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kumquat-buildroot/support/scripts/mkusers
Danomi Manchego 1ac9d83f55 mkusers: fix spelling in intro comment 
Signed-off-by: Danomi Manchego <danomimanchego123@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2016-12-20 09:32:06 +01:00

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#!/usr/bin/env bash
set -e
myname="${0##*/}"
#----------------------------------------------------------------------------
# Configurable items
MIN_UID=1000
MAX_UID=1999
MIN_GID=1000
MAX_GID=1999
# No more is configurable below this point
#----------------------------------------------------------------------------
#----------------------------------------------------------------------------
error() {
local fmt="${1}"
shift
printf "%s: " "${myname}" >&2
printf "${fmt}" "${@}" >&2
}
fail() {
error "$@"
exit 1
}
#----------------------------------------------------------------------------
if [ ${#} -ne 2 ]; then
fail "usage: %s USERS_TABLE TARGET_DIR\n"
fi
USERS_TABLE="${1}"
TARGET_DIR="${2}"
shift 2
PASSWD="${TARGET_DIR}/etc/passwd"
SHADOW="${TARGET_DIR}/etc/shadow"
GROUP="${TARGET_DIR}/etc/group"
# /etc/gshadow is not part of the standard skeleton, so not everybody
# will have it, but some may have it, and its content must be in sync
# with /etc/group, so any use of gshadow must be conditional.
GSHADOW="${TARGET_DIR}/etc/gshadow"
# We can't simply source ${BR2_CONFIG} as it may contains constructs
# such as:
# BR2_DEFCONFIG="$(CONFIG_DIR)/defconfig"
# which when sourced from a shell script will eventually try to execute
# a command named 'CONFIG_DIR', which is plain wrong for virtually every
# systems out there.
# So, we have to scan that file instead. Sigh... :-(
PASSWD_METHOD="$( sed -r -e '/^BR2_TARGET_GENERIC_PASSWD_METHOD="(.*)"$/!d;' \
-e 's//\1/;' \
"${BR2_CONFIG}" \
)"
#----------------------------------------------------------------------------
get_uid() {
local username="${1}"
awk -F: -v username="${username}" \
'$1 == username { printf( "%d\n", $3 ); }' "${PASSWD}"
}
#----------------------------------------------------------------------------
get_ugid() {
local username="${1}"
awk -F: -v username="${username}" \
'$1 == username { printf( "%d\n", $4 ); }' "${PASSWD}"
}
#----------------------------------------------------------------------------
get_gid() {
local group="${1}"
awk -F: -v group="${group}" \
'$1 == group { printf( "%d\n", $3 ); }' "${GROUP}"
}
#----------------------------------------------------------------------------
get_username() {
local uid="${1}"
awk -F: -v uid="${uid}" \
'$3 == uid { printf( "%s\n", $1 ); }' "${PASSWD}"
}
#----------------------------------------------------------------------------
get_group() {
local gid="${1}"
awk -F: -v gid="${gid}" \
'$3 == gid { printf( "%s\n", $1 ); }' "${GROUP}"
}
#----------------------------------------------------------------------------
get_ugroup() {
local username="${1}"
local ugid
ugid="$( get_ugid "${username}" )"
if [ -n "${ugid}" ]; then
get_group "${ugid}"
fi
}
#----------------------------------------------------------------------------
# Sanity-check the new user/group:
# - check the gid is not already used for another group
# - check the group does not already exist with another gid
# - check the user does not already exist with another gid
# - check the uid is not already used for another user
# - check the user does not already exist with another uid
# - check the user does not already exist in another group
check_user_validity() {
local username="${1}"
local uid="${2}"
local group="${3}"
local gid="${4}"
local _uid _ugid _gid _username _group _ugroup
_group="$( get_group "${gid}" )"
_gid="$( get_gid "${group}" )"
_ugid="$( get_ugid "${username}" )"
_username="$( get_username "${uid}" )"
_uid="$( get_uid "${username}" )"
_ugroup="$( get_ugroup "${username}" )"
if [ "${username}" = "root" ]; then
fail "invalid username '%s\n'" "${username}"
fi
if [ ${gid} -lt -1 -o ${gid} -eq 0 ]; then
fail "invalid gid '%d' for '%s'\n" ${gid} "${username}"
elif [ ${gid} -ne -1 ]; then
# check the gid is not already used for another group
if [ -n "${_group}" -a "${_group}" != "${group}" ]; then
fail "gid '%d' for '%s' is already used by group '%s'\n" \
${gid} "${username}" "${_group}"
fi
