Update safe_eval.sh to support --export

This update allows

safe_dot --export file ...

to export any variables that get set.

Reviewed by: obrien

libexec/rc/safe_eval.sh

@@ -1,9 +1,9 @@
 # SPDX-License-Identifier: BSD-2-Clause
 
 # RCSid:
-#	$Id: safe_eval.sh,v 1.12 2023/10/12 18:46:53 sjg Exp $
+#	$Id: safe_eval.sh,v 1.16 2024/08/15 02:28:30 sjg Exp $
 #
-#	@(#) Copyright (c) 2023 Simon J. Gerraty
+#	@(#) Copyright (c) 2023-2024 Simon J. Gerraty
 #
 #	This file is provided in the hope that it will
 #	be of use.  There is absolutely NO WARRANTY.
@@ -37,14 +37,33 @@ safe_eval() {
     eval `cat "$@" | safe_set`
 }
 
+##
+# safe_eval_export [file]
+#
+# eval variable assignments only from file
+# taking care to eliminate any shell meta chars
+# export any variables thus set
+#
+safe_eval_export() {
+    eval `cat "$@" | safe_set | ${SED:-sed} 's/^\([^=]*\)=.*/&; export \1/'`
+}
+
 ##
 # safe_dot file [...]
 #
 # feed all "file" that exist to safe_eval
 #
 safe_dot() {
-    local ef= f
-
+    eval ${local:-:} ef ex f
+    ef=
+    ex=
+    while :
+    do
+        case "$1" in
+        --export) ex=_export; shift;;
+        *) break;;
+        esac
+    done
     for f in "$@"
     do
         test -s $f || continue
@@ -52,7 +71,7 @@ safe_dot() {
         dotted="$dotted $f"
     done
     test -z "$ef" && return 1
-    safe_eval $ef
+    safe_eval$ex $ef
     return 0
 }