admin: Add set-origin command

See projectatomic/rpm-ostree#42 for rationale. There are two high
level use cases:

 - If the OS comes unconfigured, this is a way to point it at a repo of your choice.
 - To switch between repositories while keeping the same branch easily.

src/ostree/ot-admin-builtin-set-origin.c

@@ -0,0 +1,146 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2015 Colin Walters <walters@verbum.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "ot-main.h"
+#include "ot-admin-builtins.h"
+#include "ot-admin-functions.h"
+#include "ostree.h"
+#include "ot-tool-util.h"
+#include "otutil.h"
+#include "libgsystem.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <glib/gi18n.h>
+
+static int opt_index = -1;
+static char **opt_set;
+
+static GOptionEntry options[] = {
+  { "set", 's', 0, G_OPTION_ARG_STRING_ARRAY, &opt_set, "Set config option KEY=VALUE for remote", "KEY=VALUE" },
+  { "index", 0, 0, G_OPTION_ARG_INT, &opt_index, "Operate on the deployment INDEX, starting from zero", "INDEX" },
+  { NULL }
+};
+
+gboolean
+ot_admin_builtin_set_origin (int argc, char **argv, GCancellable *cancellable, GError **error)
+{
+  gboolean ret = FALSE;
+  GOptionContext *context;
+  const char *remotename = NULL;
+  const char *url = NULL;
+  const char *branch = NULL;
+  gs_unref_object OstreeRepo *repo = NULL;
+  gs_unref_object OstreeSysroot *sysroot = NULL;
+  OstreeDeployment *target_deployment = NULL;
+
+  context = g_option_context_new ("REMOTENAME URL [BRANCH]");
+
+  if (!ostree_admin_option_context_parse (context, options, &argc, &argv, &sysroot, cancellable, error))
+    goto out;
+
+  if (argc < 3)
+    {
+      ot_util_usage_error (context, "REMOTENAME and URL must be specified", error);
+      goto out;
+    }
+
+  remotename = argv[1];
+  url = argv[2];
+  if (argc > 3)
+    branch = argv[3];
+
+  if (!ostree_sysroot_load (sysroot, cancellable, error))
+    goto out;
+
+  if (!ostree_sysroot_get_repo (sysroot, &repo, cancellable, error))
+    goto out;
+
+  if (opt_index == -1)
+    {
+      target_deployment = ostree_sysroot_get_booted_deployment (sysroot);
+      if (target_deployment == NULL)
+        {
+          g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                               "Not currently booted into an OSTree system");
+          goto out;
+        }
+    }
+  else
+    {
+      target_deployment = ot_admin_get_indexed_deployment (sysroot, opt_index, error);
+      if (!target_deployment)
+        goto out;
+    }
+
+  { char **iter;
+    gs_unref_variant_builder GVariantBuilder *optbuilder =
+      g_variant_builder_new (G_VARIANT_TYPE ("a{sv}"));
+
+    for (iter = opt_set; iter && *iter; iter++)
+      {
+        const char *keyvalue = *iter;
+        gs_free char *subkey = NULL;
+        gs_free char *subvalue = NULL;
+
+        if (!ot_parse_keyvalue (keyvalue, &subkey, &subvalue, error))
+          goto out;
+
+        g_variant_builder_add (optbuilder, "{s@v}",
+                               subkey, g_variant_new_variant (g_variant_new_string (subvalue)));
+      }
+    
+    if (!ostree_repo_remote_change (repo, NULL,
+                                    OSTREE_REPO_REMOTE_CHANGE_ADD_IF_NOT_EXISTS, 
+                                    remotename, url,
+                                    g_variant_builder_end (optbuilder),
+                                    cancellable, error))
+      goto out;
+  }
+  
+  { GKeyFile *old_origin = ostree_deployment_get_origin (target_deployment);
+    gs_free char *origin_refspec = g_key_file_get_string (old_origin, "origin", "refspec", NULL);
+    gs_free char *new_refspec = NULL;
+    gs_free char *origin_remote = NULL;
+    gs_free char *origin_ref = NULL;
+  
+    if (!ostree_parse_refspec (origin_refspec, &origin_remote, &origin_ref, error))
+      goto out;
+
+    { gs_free char *new_refspec = g_strconcat (remotename, ":", branch ? branch : origin_ref, NULL);
+      gs_unref_keyfile GKeyFile *new_origin = NULL;
+      gs_unref_object GFile *origin_path = NULL;
+      
+      new_origin = ostree_sysroot_origin_new_from_refspec (sysroot, new_refspec);
+
+      if (!ostree_sysroot_write_origin_file (sysroot, target_deployment, new_origin,
+                                             cancellable, error))
+        goto out;
+    }
+  }
+
+  ret = TRUE;
+ out:
+  if (context)
+    g_option_context_free (context);
+  return ret;
+}

src/ostree/ot-admin-builtins.h

@@ -35,6 +35,7 @@ gboolean ot_admin_builtin_undeploy (int argc, char **argv, GCancellable *cancell
 gboolean ot_admin_builtin_deploy (int argc, char **argv, GCancellable *cancellable, GError **error);
 gboolean ot_admin_builtin_cleanup (int argc, char **argv, GCancellable *cancellable, GError **error);
 gboolean ot_admin_builtin_status (int argc, char **argv, GCancellable *cancellable, GError **error);
+gboolean ot_admin_builtin_set_origin (int argc, char **argv, GCancellable *cancellable, GError **error);
 gboolean ot_admin_builtin_diff (int argc, char **argv, GCancellable *cancellable, GError **error);
 gboolean ot_admin_builtin_switch (int argc, char **argv, GCancellable *cancellable, GError **error);
 gboolean ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GError **error);

src/ostree/ot-builtin-admin.c

@@ -44,6 +44,7 @@ static OstreeAdminCommand admin_subcommands[] = {
   { "init-fs", ot_admin_builtin_init_fs },
   { "instutil", ot_admin_builtin_instutil },
   { "os-init", ot_admin_builtin_os_init },
+  { "set-origin", ot_admin_builtin_set_origin },
   { "status", ot_admin_builtin_status },
   { "switch", ot_admin_builtin_switch },
   { "undeploy", ot_admin_builtin_undeploy },