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 # This should be set to the "fixed" UID that your user should have.
  36 # We may have to fall back to an arbitrary UID, but you still need
  37 # to specify a real, valid UID here. At the very least because our
  38 # SLOT variable needs it.
  39 [[ -z "${SYS_USER_UID}" ]] && die "SYS_USER_UID must be set"
  40
  41 # @ECLASS-VARIABLE: SYS_USER_UID_IMPORTANT
  42 # @REQUIRED
  43 # @DESCRIPTION:
  44 # Set to "true" if you want to die() if you don't get your desired UID.
  45 : ${SYS_USER_UID_IMPORTANT:=false}
  46
  47 # In many cases, if the UID of a user changes, packages depending on it
  48 # will want to rebuild. We always use SLOT=0, because you can't install
  49 # the same user twice. Then we use the UID as our subslot so that
  50 # subslot deps can be used to rebuild packages when our UID changes.
  51 SLOT="0/${SYS_USER_UID}"
  52
  53 # @ECLASS-VARIABLE: SYS_USER_HOME
  54 # @DESCRIPTION:
  55 # etc.
  56 : ${SYS_USER_HOME:=/home/${SYS_USER_NAME}}
  57
  58 # @ECLASS-VARIABLE: SYS_USER_SHELL
  59 # @DESCRIPTION:
  60 # etc.
  61 : ${SYS_USER_SHELL:=/bin/false}
  62
  63 case ${EAPI} in
  64         6) ;;
  65         *)
  66                 die "${ECLASS} is not compatible with EAPI=${EAPI}"
  67 esac
  68
  69 # Depend on any groups we might need.
  70 for _group in ${SYS_USER_GROUPS}; do
  71         DEPEND+=" sys-group/${_group} "
  72         RDEPEND+=" sys-group/${_group}:= "
  73 done
  74 unset _group
  75
  76 S="${WORKDIR}"
  77
  78 sys-user_src_unpack() { :; }
  79 sys-user_src_compile() { :; }
  80 sys-user_src_test() { :; }
  81
  82 sys-user_getuid() {
  83         # Output the real UID of the given user, or the empty string if the
  84         # user does not exist on the system.
  85         [[ $# -eq 1 ]] || die "usage: sys-user_getuid <username>"
  86         echo $(id --real --user "${1}")
  87 }
  88
  89 sys-user_getname() {
  90         # Output the username associated with the given UID, or the empty string
  91         # if the given UID is still available.
  92         [[ $# -eq 1 ]] || die "usage: sys-user_getname <uid>"
  93         echo $(egetent passwd "${1}" | cut -f1 -d':')
  94 }
  95
  96 sys-user_create() {
  97         # Create the user whose information is contained in the following
  98         # variables:
  99         #
 100         #  * SYS_USER_NAME
 101         #  * SYS_USER_UID
 102         #  * SYS_USER_SHELL
 103         #  * SYS_USER_HOME
 104         #  * SYS_USER_GROUPS
 105         #
 106         # We don't create a group with the same name; that should be the
 107         # job of the matching sys-group package.
 108         useradd --no-user-group \
 109                         ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 110                         ${SYS_USER_GROUPS:+--groups }"${SYS_USER_GROUPS}" \
 111                         --shell "${SYS_USER_SHELL}" \
 112                         --home-dir "${SYS_USER_HOME}" \
 113                         "${SYS_USER_NAME}"
 114 }
 115
 116
 117 sys-user_modify() {
 118         # Modify the existing user named $SYS_USER_NAME to match the values
 119         # contained in the following variables:
 120         #
 121         #  * SYS_USER_UID
 122         #  * SYS_USER_SHELL
 123         #  * SYS_USER_HOME
 124         #  * SYS_USER_GROUPS
 125         #
 126         usermod ${SYS_USER_UID:+--uid }"${SYS_USER_UID}" \
 127                         ${SYS_USER_GROUPS:+--append --groups }"${SYS_USER_GROUPS}" \
 128                         --shell "${SYS_USER_SHELL}" \
 129                         --home-dir "${SYS_USER_HOME}" \
 130                         "${SYS_USER_NAME}"
 131 }
 132
 133 sys-user_pkg_pretend() {
 134         # Sanity checks that would otherwise run code in global scope.
 135
 136         # Next ensure that no other username owns an important UID.
 137         if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]]; then
 138                 # Ok, the UID is important. Make sure nobody else has it. Or
 139                 # rather, nobody else *with a different username* has it.
