.deb/.rpm: add osmocom user during package install

Create osmocom user & group during package installation.
Fix the configuration dir/files permission to match.

Related: OS#4107
Change-Id: Ibb83c231231b39dc6732c0f375aeb3b21f3938ef

contrib/osmo-mgw.spec.in

@@ -37,6 +37,7 @@ BuildRequires:  pkgconfig(libosmovty) >= 1.7.0
 BuildRequires:  pkgconfig(libosmocoding) >= 1.7.0
 BuildRequires:  pkgconfig(libosmoabis) >= 1.3.0
 BuildRequires:  pkgconfig(libosmotrau) >= 1.3.0
+Requires(pre):  shadow
 %{?systemd_requires}
 
 %description
@@ -101,10 +102,17 @@ make %{?_smp_mflags} check || (find . -name testsuite.log -exec cat {} +)
 %service_del_postun osmo-mgw.service
 
 %pre
+getent group osmocom >/dev/null || groupadd --system osmocom
+getent passwd osmocom >/dev/null || useradd --system --gid osmocom --home-dir /var/lib/osmocom \
+                                            --shell /sbin/nologin --comment "Open Source Mobile Communications" osmocom
 %service_add_pre osmo-mgw.service
 
 %post
 %service_add_post osmo-mgw.service
+chown osmocom:osmocom /etc/osmocom/osmo-mgw.cfg
+chmod 0660 /etc/osmocom/osmo-mgw.cfg
+chown root:osmocom /etc/osmocom
+chmod 2775 /etc/osmocom
 %endif
 
 %files

contrib/systemd/osmo-mgw.service

@@ -5,9 +5,16 @@ Description=Osmocom Media Gateway (MGW)
 Type=simple
 StateDirectory=osmocom
 WorkingDirectory=%S/osmocom
+User=osmocom
+Group=osmocom
 Restart=always
 ExecStart=/usr/bin/osmo-mgw -s -c /etc/osmocom/osmo-mgw.cfg
 RestartSec=2
+# CPU scheduling policy:
+CPUSchedulingPolicy=rr
+# For real-time scheduling policies an integer between 1 (lowest priority) and 99 (highest priority):
+CPUSchedulingPriority=1
+# See sched(7) for further details on real-time policies and priorities
 
 [Install]
 WantedBy=multi-user.target

debian/control

@@ -18,7 +18,7 @@ Homepage: https://osmocom.org/projects/osmo-mgw
 Package: osmo-mgw
 Architecture: any
 Multi-Arch: foreign
-Depends: ${misc:Depends}, ${shlibs:Depends}
+Depends: ${misc:Depends}, ${shlibs:Depends}, adduser
 Description: OsmoMGW: Osmocom's Media Gateway for 2G and 3G circuit-switched mobile networks
 
 Package: libosmo-mgcp-client9

debian/postinst

@@ -0,0 +1,39 @@
+#!/bin/sh -e
+
+# Create 'osmocom' user and group (if it doesn't exist yet) and adjust permissions
+# of directories which are not automatically adjusted by systemd from previous (root-owned)
+# install.
+
+# N. B: the user is intentionally NOT removed during package uninstall:
+# see https://wiki.debian.org/AccountHandlingInMaintainerScripts for reasoning.
+chperms() {
+	# chperms <user> <group> <perms> <file>
+	if ! OVERRIDE=`dpkg-statoverride --list $4 2>&1`; then
+		if [ -e $4 ]; then
+			chown $1:$2 $4
+			chmod $3 $4
+		fi
+	fi
+}
+
+case "$1" in
+  configure)
+    if ! getent passwd osmocom > /dev/null; then
+        adduser --quiet \
+                --system \
+                --group \
+                --no-create-home \
+                --disabled-password \
+                --home /var/lib/osmocom \
+                --gecos "Open Source Mobile Communications" \
+                osmocom
+    fi
+# Set permissions according to https://www.debian.org/doc/debian-policy/ch-files.html#s-permissions-owners
+    chperms osmocom osmocom 0660 /etc/osmocom/osmo-mgw.cfg
+    chperms root osmocom 2775 /etc/osmocom
+  ;;
+esac
+
+# dh_installdeb(1) will replace this with shell code automatically
+# generated by other debhelper scripts.
+#DEBHELPER#