7.11. Creating the passwd, group, and log Files

#### Cross-Compiled Linux From Scratch - Version 1.0.0rc1-MIPS64-Multilib

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# 7.11. 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 must be relevant entries in the `${LFS}/etc/passwd` and `${LFS}/etc/group` files.

Create the `${LFS}/etc/passwd` file by running the following command:

    cat > ${LFS}/etc/passwd << "EOF"
    root::0:0:root:/root:/bin/bash
    bin:x:1:1:bin:/bin:/bin/false
    daemon:x:2:2:daemon:/sbin:/bin/false
    adm:x:3:4:adm:/var/adm:/bin/false
    lp:x:10:18:lp:/var/spool/lp:/bin/false
    mail:x:30:30:mail:/var/spool/mail:/bin/false
    news:x:31:31:news:/var/spool/news:/bin/false
    uucp:x:32:32:uucp:/var/spool/uucp:/bin/false
    operator:x:50:0:operator:/root:/bin/bash
    postmaster:x:51:30:postmaster:/var/spool/mail:/bin/false
    nobody:x:65534:65534:nobody:/:/bin/false
    EOF

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

Create the `${LFS}/etc/group` file by running the following command:

    cat > ${LFS}/etc/group << "EOF"
    root::0:root
    bin::1:root,bin,daemon
    daemon::2:root,bin,daemon
    sys::3:root,bin,adm
    adm::4:root,adm,daemon
    kmem::5:
    utmp::6:
    tty::10:
    video::11:root
    console::12:
    disk::13:root,adm
    floppy::14:root
    cdrom::15:
    cdrw::16:
    tape::17:root
    lp::18:lp
    usb::19:
    audio::20:
    dialout::21:root
    mail::30:mail
    news::31:news
    uucp::32:uucp
    users::100:
    nogroup::65533:
    nobody::65534:
    EOF

The created groups are not part of any standard—they are groups decided on in part by the requirements of the Udev 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.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 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 ${LFS}/var/run/utmp ${LFS}/var/log/{btmp,lastlog,wtmp}
    chmod -v 664 ${LFS}/var/run/utmp ${LFS}/var/log/lastlog
    chmod -v 600 ${LFS}/var/log/btmp

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

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