Merge pull request #2018 from sylvestre/revert-cat

Fix bug #2017 - cat isn't working

Cargo.lock

@@ -1581,8 +1581,7 @@ name = "uu_cat"
 version = "0.0.5"
 dependencies = [
  "clap",
- "nix 0.20.0",
+ "quick-error",
- "thiserror",
  "unix_socket",
  "uucore",
  "uucore_procs",

src/uu/cat/Cargo.toml

@@ -16,16 +16,13 @@ path = "src/cat.rs"
 
 [dependencies]
 clap = "2.33"
-thiserror = "1.0"
+quick-error = "1.2.3"
 uucore = { version=">=0.0.8", package="uucore", path="../../uucore", features=["fs"] }
 uucore_procs = { version=">=0.0.5", package="uucore_procs", path="../../uucore_procs" }
 
 [target.'cfg(unix)'.dependencies]
 unix_socket = "0.5.0"
 
-[target.'cfg(any(target_os = "linux", target_os = "android"))'.dependencies]
-nix = "0.20"
-
 [[bin]]
 name = "cat"
 path = "src/main.rs"

src/uu/cat/src/cat.rs

@@ -3,13 +3,14 @@
 // (c) Jordi Boggiano <j.boggiano@seld.be>
 // (c) Evgeniy Klyuchikov <evgeniy.klyuchikov@gmail.com>
 // (c) Joshua S. Miller <jsmiller@uchicago.edu>
-// (c) Árni Dagur <arni@dagur.eu>
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
 // spell-checker:ignore (ToDO) nonprint nonblank nonprinting
 
+#[macro_use]
+extern crate quick_error;
 #[cfg(unix)]
 extern crate unix_socket;
 #[macro_use]
@@ -17,9 +18,9 @@ extern crate uucore;
 
 // last synced with: cat (GNU coreutils) 8.13
 use clap::{App, Arg};
+use quick_error::ResultExt;
 use std::fs::{metadata, File};
-use std::io::{self, Read, Write};
+use std::io::{self, stderr, stdin, stdout, BufWriter, Read, Write};
-use thiserror::Error;
 use uucore::fs::is_stdin_interactive;
 
 /// Unix domain socket support
@@ -30,44 +31,12 @@ use std::os::unix::fs::FileTypeExt;
 #[cfg(unix)]
 use unix_socket::UnixStream;
 
-#[cfg(any(target_os = "linux", target_os = "android"))]
-use nix::errno::Errno;
-/// Linux splice support
-#[cfg(any(target_os = "linux", target_os = "android"))]
-use nix::fcntl::{splice, SpliceFFlags};
-#[cfg(any(target_os = "linux", target_os = "android"))]
-use nix::unistd::pipe;
-#[cfg(any(target_os = "linux", target_os = "android"))]
-use std::os::unix::io::{AsRawFd, RawFd};
-
 static NAME: &str = "cat";
 static VERSION: &str = env!("CARGO_PKG_VERSION");
 static SYNTAX: &str = "[OPTION]... [FILE]...";
 static SUMMARY: &str = "Concatenate FILE(s), or standard input, to standard output
  With no FILE, or when FILE is -, read standard input.";
 
-#[derive(Error, Debug)]
-enum CatError {
-    /// Wrapper around `io::Error`
-    #[error("{0}")]
-    Io(#[from] io::Error),
-    /// Wrapper around `nix::Error`
-    #[cfg(any(target_os = "linux", target_os = "android"))]
-    #[error("{0}")]
-    Nix(#[from] nix::Error),
-    /// Unknown file type; it's not a regular file, socket, etc.
-    #[error("{}: unknown filetype: {}", path, ft_debug)]
-    UnknownFiletype {
-        path: String,
-        /// A debug print of the file type
-        ft_debug: String,
-    },
-    #[error("{0}: Expected a file, found directory")]
-    IsDirectory(String),
-}
-
-type CatResult<T> = Result<T, CatError>;
-
 #[derive(PartialEq)]
 enum NumberingMode {
     None,
@@ -75,6 +44,39 @@ enum NumberingMode {
     All,
 }
 
