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lib/compose: Maintain /etc as /usr/etc more consistently
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Lots of confusion in the codebase about this. The basic problem is that in
*most* cases, our code doesn't care; it's conceptually operating on `/usr/etc`,
which we could maintain as `/etc` and just rename it back at the very end.

The exceptions though are the `/etc/passwd` handling and livefs. And of course
libostree needs to handle `/usr/etc` vs `/etc` for config merging.

I considered trying to keep things the other way, but while I think we have some
ugly added here in this patch for things where we need to maintain an external
view (`remove-files` and `remove-from-packages`, and boy am I glad we had tests
for those), this ends up being mostly more consistent elsewhere.

One thing that might help is to maintain a fd for it; but that'd be an even more
invasive change.

This also ends up rolling in some unified core prep from
coreos#940 in the form of
`rename_if_exists()` - basically for some minimal rootfs we may not have
`/boot`, or for that matter potentially even `etc`.

Prep for coreos#997
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@cgwalters
cgwalters committed Sep 28, 2017
1 parent cb7e84c commit 6894f3d
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Showing 2 changed files with 81 additions and 47 deletions.
13 changes: 11 additions & 2 deletions src/libpriv/rpmostree-passwd-util.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -642,13 +642,22 @@ rpmostree_passwd_migrate_except_root (int rootfs_dfd,
{
GLNX_AUTO_PREFIX_ERROR ("passwd migration", error);
const char *name = kind == RPM_OSTREE_PASSWD_MIGRATE_PASSWD ? "passwd" : "group";
struct stat stbuf;
const char *etc_path;

if (!glnx_fstatat_allow_noent (rootfs_dfd, "usr/etc", &stbuf, 0, error))
return FALSE;
if (errno == ENOENT)
etc_path = "etc";
else
etc_path = "usr/etc";

const char *src_path = glnx_strjoina ("etc/", name);
const char *src_path = glnx_strjoina (etc_path, "/", name);
g_autoptr(FILE) src_stream = open_file_stream_read_at (rootfs_dfd, src_path, error);
if (!src_stream)
return FALSE;

const char *etctmp_path = glnx_strjoina ("etc/", name, ".tmp");
const char *etctmp_path = glnx_strjoina (etc_path, "/", name, ".tmp");
g_autoptr(FILE) etcdest_stream = open_file_stream_write_at (rootfs_dfd, etctmp_path, "w", error);
if (!etcdest_stream)
return FALSE;
Expand Down
115 changes: 70 additions & 45 deletions src/libpriv/rpmostree-postprocess.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -99,6 +99,37 @@ run_bwrap_mutably (int rootfs_fd,
return TRUE;
}

static gboolean
rename_if_exists (int src_dfd,
const char *from,
int dest_dfd,
const char *to,
GError **error)
{
struct stat stbuf;
const char *errmsg = glnx_strjoina ("renaming ", from);
GLNX_AUTO_PREFIX_ERROR (errmsg, error);

if (!glnx_fstatat_allow_noent (src_dfd, from, &stbuf, 0, error))
return FALSE;
if (errno == 0)
{
if (renameat (src_dfd, from, dest_dfd, to) < 0)
{
/* Handle empty directory in legacy location */
if (errno == EEXIST)
{
if (unlinkat (src_dfd, from, AT_REMOVEDIR) < 0)
return glnx_throw_errno_prefix (error, "rmdirat(%s)", from);
}
else
return glnx_throw_errno_prefix (error, "renameat(%s)", to);
}
}

return TRUE;
}

typedef struct {
const char *target;
const char *src;
Expand Down Expand Up @@ -257,7 +288,7 @@ process_kernel_and_initramfs (int rootfs_dfd,
* /usr/lib/ostree-boot; this will also take care of moving the kernel in legacy
* paths (CentOS, Fedora <= 24), etc.
*/
if (!glnx_renameat (rootfs_dfd, "boot", rootfs_dfd, "usr/lib/ostree-boot", error))
if (!rename_if_exists (rootfs_dfd, "boot", rootfs_dfd, "usr/lib/ostree-boot", error))
return FALSE;

