MDEV-18863: Galera SST scripts can't read [mysqldN] option groups

Some users and some scripts (for example, mysqld_multi.sh) use special
option groups with names like [mysqld1], [mysqld2], ..., [mysqldN].

But SST scripts can't currently fully support these option groups.
The only option group-related value it gets from the server is
--defaults-group-suffix, if that option was set for mysqld when
the server was started.

However, the SST scripts does not get told by the server to read
these option groups, so this means that the SST script will fail
to read options like innodb-data-home-dir when it is in a option
group like [mysqld1]...[mysqldN].

Moreover, SST scripts ignore many parameters that can be passed
to them explicitly and cannot transfer them further, for example,
to the input of mariabackup utility. Ideally, we want to transfer
all the parameters of the original mysqld call to utilities such
as mariabackup, however the SST script does not receive these
parameters from the server and therefore cannot transfer them to
mariabackup.

To correct these shortcomings, we need to transfer to the scripts
all of the parameters of the original mysqld call, and in the SST
scripts themselves provide for the transfer all of these parameters
to utilities such as mariabackup. To prevent these parameters from
mixing with the script's own parameters, they should be transferred
to SST script after the special option "--mysqld-args", followed by
the string argument with the original parameters, as it received by
the mysqld call at the time of launch (further all these parameters
will be passed to mariabackup, for example).

In addition, the SST scripts themselves must be refined so that
they can read the parameters from the user-selected group, not just
from the global mysqld configuration group. And also so that they
can receive the parameters (which important for their work) as
command-line arguments.

scripts/mysqld_multi.sh

@@ -308,7 +308,9 @@ sub report_mysqlds
 
 sub start_mysqlds()
 {
-  my (@groups, $com, $tmp, $i, @options, $j, $mysqld_found, $info_sent);
+  my (@groups, $com, $tmp, $i, @options, $j, $mysqld_found, $suffix_found, $info_sent);
+
+  $suffix_found= 0;
 
   if (!$opt_no_log)
   {
@@ -347,6 +349,10 @@ sub start_mysqlds()
         $options[$j]= quote_shell_word($options[$j]);
         $tmp.= " $options[$j]";
       }
+      elseif ("--defaults-group-suffix=" eq substr($options[$j], 0, 24))
+      {
+        $suffix_found= 1;
+      }
       else
       {
 	$options[$j]= quote_shell_word($options[$j]);
@@ -364,6 +370,12 @@ sub start_mysqlds()
     }
     $com.= $tmp;
 
+    if (!$suffix_found)
+    {
+      $com.= " --defaults-group-suffix=";
+      $com.= $groups[$i];
+    }
+
     if ($opt_wsrep_new_cluster) {
       $com.= " --wsrep-new-cluster";
     }

scripts/wsrep_sst_common.sh

@@ -28,7 +28,12 @@ WSREP_SST_OPT_PSWD=${WSREP_SST_OPT_PSWD:-}
 WSREP_SST_OPT_DEFAULT=""
 WSREP_SST_OPT_EXTRA_DEFAULT=""
 WSREP_SST_OPT_SUFFIX_DEFAULT=""
+WSREP_SST_OPT_SUFFIX_VALUE=""
+WSREP_SST_OPT_MYSQLD=""
 INNODB_DATA_HOME_DIR_ARG=""
+INNODB_LOG_GROUP_HOME_ARG=""
+INNODB_UNDO_DIR_ARG=""
+LOG_BIN_ARG=""
 