+quick_error! {
+    #[derive(Debug)]
+    enum CatError {
+        /// Wrapper for io::Error with path context
+        Input(err: io::Error, path: String) {
+            display("cat: {0}: {1}", path, err)
+            context(path: &'a str, err: io::Error) -> (err, path.to_owned())
+            cause(err)
+        }
+
+        /// Wrapper for io::Error with no context
+        Output(err: io::Error) {
+            display("cat: {0}", err) from()
+            cause(err)
+        }
+
+        /// Unknown Filetype  classification
+        UnknownFiletype(path: String) {
+            display("cat: {0}: unknown filetype", path)
+        }
+
+        /// At least one error was encountered in reading or writing
+        EncounteredErrors(count: usize) {
+            display("cat: encountered {0} errors", count)
+        }
+
+        /// Denotes an error caused by trying to `cat` a directory
+        IsDirectory(path: String) {
+            display("cat: {0}: Is a directory", path)
+        }
+    }
+}
+
 struct OutputOptions {
     /// Line numbering mode
     number: NumberingMode,
@@ -85,56 +87,21 @@ struct OutputOptions {
     /// display TAB characters as `tab`
     show_tabs: bool,
 
-    /// Show end of lines
+    /// If `show_tabs == true`, this string will be printed in the
-    show_ends: bool,
+    /// place of tabs
+    tab: String,
+
+    /// Can be set to show characters other than '\n' a the end of
+    /// each line, e.g. $
+    end_of_line: String,
 
     /// use ^ and M- notation, except for LF (\\n) and TAB (\\t)
     show_nonprint: bool,
 }
 
-impl OutputOptions {
-    fn tab(&self) -> &'static str {
-        if self.show_tabs {
-            "^I"
-        } else {
-            "\t"
-        }
-    }
-
-    fn end_of_line(&self) -> &'static str {
-        if self.show_ends {
-            "$\n"
-        } else {
-            "\n"
-        }
-    }
-
-    /// We can write fast if we can simply copy the contents of the file to
-    /// stdout, without augmenting the output with e.g. line numbers.
-    fn can_write_fast(&self) -> bool {
-        !(self.show_tabs
-            || self.show_nonprint
-            || self.show_ends
-            || self.squeeze_blank
-            || self.number != NumberingMode::None)
-    }
-}
-
-/// State that persists between output of each file. This struct is only used
-/// when we can't write fast.
-struct OutputState {
-    /// The current line number
-    line_number: usize,
-
-    /// Whether the output cursor is at the beginning of a new line
-    at_line_start: bool,
-}
-
 /// Represents an open file handle, stream, or other device
-struct InputHandle<R: Read> {
+struct InputHandle {
-    #[cfg(any(target_os = "linux", target_os = "android"))]
+    reader: Box<dyn Read>,
-    file_descriptor: RawFd,
-    reader: R,
     is_interactive: bool,
 }
 
@@ -157,6 +124,8 @@ enum InputType {
     Socket,
 }
 
+type CatResult<T> = Result<T, CatError>;
+
 mod options {
     pub static FILE: &str = "file";
     pub static SHOW_ALL: &str = "show-all";
@@ -274,14 +243,30 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         None => vec!["-".to_owned()],
     };
 
-    let options = OutputOptions {
+    let can_write_fast = !(show_tabs
-        show_ends,
+        || show_nonprint
-        number: number_mode,
+        || show_ends
-        show_nonprint,
+        || squeeze_blank
-        show_tabs,
+        || number_mode != NumberingMode::None);
-        squeeze_blank,
+
+    let success = if can_write_fast {
+        write_fast(files).is_ok()
+    } else {
+        let tab = if show_tabs { "^I" } else { "\t" }.to_owned();
+
+        let end_of_line = if show_ends { "$\n" } else { "\n" }.to_owned();
+
+        let options = OutputOptions {
+            end_of_line,
+            number: number_mode,
+            show_nonprint,
+            show_tabs,
+            squeeze_blank,
+            tab,
+        };
+
+        write_lines(files, &options).is_ok()
     };
-    let success = cat_files(files, &options).is_ok();
 
     if success {
         0
@@ -290,76 +275,6 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     }
 }
 
