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kumquat-buildroot/support/scripts/mkusers
Yann E. MORIN 3fbd9887b3 filesystems: also chown symlinks 
Currently, the symlinks in the generated filesystems will have the
UID of the user running the build, because 'chown' does not change
the ownership of symlinks, by default.

Although the implications are limited, some may not want that UID
to leak in the generated filesystems.

So, use 'chown -h' so even symlinks get properly chowned.

Reported-by: Angelo Dureghello <angelo@barix.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-09 11:28:57 +02:00

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#!/bin/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 hav 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 name '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'\n" ${gid}
elif [ ${gid} -ne -1 ]; then
# check the gid is not already used for another group
if [ -n "${_group}" -a "${_group}" != "${group}" ]; then
fail "gid is already used by group '${_group}'\n"
fi
# check the group does not already exists with another gid
# Need to split the check in two, otherwise '[' complains it
# is missing arguments when _gid is empty
if [ -n "${_gid}" ] && [ ${_gid} -ne ${gid} ]; then
fail "group already exists with gid '${_gid}'\n"
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 ${gid} ]; then
fail "user already exists with gid '${_ugid}'\n"
fi
fi
if [ ${uid} -lt -1 -o ${uid} -eq 0 ]; then
fail "invalid uid '%d'\n" ${uid}
elif [ ${uid} -ne -1 ]; then
# check the uid is not already used for another user
if [ -n "${_username}" -a "${_username}" != "${username}" ]; then
fail "uid is already used by user '${_username}'\n"
fi
# check the user does not already exists with another uid
# Need to split the check in two, otherwise '[' complains it
# is missing arguments when _uid is empty
if [ -n "${_uid}" ] && [ ${_uid} -ne ${uid} ]; then
fail "user already exists with uid '${_uid}'\n"
fi
fi
# check the user does not already exist in another group
if [ -n "${_ugroup}" -a "${_ugroup}" != "${group}" ]; then
fail "user already exists with group '${_ugroup}'\n"
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='!'"$( encode_password "${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
# 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" ${MIN_GID}
fi
# We first create groups whose gid is not -1, and then we create groups
# whose gid is -1 (automatic), so that, if a group is defined both with
# a specified gid and an automatic gid, we ensure the specified gid is
# used, rather than a different automatic gid is computed.
# First, create all the main groups which gid is *not* automatic
while read username uid group gid passwd home shell groups comment; do
[ -n "${username}" ] || continue # Package with no user
[ ${gid} -ge 0 ] || continue # Automatic gid
add_one_group "${group}" "${gid}"
done <"${USERS_TABLE}"
# Then, create all the main groups which gid *is* automatic
while read username uid group gid passwd home shell groups comment; do
[ -n "${username}" ] || continue # Package with no user
[ ${gid} -eq -1 ] || continue # Non-automatic gid
add_one_group "${group}" "${gid}"
done <"${USERS_TABLE}"
# 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
while read username uid group gid passwd home shell groups comment; do
[ -n "${username}" ] || continue # Package with no user
if [ "${groups}" != "-" ]; then
for g in ${groups//,/ }; do
add_one_group "${g}" -1
done
fi
done <"${USERS_TABLE}"
# When adding users, we do as for groups, in case two packages create
# the same user, one with an automatic uid, the other with a specified
# uid, to ensure the specified uid is used, rather than an incompatible
# uid be generated.
# Now, add users whose uid is *not* automatic
while read username uid group gid passwd home shell groups comment; do
[ -n "${username}" ] || continue # Package with no user
[ ${uid} -ge 0 ] || continue # Automatic uid
add_one_user "${username}" "${uid}" "${group}" "${gid}" "${passwd}" \
"${home}" "${shell}" "${groups}" "${comment}"
done <"${USERS_TABLE}"
# Finally, add users whose uid *is* automatic
while read username uid group gid passwd home shell groups comment; do
[ -n "${username}" ] || continue # Package with no user
[ ${uid} -eq -1 ] || continue # Non-automatic uid
add_one_user "${username}" "${uid}" "${group}" "${gid}" "${passwd}" \
"${home}" "${shell}" "${groups}" "${comment}"
done <"${USERS_TABLE}"
}
#----------------------------------------------------------------------------
main "${@}"
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