 while [ $# -gt 0 ]; do
 case "$1" in
@@ -83,6 +88,18 @@ case "$1" in
         readonly INNODB_DATA_HOME_DIR_ARG="$2"
         shift
         ;;
+    '--innodb-log-group-home-dir')
+        readonly INNODB_LOG_GROUP_HOME_ARG="$2"
+        shift
+        ;;
+    '--innodb-undo-directory')
+        readonly INNODB_UNDO_DIR_ARG="$2"
+        shift
+        ;;
+    '--log-bin')
+        readonly LOG_BIN_ARG="$2"
+        shift
+        ;;
     '--defaults-file')
         readonly WSREP_SST_OPT_DEFAULT="$1=$2"
         shift
@@ -93,6 +110,7 @@ case "$1" in
         ;;
     '--defaults-group-suffix')
         readonly WSREP_SST_OPT_SUFFIX_DEFAULT="$1=$2"
+        readonly WSREP_SST_OPT_SUFFIX_VALUE="$2"
         shift
         ;;
     '--host')
@@ -143,6 +161,46 @@ case "$1" in
         readonly WSREP_SST_OPT_GTID_DOMAIN_ID="$2"
         shift
         ;;
+    '--mysqld-args')
+        original_cmd=""
+        shift
+        while [ $# -gt 0 ]; do
+           option=${1%%=*}
+           if [ "$option" != "--defaults-file" ]; then
+              value=${1#*=}
+              case "$option" in
+                  '--innodb-data-home-dir')
+                      if [ -z "$INNODB_DATA_HOME_DIR_ARG" ]; then
+                          readonly INNODB_DATA_HOME_DIR_ARG="$value"
+                      fi
+                      ;;
+                  '--innodb-log-group-home-dir')
+                      if [ -z "$INNODB_LOG_GROUP_HOME_ARG" ]; then
+                          readonly INNODB_LOG_GROUP_HOME_ARG="$value"
+                      fi
+                      ;;
+                  '--innodb-undo-directory')
+                      if [ -z "$INNODB_UNDO_DIR_ARG" ]; then
+                          readonly INNODB_UNDO_DIR_ARG="$value"
+                      fi
+                      ;;
+                  '--log-bin')
+                      if [ -z "$LOG_BIN_ARG" ]; then
+                          readonly LOG_BIN_ARG="$value"
+                      fi
+                      ;;
+              esac
+              if [ -z "$original_cmd" ]; then
+                  original_cmd="$1"
+              else
+                  original_cmd+=" $1"
+              fi
+           fi
+           shift
+        done
+        readonly WSREP_SST_OPT_MYSQLD="$original_cmd"
+        break
+        ;;
     *) # must be command
        # usage
        # exit 1

scripts/wsrep_sst_mariabackup.sh

@@ -698,8 +698,7 @@ if [[ ${FORCE_FTWRL:-0} -eq 1 ]];then
     iopts+=" --no-backup-locks "
 fi
 
-
-INNOEXTRA=""
+INNOEXTRA=$WSREP_SST_OPT_MYSQLD
 
 INNODB_DATA_HOME_DIR=${INNODB_DATA_HOME_DIR:-""}
 # Try to set INNODB_DATA_HOME_DIR from the command line:
@@ -707,6 +706,9 @@ if [ ! -z "$INNODB_DATA_HOME_DIR_ARG" ]; then
     INNODB_DATA_HOME_DIR=$INNODB_DATA_HOME_DIR_ARG
 fi
 # if INNODB_DATA_HOME_DIR env. variable is not set, try to get it from my.cnf
+if [ -z "$INNODB_DATA_HOME_DIR" ]; then
+    INNODB_DATA_HOME_DIR=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-data-home-dir '')
+fi
 if [ -z "$INNODB_DATA_HOME_DIR" ]; then
     INNODB_DATA_HOME_DIR=$(parse_cnf --mysqld innodb-data-home-dir '')
 fi
@@ -827,7 +829,9 @@ then
             exit 93
         fi
 
-        if [[ -z $(parse_cnf --mysqld tmpdir "") && -z $(parse_cnf xtrabackup tmpdir "") ]];then 
+        if [[ -z $(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE tmpdir "") && \
+              -z $(parse_cnf --mysqld tmpdir "") && \
+              -z $(parse_cnf xtrabackup tmpdir "") ]]; then
             xtmpdir=$(mktemp -d)
             tmpopts=" --tmpdir=$xtmpdir "
             wsrep_log_info "Using $xtmpdir as xtrabackup temporary directory"
@@ -950,8 +954,24 @@ then
     [[ -n $SST_PROGRESS_FILE ]] && touch $SST_PROGRESS_FILE
 
