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_prerm
  16
  17 : ${HOMEPAGE:="https://wiki.gentoo.org/wiki/User:Mjo/GLEP:User_packages"}
  18 : ${DESCRIPTION:="The ${PN} system user"}
  19
  20 # If you want a different username, use a different package name. This
  21 # prevents different people from claiming the same username.
  22 SYS_USER_NAME="${PN}"
  23
  24 # @ECLASS-VARIABLE: SYS_USER_GROUPS
  25 # @DESCRIPTION:
  26 # A space-separated list of groups that the user will belong to.
  27 # Dependencies on the appropriate sys-group packages are generated
  28 # automatically.
  29 : ${SYS_USER_GROUPS:=${PN}}
  30
  31 # @ECLASS-VARIABLE: SYS_USER_UID
  32 # @REQUIRED
  33 # @DESCRIPTION:
  34 # This should be set to the "fixed" UID that your user should have.
  35 # We may have to fall back to an arbitrary UID, but you still need
  36 # to specify a real, valid UID here. At the very least because our
  37 # SLOT variable needs it.
  38 [[ -z "${SYS_USER_UID}" ]] && die "SYS_USER_UID must be set"
  39
  40 # @ECLASS-VARIABLE: SYS_USER_UID_IMPORTANT
  41 # @REQUIRED
  42 # @DESCRIPTION:
  43 # Set to "true" if you want to die() if you don't get your desired UID.
  44 : ${SYS_USER_UID_IMPORTANT:=false}
  45
  46 # In many cases, if the UID of a user changes, packages depending on it
  47 # will want to rebuild. We always use SLOT=0, because you can't install
  48 # the same user twice. Then we use the UID as our subslot so that
  49 # subslot deps can be used to rebuild packages when our UID changes.
  50 SLOT="0/${SYS_USER_UID}"
  51
  52 # @ECLASS-VARIABLE: SYS_USER_HOME
  53 # @DESCRIPTION:
  54 # etc.
  55 : ${SYS_USER_HOME:=/home/${SYS_USER_NAME}}
  56
  57 # @ECLASS-VARIABLE: SYS_USER_SHELL
  58 # @DESCRIPTION:
  59 # etc.
  60 : ${SYS_USER_SHELL:=/bin/false}
  61
  62 case ${EAPI} in
  63         6) ;;
  64         *)
  65                 die "${ECLASS} is not compatible with EAPI=${EAPI}"
  66 esac
  67
  68 # Depend on any groups we might need.
  69 for _group in ${SYS_USER_GROUPS}; do
  70         DEPEND+=" sys-group/${_group} "
  71         RDEPEND+=" sys-group/${_group}:= "
  72 done
  73 unset _group
  74
  75 S="${WORKDIR}"
  76
  77 sys-user_src_unpack() { :; }
  78 sys-user_src_compile() { :; }
  79 sys-user_src_test() { :; }
  80
  81 sys-user_getuid() {
  82         # Output the real UID of the given user, or the empty string if the
  83         # user does not exist on the system.
  84         [[ $# -eq 1 ]] || die "usage: sys-user_getuid <username>"
  85         echo $(id --real --user "${1}")
  86 }
  87
  88 sys-user_getname() {
  89         # Output the username associated with the given UID, or the empty string
  90         # if the given UID is still available.
  91         [[ $# -eq 1 ]] || die "usage: sys-user_getname <uid>"
  92         echo $(egetent passwd "${1}" | cut -f1 -d':')
  93 }
  94
  95 sys-user_create() {
  96         # Create the user whose information is contained in the following
  97         # variables:
  98         #
  99         #  * SYS_USER_NAME
 100         #  * SYS_USER_UID
 101         #  * SYS_USER_SHELL
 102         #  * SYS_USER_HOME
 103         #  * SYS_USER_GROUPS
 104         #
 105         # We don't create a group with the same name; that should be the
 106         # job of the matching sys-group package.
 107         useradd --no-user-group \
 108                         ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 109                         ${SYS_USER_GROUPS:+--groups }"${SYS_USER_GROUPS}" \
 110                         --shell "${SYS_USER_SHELL}" \
 111                         --home-dir "${SYS_USER_HOME}" \
 112                         "${SYS_USER_NAME}"
 113 }
 114
 115
 116 sys-user_modify() {
 117         # Modify the existing user named $SYS_USER_NAME to match the values
 118         # contained in the following variables:
 119         #
 120         #  * SYS_USER_UID
 121         #  * SYS_USER_SHELL
 122         #  * SYS_USER_HOME
 123         #  * SYS_USER_GROUPS
 124         #
 125         usermod ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 126                         ${SYS_USER_GROUPS:+--append --groups }"${SYS_USER_GROUPS}" \
 127                         --shell "${SYS_USER_SHELL}" \
 128                         --home-dir "${SYS_USER_HOME}" \
 129                         "${SYS_USER_NAME}"
 130 }
 131
 132 sys-user_pkg_pretend() {
 133         # Sanity checks that would otherwise run code in global scope.
 134
 135         # Next ensure that no other username owns an important UID.