-fn cat_handle<R: Read>(
-    handle: &mut InputHandle<R>,
-    options: &OutputOptions,
-    state: &mut OutputState,
-) -> CatResult<()> {
-    if options.can_write_fast() {
-        write_fast(handle)
-    } else {
-        write_lines(handle, &options, state)
-    }
-}
-
-fn cat_path(path: &str, options: &OutputOptions, state: &mut OutputState) -> CatResult<()> {
-    if path == "-" {
-        let stdin = io::stdin();
-        let mut handle = InputHandle {
-            #[cfg(any(target_os = "linux", target_os = "android"))]
-            file_descriptor: stdin.as_raw_fd(),
-            reader: stdin,
-            is_interactive: is_stdin_interactive(),
-        };
-        return cat_handle(&mut handle, &options, state);
-    }
-    match get_input_type(path)? {
-        InputType::Directory => Err(CatError::IsDirectory(path.to_owned())),
-        #[cfg(unix)]
-        InputType::Socket => {
-            let socket = UnixStream::connect(path)?;
-            socket.shutdown(Shutdown::Write)?;
-            let mut handle = InputHandle {
-                #[cfg(any(target_os = "linux", target_os = "android"))]
-                file_descriptor: socket.as_raw_fd(),
-                reader: socket,
-                is_interactive: false,
-            };
-            cat_handle(&mut handle, &options, state)
-        }
-        _ => {
-            let file = File::open(path)?;
-            let mut handle = InputHandle {
-                #[cfg(any(target_os = "linux", target_os = "android"))]
-                file_descriptor: file.as_raw_fd(),
-                reader: file,
-                is_interactive: false,
-            };
-            cat_handle(&mut handle, &options, state)
-        }
-    }
-}
-
-fn cat_files(files: Vec<String>, options: &OutputOptions) -> Result<(), u32> {
-    let mut error_count = 0;
-    let mut state = OutputState {
-        line_number: 1,
-        at_line_start: true,
-    };
-
-    for path in &files {
-        if let Err(err) = cat_path(path, &options, &mut state) {
-            show_error!("{}", err);
-            error_count += 1;
-        }
-    }
-    if error_count == 0 {
-        Ok(())
-    } else {
-        Err(error_count)
-    }
-}
-
 /// Classifies the `InputType` of file at `path` if possible
 ///
 /// # Arguments
@@ -370,8 +285,7 @@ fn get_input_type(path: &str) -> CatResult<InputType> {
         return Ok(InputType::StdIn);
     }
 
-    let ft = metadata(path)?.file_type();
+    match metadata(path).context(path)?.file_type() {
-    match ft {
         #[cfg(unix)]
         ft if ft.is_block_device() => Ok(InputType::BlockDevice),
         #[cfg(unix)]
@@ -383,113 +297,125 @@ fn get_input_type(path: &str) -> CatResult<InputType> {
         ft if ft.is_dir() => Ok(InputType::Directory),
         ft if ft.is_file() => Ok(InputType::File),
         ft if ft.is_symlink() => Ok(InputType::SymLink),
-        _ => Err(CatError::UnknownFiletype {
+        _ => Err(CatError::UnknownFiletype(path.to_owned())),
-            path: path.to_owned(),
-            ft_debug: format!("{:?}", ft),
-        }),
     }
 }
 
