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         [[ $# -eq 1 ]] || die "usage: sys-user_getuid <username>"
  81
  82         # Output the real UID of the given user, or the empty string if the
  83         # user does not exist on the system.
  84         echo $(id --real --user "${1}")
  85 }
  86
  87 sys-user_create() {
  88         # Create the user whose information is contained in the following
  89         # variables:
  90         #
  91         #  * SYS_USER_NAME
  92         #  * SYS_USER_UID
  93         #  * SYS_USER_SHELL
  94         #  * SYS_USER_HOME
  95         #  * SYS_USER_GROUPS
  96         #
  97         # We don't create a group with the same name; that should be the
  98         # job of the matching sys-group package.
  99         useradd --no-user-group \
 100                         ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 101                         ${SYS_USER_GROUPS:+--groups }"${SYS_USER_GROUPS}" \
 102                         --shell "${SYS_USER_SHELL}" \
 103                         --home-dir "${SYS_USER_HOME}" \
 104                         "${SYS_USER_NAME}"
 105 }
 106
 107
 108 sys-user_modify() {
 109         # Modify the existing user named $SYS_USER_NAME to match the values
 110         # contained in the following variables:
 111         #
 112         #  * SYS_USER_UID
 113         #  * SYS_USER_SHELL
 114         #  * SYS_USER_HOME
 115         #  * SYS_USER_GROUPS
 116         #
 117         usermod ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 118                         ${SYS_USER_GROUPS:+--append --groups }"${SYS_USER_GROUPS}" \
 119                         --shell "${SYS_USER_SHELL}" \
 120                         --home-dir "${SYS_USER_HOME}" \
 121                         "${SYS_USER_NAME}"
 122 }
 123
 124 sys-user_pkg_pretend() {
 125         # Sanity checks that would otherwise run code in global scope.
 126         #
 127         # First ensure that the user didn't say his UID is important and
 128         # then fail to specify one.
 129         if [[ -z "${SYS_USER_UID}" ]] &&
 130                    [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]]; then
 131                 # Don't make no damn sense.
 132                 die "arbitrary UID requested with SYS_USER_UID_IMPORTANT=true"
 133         fi
 134
 135         # Next ensure that no other username owns an important UID.
 136         if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]]; then
 137                 # Ok, the UID is important. Make sure nobody else has it. Or
 138                 # rather, nobody else *with a different username* has it.
 139                 local oldname=$(egetent passwd "${SYS_USER_UID}" | cut -f1 -d':')
 140                 if [[ "${SYS_USER_NAME}" != "${oldname}" ]]; then
 141                         die "important UID ${SYS_USER_UID} already belongs to ${oldname}"
 142                 fi
 143         fi
 144
 145         # Finally, ensure that this username doesn't already exist with
 146         # another UID if its UID is supposedly important.
 147         local olduid=$(sys-user_getuid "${SYS_USER_NAME}")
 148         if [[ -n "${olduid}" ]]; then
 149                 if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]] && \
 150                            [[ "${SYS_USER_UID}" != "${olduid}" ]]; then
 151                         # The UID is important and specified, but there is already a
 152                         # system user with this name and a different UID. Halp.
 153                         die "user ${SYS_USER_NAME} already exists with UID ${olduid}"
 154                 fi
 155         fi
 156 }
 157
 158 sys-user_src_configure() {
 159         local current_uid=$(sys-user_getuid "${SYS_USER_NAME}")
 160         if [[ -n "${current_uid}" ]]; then
 161                 # UPGRADE PATH: This user already exists, so if the eclass
 162                 # consumer doesn't care about some settings, we can reuse the
 163                 # pre-existing ones.
 164                 #
 165                 # This is also useful for sys-user package upgrades, because it
 166                 # prevents us from incrementing the UID on a reinstall, and doing
 167                 # so would break most packages that need a system user to exist.
 168                 if [[ "${SYS_USER_UID_IMPORTANT}" != "true" ]]; then
 169                         SYS_USER_UID="${current_uid}"
 170                 fi
 171
 172                 if [[ -z "${SYS_USER_HOME}" ]]; then
 173                         SYS_USER_HOME=$(egethome "${SYS_USER_NAME}")
 174                 fi
 175
 176                 if [[ -z "${SYS_USER_SHELL}" ]]; then
 177                         SYS_USER_SHELL=$(egetshell "${SYS_USER_NAME}")
 178                 fi
 179         fi
 180
 181         # The "useradd" and "usermod" tools expect a comma-separated list,
 182         # so change our spaces to commas. Having duplicates in the list is
 183         # not a problem for those two tools.
