eclass/sys-user.eclass

   1 # Copyright 1999-2017 Gentoo Foundation
   2 # Distributed under the terms of the GNU General Public License v2
   3
   4 # @ECLASS: sys-user.eclass
   5 # @MAINTAINER:
   6 # Michael Orlitzky <mjo@gentoo.org>
   7 # @BLURB: handle installation and removal of system users.
   8 # @DESCRIPTION:
   9 # This eclass does most of the work for the sys-user/ packages that
  10 # supply system user accounts.
  11
  12 # Needed for egetshell and egethome.
  13 inherit user
  14
  15 EXPORT_FUNCTIONS pkg_pretend src_unpack src_configure src_compile src_install src_test pkg_preinst pkg_postinst pkg_prerm
  16
  17 : ${HOMEPAGE:="https://www.gentoo.org/"}
  18 : ${DESCRIPTION:="The ${PN} system user"}
  19 : ${LICENSE:="GPL-2"}
  20
  21 # If you want a different username, use a different package name. This
  22 # prevents different people from claiming the same username.
  23 SYS_USER_NAME="${PN}"
  24
  25 # @ECLASS-VARIABLE: SYS_USER_GROUPS
  26 # @DESCRIPTION:
  27 # A space-separated list of groups that the user will belong to.
  28 # Dependencies on the appropriate sys-group packages are generated
  29 # automatically.
  30 : ${SYS_USER_GROUPS:=${PN}}
  31
  32 # @ECLASS-VARIABLE: SYS_USER_UID
  33 # @REQUIRED
  34 # @DESCRIPTION:
  35 # etc.
  36
  37
  38 # @ECLASS-VARIABLE: SYS_USER_UID_IMPORTANT
  39 # @REQUIRED
  40 # @DESCRIPTION:
  41 # Set to "true" if you want to die() if you don't get your desired UID.
  42 : ${SYS_USER_UID_IMPORTANT:=false}
  43
  44 # In many cases, if the UID of a user changes, packages depending on it
  45 # will want to rebuild. We always use SLOT=0, because you can't install
  46 # the same user twice. Then we use the UID as our subslot so that
  47 # subslot deps can be used to rebuild packages when our UID changes.
  48 SLOT="0/${SYS_USER_UID}"
  49
  50 # @ECLASS-VARIABLE: SYS_USER_HOME
  51 # @DESCRIPTION:
  52 # etc.
  53 : ${SYS_USER_HOME:=/home/${SYS_USER_NAME}}
  54
  55 # @ECLASS-VARIABLE: SYS_USER_SHELL
  56 # @DESCRIPTION:
  57 # etc.
  58 : ${SYS_USER_SHELL:=/bin/false}
  59
  60 case ${EAPI} in
  61         6) ;;
  62         *)
  63                 die "${ECLASS} is not compatible with EAPI=${EAPI}"
  64 esac
  65
  66 # Depend on any groups we might need.
  67 for _group in ${SYS_USER_GROUPS}; do
  68         DEPEND+=" sys-group/${_group} "
  69         RDEPEND+=" sys-group/${_group}:= "
  70 done
  71 unset _group
  72
  73 S="${WORKDIR}"
  74
  75 sys-user_src_unpack() { :; }
  76 sys-user_src_compile() { :; }
  77 sys-user_src_test() { :; }
  78
  79 sys-user_getuid() {
  80         # Output the real UID of the given user, or the empty string if the
  81         # user does not exist on the system.
  82         [[ $# -eq 1 ]] || die "usage: sys-user_getuid <username>"
  83         echo $(id --real --user "${1}")
  84 }
  85
  86 sys-user_getname() {
  87         # Output the username associated with the given UID, or the empty string
  88         # if the given UID is still available.
  89         [[ $# -eq 1 ]] || die "usage: sys-user_getname <uid>"
  90         echo $(egetent passwd "${1}" | cut -f1 -d':')
  91 }
  92
  93 sys-user_create() {
  94         # Create the user whose information is contained in the following
  95         # variables:
  96         #
  97         #  * SYS_USER_NAME
  98         #  * SYS_USER_UID
  99         #  * SYS_USER_SHELL
 100         #  * SYS_USER_HOME
 101         #  * SYS_USER_GROUPS
 102         #
 103         # We don't create a group with the same name; that should be the
 104         # job of the matching sys-group package.
