fix(io): read extended attribute sizes with the size query

Cargo.toml

@@ -46,8 +46,8 @@ quick-xml = "0.42"
 percent-encoding = "2.3"
 # Write transaction: extended attributes copied through the atomic rename, fsync fallback,
 # free space and no-replace rename (rustix, fs only), ACL detection on macOS (exacl).
-xattr = "1.6"
-rustix = { version = "1.1", features = ["fs", "process"] }
+xattr = "1.7"
+rustix = { version = "1.1.6", features = ["fs", "process"] }
 exacl = "0.13"
 # Local date of the backup folders (time zone from the system); MIT OR Unlicense, used under MIT.
 jiff = { version = "0.2", default-features = false, features = ["std", "tz-system", "tzdb-zoneinfo"] }

crates/sc-io/src/txn/meta.rs

@@ -153,7 +153,8 @@ pub(crate) fn read_xattr(path: &Path, name: &OsStr) -> std::io::Result<Option<Ve
     use rustix::io::Errno;
     // The size can grow between the two calls; try again a few times.
     for _ in 0..4 {
-        let size = match rustix::fs::lgetxattr(path, name, &mut [0_u8; 0][..]) {
+        // The size query: an empty buffer is not one (since rustix 1.1.6 it reads 0 bytes).
+        let size = match rustix::fs::lgetxattr_query(path, name) {
             Ok(n) => n,
             Err(e) if e == NO_ATTR => return Ok(None),
             Err(e) => return Err(e.into()),

crates/sc-io/tests/resource_fork.rs

@@ -51,7 +51,7 @@ fn listed(p: &Path) -> bool {
 
 /// The size `getxattr(2)` gives the resource fork of `p`.
 fn attribute_size(p: &Path) -> usize {
-    rustix::fs::getxattr(p, RESOURCE_FORK, &mut [0_u8; 0][..]).expect("resource fork attribute")
+    rustix::fs::getxattr_query(p, RESOURCE_FORK).expect("resource fork attribute")
 }
 
 /// A 70,000-byte resource fork (reads of it are cut to the buffer unless sized first).