db: Add helper for escaping strings and use it

src/zm_db.cpp

@@ -267,3 +267,15 @@ void zmDbQueue::push(std::string &&sql) {
   mQueue.push(std::move(sql));
   mCondition.notify_all();
 }
+
+std::string zmDbEscapeString(const std::string& to_escape) {
+  // According to docs, size of safer_whatever must be 2 * length + 1
+  // due to unicode conversions + null terminator.
+  std::string escaped((to_escape.length() * 2) + 1, '\0');
+
+
+  size_t escaped_len = mysql_real_escape_string(&dbconn, &escaped[0], to_escape.c_str(), to_escape.length());
+  escaped.resize(escaped_len);
+
+  return escaped;
+}

src/zm_db.h

@@ -78,4 +78,6 @@ int zmDbDoUpdate(const char *query);
 MYSQL_RES * zmDbFetch(const char *query);
 zmDbRow *zmDbFetchOne(const char *query);
 
+std::string zmDbEscapeString(const std::string& to_escape);
+
 #endif // ZM_DB_H

src/zm_event.cpp

@@ -402,12 +402,9 @@ void Event::updateNotes(const StringSetMap &newNoteSetMap) {
       Error("Unable to execute sql '%s': %s", sql, mysql_stmt_error(stmt));
     }
 #else
-    char sql[ZM_SQL_LGE_BUFSIZ];
-    static char escapedNotes[ZM_SQL_MED_BUFSIZ];
+    std::string escaped_notes = zmDbEscapeString(notes);
 
-    mysql_real_escape_string(&dbconn, escapedNotes, notes.c_str(), notes.length());
-
-    snprintf(sql, sizeof(sql), "UPDATE `Events` SET `Notes` = '%s' WHERE `Id` = %" PRIu64, escapedNotes, id);
+    std::string sql = stringtf("UPDATE `Events` SET `Notes` = '%s' WHERE `Id` = %" PRIu64, escaped_notes.c_str(), id);
     dbQueue.push(std::move(sql));
 #endif
   }  // end if update

src/zm_logger.cpp

@@ -518,11 +518,7 @@ void Logger::logPrint(bool hex, const char *filepath, int line, int level, const
 
   if (level <= mDatabaseLevel) {
     if (zmDbConnected) {
-      int syslogSize = syslogEnd - syslogStart;
-      std::string escapedString;
-      escapedString.resize((syslogSize * 2) + 1);
-      mysql_real_escape_string(&dbconn, &escapedString[0], syslogStart, syslogSize);
-      escapedString.resize(std::strlen(escapedString.c_str()));
+      std::string escapedString = zmDbEscapeString({syslogStart, syslogEnd});
 
       std::string sql_string = stringtf(
           "INSERT INTO `Logs` "

src/zm_user.cpp

@@ -85,15 +85,7 @@ bool User::canAccess(int monitor_id) {
 // Function to load a user from username and password
 // Please note that in auth relay mode = none, password is NULL
 User *zmLoadUser(const char *username, const char *password) {
-  int username_length = strlen(username);
-
-  // According to docs, size of safer_whatever must be 2*length+1
-  // due to unicode conversions + null terminator.
-  std::string escaped_username((username_length * 2) + 1, '\0');
-
-
-  size_t escaped_len = mysql_real_escape_string(&dbconn, &escaped_username[0], username, username_length);
-  escaped_username.resize(escaped_len);
+  std::string escaped_username = zmDbEscapeString(username);
 
   std::string sql = stringtf("SELECT `Id`, `Username`, `Password`, `Enabled`,"
                              " `Stream`+0, `Events`+0, `Control`+0, `Monitors`+0, `System`+0,"