Chapter 15: File Attributes

In this chapter, we investigate various attributes of files (file metadata). We begin with a description of the stat() system call, which returns a structure containing many of these attributes, including file timestamps, file ownership, and file permissions. We then go on to look at various system calls used to change these attributes. (The discussion of file permissions continues in Chapter 16, where we look at access control lists.) We conclude the chapter with a discussion of i-node flags (also known as ext2 extended file attributes), which control various aspects of the treatment of files by the kernel.

15 File Attributes
15.1 Retrieving File Information: stat()
15.2 File Timestamps
        15.2.1 Changing File Timestamps with utime() and utimes()
        15.2.2 Changing File Timestamps with utimensat() and futimens()
15.3 File Ownership
        15.3.1 Ownership of New Files
        15.3.2 Changing File Ownership: chown(), fchown(), and lchown()
15.4 File Permissions
        15.4.1 Permissions on Regular Files
        15.4.2 Permissions on Directories
        15.4.3 Permission Checking Algorithm
        15.4.4 Checking File Accessibility: access()
        15.4.5 Set-user-ID, Set-group-ID, and Sticky Bits
        15.4.6 The Process File Mode Creation Mask: umask()
        15.4.7 Changing File Permissions: chmod() and fchmod()
15.5 I-node Flags (ext2 Extended File Attributes)
15.6 Summary
15.7 Exercises