 136         if [[ "${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=$(sys-user_getname "${SYS_USER_UID}")
 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         local current_name=$(sys-user_getname "${SYS_USER_UID}")
 182         if [[ "${current_name}" != "${SYS_USER_NAME}" ]]; then
 183                 # This UID is already taken by another user, but this
 184                 # specific UID was not important (we checked in
 185                 # pkg_pretend), so fall back to an arbitrary one.
 186                 unset SYS_USER_UID
 187         fi
 188
 189         # The "useradd" and "usermod" tools expect a comma-separated list,
 190         # so change our spaces to commas. Having duplicates in the list is
 191         # not a problem for those two tools.
 192         SYS_USER_GROUPS="${SYS_USER_GROUPS// /,}"
 193 }
 194
 195 sys-user_src_install() {
 196         # Install a placeholder file to /var/lib/sys-user/$uid. This will
 197         # cause collisions if two packages try to install users with the
 198         # same UID. The same problem potentially exists with the username,
 199         # but as long as SYS_USER_NAME is hard-coded to $PN, that shouldn't
 200         # be possible.
 201         #
 202         # Beware, this only works if SYS_USER_UID is guaranteed to have a
 203         # real UID and not be e.g. the empty string.
 204         #
 205         # Our sys-user_create() function makes sure to set SYS_USER_UID to
 206         # something useful, and the only place that sys-user_create() is
 207         # called from is sys-user_pkg_preinst(), which takes place before
 208         # this sys-user_src_install().
 209         #
 210         # The other way that SYS_USER_UID could be empty is during an
 211         # upgrade; however, if you're doing an upgrade and the new UID isn't
 212         # important, then you'll get the same old UID that exists on the
 213         # system from the old package. That old UID is assigned to SYS_USER_UID
 214         # in sys-user_src_configure(), so that case is handled too.
 215         touch "${T}/${SYS_USER_UID}" || die
 216         insinto "/var/lib/sys-user"
 217         doins "${T}/${SYS_USER_UID}"
 218 }
 219
 220 sys-user_pkg_preinst() {
 221         if [[ -z $(sys-user_getuid "${SYS_USER_NAME}") ]]; then
 222                 # The user does not already exist. This is the nice and easy
 223                 # case because no matter how we got here, we want to go ahead
 224                 # and create the (new) user.
 225                 sys-user_create || die "failed to add user ${SYS_USER_NAME}"
 226         elif [[ -n "${REPLACING_VERSIONS}" ]]; then
 227            # This is an upgrade from a previous version of a sys-user
 228            # package. Modify the existing user (who will not be removed; see
 229            # sys-user_pkg_prerm) rather than creating a new one.
 230                 sys-user_modify || die "failed to upgrade user ${SYS_USER_NAME}"
 231         else
 232                 # UPGRADE PATH: Ok, the user exists but this isn't an upgrade of
 233                 # a sys-user package. This is the upgrade path from the old
 234                 # style of user/group management to the new style. Lets see if
 235                 # the new user is compatible with the old one; it usually will be.
 236                 # We only bail out if there's a homedir or shell conflict.
 237                 #
 238                 # We should make it policy that new sys-user packages have the
 239                 # same homedir and shell as the existing ones created by
 240                 # ebuilds, but it can't hurt to check again here. These checks
 241                 # are done here (and not in pkg_pretend, where they would be
 242                 # more consistent) because the PMS states that REPLACING_VERSIONS
 243                 # may not be defined there.
 244                 #
 245                 # If a homedir/shell changes during a sys-user upgrade, we don't
 246                 # consider that a problem, because the change was knowingly made
 247                 # by a developer who just edited an ebuild to make that change.
 248                 local oldhome=$(egethome "${SYS_USER_NAME}")
 249                 local oldshell=$(egetshell "${SYS_USER_NAME}")
 250
 251                 if [[ "${oldhome}" != "${SYS_USER_HOME}" ]]; then
 252                         die "home directory conflict for new user: ${SYS_USER_HOME}"
 253                 fi
 254
 255                 if [[ "${oldhshell}" != "${SYS_USER_SHELL}" ]]; then
 256                         die "shell conflict for new user: ${SYS_USER_SHELL}"
 257                 fi
 258
 259                 # The user already exists, so all we have left to do is to try
 260                 # to append SYS_USER_GROUPS to the existing groups. The home
 261                 # dir, shell, and uid should all match already.
 262                 sys-user_modify \
 263                         || die "failed to append groups to existing user ${SYS_USER_NAME}"
 264         fi
 265 }
 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 ${SYS_USER_NAME}."
 272         elif [[ -z "${REPLACING_VERSIONS}" ]]; then
 273                 # The user to remove exists, and this is not an upgrade, so
 274                 # we really do remove him.
 275                 userdel "${SYS_USER_NAME}" || \
 276                         die "failed to remove user ${SYS_USER_NAME}"
 277                 einfo "Removed user ${SYS_USER_NAME} from the system."
 278
 279                 # The missing case: if the user exists and this is an upgrade,
 280                 # we leave the user alone to be modified in
 281                 # sys-user_pkg_preinst().
 282         fi
 283 }