Use binary http channel for podman socket

Cockpit's (default) text channels ignore frames with split UTF-8
multi-byte characters. This causes broken JSON. This is ultimately an
issue with cockpit's channel API design, and Cockpit should hide that by
buffering and partially decoding text channel frames, see
cockpit-project/cockpit#19235

Until that happens, convert the REST API to use a binary channel.

Fixes #1733

src/rest.js

@@ -17,28 +17,39 @@ function manage_error(reject, error, content) {
 // calls are async, so keep track of a call counter to associate a result with a call
 let call_id = 0;
 
+const NL = '\n'.charCodeAt(0); // always 10, but avoid magic constant
+
 function connect(address, system) {
     /* This doesn't create a channel until a request */
-    const http = cockpit.http(address, { superuser: system ? "require" : null });
+    /* HACK: use binary channel to work around https://github.com/cockpit-project/cockpit/issues/19235 */
+    const http = cockpit.http(address, { superuser: system ? "require" : null, binary: true });
     const connection = {};
+    const decoder = new TextDecoder();
 
     connection.monitor = function(options, callback, system, return_raw) {
         return new Promise((resolve, reject) => {
-            let buffer = "";
+            let buffer = new Uint8Array();
 
             http.request(options)
                     .stream(data => {
                         if (return_raw)
                             callback(data);
                         else {
-                            buffer += data;
-                            const chunks = buffer.split("\n");
-                            buffer = chunks.pop();
+                            buffer = new Uint8Array([...buffer, ...data]);
+
+                            // split the buffer into lines on NL (this is safe with UTF-8)
+                            for (;;) {
+                                const idx = buffer.indexOf(NL);
+                                if (idx < 0)
+                                    break;
 
-                            chunks.forEach(chunk => {
-                                debug(system, "monitor", chunk);
-                                callback(JSON.parse(chunk));
-                            });
+                                const line = buffer.slice(0, idx);
+                                buffer = buffer.slice(idx + 1);
+
+                                const line_str = decoder.decode(line);
+                                debug(system, "monitor", line_str);
+                                callback(JSON.parse(line_str));
+                            }
                         }
                     })
                     .catch((error, content) => {
@@ -55,12 +66,14 @@ function connect(address, system) {
             options = options || {};
             http.request(options)
                     .then(result => {
-                        debug(system, `call ${id} result:`, JSON.stringify(result));
-                        resolve(result);
+                        const text = decoder.decode(result);
+                        debug(system, `call ${id} result:`, text);
+                        resolve(text);
                     })
                     .catch((error, content) => {
-                        debug(system, `call ${id} error:`, JSON.stringify(error), "content", JSON.stringify(content));
-                        manage_error(reject, error, content);
+                        const text = decoder.decode(content);
+                        debug(system, `call ${id} error:`, JSON.stringify(error), "content", text);
+                        manage_error(reject, error, text);
                     });
         });
     };