Use nix & Results

src/builtins/eval.rs

@@ -26,11 +26,11 @@ pub fn eval(parser: &Parser, streams: &mut IoStreams, args: &mut [&wstr]) -> Opt
     let mut stdout_fill = None;
     if streams.out_is_piped {
         match IoBufferfill::create_opts(parser.libdata().pods.read_limit, STDOUT_FILENO) {
-            None => {
+            Err(_) => {
                 // We were unable to create a pipe, probably fd exhaustion.
                 return STATUS_CMD_ERROR;
             }
-            Some(buffer) => {
+            Ok(buffer) => {
                 stdout_fill = Some(buffer.clone());
                 ios.push(buffer);
             }
@@ -41,11 +41,11 @@ pub fn eval(parser: &Parser, streams: &mut IoStreams, args: &mut [&wstr]) -> Opt
     let mut stderr_fill = None;
     if streams.err_is_piped {
         match IoBufferfill::create_opts(parser.libdata().pods.read_limit, STDERR_FILENO) {
-            None => {
+            Err(_) => {
                 // We were unable to create a pipe, probably fd exhaustion.
                 return STATUS_CMD_ERROR;
             }
-            Some(buffer) => {
+            Ok(buffer) => {
                 stderr_fill = Some(buffer.clone());
                 ios.push(buffer);
             }

src/exec.rs

@@ -136,7 +136,7 @@ pub fn exec_job(parser: &Parser, job: &Job, block_io: IoChain) -> bool {
         let mut proc_pipes = PartialPipes::default();
         std::mem::swap(&mut proc_pipes.read, &mut pipe_next_read);
         if !p.is_last_in_job {
-            let Some(pipes) = make_autoclose_pipes() else {
+            let Ok(pipes) = make_autoclose_pipes() else {
                 FLOGF!(warning, "%ls", wgettext!(PIPE_ERROR));
                 perror("pipe");
                 aborted_pipeline = true;
@@ -1048,12 +1048,12 @@ fn exec_block_or_func_process(
     if piped_output_needs_buffering {
         // Be careful to handle failure, e.g. too many open fds.
         match IoBufferfill::create() {
-            Some(tmp) => {
+            Ok(tmp) => {
                 // Teach the job about its bufferfill, and add it to our io chain.
                 io_chain.push(tmp.clone());
                 block_output_bufferfill = Some(tmp);
             }
-            None => return Err(()),
+            Err(_) => return Err(()),
         }
     }
 
@@ -1477,8 +1477,7 @@ fn exec_subshell_internal(
 
     // IO buffer creation may fail (e.g. if we have too many open files to make a pipe), so this may
     // be null.
-    let Some(bufferfill) =
-        IoBufferfill::create_opts(parser.libdata().pods.read_limit, STDOUT_FILENO)
+    let Ok(bufferfill) = IoBufferfill::create_opts(parser.libdata().pods.read_limit, STDOUT_FILENO)
     else {
         *break_expand = true;
         return STATUS_CMD_ERROR.unwrap();

src/fd_monitor.rs

@@ -62,7 +62,7 @@ impl FdEventSignaller {
         #[cfg(not(HAVE_EVENTFD))]
         {
             // Implementation using pipes.
-            let Some(pipes) = make_autoclose_pipes() else {
+            let Ok(pipes) = make_autoclose_pipes() else {
                 perror("pipe");
                 exit_without_destructors(1);
             };

src/fds.rs

@@ -6,9 +6,8 @@ use crate::tests::prelude::*;
 use crate::wchar::prelude::*;
 use crate::wutil::perror;
 use errno::{errno, set_errno};
-use libc::{
-    c_int, EINTR, FD_CLOEXEC, F_DUPFD_CLOEXEC, F_GETFD, F_GETFL, F_SETFD, F_SETFL, O_NONBLOCK,
-};
+use libc::{c_int, EINTR, FD_CLOEXEC, F_GETFD, F_GETFL, F_SETFD, F_SETFL, O_NONBLOCK};
+use nix::fcntl::FcntlArg;
 use nix::{fcntl::OFlag, unistd};
 use std::ffi::CStr;
 use std::io::{self, Read, Write};
@@ -130,35 +129,39 @@ pub struct AutoClosePipes {
 
 /// Construct a pair of connected pipes, set to close-on-exec.
 /// \return None on fd exhaustion.
-pub fn make_autoclose_pipes() -> Option<AutoClosePipes> {
-    let mut pipes: [c_int; 2] = [-1, -1];
-
+pub fn make_autoclose_pipes() -> nix::Result<AutoClosePipes> {
     #[allow(unused_mut, unused_assignments)]
     let mut already_cloexec = false;
     #[cfg(HAVE_PIPE2)]
-    {
-        if unsafe { libc::pipe2(&mut pipes[0], libc::O_CLOEXEC) } < 0 {
+    let pipes = match nix::unistd::pipe2(OFlag::O_CLOEXEC) {
+        Ok(pipes) => {
+            already_cloexec = true;
+            pipes
+        }
+        Err(err) => {
             FLOG!(warning, PIPE_ERROR);
             perror("pipe2");
-            return None;
+            return Err(err);
         }
-        already_cloexec = true;
-    }
+    };
     #[cfg(not(HAVE_PIPE2))]
-    if unsafe { libc::pipe(&mut pipes[0]) } < 0 {
-        FLOG!(warning, PIPE_ERROR);
-        perror("pipe2");
-        return None;
-    }
+    let pipes = match nix::unistd::pipe() {
+        Ok(pipes) => pipes,
+        Err(err) => {
+            FLOG!(warning, PIPE_ERROR);
+            perror("pipe2");
+            return Err(err);
+        }
+    };
 
