /**
  * Defines and offsets for binlog encryption
  *
@@ -809,7 +827,7 @@ extern int blr_send_custom_error(DCB *, int, int, char *, char *, unsigned int);
 extern int blr_file_next_exists(ROUTER_INSTANCE *, ROUTER_SLAVE *);
 uint32_t extract_field(uint8_t *src, int bits);
 void blr_cache_read_master_data(ROUTER_INSTANCE *router);
-int blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug);
+int blr_read_events_all_events(ROUTER_INSTANCE *, const BINLOG_FILE_FIX *, int);
 int blr_save_dbusers(const ROUTER_INSTANCE *router);
 char    *blr_get_event_description(ROUTER_INSTANCE *router, uint8_t event);
 void blr_file_append(ROUTER_INSTANCE *router, char *file);

server/modules/routing/binlogrouter/blr_file.c

@@ -1297,13 +1297,15 @@ blr_file_next_exists(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave)
  *
  * Routine detects errors and pending transactions
  *
- * @param router  The router instance
+ * @param router    The router instance
- * @param fix     Whether to fix or not errors
+ * @param action    Whether to fix errors or blank events at pos
- * @param debug   Whether to enable or not the debug for events
+ * @param debug     Whether to enable or not the debug for events
- * @return        0 on success, >0 on failure
+ * @return          0 on success, >0 on failure
  */
 int
-blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug)
+blr_read_events_all_events(ROUTER_INSTANCE *router,
+                           const BINLOG_FILE_FIX *action,
+                           int debug)
 {
     unsigned long filelen = 0;
     struct stat statb;
@@ -1337,6 +1339,7 @@ blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug)
     BINLOG_EVENT_DESC fde_event;
     int fde_seen = 0;
     int start_encryption_seen = 0;
+    bool fix = action ? action->fix : false;
 
     memset(&first_event, '\0', sizeof(first_event));
     memset(&last_event, '\0', sizeof(last_event));
@@ -1973,6 +1976,27 @@ blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug)
             }
         }
 
+        /**
+         * Replace event at pos with an IGNORABLE EVENT
+         */
+
+        if (fix &&
+            action->pos > 4 &&
+            pos == action->pos)
+        {
+            char *event_desc = blr_get_event_description(router, hdr.event_type);
+
+            MXS_DEBUG("*** Filling event (%s) at pos %lu with an IGNORABLE EVENT\n",
+                      event_desc ? event_desc : "unknown",
+                      action->pos);
+
+            router->last_written = action->pos;
+            router->master_chksum = found_chksum;
+
+            /* Create and write Ingonrable event into binlog file at action->pos */
+            blr_write_special_event(router, pos, hdr.event_size, &hdr, BLRM_IGNORABLE);
+        }
+
         /* If MariaDB 10 compatibility:
          * check for MARIADB10_GTID_EVENT with flags
          * This marks the transaction starts instead of

server/modules/routing/binlogrouter/maxbinlogcheck.c

@@ -65,11 +65,12 @@ static struct option long_options[] =
     {"header",    no_argument, 0, 'H'},
     {"key_file",  required_argument, 0, 'K'},
     {"aes_algo",  required_argument, 0, 'A'},
+    {"replace",   required_argument, 0, 'R'},
     {"help",      no_argument, 0, '?'},
     {0, 0, 0, 0}
 };
 
-char *binlog_check_version = "2.1.0";
+char *binlog_check_version = "2.2.0";
 
 int
 maxscale_uptime()
@@ -81,14 +82,14 @@ int main(int argc, char **argv)
 {
     int option_index = 0;
     int debug_out = 0;
-    int fix_file = 0;
     int mariadb10_compat = 0;
     char *key_file = NULL;
     char *aes_algo = NULL;
     int report_header = 0;
     char c;
+    BINLOG_FILE_FIX binlog_file = {0, false, false};
 
-    while ((c = getopt_long(argc, argv, "dVfMHK:A:?", long_options, &option_index)) >= 0)
+    while ((c = getopt_long(argc, argv, "dVfMHK:A:R:?", long_options, &option_index)) >= 0)
     {
         switch (c)
         {
@@ -103,7 +104,7 @@ int main(int argc, char **argv)
             exit(EXIT_SUCCESS);
             break;
         case 'f':
-            fix_file = 1;
+            binlog_file.fix = true;
             break;
         case 'M':
             mariadb10_compat = 1;
@@ -114,6 +115,9 @@ int main(int argc, char **argv)
         case 'A':
             aes_algo = optarg;
             break;
+        case 'R':
+            binlog_file.pos = atol(optarg);
+            break;
         case '?':
             printUsage(*argv);
             exit(optopt ? EXIT_FAILURE : EXIT_SUCCESS);
@@ -162,7 +166,7 @@ int main(int argc, char **argv)
         exit(EXIT_FAILURE);
     }
 
-    int fd = open(path, fix_file ? O_RDWR : O_RDONLY, 0666);
+    int fd = open(path, binlog_file.fix ? O_RDWR : O_RDONLY, 0666);
     if (fd == -1)
     {
         printf("ERROR: Failed to open binlog file %s: %s.\n",
@@ -203,7 +207,7 @@ int main(int argc, char **argv)
     MXS_NOTICE("Checking %s (%s), size %lu bytes", path, inst->binlog_name, filelen);
 
     /* read binary log */
-    int ret = blr_read_events_all_events(inst, fix_file, debug_out | report_header);
+    int ret = blr_read_events_all_events(inst, &binlog_file, debug_out | report_header);
 
     mxs_log_flush_sync();
 
@@ -236,7 +240,7 @@ printUsage(const char *progname)
     printVersion(progname);
 
     printf("The MaxScale binlog check utility.\n\n");
-    printf("Usage: %s [-f] [-d] [-v] [<binlog file>]\n\n", progname);
+    printf("Usage: %s [-f] [-M] [-d] [-V] [-H] [-K file] [-A algo] [-R pos] [<binlog file>]\n\n", progname);
     printf("  -f|--fix          Fix binlog file, require write permissions (truncate)\n");
     printf("  -d|--debug        Print debug messages\n");
     printf("  -M|--mariadb10    MariaDB 10 binlog compatibility\n");
@@ -244,6 +248,7 @@ printUsage(const char *progname)
     printf("  -K|--key_file     AES Key file for MariaDB 10.1 binlog file decryption\n");
     printf("  -A|--aes_algo     AES Algorithm for MariaDB 10.1 binlog file decryption (default=AES_CBC, AES_CTR)\n");
     printf("  -H|--header       Print content of binlog event header\n");
+    printf("  -R|--replace      Replace the event at pos with an IGNORABLE EVENT\n");
     printf("  -?|--help         Print this help text\n");
 }