/* Find the kernel in the source root (at this point one of usr/lib/modules or
Expand Down Expand Up @@ -720,7 +751,7 @@ replace_nsswitch (int dfd,
GError **error)
{
g_autofree char *nsswitch_contents =
glnx_file_get_contents_utf8_at (dfd, "etc/nsswitch.conf", NULL,
glnx_file_get_contents_utf8_at (dfd, "usr/etc/nsswitch.conf", NULL,
cancellable, error);
if (!nsswitch_contents)
return FALSE;
Expand All @@ -730,7 +761,7 @@ replace_nsswitch (int dfd,
if (!new_nsswitch_contents)
return FALSE;

if (!glnx_file_replace_contents_at (dfd, "etc/nsswitch.conf",
if (!glnx_file_replace_contents_at (dfd, "usr/etc/nsswitch.conf",
(guint8*)new_nsswitch_contents, -1,
GLNX_FILE_REPLACE_NODATASYNC,
cancellable, error))
Expand Down Expand Up @@ -776,7 +807,7 @@ postprocess_selinux_policy_store_location (int rootfs_dfd,

{ g_autofree char *orig_contents = NULL;
g_autofree char *contents = NULL;
const char *semanage_path = "etc/selinux/semanage.conf";
const char *semanage_path = "usr/etc/selinux/semanage.conf";

orig_contents = glnx_file_get_contents_utf8_at (rootfs_dfd, semanage_path, NULL,
cancellable, error);
Expand All @@ -791,7 +822,7 @@ postprocess_selinux_policy_store_location (int rootfs_dfd,
return glnx_prefix_error (error, "Replacing %s", semanage_path);
}

etc_policy_location = glnx_strjoina ("etc/selinux/", name);
etc_policy_location = glnx_strjoina ("usr/etc/selinux/", name);
if (!glnx_opendirat (rootfs_dfd, etc_policy_location, TRUE, &etc_selinux_dfd, error))
return FALSE;

Expand Down Expand Up @@ -880,11 +911,9 @@ create_rootfs_from_pkgroot_content (int target_root_dfd,
}

/* We take /usr from the yum content */
g_print ("Moving /usr and /etc to target\n");
g_print ("Moving /usr to target\n");
if (!glnx_renameat (src_rootfs_fd, "usr", target_root_dfd, "usr", error))
return FALSE;
if (!glnx_renameat (src_rootfs_fd, "etc", target_root_dfd, "etc", error))
return glnx_throw_errno_prefix (error, "renameat");

if (!rpmostree_rootfs_prepare_links (target_root_dfd, cancellable, error))
return FALSE;
Expand Down Expand Up @@ -948,7 +977,7 @@ create_rootfs_from_pkgroot_content (int target_root_dfd,
* rename the source /boot to the target, and will handle everything after
* that in the target root.
*/
if (!glnx_renameat (src_rootfs_fd, "boot", target_root_dfd, "boot", error))
if (!rename_if_exists (src_rootfs_fd, "boot", target_root_dfd, "boot", error))
return FALSE;

if (!process_kernel_and_initramfs (target_root_dfd, treefile,
Expand Down Expand Up @@ -1008,36 +1037,6 @@ handle_remove_files_from_package (int rootfs_fd,
return TRUE;
}

static gboolean
rename_if_exists (int dfd,
const char *from,
const char *to,
GError **error)
{
struct stat stbuf;
const char *errmsg = glnx_strjoina ("renaming ", from);
GLNX_AUTO_PREFIX_ERROR (errmsg, error);

if (!glnx_fstatat_allow_noent (dfd, from, &stbuf, 0, error))
return FALSE;
if (errno == 0)
{
if (renameat (dfd, from, dfd, to) < 0)
{
/* Handle empty directory in legacy location */
if (errno == EEXIST)
{
if (unlinkat (dfd, from, AT_REMOVEDIR) < 0)
return glnx_throw_errno_prefix (error, "rmdirat(%s)", from);
}
else
return glnx_throw_errno_prefix (error, "renameat(%s)", to);
}
}

return TRUE;
}

gboolean
rpmostree_rootfs_symlink_emptydir_at (int rootfs_fd,
const char *dest,
Expand Down Expand Up @@ -1210,7 +1209,7 @@ rpmostree_rootfs_postprocess_common (int rootfs_fd,
GCancellable *cancellable,
GError **error)
{
if (!rename_if_exists (rootfs_fd, "etc", "usr/etc", error))
if (!rename_if_exists (rootfs_fd, "etc", rootfs_fd, "usr/etc", error))
return FALSE;

if (!cleanup_leftover_files (rootfs_fd, "usr/share/rpm", rpmdb_leftover_files,
Expand Down Expand Up @@ -1341,6 +1340,9 @@ mutate_os_release (const char *contents,
return g_string_free (new_contents, FALSE);
}

