open

      int fd = open("blookus", O_RDONLY);

• So the kernel has the directory open already

• It scans through the directory looking for blookus

        ...
        MAKE_SLIDES          802886
        blookus              142857
        Makefile             802887
        ...

• If it doesn't find it, the result is EEXIST

• Otherwise, it has the inode for blookus

• It checks the permissions in the inode

• If no good, the result is EACCESS

• Otherwise, it saves the inode

• Makes a new entry in the file pointer table with offset 0

• Makes a new entry in the open file table

• It uses the first free slot, say #37

• Then the open call returns the value 37

Next

Copyright © 2007 M. J. Dominus