sysusers,strv: export the hash ops to map char* → strv

Also make string_strv_hashmap_put return 0 only if the entry already existed.

src/basic/strv.c

@@ -889,3 +889,63 @@ int fputstrv(FILE *f, char **l, const char *separator, bool *space) {
 
         return 0;
 }
+
+static int string_strv_hashmap_put_internal(Hashmap *h, const char *key, const char *value) {
+        char **l;
+        int r;
+
+        l = hashmap_get(h, key);
+        if (l) {
+                /* A list for this key already exists, let's append to it if it is not listed yet */
+                if (strv_contains(l, value))
+                        return 0;
+
+                r = strv_extend(&l, value);
+                if (r < 0)
+                        return r;
+
+                assert_se(hashmap_update(h, key, l) >= 0);
+        } else {
+                /* No list for this key exists yet, create one */
+                _cleanup_strv_free_ char **l2 = NULL;
+                _cleanup_free_ char *t = NULL;
+
+                t = strdup(key);
+                if (!t)
+                        return -ENOMEM;
+
+                r = strv_extend(&l2, value);
+                if (r < 0)
+                        return r;
+
+                r = hashmap_put(h, t, l2);
+                if (r < 0)
+                        return r;
+                TAKE_PTR(t);
+                TAKE_PTR(l2);
+        }
+
+        return 1;
+}
+
+int string_strv_hashmap_put(Hashmap **h, const char *key, const char *value) {
+        int r;
+
+        r = hashmap_ensure_allocated(h, &string_strv_hash_ops);
+        if (r < 0)
+                return r;
+
+        return string_strv_hashmap_put_internal(*h, key, value);
+}
+
+int string_strv_ordered_hashmap_put(OrderedHashmap **h, const char *key, const char *value) {
+        int r;
+
+        r = ordered_hashmap_ensure_allocated(h, &string_strv_hash_ops);
+        if (r < 0)
+                return r;
+
+        return string_strv_hashmap_put_internal(PLAIN_HASHMAP(*h), key, value);
+}
+
+DEFINE_HASH_OPS_FULL(string_strv_hash_ops, char, string_hash_func, string_compare_func, free, char*, strv_free);

src/basic/strv.h

@@ -9,6 +9,7 @@
 
 #include "alloc-util.h"
 #include "extract-word.h"
+#include "hashmap.h"
 #include "macro.h"
 #include "string-util.h"
 
@@ -188,3 +189,7 @@ int fputstrv(FILE *f, char **l, const char *separator, bool *space);
                 (b) = NULL;                     \
                 0;                              \
         })
+
+extern const struct hash_ops string_strv_hash_ops;
+int string_strv_hashmap_put(Hashmap **h, const char *key, const char *value);
+int string_strv_ordered_hashmap_put(OrderedHashmap **h, const char *key, const char *value);