/* Move etc -> usr/etc in the rootfs, and run through treefile
* postprocessing.
*/
gboolean
rpmostree_treefile_postprocessing (int rootfs_fd,
GFile *context_directory,
Expand All @@ -1350,6 +1352,9 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
GCancellable *cancellable,
GError **error)
{
if (!rename_if_exists (rootfs_fd, "etc", rootfs_fd, "usr/etc", error))
return FALSE;

JsonArray *units = NULL;
if (json_object_has_member (treefile, "units"))
units = json_object_get_array_member (treefile, "units");
Expand All @@ -1363,10 +1368,10 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
{
glnx_fd_close int multiuser_wants_dfd = -1;

if (!glnx_shutil_mkdir_p_at (rootfs_fd, "etc/systemd/system/multi-user.target.wants", 0755,
if (!glnx_shutil_mkdir_p_at (rootfs_fd, "usr/etc/systemd/system/multi-user.target.wants", 0755,
cancellable, error))
return FALSE;
if (!glnx_opendirat (rootfs_fd, "etc/systemd/system/multi-user.target.wants", TRUE,
if (!glnx_opendirat (rootfs_fd, "usr/etc/systemd/system/multi-user.target.wants", TRUE,
&multiuser_wants_dfd, error))
return FALSE;

Expand Down Expand Up @@ -1418,7 +1423,7 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
g_autofree char *dest_default_target_path =
g_strconcat ("/usr/lib/systemd/system/", default_target, NULL);

static const char default_target_path[] = "etc/systemd/system/default.target";
static const char default_target_path[] = "usr/etc/systemd/system/default.target";
(void) unlinkat (rootfs_fd, default_target_path, 0);

if (symlinkat (dest_default_target_path, rootfs_fd, default_target_path) < 0)
Expand All @@ -1434,6 +1439,13 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
else
len = 0;

/* Put /etc back for backwards compatibility */
if (len > 0)
{
if (!rename_if_exists (rootfs_fd, "usr/etc", rootfs_fd, "etc", error))
return FALSE;
}
/* Process the remove-files element */
for (guint i = 0; i < len; i++)
{
const char *val = _rpmostree_jsonutil_array_require_string_element (remove, i, error);
Expand All @@ -1449,6 +1461,12 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
if (!glnx_shutil_rm_rf_at (rootfs_fd, val, cancellable, error))
return FALSE;
}
if (len > 0)
{
/* And put /etc back to /usr/etc */
if (!rename_if_exists (rootfs_fd, "etc", rootfs_fd, "usr/etc", error))
return FALSE;
}

/* This works around a potential issue with libsolv if we go down the
* rpmostree_get_pkglist_for_root() path. Though rpm has been using the
Expand Down Expand Up @@ -1477,12 +1495,20 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
cancellable, error))
return glnx_prefix_error (error, "Reading package set");

/* Backwards compatibility */
if (!rename_if_exists (rootfs_fd, "usr/etc", rootfs_fd, "etc", error))
return FALSE;

for (guint i = 0; i < len; i++)
{
JsonArray *elt = json_array_get_array_element (remove, i);
if (!handle_remove_files_from_package (rootfs_fd, refsack, elt, cancellable, error))
return FALSE;
}

/* Backwards compatibility */
if (!rename_if_exists (rootfs_fd, "etc", rootfs_fd, "usr/etc", error))
return FALSE;
}

{
Expand All @@ -1502,7 +1528,7 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
{
/* let's try to find the first non-symlink */
const char *os_release[] = {
"etc/os-release",
"usr/etc/os-release",
"usr/lib/os-release",
"usr/lib/os.release.d/os-release-fedora"
};
Expand Down Expand Up @@ -1593,7 +1619,6 @@ rpmostree_treefile_postprocessing (int rootfs_fd,
* Walk over the root filesystem and perform some core conversions
* from RPM conventions to OSTree conventions. For example:
*
* * Move /etc to /usr/etc
* * Checksum the kernel in /boot
* * Migrate content in /var to systemd-tmpfiles
*/
Expand Down

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