Previous Home Next

7.6. Create essential system files

Create baseline compatibility links, host identity files, account databases, temporary directories, and initial log files inside chroot.

Goal: create mtab, hosts, passwd, and group, then add a test user, create temporary directories, and initialize core log files with usable default modes. If ownership tools are not yet available in the chroot, defer the utmp group assignment until later.

Run these commands as root inside chroot.

Create `mtab` compatibility link

ln -s /system/processes/self/mounts /system/configuration/mtab

Create `hosts`

printf '127.0.0.1  localhost %s\n::1        localhost\n' "<your_hostname>" > /system/configuration/hosts

Create `passwd`

printf '%s\n' \
"root:x:0:0:root:/system/charlie:/bin/oksh" \
"bin:x:1:1:bin:/dev/null:/system/binaries/false" \
"daemon:x:6:6:Daemon User:/dev/null:/system/binaries/false" \
"messagebus:x:18:18:D-Bus Message Daemon User:/run/dbus:/system/binaries/false" \
"uuidd:x:80:80:UUID Generation Daemon User:/dev/null:/system/binaries/false" \
"nobody:x:65534:65534:Unprivileged User:/dev/null:/system/binaries/false" \
> /system/configuration/passwd

Create `group`

printf '%s\n' \
"root:x:0:" \
"bin:x:1:daemon" \
"sys:x:2:" \
"kmem:x:3:" \
"tape:x:4:" \
"tty: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:" \
"clock:x:14:" \
"cdrom:x:15:" \
"adm:x:16:" \
"messagebus:x:18:" \
"input:x:24:" \
"mail:x:34:" \
"kvm:x:61:" \
"uuidd:x:80:" \
"wheel:x:97:" \
"users:x:999:" \
"nogroup:x:65534:" \
> /system/configuration/group

Add test user and create its home

echo "tester:x:101:101::/system/users/tester:/bin/oksh" >> /system/configuration/passwd
echo "tester:x:101:" >> /system/configuration/group
mkdir -p /system/users/tester

Create temporary directories

install -d -m 1777 /tmp /system/variable/tmp

Initialize core log files

mkdir -p /system/variable/log

touch /system/variable/log/btmp \
      /system/variable/log/lastlog \
      /system/variable/log/faillog \
      /system/variable/log/wtmp

chmod 664 /system/variable/log/lastlog
chmod 600 /system/variable/log/btmp

Quick verification

ls -l /system/configuration/hosts \
      /system/configuration/passwd \
      /system/configuration/group \
      /system/configuration/mtab

grep '^tester:' /system/configuration/passwd /system/configuration/group

ls -ld /tmp /system/variable/tmp

ls -l /system/variable/log/btmp \
      /system/variable/log/lastlog \
      /system/variable/log/faillog \
      /system/variable/log/wtmp

Command Explanations

ln -s /system/processes/self/mounts /system/configuration/mtab: Provides an mtab compatibility path backed by the kernel's live mount table.
printf ... > /system/configuration/hosts: Writes a minimal hosts file with localhost and the chosen hostname.
printf ... > /system/configuration/passwd: Creates the base user account database for root and system users.
printf ... > /system/configuration/group: Creates the base group database with standard administrative and device groups.
echo "tester:..." >> ...: Adds the optional tester user and group entries for non-root checks.
mkdir -p /system/users/tester: Creates the tester account home directory.
install -d -m 1777 /tmp /system/variable/tmp: Creates the root temporary directory and the backing directory for /var/tmp with world-writable sticky permissions.
mkdir -p /system/variable/log and touch ...: Creates the initial login/accounting log files expected by user-management tools.
chmod 664 and chmod 600: Set log-file permissions so public status logs and private login-failure logs have appropriate access.
ls -l and grep: Verify that the expected configuration and account files exist after creation.