 105         useradd --no-user-group \
 106                         ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 107                         ${SYS_USER_GROUPS:+--groups }"${SYS_USER_GROUPS}" \
 108                         --shell "${SYS_USER_SHELL}" \
 109                         --home-dir "${SYS_USER_HOME}" \
 110                         "${SYS_USER_NAME}"
 111 }
 112
 113
 114 sys-user_modify() {
 115         # Modify the existing user named $SYS_USER_NAME to match the values
 116         # contained in the following variables:
 117         #
 118         #  * SYS_USER_UID
 119         #  * SYS_USER_SHELL
 120         #  * SYS_USER_HOME
 121         #  * SYS_USER_GROUPS
 122         #
 123         usermod ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 124                         ${SYS_USER_GROUPS:+--append --groups }"${SYS_USER_GROUPS}" \
 125                         --shell "${SYS_USER_SHELL}" \
 126                         --home-dir "${SYS_USER_HOME}" \
 127                         "${SYS_USER_NAME}"
 128 }
 129
 130 sys-user_pkg_pretend() {
 131         # Sanity checks that would otherwise run code in global scope.
 132         #
 133         # First ensure that the user didn't say his UID is important and
 134         # then fail to specify one.
 135         if [[ -z "${SYS_USER_UID}" ]] &&
 136                    [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]]; then
 137                 # Don't make no damn sense.
 138                 die "arbitrary UID requested with SYS_USER_UID_IMPORTANT=true"
 139         fi
 140
 141         # Next ensure that no other username owns an important UID.
 142         if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]]; then
 143                 # Ok, the UID is important. Make sure nobody else has it. Or
 144                 # rather, nobody else *with a different username* has it.
 145                 local oldname=$(sys-user_getname "${SYS_USER_UID}")
 146                 if [[ "${SYS_USER_NAME}" != "${oldname}" ]]; then
 147                         die "important UID ${SYS_USER_UID} already belongs to ${oldname}"
 148                 fi
 149         fi
 150
 151         # Finally, ensure that this username doesn't already exist with
 152         # another UID if its UID is supposedly important.
 153         local olduid=$(sys-user_getuid "${SYS_USER_NAME}")
 154         if [[ -n "${olduid}" ]]; then
 155                 if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]] && \
 156                            [[ "${SYS_USER_UID}" != "${olduid}" ]]; then
 157                         # The UID is important and specified, but there is already a
 158                         # system user with this name and a different UID. Halp.
 159                         die "user ${SYS_USER_NAME} already exists with UID ${olduid}"
 160                 fi
 161         fi
 162 }
 163
 164 sys-user_src_configure() {
 165         local current_uid=$(sys-user_getuid "${SYS_USER_NAME}")
 166         if [[ -n "${current_uid}" ]]; then
 167                 # UPGRADE PATH: This user already exists, so if the eclass
 168                 # consumer doesn't care about some settings, we can reuse the
 169                 # pre-existing ones.
 170                 #
 171                 # This is also useful for sys-user package upgrades, because it
 172                 # prevents us from incrementing the UID on a reinstall, and doing
 173                 # so would break most packages that need a system user to exist.
 174                 if [[ "${SYS_USER_UID_IMPORTANT}" != "true" ]]; then
 175                         SYS_USER_UID="${current_uid}"
 176                 fi
 177
 178                 if [[ -z "${SYS_USER_HOME}" ]]; then
 179                         SYS_USER_HOME=$(egethome "${SYS_USER_NAME}")
 180                 fi
 181
 182                 if [[ -z "${SYS_USER_SHELL}" ]]; then
 183                         SYS_USER_SHELL=$(egetshell "${SYS_USER_NAME}")
 184                 fi
 185         fi
 186
 187         if [[ -n "${SYS_USER_UID}" ]]; then
 188                 # A specific UID was requested.
 189                 local current_name=$(sys-user_getname "${SYS_USER_UID}")
 190                 if [[ "${current_name}" != "${SYS_USER_NAME}" ]]; then
 191                         # This UID is already taken by another user, but this
 192                         # specific UID was not important (we checked in
 193                         # pkg_pretend), so fall back to an arbitrary one.
 194                         SYS_USER_UID=""
 195                 fi
 196         fi
 197
 198         # The "useradd" and "usermod" tools expect a comma-separated list,
 199         # so change our spaces to commas. Having duplicates in the list is
 200         # not a problem for those two tools.
