Add support for default kargs files

Instead of merging kargs from the previous deployment, by default
regenerate kargs from the following config files:

/etc/ostree/kargs (host config)
/usr/lib/ostree-boot/kargs (base config)

The base config is sourced from the repo at the commit (revision)
being deployed, so that newly committed kargs will take effect
immediately after upgrading. The host config is sourced from the
merged /etc configuration of the new deployment, so that host
edits as well as edits to /usr/etc/ostree/kargs are reflected.

Kernel arguments present in the base config are appended to
kernel arguments in the host config.

Using the commands that modify kargs (of the form `ostree admin
deploy --karg*`) will cause kargs in later deployments to be copied
from the merge deployment, rather than regenerate from the config
files.

Resolves: #479

Makefile-tests.am

@@ -98,6 +98,7 @@ _installed_or_uninstalled_test_scripts = \
 	tests/test-admin-deploy-syslinux.sh \
 	tests/test-admin-deploy-2.sh \
 	tests/test-admin-deploy-karg.sh \
+	tests/test-admin-deploy-karg-default.sh \
 	tests/test-admin-deploy-switch.sh \
 	tests/test-admin-deploy-etcmerge-cornercases.sh \
 	tests/test-admin-deploy-uboot.sh \

src/libostree/ostree-sysroot-deploy.c

@@ -2568,9 +2568,68 @@ get_var_dfd (OstreeSysroot      *self,
   return glnx_opendirat (base_dfd, base_path, TRUE, ret_fd, error);
 }
 
+/* Get a GFile* referring to the commit object at ref for the file at path. */
+static GFile*
+get_file_from_repo (OstreeRepo    *repo,
+                    const char    *ref,
+                    const char    *path,
+                    GCancellable  *cancellable,
+                    GError       **error)
+{
+  g_autoptr(GFile) root = NULL;
+  if (!ostree_repo_read_commit (repo, ref, &root,
+                                NULL, cancellable, error))
+    return NULL;
+  return g_file_resolve_relative_path (root, path);
+}
+
+static gboolean
+sysroot_regenerate_kargs (OstreeSysroot *self,
+                          const char    *revision,
+                          int            deployment_dfd,
+                          char         **out_kargs,
+                          GCancellable  *cancellable,
+                          GError       **error)
+{
+  g_autoptr(GPtrArray) kargs_configs = g_ptr_array_new_with_free_func (g_free);
+
+  g_autofree char *host_karg_contents = NULL;
+  if (!ot_file_read_allow_noent (deployment_dfd,
+                                 _OSTREE_SYSROOT_KARGS_HOST,
+                                 &host_karg_contents,
+                                 cancellable, error))
+    return FALSE;
+  if (host_karg_contents)
+    g_ptr_array_add (kargs_configs, g_strstrip (g_steal_pointer (&host_karg_contents)));
+
+  /* Load base kargs configuration from the current commit, so that kargs will
+   * be written to the bootconfig as soon as the current deployment is
+   * finished (in install_deployment_kernel()). */
+  g_autofree char *base_karg_contents = NULL;
+  g_autoptr(GFile) base_karg_file = get_file_from_repo (ostree_sysroot_repo (self),
+                                                        revision,
+                                                        _OSTREE_SYSROOT_KARGS_BASE,
+                                                        cancellable, error);
+  if (!ot_file_load_contents_allow_not_found (base_karg_file, &base_karg_contents,
+                                              cancellable, error))
+    return FALSE;
+  if (base_karg_contents)
+    g_ptr_array_add (kargs_configs, g_strstrip (g_steal_pointer (&base_karg_contents)));
+
+  g_autoptr(OstreeKernelArgs) kargs = _ostree_kernel_args_new ();
+  for (guint i = 0; i < kargs_configs->len; i++)
+    _ostree_kernel_args_parse_append (kargs, kargs_configs->pdata[i]);
+
+  g_autofree char *kargs_contents = _ostree_kernel_args_to_string (kargs);
+
+  ot_transfer_out_value (out_kargs, &kargs_contents);
+  return TRUE;
+}
+
 static gboolean
 sysroot_finalize_deployment (OstreeSysroot     *self,
                              OstreeDeployment  *deployment,
+                             const char        *revision,
                              char             **override_kernel_argv,
                              OstreeDeployment  *merge_deployment,
                              GCancellable      *cancellable,
@@ -2581,36 +2640,52 @@ sysroot_finalize_deployment (OstreeSysroot     *self,
   if (!glnx_opendirat (self->sysroot_fd, deployment_path, TRUE, &deployment_dfd, error))
     return FALSE;
 
