sysroot: Handle ro /boot but rw /sysroot
The recent change in https://github.com/coreos/fedora-coreos-config/pull/659 broke some of our tests that do `mount -o remount,rw /sysroot` but leave `/boot` read-only. We had code for having `/boot` read-only before `/sysroot` but in practice we had a file descriptor for `/sysroot` that we opened before the remount that would happen later on. Clean things up here so that in the library, we also remount `/boot` at the same time we remount `/sysroot` if either are readonly. Delete the legacy code for remounting `/boot` rw if we're not in a mount namespace. I am fairly confident most users are either using the `ostree` CLI, or they're using the mount namespace.
This commit is contained in:
Colin Walters
parent
a1c0cffeb3
commit
9a526bbaa5
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@ -56,9 +56,6 @@
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#define OSTREE_DEPLOYMENT_FINALIZING_ID SD_ID128_MAKE(e8,64,6c,d6,3d,ff,46,25,b7,79,09,a8,e7,a4,09,94)
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#endif
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static gboolean
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is_ro_mount (const char *path);
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/*
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* Like symlinkat() but overwrites (atomically) an existing
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* symlink.
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@ -2225,57 +2222,6 @@ cleanup_legacy_current_symlinks (OstreeSysroot *self,
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return TRUE;
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}
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/* Detect whether or not @path refers to a read-only mountpoint. This is
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* currently just used to handle a potentially read-only /boot by transiently
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* remounting it read-write. In the future we might also do this for e.g.
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* /sysroot.
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*/
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static gboolean
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is_ro_mount (const char *path)
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{
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#ifdef HAVE_LIBMOUNT
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/* Dragging in all of this crud is apparently necessary just to determine
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* whether something is a mount point.
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*
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* Systemd has a totally different implementation in
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* src/basic/mount-util.c.
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*/
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struct libmnt_table *tb = mnt_new_table_from_file ("/proc/self/mountinfo");
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struct libmnt_fs *fs;
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struct libmnt_cache *cache;
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gboolean is_mount = FALSE;
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struct statvfs stvfsbuf;
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if (!tb)
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return FALSE;
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/* to canonicalize all necessary paths */
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cache = mnt_new_cache ();
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mnt_table_set_cache (tb, cache);
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fs = mnt_table_find_target(tb, path, MNT_ITER_BACKWARD);
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is_mount = fs && mnt_fs_get_target (fs);
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#ifdef HAVE_MNT_UNREF_CACHE
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mnt_unref_table (tb);
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mnt_unref_cache (cache);
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#else
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mnt_free_table (tb);
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mnt_free_cache (cache);
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#endif
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if (!is_mount)
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return FALSE;
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/* We *could* parse the options, but it seems more reliable to
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* introspect the actual mount at runtime.
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*/
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if (statvfs (path, &stvfsbuf) == 0)
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return (stvfsbuf.f_flag & ST_RDONLY) != 0;
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#endif
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return FALSE;
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}
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/**
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* ostree_sysroot_write_deployments:
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* @self: Sysroot
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@ -2577,42 +2523,13 @@ ostree_sysroot_write_deployments_with_options (OstreeSysroot *self,
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}
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else
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{
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gboolean boot_was_ro_mount = FALSE;
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if (self->booted_deployment)
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boot_was_ro_mount = is_ro_mount ("/boot");
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g_debug ("boot is ro: %s", boot_was_ro_mount ? "yes" : "no");
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if (boot_was_ro_mount)
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{
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if (mount ("/boot", "/boot", NULL, MS_REMOUNT | MS_SILENT, NULL) < 0)
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return glnx_throw_errno_prefix (error, "Remounting /boot read-write");
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}
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if (!_ostree_sysroot_query_bootloader (self, &bootloader, cancellable, error))
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return FALSE;
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bootloader_is_atomic = bootloader != NULL && _ostree_bootloader_is_atomic (bootloader);
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/* Note equivalent of try/finally here */
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gboolean success = write_deployments_bootswap (self, new_deployments, opts, bootloader,
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&syncstats, cancellable, error);
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/* Below here don't set GError until the if (!success) check.
