cksum: Don't panic when checked file returned EIO (uutils#10534)

Author: oech3

src/uucore/src/lib/features/checksum/validate.rs

@@ -676,8 +676,26 @@ fn compute_and_check_digest_from_file(
 
     // TODO: improve function signature to use ReadingMode instead of binary bool
     // Set binary to false because --binary is not supported with --check
-    let (calculated_checksum, _) =
-        digest_reader(&mut digest, &mut file_reader, /* binary */ false).unwrap();
+
+    let (calculated_checksum, _) = match digest_reader(&mut digest, &mut file_reader, false) {
+        Ok(result) => result,
+        Err(err) => {
+            show!(err.map_err_context(|| {
+                locale_aware_escape_name(&real_filename_to_check, QuotingStyle::SHELL_ESCAPE)
+                    .to_string_lossy()
+                    .to_string()
+            }));
+
+            write_file_report(
+                std::io::stdout(),
+                filename,
+                FileChecksumResult::CantOpen,
+                prefix,
+                opts.verbose,
+            );
+            return Err(LineCheckError::CantOpenFile);
+        }
+    };
 
     // Do the checksum validation
     let checksum_correct = match calculated_checksum {

tests/by-util/test_cksum.rs

@@ -3046,3 +3046,17 @@ mod debug_flag {
             .stderr_contains("pclmul");
     }
 }
+
+#[test]
+#[cfg(all(target_os = "linux", not(target_env = "musl")))]
+fn test_check_file_with_io_error() {
+    // /proc/self/mem causes EIO when read without proper seeking
+    new_ucmd!()
+        .arg("-a")
+        .arg("md5")
+        .arg("--check")
+        .pipe_in("d8e8fca2dc0f896fd7cb4cb0031ba249  /proc/self/mem\n")
+        .fails()
+        .stderr_contains("Input/output error")
+        .stdout_contains("FAILED open or read");
+}