Use blkid instead of lsblk to get disk info when udev is not present

- OSBuild does not allow udev rules in loop
devices, for this reason can not rely on labels on
the partitions to create the osmet image, due it
use blkid instead of lsblk that relys on udev.

Signed-off-by: Renata Ravanelli <[email protected]>

docs/release-notes.md

@@ -14,6 +14,7 @@ Minor changes:
 
 Internal changes:
 
+- osmet: Use blkid to get partition information if udev is unavailable
 
 Packaging changes:
 

src/blockdev.rs

@@ -109,19 +109,34 @@ impl Disk {
                 if devinfo.get("TYPE").map(|s| s.as_str()) != Some("part") {
                     continue;
                 }
-                let (mountpoint, swap) = match devinfo.get("MOUNTPOINT") {
-                    Some(mp) if mp == "[SWAP]" => (None, true),
-                    Some(mp) => (Some(mp.to_string()), false),
-                    None => (None, false),
-                };
-                result.push(Partition {
-                    path: name.to_owned(),
-                    label: devinfo.get("LABEL").map(<_>::to_string),
-                    fstype: devinfo.get("FSTYPE").map(<_>::to_string),
-                    parent: self.path.to_owned(),
-                    mountpoint,
-                    swap,
-                });
+                // only trust lsblk output for the following fields if we have udev
+                if have_udev() {
+                    let (mountpoint, swap) = match devinfo.get("MOUNTPOINT") {
+                        Some(mp) if mp == "[SWAP]" => (None, true),
+                        Some(mp) => (Some(mp.to_string()), false),
+                        None => (None, false),
+                    };
+                    result.push(Partition {
+                        path: name.to_owned(),
+                        label: devinfo.get("LABEL").map(<_>::to_string),
+                        fstype: devinfo.get("FSTYPE").map(<_>::to_string),
+                        parent: self.path.to_owned(),
+                        mountpoint,
+                        swap,
+                    });
+                } else {
+                    let devinfo = blkid_single(Path::new(name))?;
+                    // note TYPE here: blkid uses TYPE instead of FSTYPE
+                    let fstype = devinfo.get("TYPE").map(<_>::to_string);
+                    result.push(Partition {
+                        path: name.to_owned(),
+                        label: devinfo.get("LABEL").map(<_>::to_string),
+                        fstype: fstype.to_owned(),
+                        parent: self.path.to_owned(),
+                        mountpoint: None,
+                        swap: fstype.is_some_and(|s| s == "swap"),
+                    });
+                }
             }
         }
         Ok(result)
@@ -800,6 +815,17 @@ pub fn lsblk_single(dev: &Path) -> Result<HashMap<String, String>> {
     Ok(devinfos.remove(0))
 }
 
+pub fn blkid_single(dev: &Path) -> Result<HashMap<String, String>> {
+    let mut devinfos = blkid(Some(vec![dev]))?;
+    if devinfos.len() != 1 {
+        bail!(
+            "expected one blkid result for {}, got: {:?}",
+            dev.display(),
+            devinfos
+        );
+    }
+    Ok(devinfos.remove(0))
+}
 /// Returns all available filesystems.
 /// rereadpt mitigates possible issue with outdated UUIDs on different
 /// paths to the same disk: after 'ignition-ostree-firstboot-uuid'
@@ -822,7 +848,7 @@ fn get_all_filesystems(rereadpt: bool) -> Result<Vec<HashMap<String, String>>> {
         }
         udev_settle()?;
     }
-    blkid()
+    blkid(None)
 }
 
 /// Returns filesystems with given label.
@@ -884,7 +910,7 @@ fn split_blkid_line(line: &str) -> HashMap<String, String> {
     fields
 }
 
-fn blkid() -> Result<Vec<HashMap<String, String>>> {
+fn blkid(devs: Option<Vec<&Path>>) -> Result<Vec<HashMap<String, String>>> {
     // Run blkid with a clean cache to avoid collecting old devices which no
     // longer exist.
     // https://github.com/coreos/coreos-installer/pull/1288#discussion_r1312008111
@@ -893,19 +919,24 @@ fn blkid() -> Result<Vec<HashMap<String, String>>> {
     // the blkid -p below, which we use to probe the devices to not rely on
     // the blkid cache:
     // https://github.com/coreos/fedora-coreos-config/pull/2181#issuecomment-1397386896
-    let devices = {
-        let mut cmd = Command::new("blkid");
-        cmd.arg("--cache-file");
-        cmd.arg("/dev/null");
-        cmd.arg("-o");
-        cmd.arg("device");
-        cmd_output(&mut cmd)?
+    let devices;
+    let cmd_dev: Vec<&Path> = if let Some(paths) = devs {
+        paths
+    } else {
+        devices = {
+            let mut cmd = Command::new("blkid");
+            cmd.arg("--cache-file");
+            cmd.arg("/dev/null");
+            cmd.arg("-o");
+            cmd.arg("device");
+            cmd_output(&mut cmd)?
+        };
+        devices.lines().map(|line| Path::new(line.trim())).collect()
     };
-
     let output = {
         let mut cmd = Command::new("blkid");
         cmd.arg("-p");
-        cmd.args(devices.lines());
+        cmd.args(cmd_dev);
         cmd_output(&mut cmd)?
     };
 
@@ -1141,10 +1172,13 @@ fn disk_has_mbr(file: &mut (impl Read + Seek)) -> Result<bool> {
     Ok(sig == [0x55, 0xaa])
 }
 
+pub fn have_udev() -> bool {
+    Path::new("/run/udev/control").exists()
+}
 pub fn udev_settle() -> Result<()> {
     // "udevadm settle" silently no-ops if the udev socket is missing, and
     // then lsblk can't find partition labels.  Catch this early.
-    if !Path::new("/run/udev/control").exists() {
+    if !have_udev() {
         bail!("udevd socket missing; are we running in a container without /run/udev mounted?");
     }