add KV_RAW to kvline.c

Add the KV_RAW flag to kvline_encode().  This allows generation of
output that is compatible with some quirks of the control protocol.

Part of #30984.

src/lib/encoding/kvline.c

@@ -85,8 +85,9 @@ kvline_can_encode_lines(const config_line_t *line, unsigned flags)
       return false;
     }
 
-    if (needs_escape(line->value, keyless) && ! (flags & KV_QUOTED)) {
-      /* If KV_QUOTED is false, we can't encode a value that needs quotes. */
+    if (needs_escape(line->value, keyless) && ! (flags & (KV_QUOTED|KV_RAW))) {
+      /* If both KV_QUOTED and KV_RAW are false, we can't encode a
+         value that needs quotes. */
       return false;
     }
     if (!keyless && needs_escape(line->key, true)) {
@@ -104,7 +105,7 @@ kvline_can_encode_lines(const config_line_t *line, unsigned flags)
  *
  * If KV_QUOTED is set in <b>flags</b>, then all values that contain
  * spaces or unusual characters are escaped and quoted.  Otherwise, such
- * values are not allowed.
+ * values are not allowed.  Mutually exclusive with KV_RAW.
  *
  * If KV_OMIT_KEYS is set in <b>flags</b>, then pairs with empty keys are
  * allowed, and are encoded as 'Value'.  Otherwise, such pairs are not
@@ -114,6 +115,11 @@ kvline_can_encode_lines(const config_line_t *line, unsigned flags)
  * encoded as 'Key', not as 'Key=' or 'Key=""'.  Mutually exclusive with
  * KV_OMIT_KEYS.
  *
+ * If KV_RAW is set in <b>flags</b>, then don't apply any quoting to
+ * the value, and assume that the caller has adequately quoted it.
+ * (The control protocol has some quirks that make this necessary.)
+ * Mutually exclusive with KV_QUOTED.
+ *
  * KV_QUOTED_QSTRING is not supported.
  */
 char *
@@ -122,11 +128,12 @@ kvline_encode(const config_line_t *line,
 {
   tor_assert(! (flags & KV_QUOTED_QSTRING));
 
-  if (!kvline_can_encode_lines(line, flags))
-    return NULL;
-
   tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
              (KV_OMIT_KEYS|KV_OMIT_VALS));
+  tor_assert((flags & (KV_QUOTED|KV_RAW)) != (KV_QUOTED|KV_RAW));
+
+  if (!kvline_can_encode_lines(line, flags))
+    return NULL;
 
   smartlist_t *elements = smartlist_new();
 
@@ -148,7 +155,7 @@ kvline_encode(const config_line_t *line,
     if ((flags & KV_OMIT_VALS) && line_has_no_val(line)) {
       eq = "";
       v = "";
-    } else if (esc) {
+    } else if (!(flags & KV_RAW) && esc) {
       tmp = esc_for_log(line->value);
       v = tmp;
     } else {
@@ -185,12 +192,15 @@ kvline_encode(const config_line_t *line,
  * If KV_QUOTED_QSTRING is set in <b>flags</b>, then double-quoted values
  * are allowed and handled as QuotedStrings per qstring.c.  Do not add
  * new users of this flag.
+ *
+ * KV_RAW is not supported.
  */
 config_line_t *
 kvline_parse(const char *line, unsigned flags)
 {
   tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
              (KV_OMIT_KEYS|KV_OMIT_VALS));
+  tor_assert(!(flags & KV_RAW));
 
   const char *cp = line, *cplast = NULL;
   const bool omit_keys = (flags & KV_OMIT_KEYS) != 0;

src/lib/encoding/kvline.h

@@ -19,6 +19,7 @@ struct config_line_t;
 #define KV_OMIT_KEYS (1u<<1)
 #define KV_OMIT_VALS (1u<<2)
 #define KV_QUOTED_QSTRING (1u<<3)
+#define KV_RAW       (1u<<4)
 
 struct config_line_t *kvline_parse(const char *line, unsigned flags);
 char *kvline_encode(const struct config_line_t *line, unsigned flags);

src/test/test_config.c

@@ -6072,6 +6072,14 @@ test_config_kvline_parse(void *arg)
   lines->value = tor_strdup("CD");
   enc = kvline_encode(lines, 0);
   tt_assert(!enc);
+  config_free_lines(lines);
+
+  config_line_append(&lines, "A", "B C");
+  enc = kvline_encode(lines, 0);
+  tt_assert(!enc);
+  enc = kvline_encode(lines, KV_RAW);
+  tt_assert(enc);
+  tt_str_op(enc, OP_EQ, "A=B C");
 
  done:
   config_free_lines(lines);