1 files changed, 56 insertions, 0 deletions
diff --git a/mysqld-wait-ready b/mysqld-wait-ready
new file mode 100644
index 0000000..9e5d3e4
--- /dev/null
+++ b/mysqld-wait-ready
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+# This script waits for mysqld to be ready to accept connections
+# (which can be many seconds or even minutes after launch, if there's
+# a lot of crash-recovery work to do).
+# Running this as ExecStartPost is useful so that services declared as
+# "After mysqld" won't be started until the database is really ready.
+
+# Service file passes us the daemon's PID (actually, mysqld_safe's PID)
+daemon_pid="$1"
+
+# extract value of a MySQL option from config files
+# Usage: get_mysql_option SECTION VARNAME DEFAULT
+# result is returned in $result
+# We use my_print_defaults which prints all options from multiple files,
+# with the more specific ones later; hence take the last match.
+get_mysql_option(){
+	result=`/usr/bin/my_print_defaults "$1" | sed -n "s/^--$2=//p" | tail -n 1`
+	if [ -z "$result" ]; then
+	    # not found, use default
+	    result="$3"
+	fi
+}
+
+# Defaults here had better match what mysqld_safe will default to
+get_mysql_option mysqld datadir "/var/lib/mysql"
+datadir="$result"
+get_mysql_option mysqld socket "/var/lib/mysql/mysql.sock"
+socketfile="$result"
+
+# Wait for the server to come up or for the mysqld process to disappear
+ret=0
+while /bin/true; do
+	RESPONSE=`/usr/bin/mysqladmin --no-defaults --socket="$socketfile" --user=UNKNOWN_MYSQL_USER ping 2>&1`
+	mret=$?
+	if [ $mret -eq 0 ]; then
+	    break
+	fi
+	# exit codes 1, 11 (EXIT_CANNOT_CONNECT_TO_SERVICE) are expected,
+	# anything else suggests a configuration error
+	if [ $mret -ne 1 -a $mret -ne 11 ]; then
+	    ret=1
+	    break
+	fi
+	# "Access denied" also means the server is alive
+	echo "$RESPONSE" | grep -q "Access denied for user" && break
+
+	# Check process still exists
+	if ! /bin/kill -0 $daemon_pid 2>/dev/null; then
+	    ret=1
+	    break
+	fi
+	sleep 1
+done
+
+exit $ret