Add new ex initramfs-etc command

This command allows users to cheaply inject configuration files in the
initramfs stage without having to regenerate the whole initramfs (or
even a new OSTree commit). This will be useful for configuring services
involved in bringing up the root block device.

```
$ echo 'hello world' > /etc/foobar
$ rpm-ostree ex initramfs-etc --track /etc/foobar
Staging deployment... done
Run "systemctl reboot" to start a reboot
$ rpm-ostree status
State: idle
Deployments:
  ostree://fedora:fedora/x86_64/coreos/testing-devel
                   Version: 32.20200716.dev.1 (2020-07-16T02:47:29Z)
                    Commit: 9a817d75bef81b955179be6e602d1e6ae350645b6323231a62ba2ee6e5b9644b
              GPGSignature: (unsigned)
              InitramfsEtc: /etc/foobar
                  Unlocked: development

● ostree://fedora:fedora/x86_64/coreos/testing-devel
                   Version: 32.20200716.dev.1 (2020-07-16T02:47:29Z)
                    Commit: 9a817d75bef81b955179be6e602d1e6ae350645b6323231a62ba2ee6e5b9644b
              GPGSignature: (unsigned)
$ reboot
(boot into rd.break)
sh-5.0# cat /etc/foobar
hello world
```

See the libostree side of this at:
ostreedev/ostree#2155

Lots more discussions in:
coreos/fedora-coreos-tracker#94

Makefile-rpm-ostree.am

@@ -32,6 +32,7 @@ rpm_ostree_SOURCES = src/app/main.c \
 	src/app/rpmostree-builtin-cliwrap.c \
 	src/app/rpmostree-builtin-cleanup.c \
 	src/app/rpmostree-builtin-initramfs.c \
+	src/app/rpmostree-builtin-initramfs-etc.c \
 	src/app/rpmostree-builtin-livefs.c \
 	src/app/rpmostree-builtin-usroverlay.c \
 	src/app/rpmostree-builtin-override.c \

configure.ac

@@ -94,7 +94,7 @@ LIBS="$save_LIBS"
 # Remember to update AM_CPPFLAGS in Makefile.am when bumping GIO req.
 PKG_CHECK_MODULES(PKGDEP_GIO_UNIX, [gio-unix-2.0])
 PKG_CHECK_MODULES(PKGDEP_RPMOSTREE, [gio-unix-2.0 >= 2.50.0 json-glib-1.0
-				     ostree-1 >= 2020.1
+				     ostree-1 >= 2020.5
 				     libsystemd
 				     polkit-gobject-1
 				     rpm librepo libsolv

man/rpm-ostree.xml

@@ -662,6 +662,36 @@ Boston, MA 02111-1307, USA.
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><command>ex initramfs-etc</command></term>
+
+        <listitem>
+          <para>
+            Experimental feature; subject to change.
+          </para>
+
+          <para>
+            Track/untrack additional files for the initramfs. This avoids a full
+            regeneration of the initramfs, but is limited to configuration files. This is
+            useful to be able to configure services backing the root block device in
+            a lightweight manner.
+          </para>
+
+          <para>
+            Use <command>--track</command> to start tracking a specific file. Can be
+            specified multiple times. A new deployment will be generated. Use
+            <command>--untrack</command> or <command>--untrack-all</command> to stop
+            tracking files.
+          </para>
+
+          <para>
+            When there are tracked files, any future created deployment (e.g. when doing an
+            upgrade) will ensure that they are synced. You can additionally use
+            <command>--force-sync</command> to simply generate a new deployment with the
+            latest versions of tracked files without upgrading.
+          </para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

packaging/rpm-ostree.spec.in

@@ -42,7 +42,7 @@ BuildRequires: gnome-common
 BuildRequires: /usr/bin/g-ir-scanner
 # Core requirements
 # One way to check this: `objdump -p /path/to/rpm-ostree | grep LIBOSTREE` and pick the highest (though that might miss e.g. new struct members)
-BuildRequires: pkgconfig(ostree-1) >= 2019.2
+BuildRequires: pkgconfig(ostree-1) >= 2020.5
 BuildRequires: pkgconfig(polkit-gobject-1)
 BuildRequires: pkgconfig(json-glib-1.0)
 BuildRequires: pkgconfig(rpm)

