Move from libc read/write to nix read/write

Replace std from_raw_fd/into_raw_fd dance with nix write

Fixup notifyd build

src/builtins/read.rs

@@ -285,13 +285,14 @@ fn read_in_chunks(fd: RawFd, buff: &mut WString, split_null: bool, do_seek: bool
 
     while !finished {
         let mut inbuf = [0_u8; READ_CHUNK_SIZE];
-        let bytes_read = read_blocked(fd, &mut inbuf);
 
-        if bytes_read <= 0 {
-            eof = true;
-            break;
-        }
-        let bytes_read = bytes_read as usize;
+        let bytes_read = match read_blocked(fd, &mut inbuf) {
+            Ok(0) | Err(_) => {
+                eof = true;
+                break;
+            }
+            Ok(read) => read,
+        };
 
         let bytes_consumed = inbuf[..bytes_read]
             .iter()
@@ -352,9 +353,12 @@ fn read_one_char_at_a_time(
 
         while !finished {
             let mut b = [0_u8; 1];
-            if read_blocked(fd, &mut b) <= 0 {
-                eof = true;
-                break;
+            match read_blocked(fd, &mut b) {
+                Ok(0) | Err(_) => {
+                    eof = true;
+                    break;
+                }
+                _ => {}
             }
             let b = b[0];
 

src/common.rs

@@ -18,7 +18,7 @@ use crate::wutil::encoding::{mbrtowc, wcrtomb, zero_mbstate, AT_LEAST_MB_LEN_MAX
 use crate::wutil::fish_iswalnum;
 use bitflags::bitflags;
 use core::slice;
-use libc::{EINTR, EIO, O_WRONLY, SIGTTOU, SIG_IGN, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO};
+use libc::{EIO, O_WRONLY, SIGTTOU, SIG_IGN, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO};
 use num_traits::ToPrimitive;
 use once_cell::sync::OnceCell;
 use std::env;
@@ -1469,10 +1469,10 @@ fn can_be_encoded(wc: char) -> bool {
 
 /// Call read, blocking and repeating on EINTR. Exits on EAGAIN.
 /// \return the number of bytes read, or 0 on EOF. On EAGAIN, returns -1 if nothing was read.
-pub fn read_blocked(fd: RawFd, buf: &mut [u8]) -> isize {
+pub fn read_blocked(fd: RawFd, buf: &mut [u8]) -> nix::Result<usize> {
     loop {
-        let res = unsafe { libc::read(fd, buf.as_mut_ptr().cast(), buf.len()) };
-        if res < 0 && errno::errno().0 == EINTR {
+        let res = nix::unistd::read(fd, buf);
+        if let Err(nix::Error::EINTR) = res {
             continue;
         }
         return res;
@@ -1496,16 +1496,17 @@ pub fn write_loop<Fd: AsRawFd>(fd: &Fd, buf: &[u8]) -> std::io::Result<usize> {
     let fd = fd.as_raw_fd();
     let mut total = 0;
     while total < buf.len() {
-        let written =
-            unsafe { libc::write(fd, buf[total..].as_ptr() as *const _, buf.len() - total) };
-        if written < 0 {
-            let errno = errno::errno().0;
-            if matches!(errno, libc::EAGAIN | libc::EINTR) {
-                continue;
+        match nix::unistd::write(fd, &buf[total..]) {
+            Ok(written) => {
+                total += written;
+            }
+            Err(err) => {
+                if matches!(err, nix::Error::EAGAIN | nix::Error::EINTR) {
+                    continue;
+                }
+                return Err(std::io::Error::from(err));
             }
-            return Err(std::io::Error::from_raw_os_error(errno));
         }
-        total += written as usize;
     }
     Ok(total)
 }
@@ -1517,15 +1518,17 @@ pub fn write_loop<Fd: AsRawFd>(fd: &Fd, buf: &[u8]) -> std::io::Result<usize> {
 pub fn read_loop<Fd: AsRawFd>(fd: &Fd, buf: &mut [u8]) -> std::io::Result<usize> {
     let fd = fd.as_raw_fd();
     loop {
-        let read = unsafe { libc::read(fd, buf.as_mut_ptr() as *mut _, buf.len()) };
-        if read < 0 {
-            let errno = errno::errno().0;
-            if matches!(errno, libc::EAGAIN | libc::EINTR) {
-                continue;
+        match nix::unistd::read(fd, buf) {
+            Ok(read) => {
+                return Ok(read);
+            }
+            Err(err) => {
+                if matches!(err, nix::Error::EAGAIN | nix::Error::EINTR) {
+                    continue;
+                }
+                return Err(std::io::Error::from(err));
             }
-            return Err(std::io::Error::from_raw_os_error(errno));
         }
-        return Ok(read as usize);
     }
 }
 