-  /* If we didn't get an override in this deployment, copy kargs directly from
-   * the merge deployment. */
+  /* If we didn't get an override in this deployment, check if an override
+   * has been done previously. */
+  gboolean kargs_previously_overridden = FALSE;
   if (!override_kernel_argv)
     {
-      OstreeBootconfigParser *merge_bootconfig = NULL;
-      gboolean kargs_overridden = FALSE;
       if (merge_deployment)
         {
-          merge_bootconfig = ostree_deployment_get_bootconfig (merge_deployment);
+          OstreeBootconfigParser *merge_bootconfig = ostree_deployment_get_bootconfig (merge_deployment);
           if (merge_bootconfig)
             {
-              /* Copy kargs from the merge deployment. */
-              const char *opts = ostree_bootconfig_parser_get (merge_bootconfig, "options");
-              ostree_bootconfig_parser_set (ostree_deployment_get_bootconfig (deployment), "options", opts);
-              kargs_overridden = g_strcmp0 (ostree_bootconfig_parser_get (merge_bootconfig, "ostree-kargs-override"),
-                                            "true") == 0;
+              kargs_previously_overridden = g_strcmp0 (ostree_bootconfig_parser_get (merge_bootconfig, "ostree-kargs-override"),
+                                                       "true") == 0;
+              if (kargs_previously_overridden)
+                {
+                  /* Copy kargs from the merge deployment. */
+                  const char *opts = ostree_bootconfig_parser_get (merge_bootconfig, "options");
+                  ostree_bootconfig_parser_set (ostree_deployment_get_bootconfig (deployment), "options", opts);
+                  /* Write the override flag again so it persists to the next deployment. */
+                  ostree_bootconfig_parser_set (ostree_deployment_get_bootconfig (deployment), "ostree-kargs-override", "true");
+                }
             }
-          if (kargs_overridden)
-            ostree_bootconfig_parser_set (ostree_deployment_get_bootconfig (deployment), "ostree-kargs-override", "true");
         }
     }
 
   if (merge_deployment)
     {
-      /* And do the /etc merge */
+      /* Do the /etc merge. */
       if (!merge_configuration_from (self, merge_deployment, deployment, deployment_dfd,
                                      cancellable, error))
         return FALSE;
     }
 
+  /* If we didn't get an override in this deployment, and an override has not
+   * been done before, then regenerate from the config files of this
+   * deployment. */
+  if (!override_kernel_argv && !kargs_previously_overridden)
+    {
+      /* Note this occurs after merge_configuration_from() so that
+       * /etc/ostree/kargs as a result of the /etc merge is used. */
+      g_autofree char *opts = NULL;
+      if (!sysroot_regenerate_kargs (self, revision, deployment_dfd, &opts,
+                                      cancellable, error))
+        return FALSE;
+      ostree_bootconfig_parser_set (ostree_deployment_get_bootconfig (deployment), "options", opts);
+    }
+
   const char *osdeploypath = glnx_strjoina ("ostree/deploy/", ostree_deployment_get_osname (deployment));
   glnx_autofd int os_deploy_dfd = -1;
   if (!glnx_opendirat (self->sysroot_fd, osdeploypath, TRUE, &os_deploy_dfd, error))
@@ -2689,7 +2764,8 @@ ostree_sysroot_deploy_tree (OstreeSysroot     *self,
                                       &deployment, cancellable, error))
     return FALSE;
 
-  if (!sysroot_finalize_deployment (self, deployment, override_kernel_argv,
+  if (!sysroot_finalize_deployment (self, deployment, revision,
+                                    override_kernel_argv,
                                     provided_merge_deployment,
                                     cancellable, error))
     return FALSE;
@@ -2948,8 +3024,8 @@ _ostree_sysroot_finalize_staged (OstreeSysroot *self,
   if (!glnx_unlinkat (AT_FDCWD, _OSTREE_SYSROOT_RUNSTATE_STAGED, 0, error))
     return FALSE;
 
-  if (!sysroot_finalize_deployment (self, self->staged_deployment, kargs, merge_deployment,
-                                    cancellable, error))
+  if (!sysroot_finalize_deployment (self, self->staged_deployment, self->staged_deployment->csum,
+                                    kargs, merge_deployment, cancellable, error))
     return FALSE;
 
   /* Now, take ownership of the staged state, as normally the API below strips

src/libostree/ostree-sysroot-private.h

@@ -78,6 +78,8 @@ struct OstreeSysroot {
 #define _OSTREE_SYSROOT_RUNSTATE_STAGED "/run/ostree/staged-deployment"
 #define _OSTREE_SYSROOT_DEPLOYMENT_RUNSTATE_DIR "/run/ostree/deployment-state/"
 #define _OSTREE_SYSROOT_DEPLOYMENT_RUNSTATE_FLAG_DEVELOPMENT "unlocked-development"
+#define _OSTREE_SYSROOT_KARGS_HOST "etc/ostree/kargs"
+#define _OSTREE_SYSROOT_KARGS_BASE "usr/lib/ostree-boot/kargs"
 
 void
 _ostree_sysroot_emit_journal_msg (OstreeSysroot  *self,

src/libotutil/ot-gio-utils.c

@@ -177,3 +177,64 @@ ot_file_get_path_cached (GFile *file)
 