# check the group does not already exists with another gid
# Need to split the check in two, otherwise '[' complains it
# is missing arguments when _gid is empty
if [ -n "${_gid}" ] && [ ${_gid} -ne ${gid} ]; then
fail "group '%s' for '%s' already exists with gid '%d' (wants '%d')\n" \
"${group}" "${username}" ${_gid} ${gid}
fi
# check the user does not already exists with another gid
# Need to split the check in two, otherwise '[' complains it
# is missing arguments when _ugid is empty
if [ -n "${_ugid}" ] && [ ${_ugid} -ne ${gid} ]; then
fail "user '%s' already exists with gid '%d' (wants '%d')\n" \
"${username}" ${_ugid} ${gid}
fi
fi
if [ ${uid} -lt -1 -o ${uid} -eq 0 ]; then
fail "invalid uid '%d' for '%s'\n" ${uid} "${username}"
elif [ ${uid} -ne -1 ]; then
# check the uid is not already used for another user
if [ -n "${_username}" -a "${_username}" != "${username}" ]; then
fail "uid '%d' for '%s' already used by user '%s'\n" \
${uid} "${username}" "${_username}"
fi
# check the user does not already exists with another uid
# Need to split the check in two, otherwise '[' complains it
# is missing arguments when _uid is empty
if [ -n "${_uid}" ] && [ ${_uid} -ne ${uid} ]; then
fail "user '%s' already exists with uid '%d' (wants '%d')\n" \
"${username}" ${_uid} ${uid}
fi
fi
# check the user does not already exist in another group
if [ -n "${_ugroup}" -a "${_ugroup}" != "${group}" ]; then
fail "user '%s' already exists with group '%s' (wants '%s')\n" \
"${username}" "${_ugroup}" "${group}"
fi
return 0
}
#----------------------------------------------------------------------------
# Generate a unique GID for given group. If the group already exists,
# then simply report its current GID. Otherwise, generate the lowest GID
# that is:
# - not 0
# - comprised in [MIN_GID..MAX_GID]
# - not already used by a group
generate_gid() {
local group="${1}"
local gid
gid="$( get_gid "${group}" )"
if [ -z "${gid}" ]; then
for(( gid=MIN_GID; gid<=MAX_GID; gid++ )); do
if [ -z "$( get_group "${gid}" )" ]; then
break
fi
done
if [ ${gid} -gt ${MAX_GID} ]; then
fail "can not allocate a GID for group '%s'\n" "${group}"
fi
fi
printf "%d\n" "${gid}"
}
#----------------------------------------------------------------------------
# Add a group; if it does already exist, remove it first
add_one_group() {
local group="${1}"
local gid="${2}"
local _f
# Generate a new GID if needed
if [ ${gid} -eq -1 ]; then
gid="$( generate_gid "${group}" )"
fi
# Remove any previous instance of this group, and re-add the new one
sed -i -e '/^'"${group}"':.*/d;' "${GROUP}"
printf "%s:x:%d:\n" "${group}" "${gid}" >>"${GROUP}"
# Ditto for /etc/gshadow if it exists
if [ -f "${GSHADOW}" ]; then
sed -i -e '/^'"${group}"':.*/d;' "${GSHADOW}"
printf "%s:*::\n" "${group}" >>"${GSHADOW}"
fi
}
#----------------------------------------------------------------------------
# Generate a unique UID for given username. If the username already exists,
# then simply report its current UID. Otherwise, generate the lowest UID
# that is:
# - not 0
# - comprised in [MIN_UID..MAX_UID]
# - not already used by a user
generate_uid() {
local username="${1}"
local uid
uid="$( get_uid "${username}" )"
if [ -z "${uid}" ]; then
for(( uid=MIN_UID; uid<=MAX_UID; uid++ )); do
if [ -z "$( get_username "${uid}" )" ]; then
break
fi
done
if [ ${uid} -gt ${MAX_UID} ]; then
fail "can not allocate a UID for user '%s'\n" "${username}"
fi
fi
printf "%d\n" "${uid}"
}
#----------------------------------------------------------------------------
# Add given user to given group, if not already the case
add_user_to_group() {
local username="${1}"
local group="${2}"
local _f
for _f in "${GROUP}" "${GSHADOW}"; do
[ -f "${_f}" ] || continue
sed -r -i -e 's/^('"${group}"':.*:)(([^:]+,)?)'"${username}"'(,[^:]+*)?$/\1\2\4/;' \
-e 's/^('"${group}"':.*)$/\1,'"${username}"'/;' \
-e 's/,+/,/' \
-e 's/:,/:/' \
"${_f}"
done
}
#----------------------------------------------------------------------------
# Encode a password
encode_password() {
local passwd="${1}"
mkpasswd -m "${PASSWD_METHOD}" "${passwd}"
}
#----------------------------------------------------------------------------
# Add a user; if it does already exist, remove it first
add_one_user() {
local username="${1}"
local uid="${2}"
local group="${3}"
local gid="${4}"
local passwd="${5}"