 201         SYS_USER_GROUPS="${SYS_USER_GROUPS// /,}"
 202 }
 203
 204 sys-user_src_install() {
 205         # Install a placeholder file to /var/lib/sys-user/$uid. This will
 206         # cause collisions if two packages try to install users with the
 207         # same UID. The same problem potentially exists with the username,
 208         # but as long as SYS_USER_NAME is hard-coded to $PN, that shouldn't
 209         # be possible.
 210         #
 211         # Beware, this only works if SYS_USER_UID is guaranteed to have a
 212         # real UID and not, for example, -1.
 213         #
 214         # TODO: this is a problem now!
 215         #
 216         #touch "${T}/${SYS_USER_UID}" || die
 217         #insinto "/var/lib/sys-user"
 218         #doins "${T}/${SYS_USER_UID}"
 219 }
 220
 221 sys-user_pkg_preinst() {
 222         if [[ -z $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 223                 # The user does not already exist. This is the nice and easy
 224                 # case because no matter how we got here, we want to go ahead
 225                 # and create the (new) user.
 226                 sys-user_create || die "failed to add user ${SYS_USER_NAME}"
 227         elif [[ -n "${REPLACING_VERSIONS}" ]]; then
 228                 #
 229                 # This case is done in pkg_postint() to avoid clobbering a
 230                 # new user when we remove the old one.
 231                 #
 232                 :
 233         else
 234                 # UPGRADE PATH: Ok, the user exists but this isn't an upgrade of
 235                 # a sys-user package. This is the upgrade path from the old
 236                 # style of user/group management to the new style. Lets see if
 237                 # the new user is compatible with the old one; it usually will be.
 238                 # We only bail out if there's a homedir or shell conflict.
 239                 #
 240                 # We should make it policy that new sys-user packages have the
 241                 # same homedir and shell as the existing ones created by
 242                 # ebuilds, but it can't hurt to check again here. These checks
 243                 # are done here (and not in pkg_pretend, where they would be
 244                 # more consistent) because the PMS states that REPLACING_VERSIONS
 245                 # may not be defined there.
 246                 #
 247                 # If a homedir/shell changes during a sys-user upgrade, we don't
 248                 # consider that a problem, because the change was knowingly made
 249                 # by a developer who just edited an ebuild to make that change.
 250                 local oldhome=$(egethome "${SYS_USER_NAME}")
 251                 local oldshell=$(egetshell "${SYS_USER_NAME}")
 252
 253                 if [[ "${oldhome}" != "${SYS_USER_HOME}" ]]; then
 254                         die "home directory conflict for new user: ${SYS_USER_HOME}"
 255                 fi
 256
 257                 if [[ "${oldhshell}" != "${SYS_USER_SHELL}" ]]; then
 258                         die "shell conflict for new user: ${SYS_USER_SHELL}"
 259                 fi
 260
 261                 # The user already exists, so all we have left to do is to try
 262                 # to append SYS_USER_GROUPS to the existing groups. The home
 263                 # dir, shell, and uid should all match already.
 264                 sys-user_modify \
 265                         || die "failed to append groups to existing user ${SYS_USER_NAME}"
 266         fi
 267 }
 268
 269 sys-user_pkg_postinst() {
 270         if [[ -n "${REPLACING_VERSIONS}" ]]; then
 271            # This is an upgrade from a previous version of a sys-user
 272            # package. This case has to be handled carefully to make sure
 273            # that the pkg_prerm() of the old version doesn't remove the user
 274            # that this new version is going to add. At this point, in our
 275            # pkg_postinst(), the old version's pkg_prerm() phase should have
 276            # already happened.
 277            if [[ -n $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 278                    die "User ${SYS_USER_NAME} already exists during an upgrade."
 279            else
 280                    sys-user_create || die "failed to add user ${SYS_USER_NAME}"
 281            fi
 282         fi
 283 }
 284
 285 sys-user_pkg_prerm() {
 286         if [[ -z $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 287                 # We have successfully done nothing.
 288                 ewarn "Tried to remove nonexistent user ${SYS_USER_NAME}."
 289         else
 290                 userdel "${SYS_USER_NAME}" || \
 291                         die "failed to remove user ${SYS_USER_NAME}"
 292                 einfo "Removed user ${SYS_USER_NAME} from the system."
 293         fi
 294 }