   return path;
 }
+
+/**
+ * ot_file_load_contents_allow_not_found:
+ *
+ * Load the contents of file, allowing G_IO_ERROR_NOT_FOUND.
+ * If file exists, return the contents in out_contents (otherwise out_contents
+ * holds NULL).
+ *
+ * Return FALSE for any other error.
+ */
+gboolean
+ot_file_load_contents_allow_not_found (GFile         *file,
+                                       char         **out_contents,
+                                       GCancellable  *cancellable,
+                                       GError       **error)
+{
+  g_return_val_if_fail (file != NULL, FALSE);
+
+  GError *local_error = NULL;
+  g_autofree char *ret_contents = NULL;
+  if (!g_file_load_contents (file, cancellable, &ret_contents, NULL, NULL, &local_error))
+    {
+      if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
+        {
+          g_clear_error (&local_error);
+        }
+      else
+        {
+          g_propagate_error (error, local_error);
+          return FALSE;
+        }
+    }
+
+  ot_transfer_out_value (out_contents, &ret_contents);
+  return TRUE;
+}
+
+gboolean
+ot_file_read_allow_noent (int            dfd,
+                          char          *path,
+                          char         **out_contents,
+                          GCancellable  *cancellable,
+                          GError       **error)
+{
+  struct stat stbuf;
+  if (!glnx_fstatat_allow_noent (dfd, path, &stbuf, 0, error))
+    return FALSE;
+  const gboolean file_exists = (errno == 0);
+
+  g_autofree char *ret_contents = NULL;
+  if (file_exists)
+    {
+      ret_contents = glnx_file_get_contents_utf8_at (dfd, path, NULL,
+                                                     cancellable, error);
+      if (!ret_contents)
+        return FALSE;
+    }
+
+  ot_transfer_out_value (out_contents, &ret_contents);
+  return TRUE;
+}

src/libotutil/ot-gio-utils.h

@@ -79,4 +79,17 @@ gs_file_get_path_cached (GFile *file)
   return ot_file_get_path_cached (file);
 }
 
+gboolean
+ot_file_load_contents_allow_not_found (GFile         *file,
+                                       char         **out_contents,
+                                       GCancellable  *cancellable,
+                                       GError       **error);
+
+gboolean
+ot_file_read_allow_noent (int            dfd,
+                          char          *path,
+                          char         **out_contents,
+                          GCancellable  *cancellable,
+                          GError       **error);
+
 G_END_DECLS

tests/libtest.sh

@@ -512,6 +512,55 @@ os_repository_new_commit ()
     cd ${test_tmpdir}
 }
 
+os_repository_commit ()
+{
+    repo=${1:-testos-repo}
+    boot_checksum_iteration=${2:-0}
+    content_iteration=${3:-0}
+    branch=${4:-testos/buildmaster/x86_64-runtime}
+    export version=${5:-$(date "+%Y%m%d.${content_iteration}")}
+    echo "BOOT ITERATION: $boot_checksum_iteration"
+    cd ${test_tmpdir}/osdata
+    kver=3.6.0
+    if test -f usr/lib/modules/${kver}/vmlinuz; then
+        bootdir=usr/lib/modules/${kver}
+    else
+        if test -d usr/lib/ostree-boot; then
+            bootdir=usr/lib/ostree-boot
+        else
+            bootdir=boot
+        fi
+    fi
+    rm ${bootdir}/*
+    kernel_path=${bootdir}/vmlinuz
+    initramfs_path=${bootdir}/initramfs.img
+    if [[ $bootdir != usr/lib/modules/* ]]; then
+        kernel_path=${kernel_path}-${kver}
+        initramfs_path=${bootdir}/initramfs-${kver}.img
+    fi
+    echo "new: a kernel ${boot_checksum_iteration}" > ${kernel_path}
+    echo "new: an initramfs ${boot_checksum_iteration}" > ${initramfs_path}
+    bootcsum=$(cat ${kernel_path} ${initramfs_path} | sha256sum | cut -f 1 -d ' ')
+    export bootcsum
+    if [[ $bootdir != usr/lib/modules/* ]]; then
+        mv ${kernel_path}{,-${bootcsum}}
+        mv ${initramfs_path}{,-${bootcsum}}
+    fi
+
+    commithash=$(${CMD_PREFIX} ostree --repo=${test_tmpdir}/${repo} commit  --add-metadata-string "version=${version}" -b $branch -s "Build")
+    export commithash
+    cd ${test_tmpdir}
+}
+
+os_tree_write_file ()
+{
+    path=${1}
+    contents="${2}"
+    cd ${test_tmpdir}/osdata
+    echo "${contents}" > ${path}
+    cd ${test_tmpdir}
+}
+
 _have_user_xattrs=''
 have_user_xattrs() {
     assert_has_setfattr