 140                 local oldname=$(sys-user_getname "${SYS_USER_UID}")
 141                 if [[ "${SYS_USER_NAME}" != "${oldname}" ]]; then
 142                         die "important UID ${SYS_USER_UID} already belongs to ${oldname}"
 143                 fi
 144         fi
 145
 146         # Finally, ensure that this username doesn't already exist with
 147         # another UID if its UID is supposedly important.
 148         local olduid=$(sys-user_getuid "${SYS_USER_NAME}")
 149         if [[ -n "${olduid}" ]]; then
 150                 if [[ "${SYS_USER_UID_IMPORTANT}" == "true" ]] && \
 151                            [[ "${SYS_USER_UID}" != "${olduid}" ]]; then
 152                         # The UID is important and specified, but there is already a
 153                         # system user with this name and a different UID. Halp.
 154                         die "user ${SYS_USER_NAME} already exists with UID ${olduid}"
 155                 fi
 156         fi
 157 }
 158
 159 sys-user_src_configure() {
 160         local current_uid=$(sys-user_getuid "${SYS_USER_NAME}")
 161         if [[ -n "${current_uid}" ]]; then
 162                 # UPGRADE PATH: This user already exists, so if the eclass
 163                 # consumer doesn't care about some settings, we can reuse the
 164                 # pre-existing ones.
 165                 #
 166                 # This is also useful for sys-user package upgrades, because it
 167                 # prevents us from incrementing the UID on a reinstall, and doing
 168                 # so would break most packages that need a system user to exist.
 169                 if [[ "${SYS_USER_UID_IMPORTANT}" != "true" ]]; then
 170                         SYS_USER_UID="${current_uid}"
 171                 fi
 172
 173                 if [[ -z "${SYS_USER_HOME}" ]]; then
 174                         SYS_USER_HOME=$(egethome "${SYS_USER_NAME}")
 175                 fi
 176
 177                 if [[ -z "${SYS_USER_SHELL}" ]]; then
 178                         SYS_USER_SHELL=$(egetshell "${SYS_USER_NAME}")
 179                 fi
 180         fi
 181
 182         local current_name=$(sys-user_getname "${SYS_USER_UID}")
 183         if [[ "${current_name}" != "${SYS_USER_NAME}" ]]; then
 184                 # This UID is already taken by another user, but this
 185                 # specific UID was not important (we checked in
 186                 # pkg_pretend), so fall back to an arbitrary one.
 187                 unset SYS_USER_UID
 188         fi
 189
 190         # The "useradd" and "usermod" tools expect a comma-separated list,
 191         # so change our spaces to commas. Having duplicates in the list is
 192         # not a problem for those two tools.
 193         SYS_USER_GROUPS="${SYS_USER_GROUPS// /,}"
 194 }
 195
 196 sys-user_src_install() {
 197         # Install a placeholder file to /var/lib/sys-user/$uid. This will
 198         # cause collisions if two packages try to install users with the
 199         # same UID. The same problem potentially exists with the username,
 200         # but as long as SYS_USER_NAME is hard-coded to $PN, that shouldn't
 201         # be possible.
 202         #
 203         # Beware, this only works if SYS_USER_UID is guaranteed to have a
 204         # real UID and not be e.g. the empty string.
 205         #
 206         # Our sys-user_create() function makes sure to set SYS_USER_UID to
 207         # something useful, and the only place that sys-user_create() is
 208         # called from is sys-user_pkg_preinst(), which takes place before
 209         # this sys-user_src_install().
 210         #
 211         # The other way that SYS_USER_UID could be empty is during an
 212         # upgrade; however, if you're doing an upgrade and the new UID isn't
 213         # important, then you'll get the same old UID that exists on the
 214         # system from the old package. That old UID is assigned to SYS_USER_UID
 215         # in sys-user_src_configure(), so that case is handled too.
 216         touch "${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_modify || 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 ${SYS_USER_NAME}."
 289         elif [[ -z "${REPLACING_VERSIONS}" ]]; then
 290                 # The user to remove exists, and this is not an upgrade, so
 291                 # we really do remove him.
 292                 userdel "${SYS_USER_NAME}" || \
 293                         die "failed to remove user ${SYS_USER_NAME}"
 294                 einfo "Removed user ${SYS_USER_NAME} from the system."
 295
 296                 # The missing case: if the user exista and this is an upgrade,
 297                 # we leave the user alone to be modified in
 298                 # sys-user_pkg_postinst().
 299         fi
 300 }