In order for user root to be able to
login and for the name “root”
to be recognized, there must 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/bashbin:x:1:1:/bin:/bin/falsedaemon:x:2:6:/sbin:/bin/falsemessagebus:x:27:27:D-Bus Message Daemon User:/dev/null:/bin/falsenobody:x:65534:65533:Unprivileged User:/dev/null:/bin/falseEOF
The actual password for root (the
“x” used here is just a
placeholder) will be set later.
Additional users you may want to add if not already included:
adm:x:3:16:adm:/var/adm:/bin/false
Was used for programs that performed administrative tasks.
lp:x:10:9:lp:/var/spool/lp:/bin/false
Used by programs for printing
mail:x:30:30:mail:/var/mail:/bin/false
Often used by email programs
messagebus:x:27:27:D-Bus
Message Daemon User:/dev/null:/bin/false
Used by the D-Bus systemwide message bus
news:x:31:31:news:/var/spool/news:/bin/false
Often used for network news servers
operator:x:50:0:operator:/root:/bin/bash
Often used to allow system operators to access the system
postmaster:x:51:30:postmaster:/var/spool/mail:/bin/false
Generally used as an account that receives all the information of troubles with the mail server
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:5:
tape:x:4:
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:
cdrom:x:15:
adm:x:16:
messagebus:x:27:
mail:x:30:
wheel:x:39:
nogroup:x:65533:
EOF
Additional groups you may want to add if not already included:
console:x:17:
This group has direct access to the console
cdrw:x:18:
This group is allowed to use the CDRW drive
messagebus:x:27:
User for D-Bus
news:x:31:news
Used by Network News Servers
users:x:1000:
The default GID used by shadow for new users
nobody:x:65533:
This is used by NFS
The created groups are not part of any standard—they are groups decided on in part by the requirements of the Systemd configuration in the final system, and in part by common convention employed by a number of existing Linux distributions. The Linux Standard Base (LSB, available at http://www.linuxfoundation.org/collaborate/workgroups/lsb) 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 programs do not depend on GID numbers, but rather use the group's name.
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/log/{btmp,faillog,lastlog,wtmp}
chgrp -v utmp /var/log/{faillog,lastlog}
chmod -v 664 /var/log/{faillog,lastlog}
chmod -v 600 /var/log/btmp
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.
To remove the “I have no
name!” prompt, start a new shell. Since a full Glibc was
installed in Constructing
Cross-Compile Tools 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. To ensure the use of the newly compiled
binaries as soon as they are installed, the +h directive will be used for the
duration of the next chapters.