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* Note we only bother remounting if a mount namespace isn't in use.
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* */
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if (boot_was_ro_mount && !self->mount_namespace_in_use)
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{
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if (mount ("/boot", "/boot", NULL, MS_REMOUNT | MS_RDONLY | MS_SILENT, NULL) < 0)
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{
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/* Only make this a warning because we don't want to
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* completely bomb out if some other process happened to
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* jump in and open a file there. See above TODO
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* around doing this in a new mount namespace.
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*/
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g_printerr ("warning: Failed to remount /boot read-only: %s\n", strerror (errno));
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}
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}
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if (!success)
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if (!write_deployments_bootswap (self, new_deployments, opts, bootloader,
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&syncstats, cancellable, error))
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return FALSE;
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}
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@ -295,6 +295,31 @@ _ostree_sysroot_ensure_boot_fd (OstreeSysroot *self, GError **error)
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return TRUE;
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}
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static gboolean
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remount_writable (const char *path, gboolean *did_remount, GError **error)
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{
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*did_remount = FALSE;
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struct statvfs stvfsbuf;
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if (statvfs (path, &stvfsbuf) < 0)
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{
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if (errno != ENOENT)
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return glnx_throw_errno_prefix (error, "statvfs(%s)", path);
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else
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return TRUE;
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}
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if ((stvfsbuf.f_flag & ST_RDONLY) != 0)
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{
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/* OK, let's remount writable. */
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if (mount (path, path, NULL, MS_REMOUNT | MS_RELATIME, "") < 0)
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return glnx_throw_errno_prefix (error, "Remounting %s read-write", path);
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*did_remount = TRUE;
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g_debug ("remounted %s writable", path);
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}
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return TRUE;
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}
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/* Remount /sysroot read-write if necessary */
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gboolean
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_ostree_sysroot_ensure_writable (OstreeSysroot *self,
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@ -314,19 +339,19 @@ _ostree_sysroot_ensure_writable (OstreeSysroot *self,
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if (!self->root_is_ostree_booted)
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return TRUE;
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/* Check if /sysroot is a read-only mountpoint */
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struct statvfs stvfsbuf;
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if (statvfs ("/sysroot", &stvfsbuf) < 0)
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return glnx_throw_errno_prefix (error, "fstatvfs(/sysroot)");
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if ((stvfsbuf.f_flag & ST_RDONLY) == 0)
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return TRUE;
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/* In these cases we also require /boot */
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if (!_ostree_sysroot_ensure_boot_fd (self, error))
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return FALSE;
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/* OK, let's remount writable. */
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if (mount ("/sysroot", "/sysroot", NULL, MS_REMOUNT | MS_RELATIME, "") < 0)
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return glnx_throw_errno_prefix (error, "Remounting /sysroot read-write");
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gboolean did_remount_sysroot = FALSE;
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if (!remount_writable ("/sysroot", &did_remount_sysroot, error))
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return FALSE;
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gboolean did_remount_boot = FALSE;
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if (!remount_writable ("/boot", &did_remount_boot, error))
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return FALSE;
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/* Reopen our fd */
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glnx_close_fd (&self->sysroot_fd);
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/* Now close and reopen our file descriptors */
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ostree_sysroot_unload (self);
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if (!ensure_sysroot_fd (self, error))
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return FALSE;
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@ -34,6 +34,12 @@
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#define OT_VARIANT_BUILDER_INITIALIZER {{{0,}}}
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#endif
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static inline const char *
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ot_booltostr (int b)
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{
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return b ? "true" : "false";
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}
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#define ot_gobject_refz(o) (o ? g_object_ref (o) : o)
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#define ot_transfer_out_value(outp, srcp) G_STMT_START { \
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