src/app/rpmostree-builtin-ex.c

@@ -34,6 +34,8 @@ static RpmOstreeCommand ex_subcommands[] = {
     "Convert an rpm-ostree rojig into an OSTree commit", rpmostree_ex_builtin_rojig2commit },
   { "history", RPM_OSTREE_BUILTIN_FLAG_LOCAL_CMD,
     "Inspect rpm-ostree history of the system", rpmostree_ex_builtin_history },
+  { "initramfs-etc", RPM_OSTREE_BUILTIN_FLAG_REQUIRES_ROOT,
+    "Track/untrack initramfs configuration files", rpmostree_ex_builtin_initramfs_etc },
   { NULL, 0, NULL, NULL }
 };
 

src/app/rpmostree-builtin-initramfs-etc.c

@@ -0,0 +1,136 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2020 Jonathan Lebon <jonathan@jlebon.com>
+ *
+ * This program 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 licence 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 <string.h>
+#include <glib-unix.h>
+
+#include "rpmostree-ex-builtins.h"
+#include "rpmostree-libbuiltin.h"
+#include "rpmostree-dbus-helpers.h"
+
+#include <libglnx.h>
+
+static char *opt_osname;
+static gboolean opt_force_sync;
+static char **opt_track;
+static char **opt_untrack;
+static gboolean opt_untrack_all;
+static gboolean opt_reboot;
+static gboolean opt_lock_finalization;
+static gboolean opt_unchanged_exit_77;
+
+static GOptionEntry option_entries[] = {
+  { "os", 0, 0, G_OPTION_ARG_STRING, &opt_osname, "Operate on provided OSNAME", "OSNAME" },
+  { "force-sync", 0, 0, G_OPTION_ARG_NONE, &opt_force_sync, "Deploy a new tree with the latest tracked /etc files", NULL },
+  { "track", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_track, "Track root /etc file", "FILE" },
+  { "untrack", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_untrack, "Untrack root /etc file", "FILE" },
+  { "untrack-all", 0, 0, G_OPTION_ARG_NONE, &opt_untrack_all, "Untrack all root /etc files", NULL },
+  { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Initiate a reboot after operation is complete", NULL },
+  { "lock-finalization", 0, G_OPTION_FLAG_HIDDEN, G_OPTION_ARG_NONE, &opt_lock_finalization, "Prevent automatic deployment finalization on shutdown", NULL },
+  { "unchanged-exit-77", 0, 0, G_OPTION_ARG_NONE, &opt_unchanged_exit_77, "If no new deployment made, exit 77", NULL },
+
+  { NULL }
+};
+
+gboolean
+rpmostree_ex_builtin_initramfs_etc (int             argc,
+                                    char          **argv,
+                                    RpmOstreeCommandInvocation *invocation,
+                                    GCancellable   *cancellable,
+                                    GError        **error)
+{
+  g_autoptr(GOptionContext) context = g_option_context_new ("");
+
+  _cleanup_peer_ GPid peer_pid = 0;
+  glnx_unref_object RPMOSTreeSysroot *sysroot_proxy = NULL;
+  if (!rpmostree_option_context_parse (context,
+                                       option_entries,
+                                       &argc, &argv,
+                                       invocation,
+                                       cancellable,
+                                       NULL, NULL,
+                                       &sysroot_proxy,
+                                       &peer_pid,
+                                       NULL,
+                                       error))
+    return FALSE;
+
+  glnx_unref_object RPMOSTreeOS *os_proxy = NULL;
+  if (!rpmostree_load_os_proxy (sysroot_proxy, opt_osname,
+                                cancellable, &os_proxy, error))
+    return FALSE;
+
+  g_autoptr(GVariant) previous_deployment = rpmostree_os_dup_default_deployment (os_proxy);
+
+  if (!(opt_track || opt_untrack || opt_untrack_all || opt_force_sync))
+    {
+      /* XXX: could print state here like `rpm-ostree initramfs` */
+      return glnx_throw (error, "Must use at least one of --force-sync, --track, --untrack, or --untrack-all");
+    }
+  else
+    {
+      char *empty_strv[] = {NULL};
+      if (!opt_track)
+        opt_track = empty_strv;
+      if (!opt_untrack)
+        opt_untrack = empty_strv;
+
+      GVariantDict dict;
+      g_variant_dict_init (&dict, NULL);
+      g_variant_dict_insert (&dict, "reboot", "b", opt_reboot);
+      g_variant_dict_insert (&dict, "initiating-command-line", "s", invocation->command_line);
+      g_variant_dict_insert (&dict, "lock-finalization", "b", opt_lock_finalization);
+      g_autoptr(GVariant) options = g_variant_ref_sink (g_variant_dict_end (&dict));
+
+      g_autofree char *transaction_address = NULL;
+      if (!rpmostree_os_call_initramfs_etc_sync (os_proxy,
+                                                 (const char *const*)opt_track,
+                                                 (const char *const*)opt_untrack,
+                                                 opt_untrack_all,
+                                                 opt_force_sync,
+                                                 options,
+                                                 &transaction_address,
+                                                 cancellable,
+                                                 error))
+        return FALSE;
+
+      if (!rpmostree_transaction_get_response_sync (sysroot_proxy,
+                                                    transaction_address,
+                                                    cancellable,
+                                                    error))
+        return FALSE;
+
+      if (!opt_reboot)
+        {
+          if (!rpmostree_has_new_default_deployment (os_proxy, previous_deployment))
+            {
+              if (opt_unchanged_exit_77)
+                invocation->exit_code = RPM_OSTREE_EXIT_UNCHANGED;
+              return TRUE;
+            }
+
+          g_print ("Run \"systemctl reboot\" to start a reboot\n");
+        }
+    }
+
+  return TRUE;
+}