-/// Writes handle to stdout with no configuration. This allows a
+/// Returns an InputHandle from which a Reader can be accessed or an
-/// simple memory copy.
+/// error
-fn write_fast<R: Read>(handle: &mut InputHandle<R>) -> CatResult<()> {
-    let stdout = io::stdout();
-    let mut stdout_lock = stdout.lock();
-    #[cfg(any(target_os = "linux", target_os = "android"))]
-    {
-        // If we're on Linux or Android, try to use the splice() system call
-        // for faster writing. If it works, we're done.
-        if !write_fast_using_splice(handle, stdout.as_raw_fd())? {
-            return Ok(());
-        }
-    }
-    // If we're not on Linux or Android, or the splice() call failed,
-    // fall back on slower writing.
-    let mut buf = [0; 1024 * 64];
-    while let Ok(n) = handle.reader.read(&mut buf) {
-        if n == 0 {
-            break;
-        }
-        stdout_lock.write_all(&buf[..n])?;
-    }
-    Ok(())
-}
-
-/// This function is called from `write_fast()` on Linux and Android. The
-/// function `splice()` is used to move data between two file descriptors
-/// without copying between kernel- and userspace. This results in a large
-/// speedup.
 ///
-/// The `bool` in the result value indicates if we need to fall back to normal
+/// # Arguments
-/// copying or not. False means we don't have to.
+///
-#[cfg(any(target_os = "linux", target_os = "android"))]
+/// * `path` - `InputHandler` will wrap a reader from this file path
-#[inline]
+fn open(path: &str) -> CatResult<InputHandle> {
-fn write_fast_using_splice<R: Read>(handle: &mut InputHandle<R>, writer: RawFd) -> CatResult<bool> {
+    if path == "-" {
-    const BUF_SIZE: usize = 1024 * 16;
+        let stdin = stdin();
+        return Ok(InputHandle {
+            reader: Box::new(stdin) as Box<dyn Read>,
+            is_interactive: is_stdin_interactive(),
+        });
+    }
 
-    let (pipe_rd, pipe_wr) = pipe()?;
+    match get_input_type(path)? {
-
+        InputType::Directory => Err(CatError::IsDirectory(path.to_owned())),
-    // We only fall back if splice fails on the first call.
+        #[cfg(unix)]
-    match splice(
+        InputType::Socket => {
-        handle.file_descriptor,
+            let socket = UnixStream::connect(path).context(path)?;
-        None,
+            socket.shutdown(Shutdown::Write).context(path)?;
-        pipe_wr,
+            Ok(InputHandle {
-        None,
+                reader: Box::new(socket) as Box<dyn Read>,
-        BUF_SIZE,
+                is_interactive: false,
-        SpliceFFlags::empty(),
+            })
-    ) {
-        Ok(n) => {
-            if n == 0 {
-                return Ok(false);
-            }
         }
-        Err(err) => {
+        _ => {
-            match err.as_errno() {
+            let file = File::open(path).context(path)?;
-                Some(Errno::EPERM) | Some(Errno::ENOSYS) | Some(Errno::EINVAL) => {
+            Ok(InputHandle {
-                    // EPERM indicates the call was blocked by seccomp.
+                reader: Box::new(file) as Box<dyn Read>,
-                    // ENOSYS indicates we're running on an ancient Kernel.
+                is_interactive: false,
-                    // EINVAL indicates some other failure.
+            })
-                    return Ok(true);
+        }
-                }
+    }
-                _ => {
+}
-                    // Other errors include running out of memory, etc. We
+
-                    // don't attempt to fall back from these.
+/// Writes files to stdout with no configuration.  This allows a
-                    return Err(err)?;
+/// simple memory copy. Returns `Ok(())` if no errors were
+/// encountered, or an error with the number of errors encountered.
+///
+/// # Arguments
+///
+/// * `files` - There is no short circuit when encountering an error
+/// reading a file in this vector
+fn write_fast(files: Vec<String>) -> CatResult<()> {
+    let mut writer = stdout();
+    let mut in_buf = [0; 1024 * 64];
+    let mut error_count = 0;
+
+    for file in files {
+        match open(&file[..]) {
+            Ok(mut handle) => {
+                while let Ok(n) = handle.reader.read(&mut in_buf) {
+                    if n == 0 {
+                        break;
+                    }
+                    writer.write_all(&in_buf[..n]).context(&file[..])?;
                 }
             }
+            Err(error) => {
+                writeln!(&mut stderr(), "{}", error)?;
+                error_count += 1;
+            }
         }
     }
 
