remote: split URI scheme into driver and transport upfront

Currently the remote driver extracts the transport from URI scheme and
plays games to temporarily hide the driver part when formatting URIs.
Refactor the code to split the URI scheme upfront so the two pieces are
easily available where needed.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

src/remote/remote_driver.c

@@ -24,7 +24,6 @@
 #include <config.h>
 
 #include <unistd.h>
-#include <assert.h>
 
 #include "virnetclient.h"
 #include "virnetclientprogram.h"
@@ -162,7 +161,26 @@ static void make_nonnull_domain_snapshot(remote_nonnull_domain_snapshot *snapsho
 /*----------------------------------------------------------------------*/
 
 /* Helper functions for remoteOpen. */
-static char *get_transport_from_scheme(char *scheme);
+static int remoteSplitURIScheme(virURIPtr uri,
+                                char **driver,
+                                char **transport)
+{
+    char *p = strchr(uri->scheme, '+');
+
+    *driver = *transport = NULL;
+
+    if (VIR_STRNDUP(*driver, uri->scheme, p ? p - uri->scheme : -1) < 0)
+        return -1;
+
+    if (p &&
+        VIR_STRDUP(*transport, p + 1) < 0) {
+        VIR_FREE(*driver);
+        return -1;
+    }
+
+    return 0;
+}
+
 
 static int
 remoteStateInitialize(bool privileged ATTRIBUTE_UNUSED,
@@ -715,11 +733,12 @@ remoteConnectSupportsFeatureUnlocked(virConnectPtr conn,
 static int
 doRemoteOpen(virConnectPtr conn,
              struct private_data *priv,
+             const char *driver_str,
+             const char *transport_str,
              virConnectAuthPtr auth ATTRIBUTE_UNUSED,
              virConfPtr conf,
              unsigned int flags)
 {
-    char *transport_str = NULL;
     enum {
         trans_tls,
         trans_unix,
@@ -738,8 +757,6 @@ doRemoteOpen(virConnectPtr conn,
      * URIs we don't care about */
 
     if (conn->uri) {
-        transport_str = get_transport_from_scheme(conn->uri->scheme);
-
         if (!transport_str) {
             if (conn->uri->server)
                 transport = trans_tls;
@@ -873,26 +890,16 @@ doRemoteOpen(virConnectPtr conn,
                     goto failed;
             } else {
                 virURI tmpuri = {
-                    .scheme = conn->uri->scheme,
+                    .scheme = (char *)driver_str,
                     .query = virURIFormatParams(conn->uri),
                     .path = conn->uri->path,
                     .fragment = conn->uri->fragment,
                 };
 
-                /* Evil, blank out transport scheme temporarily */
-                if (transport_str) {
-                    assert(transport_str[-1] == '+');
-                    transport_str[-1] = '\0';
-                }
-
                 name = virURIFormat(&tmpuri);
 
                 VIR_FREE(tmpuri.query);
 
-                /* Restore transport scheme */
-                if (transport_str)
-                    transport_str[-1] = '+';
-
                 if (!name)
                     goto failed;
             }
@@ -1297,14 +1304,23 @@ remoteConnectOpen(virConnectPtr conn,
                   unsigned int flags)
 {
     struct private_data *priv;
-    int ret, rflags = 0;
+    int ret = VIR_DRV_OPEN_ERROR;
+    int rflags = 0;
     const char *autostart = virGetEnvBlockSUID("LIBVIRT_AUTOSTART");
+    char *driver = NULL;
+    char *transport = NULL;
 
-    if (inside_daemon && (!conn->uri || !conn->uri->server))
+    if (conn->uri &&
-        return VIR_DRV_OPEN_DECLINED;
+        remoteSplitURIScheme(conn->uri, &driver, &transport) < 0)
+        goto cleanup;
+
+    if (inside_daemon && (!conn->uri || !conn->uri->server)) {
+        ret = VIR_DRV_OPEN_DECLINED;
+        goto cleanup;
+    }
 
     if (!(priv = remoteAllocPrivateData()))
-        return VIR_DRV_OPEN_ERROR;
+        goto cleanup;
 
     if (flags & VIR_CONNECT_RO)
         rflags |= VIR_DRV_OPEN_REMOTE_RO;
@@ -1319,8 +1335,7 @@ remoteConnectOpen(virConnectPtr conn,
         !conn->uri->server &&
         conn->uri->path &&
         conn->uri->scheme &&
-        ((strchr(conn->uri->scheme, '+') == 0)||
+        (transport == NULL || STREQ(transport, "unix")) &&
-         (strstr(conn->uri->scheme, "+unix") != NULL)) &&
         (STREQ(conn->uri->path, "/session") ||
          STRPREFIX(conn->uri->scheme, "test+")) &&
         geteuid() > 0) {
@@ -1348,7 +1363,7 @@ remoteConnectOpen(virConnectPtr conn,
         }
     }
 
-    ret = doRemoteOpen(conn, priv, auth, conf, rflags);
+    ret = doRemoteOpen(conn, priv, driver, transport, auth, conf, rflags);
     if (ret != VIR_DRV_OPEN_SUCCESS) {
         conn->privateData = NULL;
         remoteDriverUnlock(priv);
@@ -1357,18 +1372,14 @@ remoteConnectOpen(virConnectPtr conn,
         conn->privateData = priv;
         remoteDriverUnlock(priv);
     }
+
+ cleanup:
+    VIR_FREE(driver);
+    VIR_FREE(transport);
     return ret;
 }
 
 
-/* In a string "driver+transport" return a pointer to "transport". */
-static char *
-get_transport_from_scheme(char *scheme)
-{
-    char *p = strchr(scheme, '+');
-    return p ? p + 1 : NULL;
-}
-
 /*----------------------------------------------------------------------*/