Merge 9593fd370e into 8aaea0c65d

Release 2024.10

Cargo.toml

@@ -31,7 +31,7 @@ name = "integration"
 path = "rust-bindings/tests/tests.rs"
 
 [workspace]
-members = [".", "rust-bindings/sys"]
+members = [".", "src/sysroot-rs", "rust-bindings/sys"]
 
 [dependencies]
 base64 = "0.20.0"

Makefile-sysroot-rs.am

@@ -0,0 +1,23 @@
+# Makefile for Rust lib
+#
+# SPDX-License-Identifier: LGPL-2.0+
+#
+# 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, see <https://www.gnu.org/licenses/>.
+
+
+target/release/libostreesysrs.so: src/sysroot-rs/src/lib.rs
+	cargo build --release --workspace
+
+libostreesysrs_DATA = target/release/libostreesysrs.so
+libostreesysrsdir = $(pkglibexecdir)

Makefile.am

@@ -128,6 +128,7 @@ include Makefile-switchroot.am
 if BUILDOPT_FUSE
 include src/rofiles-fuse/Makefile-inc.am
 endif
+include Makefile-sysroot-rs.am
 include Makefile-tests.am
 include Makefile-boot.am
 include Makefile-man.am

configure.ac

@@ -1,7 +1,7 @@
 AC_PREREQ([2.63])
 dnl To perform a release, follow the instructions in `docs/CONTRIBUTING.md`.
 m4_define([year_version], [2024])
-m4_define([release_version], [10])
+m4_define([release_version], [11])
 m4_define([package_version], [year_version.release_version])
 AC_INIT([libostree], [package_version], [walters@verbum.org])
 is_release_build=no

man/ostree-prepare-root.xml

@@ -120,20 +120,25 @@ License along with this library. If not, see <https://www.gnu.org/licenses/>.
             <varlistentry>
                 <term><varname>root.transient</varname></term>
                 <listitem><para>A boolean value; the default is <literal>false</literal>.
-                   If this is set to <literal>true</literal>, then the <literal>/</literal> filesystem will be a writable <literal>overlayfs</literal>,
-                   with the upper directory being a hidden directory (in the underlying system root filesystem) that will persist across reboots by default.
-                   However, changes will <emphasis>be discarded</emphasis> on OS updates!
+                   Setting this flag to <literal>true</literal> requires composefs (See <literal>composefs.enabled</literal>).
+                   When enabled, the root mount point <literal>/</literal> will be an overlayfs whose contents will be stored
+                   in a tmpfs, and hence discarded on OS upgrade or reboot.
                 </para>
                 <para>
-                   Enabling this option can be very useful for cases such as packages (dpkg/rpm/etc) that write content into <literal>/opt</literal>,
-                   particularly where they expect the target to be writable at runtime.  To make that work, ensure that your <literal>/opt</literal>
-                   directory is *not* a symlink to <literal>/var/opt</literal>, but is just an empty directory.
-                </para>
-                <para>
-                   Note the <literal>/usr</literal> mount point remains read-only by default.  This option is independent of <literal>etc.transient</literal> and <literal>sysroot.readonly</literal>;
+                   This option is independent of <literal>etc.transient</literal> and <literal>sysroot.readonly</literal>;
                    it is supported for example to have <literal>root.transient=true</literal> but <literal>etc.transient=false</literal> in which case changes to <literal>/etc</literal> continue
                    to persist across updates, with the default OSTree 3-way merge applied.
-                </para></listitem>
+                   Also related to persistence it is important to emphasize that <literal>/sysroot</literal> (the physical root filesystem) is still persistent
+                   by default; in-place OS upgrades can be applied.
+                </para>
+                <para>
+                  Enabling this option can make it significantly easier to adopt an image-based model in some circumstances.
+                  For example, if you have a configuration management system that is inspecting machine-specific state and
+                  e.g. dynamically installing packages or applying configuration, it can more easily be adapted to
+                  run on each boot, while still shifting a portion (or ideally most) image configuration to build time
+                  as part of the base image/commit.
+                </para>
+                </listitem>
             </varlistentry>
             <varlistentry>
                 <term><varname>composefs.enabled</varname></term>

src/libostree/ostree-sysroot.c

@@ -21,6 +21,7 @@
 #include "config.h"
 
