jenkins helpers: some minimal documentation/comments + print errors

We should print meaningful error messages in case a user doesn't have
the required local PATH set up, or doesn't specify a required command
line argument.

Change-Id: I30a2935f93ade69222b1e0c3e212ee10e17c1823

contrib/jenkins_bts_model.sh

@@ -1,6 +1,14 @@
 #!/bin/sh
+# this is a dispatcher script which will call the bts-model-specific
+# script based on the bts model specified as command line argument
+
 bts_model="$1"
 
+if [ "x$bts_model" == "x" ]; then
+	echo "Error: You have to specify the BTS model as first argument, e.g. $0 sysmo"
+	exit 2
+fi
+
 if [ ! -d "./contrib" ]; then
   echo "Run ./contrib/jenkins_bts_model.sh from the root of the osmo-bts tree"
   exit 1

contrib/jenkins_bts_trx.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# jenkins build helper script for osmo-bts-trx
 
 # shellcheck source=contrib/jenkins_common.sh
 . $(dirname "$0")/jenkins_common.sh

contrib/jenkins_common.sh

@@ -1,5 +1,14 @@
 #!/bin/sh
 
+# this is a common helper script that is shared among all BTS model
+# specific helper scripts like jenkins_sysmobts.sh.  You shouldn't call
+# this directly, but rather indirectly via the bts-specific scripts
+
+if ! [ -x "$(command -v osmo-deps.sh)" ]; then
+	echo "Error: We need to have scripts/osmo-deps.sh from http://git.osmocom.org/osmo-ci/ in PATH !"
+	exit 2
+fi
+
 set -ex
 
 base="$PWD"

contrib/jenkins_lc15.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# jenkins build helper script for osmo-bts-lc15
 
 # shellcheck source=contrib/jenkins_common.sh
 . $(dirname "$0")/jenkins_common.sh

contrib/jenkins_oct.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# jenkins build helper script for osmo-bts-octphy
 
 # shellcheck source=contrib/jenkins_common.sh
 . $(dirname "$0")/jenkins_common.sh

contrib/jenkins_oct_and_bts_trx.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# jenkins build helper script for osmo-bts-octphy + osmo-bts-trx
 
 # shellcheck source=contrib/jenkins_common.sh
 . $(dirname "$0")/jenkins_common.sh

contrib/jenkins_sysmobts.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# jenkins build helper script for osmo-bts-sysmo
 
 # shellcheck source=contrib/jenkins_common.sh
 . $(dirname "$0")/jenkins_common.sh