sync: open file with nonblock (#10765)

* open file with nonblock and add test

* fix spellcheck

* remove libc dependency; improve errors

---------

Co-authored-by: Sylvestre Ledru <sylvestre@debian.org>

src/uu/sync/locales/en-US.ftl

@@ -9,6 +9,7 @@ sync-help-data = sync only file data, no unneeded metadata (Linux only)
 sync-error-data-needs-argument = --data needs at least one argument
 sync-error-opening-file = error opening { $file }
 sync-error-no-such-file = error opening { $file }: No such file or directory
+sync-error-syncing-file = error syncing { $file }
 
 # Warning messages
 sync-warning-fcntl-failed = warning: failed to reset O_NONBLOCK flag for { $file }: { $error }

src/uu/sync/locales/fr-FR.ftl

@@ -9,6 +9,7 @@ sync-help-data = synchroniser seulement les données des fichiers, pas les méta
 sync-error-data-needs-argument = --data nécessite au moins un argument
 sync-error-opening-file = erreur lors de l'ouverture de { $file }
 sync-error-no-such-file = erreur lors de l'ouverture de { $file } : Aucun fichier ou répertoire de ce type
+sync-error-syncing-file = erreur lors de la synchronisation de { $file }
 
 # Messages d'avertissement
 sync-warning-fcntl-failed = avertissement : échec de la réinitialisation du drapeau O_NONBLOCK pour { $file } : { $error }

src/uu/sync/src/sync.rs

@@ -35,7 +35,11 @@ mod platform {
     #[cfg(any(target_os = "linux", target_os = "android"))]
     use nix::unistd::{fdatasync, syncfs};
     #[cfg(any(target_os = "linux", target_os = "android"))]
-    use std::fs::File;
+    use std::fs::{File, OpenOptions};
+    #[cfg(any(target_os = "linux", target_os = "android"))]
+    use std::os::unix::fs::OpenOptionsExt;
+    #[cfg(any(target_os = "linux", target_os = "android"))]
+    use uucore::display::Quotable;
     #[cfg(any(target_os = "linux", target_os = "android"))]
     use uucore::error::FromIo;
     #[cfg(any(target_os = "linux", target_os = "android"))]
@@ -57,7 +61,11 @@ mod platform {
     /// Logs a warning if fcntl fails but doesn't abort the operation.
     #[cfg(any(target_os = "linux", target_os = "android"))]
     fn open_and_reset_nonblock(path: &str) -> UResult<File> {
-        let f = File::open(path).map_err_context(|| path.to_string())?;
+        let f = OpenOptions::new()
+            .read(true)
+            .custom_flags(OFlag::O_NONBLOCK.bits())
+            .open(path)
+            .map_err_context(|| path.to_string())?;
         // Reset O_NONBLOCK flag if it was set (matches GNU behavior)
         // This is non-critical, so we log errors but don't fail
         if let Err(e) = fcntl(&f, FcntlArg::F_SETFL(OFlag::empty())) {
@@ -73,7 +81,9 @@ mod platform {
     pub fn do_syncfs(files: Vec<String>) -> UResult<()> {
         for path in files {
             let f = open_and_reset_nonblock(&path)?;
-            syncfs(f)?;
+            syncfs(f).map_err_context(
+                || translate!("sync-error-syncing-file", "file" => path.quote()),
+            )?;
         }
         Ok(())
     }
@@ -82,7 +92,9 @@ mod platform {
     pub fn do_fdatasync(files: Vec<String>) -> UResult<()> {
         for path in files {
             let f = open_and_reset_nonblock(&path)?;
-            fdatasync(f)?;
+            fdatasync(f).map_err_context(
+                || translate!("sync-error-syncing-file", "file" => path.quote()),
+            )?;
         }
         Ok(())
     }

tests/by-util/test_sync.rs

@@ -167,3 +167,24 @@ fn test_sync_multiple_files() {
     // Sync both files
     new_ucmd!().arg("--data").arg(&file1).arg(&file2).succeeds();
 }
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[test]
+fn test_sync_data_fifo_fails_immediately() {
+    use std::time::Duration;
+    use uutests::util::TestScenario;
+    use uutests::util_name;
+
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+    at.mkfifo("test-fifo");
+
+    ts.ucmd()
+        .arg("--data")
+        .arg(at.plus_as_string("test-fifo"))
+        .timeout(Duration::from_secs(2))
+        .fails()
+        .stderr_contains("error syncing")
+        .stderr_contains("test-fifo")
+        .stderr_contains("Invalid input");
+}