Windows Internals covering windows server 2008 and windows vista- P4: In this chapter, we’ll introduce the key Microsoft Windows operating system concepts and terms we’ll be using throughout this book, such as the Windows API, processes, threads, virtual memory, kernel mode and user mode, objects, handles, security, and the registry. | taele 3-6 Object Header Fields Field Handle count Purpose Maintains a count of the nu mber of currently opened handles to the object. Pointer count Maintains a count of the nu mber of references to the object including one reference for each handle . Kernel-mode components can reference an object by pointer without using a handle. Security descriptor Determines who can use the object and what they can do with it Note that unnamed objects by definition cannot have security. Object type Points to a type object that contains attributes common to objects of this type. Subheader offsets Negative offsets to the optional subheader structures described in Table 3-7 except for the creator information subheader which if present always precedes the object header. Flags Characteristics and object attributes for the object. See Table 3-9 for a list of all the object flags In addition to the object header which contains information that applies to any kind of object the subheaders contain optional information regarding specific aspects of the object. Note that these structures are located at a variable offset from the top of the object header the value of which is stored in the object header itself except as mentioned above for creator information . If any of these offsets is 0 the object manager assumes that no subheader is associated with that offset. In the case of creator information a value in the object header flags determines whether the subheader is present. See Table 3-9 for information about these flags. table 3-7 Optional Object Subheaders Name Name information Purpose Contains the object name responsible for making an object visible to other processes for sharing and a pointer to the object directory which provides the hierarchical structure in which the object names are stored Location Object header NamelnfoOffset Quota information Lists the resource charges levied against a process when it opens a handle to the object Object header QuotalnfoOffset Handle .