 184         SYS_USER_GROUPS="${SYS_USER_GROUPS// /,}"
 185 }
 186
 187 sys-user_src_install() {
 188         # Install a placeholder file to /var/lib/sys-user/$uid. This will
 189         # cause collisions if two packages try to install users with the
 190         # same UID. The same problem potentially exists with the username,
 191         # but as long as SYS_USER_NAME is hard-coded to $PN, that shouldn't
 192         # be possible.
 193         #
 194         # Beware, this only works if SYS_USER_UID is guaranteed to have a
 195         # real UID and not, for example, -1.
 196         #
 197         # TODO: this is a problem now!
 198         #
 199         #touch "${T}/${SYS_USER_UID}" || die
 200         #insinto "/var/lib/sys-user"
 201         #doins "${T}/${SYS_USER_UID}"
 202 }
 203
 204 sys-user_pkg_preinst() {
 205         if [[ -z $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 206                 # The user does not already exist. This is the nice and easy
 207                 # case because no matter how we got here, we want to go ahead
 208                 # and create the (new) user.
 209                 sys-user_create || die "failed to add user ${SYS_USER_NAME}"
 210         elif [[ -n "${REPLACING_VERSIONS}" ]]; then
 211                 #
 212                 # This case is done in pkg_postint() to avoid clobbering a
 213                 # new user when we remove the old one.
 214                 #
 215                 :
 216         else
 217                 # UPGRADE PATH: Ok, the user exists but this isn't an upgrade of
 218                 # a sys-user package. This is the upgrade path from the old
 219                 # style of user/group management to the new style. Lets see if
 220                 # the new user is compatible with the old one; it usually will be.
 221                 # We only bail out if there's a homedir or shell conflict.
 222                 #
 223                 # We should make it policy that new sys-user packages have the
 224                 # same homedir and shell as the existing ones created by
 225                 # ebuilds, but it can't hurt to check again here. These checks
 226                 # are done here (and not in pkg_pretend, where they would be
 227                 # more consistent) because the PMS states that REPLACING_VERSIONS
 228                 # may not be defined there.
 229                 #
 230                 # If a homedir/shell changes during a sys-user upgrade, we don't
 231                 # consider that a problem, because the change was knowingly made
 232                 # by a developer who just edited an ebuild to make that change.
 233                 local oldhome=$(egethome "${SYS_USER_NAME}")
 234                 local oldshell=$(egetshell "${SYS_USER_NAME}")
 235
 236                 if [[ "${oldhome}" != "${SYS_USER_HOME}" ]]; then
 237                         die "home directory conflict for new user: ${SYS_USER_HOME}"
 238                 fi
 239
 240                 if [[ "${oldhshell}" != "${SYS_USER_SHELL}" ]]; then
 241                         die "shell conflict for new user: ${SYS_USER_SHELL}"
 242                 fi
 243
 244                 # The user already exists, so all we have left to do is to try
 245                 # to append SYS_USER_GROUPS to the existing groups. The home
 246                 # dir, shell, and uid should all match already.
 247                 sys-user_modify \
 248                         || die "failed to append groups to existing user ${SYS_USER_NAME}"
 249         fi
 250 }
 251
 252 sys-user_pkg_postinst() {
 253         if [[ -n "${REPLACING_VERSIONS}" ]]; then
 254            # This is an upgrade from a previous version of a sys-user
 255            # package. This case has to be handled carefully to make sure
 256            # that the pkg_prerm() of the old version doesn't remove the user
 257            # that this new version is going to add. At this point, in our
 258            # pkg_postinst(), the old version's pkg_prerm() phase should have
 259            # already happened.
 260            if [[ -n $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 261                    die "User ${SYS_USER_NAME} already exists during an upgrade."
 262            else
 263                    sys-user_create || die "failed to add user ${SYS_USER_NAME}"
 264            fi
 265         fi
 266 }
 267
 268 sys-user_pkg_prerm() {
 269         if [[ -z $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 270                 # We have successfully done nothing.
 271                 ewarn "Tried to remove nonexistent user ${SYS_USER_NAME}."
 272         else
 273                 userdel "${SYS_USER_NAME}" || \
 274                         die "failed to remove user ${SYS_USER_NAME}"
 275                 einfo "Removed user ${SYS_USER_NAME} from the system."
 276         fi
 277 }