local home="${6}"
local shell="${7}"
local groups="${8}"
local comment="${9}"
local _f _group _home _shell _gid _passwd
# First, sanity-check the user
check_user_validity "${username}" "${uid}" "${group}" "${gid}"
# Generate a new UID if needed
if [ ${uid} -eq -1 ]; then
uid="$( generate_uid "${username}" )"
fi
# Remove any previous instance of this user
for _f in "${PASSWD}" "${SHADOW}"; do
sed -r -i -e '/^'"${username}"':.*/d;' "${_f}"
done
_gid="$( get_gid "${group}" )"
_shell="${shell}"
if [ "${shell}" = "-" ]; then
_shell="/bin/false"
fi
case "${home}" in
-) _home="/";;
/) fail "home can not explicitly be '/'\n";;
/*) _home="${home}";;
*) fail "home must be an absolute path\n";;
esac
case "${passwd}" in
-)
_passwd=""
;;
!=*)
_passwd='!'"$( encode_password "${passwd#!=}" )"
;;
=*)
_passwd="$( encode_password "${passwd#=}" )"
;;
*)
_passwd="${passwd}"
;;
esac
printf "%s:x:%d:%d:%s:%s:%s\n" \
"${username}" "${uid}" "${_gid}" \
"${comment}" "${_home}" "${_shell}" \
>>"${PASSWD}"
printf "%s:%s:::::::\n" \
"${username}" "${_passwd}" \
>>"${SHADOW}"
# Add the user to its additional groups
if [ "${groups}" != "-" ]; then
for _group in ${groups//,/ }; do
add_user_to_group "${username}" "${_group}"
done
fi
# If the user has a home, chown it
# (Note: stdout goes to the fakeroot-script)
if [ "${home}" != "-" ]; then
mkdir -p "${TARGET_DIR}/${home}"
printf "chown -h -R %d:%d '%s'\n" "${uid}" "${_gid}" "${TARGET_DIR}/${home}"
fi
}
#----------------------------------------------------------------------------
main() {
local username uid group gid passwd home shell groups comment
local line
local -a LINES
# Some sanity checks
if [ ${MIN_UID} -le 0 ]; then
fail "MIN_UID must be >0 (currently %d)\n" ${MIN_UID}
fi
if [ ${MIN_GID} -le 0 ]; then
fail "MIN_GID must be >0 (currently %d)\n" ${MIN_GID}
fi
# Read in all the file in memory, exclude empty lines and comments
while read line; do
LINES+=( "${line}" )
done < <( sed -r -e 's/#.*//; /^[[:space:]]*$/d;' "${USERS_TABLE}" )
# We first create groups whose gid is not -1, and then we create groups
# whose gid is -1 (automatic), so that, if a group is defined both with
# a specified gid and an automatic gid, we ensure the specified gid is
# used, rather than a different automatic gid is computed.
# First, create all the main groups which gid is *not* automatic
for line in "${LINES[@]}"; do
read username uid group gid passwd home shell groups comment <<<"${line}"
[ ${gid} -ge 0 ] || continue # Automatic gid
add_one_group "${group}" "${gid}"
done
# Then, create all the main groups which gid *is* automatic
for line in "${LINES[@]}"; do
read username uid group gid passwd home shell groups comment <<<"${line}"
[ ${gid} -eq -1 ] || continue # Non-automatic gid
add_one_group "${group}" "${gid}"
done
# Then, create all the additional groups
# If any additional group is already a main group, we should use
# the gid of that main group; otherwise, we can use any gid
for line in "${LINES[@]}"; do
read username uid group gid passwd home shell groups comment <<<"${line}"
if [ "${groups}" != "-" ]; then
for g in ${groups//,/ }; do
add_one_group "${g}" -1
done
fi
done
# When adding users, we do as for groups, in case two packages create
# the same user, one with an automatic uid, the other with a specified
# uid, to ensure the specified uid is used, rather than an incompatible
# uid be generated.
# Now, add users whose uid is *not* automatic
for line in "${LINES[@]}"; do
read username uid group gid passwd home shell groups comment <<<"${line}"
[ "${username}" != "-" ] || continue # Magic string to skip user creation
[ ${uid} -ge 0 ] || continue # Automatic uid
add_one_user "${username}" "${uid}" "${group}" "${gid}" "${passwd}" \
"${home}" "${shell}" "${groups}" "${comment}"
done
# Finally, add users whose uid *is* automatic
for line in "${LINES[@]}"; do
read username uid group gid passwd home shell groups comment <<<"${line}"
[ "${username}" != "-" ] || continue # Magic string to skip user creation
[ ${uid} -eq -1 ] || continue # Non-automatic uid
add_one_user "${username}" "${uid}" "${group}" "${gid}" "${passwd}" \
"${home}" "${shell}" "${groups}" "${comment}"
done
}
#----------------------------------------------------------------------------
main "${@}"
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