-    loop {
+    match error_count {
-        let n = splice(
+        0 => Ok(()),
-            handle.file_descriptor,
+        _ => Err(CatError::EncounteredErrors(error_count)),
-            None,
+    }
-            pipe_wr,
+}
-            None,
+
-            BUF_SIZE,
+/// State that persists between output of each file
-            SpliceFFlags::empty(),
+struct OutputState {
-        )?;
+    /// The current line number
-        if n == 0 {
+    line_number: usize,
-            // We read 0 bytes from the input,
+
-            // which means we're done copying.
+    /// Whether the output cursor is at the beginning of a new line
-            break;
+    at_line_start: bool,
+}
+
+/// Writes files to stdout with `options` as configuration.  Returns
+/// `Ok(())` if no errors were encountered, or an error with the
+/// number of errors encountered.
+///
+/// # Arguments
+///
+/// * `files` - There is no short circuit when encountering an error
+/// reading a file in this vector
+fn write_lines(files: Vec<String>, options: &OutputOptions) -> CatResult<()> {
+    let mut error_count = 0;
+    let mut state = OutputState {
+        line_number: 1,
+        at_line_start: true,
+    };
+
+    for file in files {
+        if let Err(error) = write_file_lines(&file, options, &mut state) {
+            writeln!(&mut stderr(), "{}", error).context(&file[..])?;
+            error_count += 1;
         }
-        splice(pipe_rd, None, writer, None, BUF_SIZE, SpliceFFlags::empty())?;
     }
 
-    Ok(false)
+    match error_count {
+        0 => Ok(()),
+        _ => Err(CatError::EncounteredErrors(error_count)),
+    }
 }
 
 /// Outputs file contents to stdout in a line-by-line fashion,
 /// propagating any errors that might occur.
-fn write_lines<R: Read>(
+fn write_file_lines(file: &str, options: &OutputOptions, state: &mut OutputState) -> CatResult<()> {
-    handle: &mut InputHandle<R>,
+    let mut handle = open(file)?;
-    options: &OutputOptions,
-    state: &mut OutputState,
-) -> CatResult<()> {
     let mut in_buf = [0; 1024 * 31];
-    let stdout = io::stdout();
+    let mut writer = BufWriter::with_capacity(1024 * 64, stdout());
-    let mut writer = stdout.lock();
     let mut one_blank_kept = false;
 
     while let Ok(n) = handle.reader.read(&mut in_buf) {
@@ -507,9 +433,9 @@ fn write_lines<R: Read>(
                         write!(&mut writer, "{0:6}\t", state.line_number)?;
                         state.line_number += 1;
                     }
-                    writer.write_all(options.end_of_line().as_bytes())?;
+                    writer.write_all(options.end_of_line.as_bytes())?;
                     if handle.is_interactive {
-                        writer.flush()?;
+                        writer.flush().context(file)?;
                     }
                 }
                 state.at_line_start = true;
@@ -524,7 +450,7 @@ fn write_lines<R: Read>(
 
             // print to end of line or end of buffer
             let offset = if options.show_nonprint {
-                write_nonprint_to_end(&in_buf[pos..], &mut writer, options.tab().as_bytes())
+                write_nonprint_to_end(&in_buf[pos..], &mut writer, options.tab.as_bytes())
             } else if options.show_tabs {
                 write_tab_to_end(&in_buf[pos..], &mut writer)
             } else {
@@ -536,7 +462,7 @@ fn write_lines<R: Read>(
                 break;
             }
             // print suitable end of line
-            writer.write_all(options.end_of_line().as_bytes())?;
+            writer.write_all(options.end_of_line.as_bytes())?;
             if handle.is_interactive {
                 writer.flush()?;
             }