src/app/rpmostree-builtin-status.c

@@ -870,6 +870,13 @@ print_one_deployment (RPMOSTreeSysroot *sysroot_proxy,
         g_string_append (buf, "regenerate");
       rpmostree_print_kv ("Initramfs", max_key_len, buf->str);
     }
+
+  g_autofree char **initramfs_etc_files = NULL;
+  g_variant_dict_lookup (dict, "initramfs-etc", "^a&s", &initramfs_etc_files);
+  if (initramfs_etc_files && *initramfs_etc_files)
+    /* XXX: not really packages but it works... should just rename that function */
+    print_packages ("InitramfsEtc", max_key_len, (const char**)initramfs_etc_files, NULL);
+
   gboolean pinned = FALSE;
   g_variant_dict_lookup (dict, "pinned", "b", &pinned);
   if (pinned)

src/app/rpmostree-ex-builtins.h

@@ -35,6 +35,7 @@ BUILTINPROTO(livefs);
 BUILTINPROTO(commit2rojig);
 BUILTINPROTO(rojig2commit);
 BUILTINPROTO(history);
+BUILTINPROTO(initramfs_etc);
 
 #undef BUILTINPROTO
 

src/daemon/org.projectatomic.rpmostree1.xml

@@ -253,6 +253,15 @@
       <arg type="s" name="transaction_address" direction="out"/>
     </method>
 
+    <method name="InitramfsEtc">
+      <arg type="as" name="track" direction="in"/>
+      <arg type="as" name="untrack" direction="in"/>
+      <arg type="b" name="untrack_all" direction="in"/>
+      <arg type="b" name="force_sync" direction="in"/>
+      <arg type="a{sv}" name="options" direction="in"/>
+      <arg type="s" name="transaction_address" direction="out"/>
+    </method>
+
    <!-- Available options:
         "reboot" (type 'b')
     -->

src/daemon/rpmostree-sysroot-core.h

@@ -35,6 +35,8 @@
  * /run/ostree/staged-deployment path and company. */
 #define _OSTREE_SYSROOT_RUNSTATE_STAGED_LOCKED "/run/ostree/staged-deployment-locked"
 
+#define RPMOSTREE_INITRAMFS_ETC_OVERLAY "/run/rpm-ostree/initramfs-etc-overlay.img"
+
 gboolean
 rpmostree_syscore_cleanup (OstreeSysroot            *sysroot,
                            OstreeRepo               *repo,