strv: Add strv_shell_escape

This modifies the strv in-place, replacing strings with their escaped
version. It's mostly just a convenience function for when you need to
join a strv together because it's passed as a string to something, and
the separator needs escaping.

src/basic/strv.c

@@ -694,6 +694,26 @@ char **strv_reverse(char **l) {
         return l;
 }
 
+char **strv_shell_escape(char **l, const char *bad) {
+        char **s;
+
+        /* Escapes every character in every string in l that is in bad,
+         * edits in-place, does not roll-back on error. */
+
+        STRV_FOREACH(s, l) {
+                char *v;
+
+                v = shell_escape(*s, bad);
+                if (!v)
+                        return NULL;
+
+                free(*s);
+                *s = v;
+        }
+
+        return l;
+}
+
 bool strv_fnmatch(char* const* patterns, const char *s, int flags) {
         char* const* p;
 

src/basic/strv.h

@@ -145,6 +145,7 @@ void strv_print(char **l);
         }))
 
 char **strv_reverse(char **l);
+char **strv_shell_escape(char **l, const char *bad);
 
 bool strv_fnmatch(char* const* patterns, const char *s, int flags);