Emulate pkill if it is not present

libexec/bats-core/bats-exec-test

@@ -204,6 +204,42 @@ bats_timeout_trap() {
   exit 1
 }
 
+bats_get_child_processes_of() {
+    child_processes=()
+    {
+      read -ra header
+      local pid_col ppid_col
+      for (( i = 0; i < ${#header[@]}; ++i )); do
+        if [[ ${header[$i]} == "PID" ]]; then
+          pid_col=$i
+        fi
+        if [[ ${header[$i]} == "PPID" ]]; then
+          ppid_col=$i
+        fi
+      done
+      while read -ra row; do
+        if (( ${row[$ppid_col]} == parent_pid )); then
+          child_processes+=("${row[$pid_col]}")
+        fi
+      done
+    } < <(ps -ef "$parent_pid")
+}
+
+bats_kill_childprocesses_of() { # <parent-pid>
+  local -ir parent_pid="${1?}"
+  if command -v pkill; then
+    pkill -P "$parent_pid"
+  else
+    bats_get_child_processes_of "$parent_pid"
+    # kill in reverse order (latest first)
+    IFS=$'\n' child_processes=($(sort -r "${child_processes[@]}"))
+
+    for (( i=0; i < ${#child_processes[@]}; ++i )); do
+      kill "${child_processes[$i]}"
+    done
+  fi #TODO: &>/dev/null
+}
+
 # sets a timeout for this process
 #
 # using SIGABRT for interprocess communication.
@@ -229,7 +265,7 @@ bats_start_timeout_countdown() { # <timeout>
      if kill -ABRT "$target_pid"; then
         ps -ef >&3
         # get rid of signal blocking child processes (like sleep)
-        pkill -P "$target_pid"
+        bats_kill_childprocesses_of "$target_pid"
     else
       printf "Could not signal ABRT (%d)\n" "$?" >&3
      fi  2>&3