ZTS: Provide an alternative to shuf for FreeBSD

There was a shuf package but the upstream for the port has recently
disappeared, so it is no longer available.

Create a function to hide the usage of shuf. Implement using seq|random
on FreeBSD.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes #9824

tests/zfs-tests/include/commands.cfg

@@ -82,7 +82,6 @@ export SYSTEM_FILES_COMMON='arp
     seq
     setfacl
     sh
-    shuf
     sleep
     sort
     ssh
@@ -122,6 +121,7 @@ export SYSTEM_FILES_FREEBSD='chflags
     mkfifo
     newfs
     pw
+    random
     sha256
     swapctl
     sysctl
@@ -157,6 +157,7 @@ export SYSTEM_FILES_LINUX='attr
     setenforce
     setfattr
     sha256sum
+    shuf
     udevadm
     useradd
     userdel

tests/zfs-tests/include/libtest.shlib

@@ -3934,3 +3934,18 @@ function faketty
         script --return --quiet -c "$*" /dev/null
     fi
 }
+
+#
+# Produce a random permutation of the integers in a given range (inclusive).
+#
+function range_shuffle # begin end
+{
+	typeset -i begin=$1
+	typeset -i end=$2
+
+	if is_freebsd; then
+		seq ${begin} ${end} | random -f -
+	else
+		shuf -i ${begin}-${end}
+	fi
+}

tests/zfs-tests/include/properties.shlib

@@ -51,7 +51,7 @@ function get_rand_prop
 
 	typeset prop_max=$((${#prop_array[@]} - 1))
 	typeset -i i
-	for i in $(shuf -i $start-$prop_max -n $num_props); do
+	for i in $(range_shuffle $start $prop_max | head -n $num_props); do
 		retstr="${prop_array[$i]} $retstr"
 	done
 	echo $retstr

tests/zfs-tests/tests/functional/mv_files/random_creation.ksh

@@ -11,7 +11,7 @@ DIR="${TESTDIR}/RANDOM_SMALL"
 log_must mkdir "${DIR}"
 
 count=0
-for i in $(shuf -i 1-"${RC_PASS1}") ; do
+for i in $(range_shuffle 1 "${RC_PASS1}") ; do
     if ! touch "${DIR}/${i}" ; then
 	    log_fail "error creating ${i} after ${count} files"
     fi

tests/zfs-tests/tests/functional/zvol/zvol_swap/zvol_swap_005_pos.ksh

@@ -63,9 +63,9 @@ typeset -i pageblocks volblocks max_swaplow
 ((max_swaplow = (volblocks - (pageblocks * 2))))
 
 for i in {0..10}; do
-	swaplow=$(shuf -n 1 -i ${pageblocks}-${max_swaplow})
+	swaplow=$(range_shuffle ${pageblocks} ${max_swaplow} | head -n 1)
 	((maxlen = max_swaplow - swaplow))
-	swaplen=$(shuf -n 1 -i ${pageblocks}-${maxlen})
+	swaplen=$(range_shuffle ${pageblocks} ${maxlen} | head -n 1)
 	log_must swap -a $swapname $swaplow $swaplen
 	log_must swap -d $swapname $swaplow
 done