     ib_home_dir=$INNODB_DATA_HOME_DIR
-    ib_log_dir=$(parse_cnf --mysqld innodb-log-group-home-dir "")
-    ib_undo_dir=$(parse_cnf --mysqld innodb-undo-directory "")
+
+    # Try to set ib_log_dir from the command line:
+    ib_log_dir=$INNODB_LOG_GROUP_HOME_ARG
+    if [ -z "$ib_log_dir" ]; then
+        ib_log_dir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-log-group-home-dir "")
+    fi
+    if [ -z "$ib_log_dir" ]; then
+        ib_log_dir=$(parse_cnf --mysqld innodb-log-group-home-dir "")
+    fi
+
+    # Try to set ib_undo_dir from the command line:
+    ib_undo_dir=$INNODB_UNDO_DIR_ARG
+    if [ -z "$ib_undo_dir" ]; then
+        ib_undo_dir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-undo-directory "")
+    fi
+    if [ -z "$ib_undo_dir" ]; then
+        ib_undo_dir=$(parse_cnf --mysqld innodb-undo-directory "")
+    fi
 
     stagemsg="Joiner-Recv"
 
@@ -1028,7 +1048,13 @@ then
             find $ib_home_dir $ib_log_dir $ib_undo_dir $DATA -mindepth 1 -prune -regex $cpat -o -exec rm -rfv {} 1>&2 \+
 	fi
 
-        tempdir=$(parse_cnf --mysqld log-bin "")
+        tempdir=$LOG_BIN_ARG
+        if [ -z "$tempdir" ]; then
+           tempdir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE log-bin "")
+        fi
+        if [ -z "$tempdir" ]; then
+            tempdir=$(parse_cnf --mysqld log-bin "")
+        fi
         if [[ -n ${tempdir:-} ]];then
             binlog_dir=$(dirname $tempdir)
             binlog_file=$(basename $tempdir)

scripts/wsrep_sst_rsync.sh

@@ -149,7 +149,14 @@ then
 fi
 
 WSREP_LOG_DIR=${WSREP_LOG_DIR:-""}
+# Try to set WSREP_LOG_DIR from the command line:
+if [ -z "$WSREP_LOG_DIR" ]; then
+    WSREP_LOG_DIR=$INNODB_LOG_GROUP_HOME_ARG
+fi
 # if WSREP_LOG_DIR env. variable is not set, try to get it from my.cnf
+if [ -z "$WSREP_LOG_DIR" ]; then
+    WSREP_LOG_DIR=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-log-group-home-dir '')
+fi
 if [ -z "$WSREP_LOG_DIR" ]; then
     WSREP_LOG_DIR=$(parse_cnf --mysqld innodb-log-group-home-dir '')
 fi
@@ -168,6 +175,9 @@ if [ ! -z "$INNODB_DATA_HOME_DIR_ARG" ]; then
     INNODB_DATA_HOME_DIR=$INNODB_DATA_HOME_DIR_ARG
 fi
 # if INNODB_DATA_HOME_DIR env. variable is not set, try to get it from my.cnf
+if [ -z "$INNODB_DATA_HOME_DIR" ]; then
+    INNODB_DATA_HOME_DIR=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-data-home-dir '')
+fi
 if [ -z "$INNODB_DATA_HOME_DIR" ]; then
     INNODB_DATA_HOME_DIR=$(parse_cnf --mysqld innodb-data-home-dir '')
 fi

sql/wsrep_sst.cc

@@ -648,17 +648,76 @@ static int sst_append_data_dir(wsp::env& env, const char* data_dir)
   return -env.error();
 }
 
+static size_t estimate_cmd_len (bool* extra_args)
+{
+  /*
+    The length of the area reserved for the control parameters
+    of the SST script (excluding the copying of the original
+    mysqld arguments):
+  */
+  size_t cmd_len= 4096;
+  bool extra= false;
+  /*
+    If mysqld was started with arguments, add them all:
+  */
+  if (orig_argc > 1)
+  {
+    for (int i = 1; i < orig_argc; i++)
+    {
+      cmd_len += strlen(orig_argv[i]);
+    }
+    extra = true;
+    cmd_len += strlen(WSREP_SST_OPT_MYSQLD);
+    /*
+      Add the separating spaces between arguments,
+      and one additional space before "--mysqld-args":
+    */
+    cmd_len += orig_argc;
+  }
+  *extra_args= extra;
+  return cmd_len;
+}
+
+static void copy_orig_argv (char* cmd_str)
+{
+  /*
+     If mysqld was started with arguments, copy them all:
+  */
+  if (orig_argc > 1)
+  {
+    size_t n = strlen(WSREP_SST_OPT_MYSQLD);
+    *cmd_str++ = ' ';
+    memcpy(cmd_str, WSREP_SST_OPT_MYSQLD, n * sizeof(char));
+    cmd_str += n;
+    for (int i = 1; i < orig_argc; i++)
+    {
+      char* arg= orig_argv[i];
+      *cmd_str++ = ' ';
+      n = strlen(arg);
+      memcpy(cmd_str, arg, n * sizeof(char));
+      cmd_str += n;
+    }
+    /*
+      Add a terminating null character (not counted in the length,
+      since we've overwritten the original null character which
+      was previously added by snprintf:
+    */
+    *cmd_str = 0;
+  }
+}
+
 static ssize_t sst_prepare_other (const char*  method,
                                   const char*  sst_auth,
                                   const char*  addr_in,
                                   const char** addr_out)
 {
-  int const cmd_len= 4096;
+  bool extra_args;
+  size_t const cmd_len= estimate_cmd_len(&extra_args);
   wsp::string cmd_str(cmd_len);
 
