tst: Extend cross-test-ssh.sh to specify if target date can be altered

This code adds new flag - '--allow-time-setting' to cross-test-ssh.sh
script to indicate if it is allowed to alter the date on the system
on which tests are executed. This change is supposed to be used with
test systems, which use virtual machines for testing.

The GLIBC_TEST_ALLOW_TIME_SETTING env variable is exported to the
remote environment on which the eligible test is run and brings no
functional change when it is not.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 24 insertions, 1 deletions

diff --git a/scripts/cross-test-ssh.sh b/scripts/cross-test-ssh.sh
index 6d8fbcdfd2..a839e22dd0 100755
--- a/scripts/cross-test-ssh.sh
+++ b/scripts/cross-test-ssh.sh
@@ -22,7 +22,7 @@
 
 progname="$(basename $0)"
 
-usage="usage: ${progname} [--ssh SSH] HOST COMMAND ..."
+usage="usage: ${progname} [--ssh SSH] [--allow-time-setting] HOST COMMAND ..."
 help="Run a glibc test COMMAND on the remote machine HOST, via ssh,
 preserving the current working directory, and respecting quoting.
 
@@ -32,6 +32,10 @@ instead of ordinary 'ssh'.
 If the '--timeoutfactor FACTOR' flag is present, set TIMEOUTFACTOR on
 the remote machine to the specified FACTOR.
 
+If the '--allow-time-setting' flag is present, set
+GLIBC_TEST_ALLOW_TIME_SETTING on the remote machine to indicate that
+time can be safely adjusted (e.g. on a virtual machine).
+
 To use this to run glibc tests, invoke the tests as follows:
 
   $ make test-wrapper='ABSPATH/cross-test-ssh.sh HOST' tests
@@ -81,6 +85,10 @@ while [ $# -gt 0 ]; do
       timeoutfactor="$1"
       ;;
 
+    "--allow-time-setting")
+      settimeallowed="1"
+      ;;
+
     "--help")
       echo "$usage"
       echo "$help"
@@ -127,6 +135,21 @@ if [ "$timeoutfactor" ]; then
 ${command}"
 fi
 
+# Add command to set the info that time on target can be adjusted,
+# if required.
+# Serialize execution of this script on target to prevent from unintended
+# change of target time.
+FLOCK_PATH="${FLOCK_PATH:-/var/lock/clock_settime}"
+FLOCK_TIMEOUT="${FLOCK_TIMEOUT:-20}"
+FLOCK_FD="${FLOCK_FD:-99}"
+if [ "$settimeallowed" ]; then
+  command="exec ${FLOCK_FD}<>${FLOCK_PATH}
+flock -w ${FLOCK_TIMEOUT} ${FLOCK_FD}
+if [ $? -ne 0 ]; then exit 1; fi
+export GLIBC_TEST_ALLOW_TIME_SETTING=1
+${command}"
+fi
+
 # HOST's sshd simply concatenates its arguments with spaces and
 # passes them to some shell.  We want to force the use of /bin/sh,
 # so we need to re-quote the whole command to ensure it appears as