1 files changed, 90 insertions, 0 deletions

diff --git a/src/udev/udev-builtin-blkid.c b/src/udev/udev-builtin-blkid.c
index 23a24da907..a49dd31b8b 100644
--- a/src/udev/udev-builtin-blkid.c
+++ b/src/udev/udev-builtin-blkid.c
@@ -29,6 +29,9 @@
 #include <sys/stat.h>
 #include <blkid/blkid.h>
 
+#include "sd-id128.h"
+#include "gpt.h"
+#include "efivars.h"
 #include "udev.h"
 
 static void print_property(struct udev_device *dev, bool test, const char *name, const char *value)
@@ -100,6 +103,85 @@ static void print_property(struct udev_device *dev, bool test, const char *name,
         }
 }
 
+static int find_gpt_root(struct udev_device *dev, blkid_probe pr, bool test) {
+
+#if defined(GPT_ROOT_NATIVE) && defined(ENABLE_EFI)
+
+        _cleanup_free_ char *root_id = NULL;
+        bool found_esp = false;
+        blkid_partlist pl;
+        int i, nvals, r;
+
+        assert(pr);
+
+        /* Iterate through the partitions on this disk, and see if the
+         * EFI ESP we booted from is on it. If so, find the first root
+         * disk, and add a property indicating its partition UUID. */
+
+        errno = 0;
+        pl = blkid_probe_get_partitions(pr);
+        if (!pl)
+                return errno ? -errno : -ENOMEM;
+
+        nvals = blkid_partlist_numof_partitions(pl);
+        for (i = 0; i < nvals; i++) {
+                blkid_partition pp;
+                const char *stype, *sid;
+                sd_id128_t type;
+
+                pp = blkid_partlist_get_partition(pl, i);
+                if (!pp)
+                        continue;
+
+                sid = blkid_partition_get_uuid(pp);
+                if (!sid)
+                        continue;
+
+                stype = blkid_partition_get_type_string(pp);
+                if (!stype)
+                        continue;
+
+                if (sd_id128_from_string(stype, &type) < 0)
+                        continue;
+
+                if (sd_id128_equal(type, GPT_ESP)) {
+                        sd_id128_t id, esp;
+
+                        /* We found an ESP, let's see if it matches
+                         * the ESP we booted from. */
+
+                        if (sd_id128_from_string(sid, &id) < 0)
+                                continue;
+
+                        r = efi_loader_get_device_part_uuid(&esp);
+                        if (r < 0)
+                                return r;
+
+                        if (sd_id128_equal(id, esp))
+                                found_esp = true;
+
+                } else if (sd_id128_equal(type, GPT_ROOT_NATIVE)) {
+
+                        /* We found a suitable root partition, let's
+                         * remember the first one. */
+
+                        if (!root_id) {
+                                root_id = strdup(sid);
+                                if (!root_id)
+                                        return -ENOMEM;
+                        }
+                }
+        }
+
+        /* We found the ESP on this disk, and also found a root
+         * partition, nice! Let's export its UUID*/
+        if (found_esp && root_id)
+                udev_builtin_add_property(dev, test, "ID_PART_GPT_AUTO_ROOT", root_id);
+#endif
+
+        return 0;
+}
+
 static int probe_superblocks(blkid_probe pr)
 {
         struct stat st;
@@ -145,6 +227,7 @@ static int builtin_blkid(struct udev_device *dev, int argc, char *argv[], bool t
         int i;
         size_t len;
         int err = 0;
+        bool is_gpt = false;
 
         static const struct option options[] = {
                 { "offset", optional_argument, NULL, 'o' },
@@ -203,10 +286,17 @@ static int builtin_blkid(struct udev_device *dev, int argc, char *argv[], bool t
         for (i = 0; i < nvals; i++) {
                 if (blkid_probe_get_value(pr, i, &name, &data, &len))
                         continue;
+
                 len = strnlen((char *) data, len);
                 print_property(dev, test, name, (char *) data);
+
+                if (streq(name, "PTTYPE") && streq(data, "gpt"))
+                        is_gpt = true;
         }
 
+        if (is_gpt)
+                find_gpt_root(dev, pr, test);
+
         blkid_free_probe(pr);
 out:
         if (err < 0)