Final answer:
The final permissions for the file 'examfile' created with a umask of 0126 will be read and write for the user, and read-only for both the group and others, resulting in an octal permission set of 0644.
Step-by-step explanation:
The question asks about the resultant file permissions after a file is created with a specific umask value and a set of permissions using the open system call in a UNIX-like operating system.
When a file is created, the system's umask value is used to determine which permissions will not be set. To calculate the final permissions of the file, we start with the requested permissions and then apply the umask value.
Requested permissions (as per the open call):
- User: read and write (rw-)
- Group: read and write (rw-)
- Others: read (r--)
The umask value is 0126, which in binary is:
- User: 000 (---)
- Group: 010 (w-)
- Others: 110 (-w-)
To determine the effective permissions, we subtract the umask from the requested permissions:
- User: rw- minus --- = rw-
- Group: rw- minus w- = r--
- Others: r-- minus -w- = r--
Therefore, the final permissions for the file examfile will be:
- User: read and write (rw-)
- Group: read only (r--)
- Others: read only (r--)
The octal representation of these permissions is 0644.