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6.7. Creating the passwd, group, and log Files

In order for user root to be able to login and for the name “root” to be recognized, there need to be relevant entries in the /etc/passwd and /etc/group files.

Create the /etc/passwd file by running the following command:

cat > /etc/passwd << "EOF"
root:x:0:0:root:/root:/bin/bash
EOF

The actual password for root (the “x” used here is just a placeholder) will be set later.

Create the /etc/group file by running the following command:

cat > /etc/group << "EOF"
root:x:0:
bin:x:1:
sys:x:2:
kmem:x:3:
tty:x:4:
tape:x:5:
daemon:x:6:
floppy:x:7:
disk:x:8:
lp:x:9:
dialout:x:10:
audio:x:11:
video:x:12:
utmp:x:13:
usb:x:14:
EOF

The created groups are not part of any standard—they are some of the groups that the Udev configuration will be using in the next section. The Linux Standard Base (LSB, available at http://www.linuxbase.org) recommends only that, besides the group “root” with a Group ID (GID) of 0, a group “bin” with a GID of 1 be present. All other group names and GIDs can be chosen freely by the system administrator since well-written packages do not depend on GID numbers, but rather use the group's name.

To remove the “I have no name!” prompt, start a new shell. Since a full Glibc was installed in Chapter 5 and the /etc/passwd and /etc/group files have been created, user name and group name resolution will now work.

exec /tools/bin/bash --login +h

Note the use of the +h directive. This tells bash not to use its internal path hashing. Without this directive, bash would remember the paths to binaries it has executed. In order to use the newly compiled binaries as soon as they are installed, turn off this function for the duration of this chapter.

The login, agetty, and init programs (and others) use a number of log files to record information such as who was logged into the system and when. However, these programs will not write to the log files if they do not already exist. Initialize the log files and give them proper permissions:

touch /var/run/utmp /var/log/{btmp,lastlog,wtmp}
chgrp utmp /var/run/utmp /var/log/lastlog
chmod 664 /var/run/utmp /var/log/lastlog

The /var/run/utmp file records the users that are currently logged in. The /var/log/wtmp file records all logins and logouts. The /var/log/lastlog file records when each user last logged in. The /var/log/btmp file records the bad login attempts.