import: add new "--direct" mode + add controls for turning certain features on/off

This reworks/modernizes the tar/raw import logic and adds the following
new features:

- Adds the ability to control btrfs subvol and quota behaviour which was
  previously always on via an env var and cmdline arg

- Adds control whether to sync() stuff after writing it, similar via env
  var + cmdline arg

- Similar, the QCOW2 unpacking logic that was previously the implied
  default may now be controlled via env var + cmdline arg.

- adds a "direct" mode. In this mode, the systemd-import tool can be
  used as a simple tool for decompressing/unpacking/installing arbitrary
  files, without all the additional meta data and auxiliary resources,
  i.e.  outside of the immediate disk image context. Via the new
  --offset= and --size-max= switches the downloaded data can be written
  to specific locations of a file (which is particularly useful to use
  the tool to download fs images and write them to a partition location
  before actually creating the partition).

We'll later use the latter feature for "sysupdate" concept, where images
can be directly be written to partitions. That way the systemd-import
binary will be used as backend for both "systemd-importd" and
"systemd-sysupdate" and share most of the same code.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/import/import-common.h b/src/import/import-common.h
index d7e8fc485f..36052a2952 100644
--- a/src/import/import-common.h
+++ b/src/import/import-common.h
@@ -3,11 +3,19 @@
 
 #include <sys/types.h>
 
+#include "sd-event.h"
+
 typedef enum ImportFlags {
-        IMPORT_FORCE     = 1 << 0, /* replace existing image */
-        IMPORT_READ_ONLY = 1 << 1, /* make generated image read-only */
+        IMPORT_FORCE          = 1 << 0, /* replace existing image */
+        IMPORT_READ_ONLY      = 1 << 1, /* make generated image read-only */
+        IMPORT_BTRFS_SUBVOL   = 1 << 2, /* tar: preferably create images as btrfs subvols */
+        IMPORT_BTRFS_QUOTA    = 1 << 3, /* tar: set up btrfs quota for new subvolume as child of parent subvolume */
+        IMPORT_CONVERT_QCOW2  = 1 << 4, /* raw: if we detect a qcow2 image, unpack it */
+        IMPORT_DIRECT         = 1 << 5, /* import without rename games */
+        IMPORT_SYNC           = 1 << 6, /* fsync() right before we are done */
 
-        IMPORT_FLAGS_MASK = IMPORT_FORCE|IMPORT_READ_ONLY,
+        IMPORT_FLAGS_MASK_TAR = IMPORT_FORCE|IMPORT_READ_ONLY|IMPORT_BTRFS_SUBVOL|IMPORT_BTRFS_QUOTA|IMPORT_DIRECT|IMPORT_SYNC,
+        IMPORT_FLAGS_MASK_RAW = IMPORT_FORCE|IMPORT_READ_ONLY|IMPORT_CONVERT_QCOW2|IMPORT_DIRECT|IMPORT_SYNC,
 } ImportFlags;
 
 int import_make_read_only_fd(int fd);
@@ -17,3 +25,7 @@ int import_fork_tar_c(const char *path, pid_t *ret);
 int import_fork_tar_x(const char *path, pid_t *ret);
 
 int import_mangle_os_tree(const char *path);
+
+bool import_validate_local(const char *name, ImportFlags flags);
+
+int import_allocate_event_with_signals(sd_event **ret);