fix: report read error for device files with -files0-from

src/find/matchers/mod.rs

@@ -62,6 +62,8 @@ use ::regex::Regex;
 use chrono::{DateTime, Datelike, NaiveDateTime, Utc};
 use fs::FileSystemMatcher;
 use ls::Ls;
+#[cfg(unix)]
+use std::os::unix::fs::FileTypeExt;
 use std::{
     error::Error,
     fs::{File, Metadata},
@@ -1031,6 +1033,29 @@ fn parse_files0_args(config: &mut Config) -> Result<(), Box<dyn Error>> {
         let mut file =
             File::open(mode).map_err(|e| format!("cannot open '{}' for reading: {}", mode, e))?;
         file.read_to_end(&mut buffer)?;
+
+        // Read the entire file.
+        let bytes_read = file.read_to_end(&mut buffer)?;
+
+        let is_special = {
+            #[cfg(unix)]
+            {
+                let meta = file
+                    .metadata()
+                    .map_err(|e| format!("cannot stat '{}': {}", mode, e))?;
+                let file_type = meta.file_type();
+                file_type.is_char_device() || file_type.is_block_device()
+            }
+            #[cfg(not(unix))]
+            {
+                false
+            }
+        };
+
+        if bytes_read == 0 && is_special {
+            let err = std::io::Error::other("File descriptor in bad state");
+            return Err(format!("read error: {}: {}", mode, err).into());
+        }
     }
 
     let mut buffer_split: Vec<&[u8]> = buffer.split(|&b| b == 0).collect();

tests/test_find.rs

@@ -1434,3 +1434,23 @@ fn find_exits_cleanly_on_broken_pipe() {
         "find panicked instead of exiting cleanly on a broken pipe:\n{stderr}"
     );
 }
+
+#[test]
+#[cfg(target_os = "linux")]
+fn files0_from_special_file_read_error() {
+    for path in &["/dev/vhost-net", "/dev/vhost-vsock"] {
+        if !Path::new(path).exists() {
+            continue;
+        }
+
+        let file_list_failure = ucmd().arg("-files0-from").arg(path).fails();
+
+        let error_output = file_list_failure.no_stdout().stderr_str();
+        assert!(
+            error_output.contains("read error")
+                || (error_output.contains("cannot open")
+                    && error_output.contains("Permission denied")),
+            "unexpected stderr for {path}: {error_output}"
+        );
+    }
+}