-    let readp = unsafe { OwnedFd::from_raw_fd(pipes[0]) };
-    let writep = unsafe { OwnedFd::from_raw_fd(pipes[1]) };
+    let readp = unsafe { OwnedFd::from_raw_fd(pipes.0) };
+    let writep = unsafe { OwnedFd::from_raw_fd(pipes.1) };
 
     // Ensure our fds are out of the user range.
     let readp = heightenize_fd(readp, already_cloexec)?;
     let writep = heightenize_fd(writep, already_cloexec)?;
 
-    Some(AutoClosePipes {
+    Ok(AutoClosePipes {
         read: readp,
         write: writep,
     })
@@ -170,23 +173,26 @@ pub fn make_autoclose_pipes() -> Option<AutoClosePipes> {
 /// setting it again.
 /// \return the fd, which always has CLOEXEC set; or an invalid fd on failure, in
 /// which case an error will have been printed, and the input fd closed.
-fn heightenize_fd(fd: OwnedFd, input_has_cloexec: bool) -> Option<OwnedFd> {
+fn heightenize_fd(fd: OwnedFd, input_has_cloexec: bool) -> nix::Result<OwnedFd> {
     let raw_fd = fd.as_raw_fd();
 
     if raw_fd >= FIRST_HIGH_FD {
         if !input_has_cloexec {
             set_cloexec(raw_fd, true);
         }
-        return Some(fd);
-    }
-    // Here we are asking the kernel to give us a cloexec fd.
-    let newfd = unsafe { libc::fcntl(raw_fd, F_DUPFD_CLOEXEC, FIRST_HIGH_FD) };
-    if newfd < 0 {
-        perror("fcntl");
-        return None;
+        return Ok(fd);
     }
 
-    Some(unsafe { OwnedFd::from_raw_fd(newfd) })
+    // Here we are asking the kernel to give us a cloexec fd.
+    let newfd = match nix::fcntl::fcntl(raw_fd, FcntlArg::F_DUPFD_CLOEXEC(FIRST_HIGH_FD)) {
+        Ok(newfd) => newfd,
+        Err(err) => {
+            perror("fcntl");
+            return Err(err);
+        }
+    };
+
+    Ok(unsafe { OwnedFd::from_raw_fd(newfd) })
 }
 
 /// Sets CLO_EXEC on a given fd according to the value of \p should_set.
@@ -292,7 +298,7 @@ fn test_pipes() {
     // Note pipe creation may fail due to fd exhaustion; don't fail in that case.
     let mut pipes = vec![];
     for _i in 0..10 {
-        if let Some(pipe) = make_autoclose_pipes() {
+        if let Ok(pipe) = make_autoclose_pipes() {
             pipes.push(pipe);
         }
     }

src/io.rs

@@ -21,6 +21,7 @@ use libc::{EAGAIN, EINTR, ENOENT, ENOTDIR, EPIPE, EWOULDBLOCK, STDOUT_FILENO};
 use nix::fcntl::OFlag;
 use nix::sys::stat::Mode;
 use std::cell::{RefCell, UnsafeCell};
+use std::io;
 use std::os::fd::{AsRawFd, IntoRawFd, OwnedFd, RawFd};
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::{Arc, Condvar, Mutex, MutexGuard};
@@ -345,14 +346,14 @@ pub struct IoBufferfill {
 impl IoBufferfill {
     /// Create an io_bufferfill_t which, when written from, fills a buffer with the contents.
     /// \returns nullptr on failure, e.g. too many open fds.
-    pub fn create() -> Option<Arc<IoBufferfill>> {
+    pub fn create() -> io::Result<Arc<IoBufferfill>> {
         Self::create_opts(0, STDOUT_FILENO)
     }
     /// Create an io_bufferfill_t which, when written from, fills a buffer with the contents.
     /// \returns nullptr on failure, e.g. too many open fds.
     ///
     /// \param target the fd which this will be dup2'd to - typically stdout.
-    pub fn create_opts(buffer_limit: usize, target: RawFd) -> Option<Arc<IoBufferfill>> {
+    pub fn create_opts(buffer_limit: usize, target: RawFd) -> io::Result<Arc<IoBufferfill>> {
         assert!(target >= 0, "Invalid target fd");
 
         // Construct our pipes.
@@ -365,13 +366,13 @@ impl IoBufferfill {
             Err(e) => {
                 FLOG!(warning, PIPE_ERROR);
                 perror_io("fcntl", &e);
-                return None;
+                return Err(e);
             }
         }
         // Our fillthread gets the read end of the pipe; out_pipe gets the write end.
         let buffer = Arc::new(IoBuffer::new(buffer_limit));
         begin_filling(&buffer, pipes.read);
-        Some(Arc::new(IoBufferfill {
+        Ok(Arc::new(IoBufferfill {
             target,
             write_fd: pipes.write,
             buffer,