remote: fix logic for known_hosts and keyfile checks

If any of them is specified for the libssh and libssh2 drivers, there is
no need to depend on checks based on other paths: in particular, a
specified path for known_hosts was ignored if the local config directory
could not be determined, and the path for keyfile was ignored if the
home could not be determined.

Instead, lazily determine and use these two paths only in case they are
needed.

src/rpc/virnetclient.c

@@ -450,32 +450,34 @@ virNetClientPtr virNetClientNewLibSSH2(const char *host,
     char *nc = NULL;
     char *command = NULL;
 
-    char *homedir = virGetUserDirectory();
-    char *confdir = virGetUserConfigDirectory();
+    char *homedir = NULL;
+    char *confdir = NULL;
     char *knownhosts = NULL;
     char *privkey = NULL;
 
     /* Use default paths for known hosts an public keys if not provided */
-    if (confdir) {
-        if (!knownHostsPath) {
+    if (knownHostsPath) {
+        if (VIR_STRDUP(knownhosts, knownHostsPath) < 0)
+            goto cleanup;
+    } else {
+        confdir = virGetUserConfigDirectory();
+        if (confdir) {
             if (virFileExists(confdir)) {
                 virBufferAsprintf(&buf, "%s/known_hosts", confdir);
                 if (!(knownhosts = virBufferContentAndReset(&buf)))
                     goto no_memory;
             }
-        } else {
-            if (VIR_STRDUP(knownhosts, knownHostsPath) < 0)
-                goto cleanup;
         }
     }
 
-    if (homedir) {
-        if (!privkeyPath) {
+    if (privkeyPath) {
+        if (VIR_STRDUP(privkey, privkeyPath) < 0)
+            goto cleanup;
+    } else {
+        homedir = virGetUserDirectory();
+        if (homedir) {
             if (virNetClientFindDefaultSshKey(homedir, &privkey) < 0)
                 goto no_memory;
-        } else {
-            if (VIR_STRDUP(privkey, privkeyPath) < 0)
-                goto cleanup;
         }
     }
 
@@ -559,31 +561,33 @@ virNetClientPtr virNetClientNewLibssh(const char *host,
     char *nc = NULL;
     char *command = NULL;
 
-    char *homedir = virGetUserDirectory();
-    char *confdir = virGetUserConfigDirectory();
+    char *homedir = NULL;
+    char *confdir = NULL;
     char *knownhosts = NULL;
     char *privkey = NULL;
 
     /* Use default paths for known hosts an public keys if not provided */
-    if (confdir) {
-        if (!knownHostsPath) {
+    if (knownHostsPath) {
+        if (VIR_STRDUP(knownhosts, knownHostsPath) < 0)
+            goto cleanup;
+    } else {
+        confdir = virGetUserConfigDirectory();
+        if (confdir) {
             if (virFileExists(confdir)) {
                 if (virAsprintf(&knownhosts, "%s/known_hosts", confdir) < 0)
                     goto cleanup;
             }
-        } else {
-            if (VIR_STRDUP(knownhosts, knownHostsPath) < 0)
-                goto cleanup;
         }
     }
 
-    if (homedir) {
-        if (!privkeyPath) {
+    if (privkeyPath) {
+        if (VIR_STRDUP(privkey, privkeyPath) < 0)
+            goto cleanup;
+    } else {
+        homedir = virGetUserDirectory();
+        if (homedir) {
             if (virNetClientFindDefaultSshKey(homedir, &privkey) < 0)
                 goto no_memory;
-        } else {
-            if (VIR_STRDUP(privkey, privkeyPath) < 0)
-                goto cleanup;
         }
     }