 #include "otutil.h"
+#include <dlfcn.h>
 #include <err.h>
 #include <sys/file.h>
 #include <sys/mount.h>
@@ -76,6 +77,29 @@ enum
 
 G_DEFINE_TYPE (OstreeSysroot, ostree_sysroot, G_TYPE_OBJECT)
 
+static void *
+load_sysroot_rs (void)
+{
+  static gssize initialized = 0;
+  static void *sysrootrs = NULL;
+  if (g_once_init_enter (&initialized))
+    {
+      const char *uninstalled = g_getenv ("OSTREE_UNINSTALLED");
+      g_autofree char *path = NULL;
+      if (uninstalled)
+        path = g_strdup_printf ("%s/target/release/libostreesysrs.so", uninstalled);
+      else
+        path = g_strdup_printf ("%s/libostreesysrs.so", PKGLIBEXECDIR);
+      sysrootrs = dlopen (path, RTLD_NOW);
+      if (sysrootrs == NULL)
+        {
+          errx (EXIT_FAILURE, "failed to initialize libostreesysrs.so: %s", dlerror ());
+        }
+      g_once_init_leave (&initialized, 1);
+    }
+  return sysrootrs;
+}
+
 static void
 ostree_sysroot_finalize (GObject *object)
 {
@@ -448,11 +472,16 @@ ostree_sysroot_is_booted (OstreeSysroot *self)
 gboolean
 _ostree_sysroot_bump_mtime (OstreeSysroot *self, GError **error)
 {
+  void *lib = load_sysroot_rs ();
+  int (*f) (int fd) = dlsym (lib, "_ostreesys_bump_mtime");
+  g_assert (f);
+
   /* Allow other systems to monitor for changes */
-  if (utimensat (self->sysroot_fd, "ostree/deploy", NULL, 0) < 0)
+  int r = f (self->sysroot_fd);
+  if (r < 0)
     {
-      glnx_set_prefix_error_from_errno (error, "%s", "futimens");
-      return FALSE;
+      errno = r;
+      return glnx_throw_errno_prefix (error, "futimens");
     }
   return TRUE;
 }

src/sysroot-rs/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+description = "Internal Rust sysroot code"
+edition = "2021"
+keywords = ["ostree", "libostree"]
+license = "MIT"
+name = "ostreesysrs"
+readme = "rust-bindings/README.md"
+repository = "https://github.com/ostreedev/ostree"
+rust-version = "1.70.0"
+version = "0.0.0"
+publish = false
+
+[lib]
+name = "ostreesysrs"
+crate-type = ["cdylib"]
+
+[dependencies]
+ostree = { package = "ostree", path = "../..", version = "0.19", features = ["v2022_6"] }
+libc = "0.2"
+rustix = { version = "0.38", features = ["fs"] }

src/sysroot-rs/src/lib.rs

@@ -0,0 +1,17 @@
+#[no_mangle]
+pub extern "C" fn _ostreesys_bump_mtime(fd: libc::c_int) -> libc::c_int {
+    let fd = unsafe { std::os::fd::BorrowedFd::borrow_raw(fd) };
+    let now = rustix::fs::Timespec {
+        tv_sec: 0,
+        tv_nsec: rustix::fs::UTIME_NOW,
+    };
+    let ts = rustix::fs::Timestamps {
+        last_access: now.clone(),
+        last_modification: now.clone(),
+    };
+    if let Err(e) = rustix::fs::utimensat(fd, "ostree/deploy", &ts, rustix::fs::AtFlags::empty()) {
+        e.raw_os_error().into()
+    } else {
+        0
+    }
+}