   if (!cmd_str())
   {
-    WSREP_ERROR("sst_prepare_other(): could not allocate cmd buffer of %d bytes",
+    WSREP_ERROR("sst_prepare_other(): could not allocate cmd buffer of %zd bytes",
                 cmd_len);
     return -ENOMEM;
   }
@@ -709,6 +768,9 @@ static ssize_t sst_prepare_other (const char*  method,
     return (ret < 0 ? ret : -EMSGSIZE);
   }
 
+  if (extra_args)
+    copy_orig_argv(cmd_str() + ret);
+
   wsp::env env(NULL);
   if (env.error())
   {
@@ -972,13 +1034,14 @@ static int sst_donate_mysqldump (const char*         addr,
   }
   memcpy(host, address.get_address(), address.get_address_len());
   int port= address.get_port();
-  int const cmd_len= 4096;
-  wsp::string  cmd_str(cmd_len);
+  bool extra_args;
+  size_t const cmd_len= estimate_cmd_len(&extra_args);
+  wsp::string cmd_str(cmd_len);
 
   if (!cmd_str())
   {
     WSREP_ERROR("sst_donate_mysqldump(): "
-                "could not allocate cmd buffer of %d bytes", cmd_len);
+                "could not allocate cmd buffer of %zd bytes", cmd_len);
     return -ENOMEM;
   }
 
@@ -1007,6 +1070,9 @@ static int sst_donate_mysqldump (const char*         addr,
     return (ret < 0 ? ret : -EMSGSIZE);
   }
 
+  if (extra_args)
+    copy_orig_argv(cmd_str() + ret);
+
   WSREP_DEBUG("Running: '%s'", cmd_str());
 
   ret= sst_run_shell (cmd_str(), env, 3);
@@ -1326,13 +1392,14 @@ static int sst_donate_other (const char*   method,
                              bool          bypass,
                              char**        env) // carries auth info
 {
-  int const cmd_len= 4096;
-  wsp::string  cmd_str(cmd_len);
+  bool extra_args;
+  size_t const cmd_len= estimate_cmd_len(&extra_args);
+  wsp::string cmd_str(cmd_len);
 
   if (!cmd_str())
   {
     WSREP_ERROR("sst_donate_other(): "
-                "could not allocate cmd buffer of %d bytes", cmd_len);
+                "could not allocate cmd buffer of %zd bytes", cmd_len);
     return -ENOMEM;
   }
 
@@ -1373,6 +1440,9 @@ static int sst_donate_other (const char*   method,
     return (ret < 0 ? ret : -EMSGSIZE);
   }
 
+  if (extra_args)
+    copy_orig_argv(cmd_str() + ret);
+
   if (!bypass && wsrep_sst_donor_rejects_queries) sst_reject_queries(FALSE);
 
   pthread_t tmp;

sql/wsrep_sst.h

@@ -32,6 +32,7 @@
 #define WSREP_SST_OPT_PARENT   "--parent"
 #define WSREP_SST_OPT_BINLOG   "--binlog"
 #define WSREP_SST_OPT_BINLOG_INDEX "--binlog-index"
+#define WSREP_SST_OPT_MYSQLD   "--mysqld-args"
 
 // mysqldump-specific options
 #define WSREP_SST_OPT_USER     "--user"