src/fd_monitor.rs

@@ -120,20 +120,21 @@ impl FdEventSignaller {
         let c = 1_u8;
         let mut ret;
         loop {
-            ret = unsafe {
-                libc::write(
-                    self.write_fd(),
-                    &c as *const _ as *const c_void,
-                    std::mem::size_of_val(&c),
-                )
-            };
-            if ret >= 0 || errno().0 != EINTR {
-                break;
+            let bytes = c.to_ne_bytes();
+            ret = nix::unistd::write(self.write_fd(), &bytes);
+
+            match ret {
+                Ok(_) => break,
+                Err(nix::Error::EINTR) => continue,
+                Err(_) => break,
             }
         }
-        // EAGAIN occurs if either the pipe buffer is full or the eventfd overflows (very unlikely).
-        if ret < 0 && ![EAGAIN, EWOULDBLOCK].contains(&errno().0) {
-            perror("write");
+
+        if let Err(err) = ret {
+            // EAGAIN occurs if either the pipe buffer is full or the eventfd overflows (very unlikely).
+            if ![nix::Error::EAGAIN, nix::Error::EWOULDBLOCK].contains(&err) {
+                perror("write");
+            }
         }
     }
 

src/fds.rs

@@ -33,23 +33,13 @@ pub struct AutoCloseFd {
 
 impl Read for AutoCloseFd {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
-        unsafe {
-            match libc::read(self.as_raw_fd(), buf.as_mut_ptr() as *mut _, buf.len()) {
-                -1 => Err(std::io::Error::from_raw_os_error(errno::errno().0)),
-                bytes => Ok(bytes as usize),
-            }
-        }
+        nix::unistd::read(self.as_raw_fd(), buf).map_err(std::io::Error::from)
     }
 }
 
 impl Write for AutoCloseFd {
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        unsafe {
-            match libc::write(self.as_raw_fd(), buf.as_ptr() as *const _, buf.len()) {
-                -1 => Err(std::io::Error::from_raw_os_error(errno::errno().0)),
-                bytes => Ok(bytes as usize),
-            }
-        }
+        nix::unistd::write(self.as_raw_fd(), buf).map_err(std::io::Error::from)
     }
 
     fn flush(&mut self) -> std::io::Result<()> {

src/fork_exec/flog_safe.rs

@@ -84,9 +84,7 @@ pub fn flog_impl_async_safe(fd: i32, s: impl FloggableDisplayAsyncSafe) {
     let bytes: &[u8] = s.to_flog_str_async_safe(&mut storage);
     // Note we deliberately do not retry on signals, etc.
     // This is used to report error messages after fork() in the child process.
-    unsafe {
-        let _ = libc::write(fd, bytes.as_ptr() as *const libc::c_void, bytes.len());
-    }
+    let _ = nix::unistd::write(fd, bytes);
 }
 
 /// Variant of FLOG which is async-safe to use after fork().

src/history/file.rs

@@ -7,10 +7,9 @@ use std::{
     time::{Duration, SystemTime, UNIX_EPOCH},
 };
 
-use errno::errno;
 use libc::{
-    c_void, lseek, mmap, munmap, EINTR, MAP_ANONYMOUS, MAP_FAILED, MAP_PRIVATE, PROT_READ,
-    PROT_WRITE, SEEK_END, SEEK_SET,
+    lseek, mmap, munmap, MAP_ANONYMOUS, MAP_FAILED, MAP_PRIVATE, PROT_READ, PROT_WRITE, SEEK_END,
+    SEEK_SET,
 };
 
 use super::{HistoryItem, PersistenceMode};
@@ -137,7 +136,7 @@ impl HistoryFileContents {
             if unsafe { lseek(fd, 0, SEEK_SET) } != 0 {
                 return None;
             }
-            if !read_from_fd(fd, region.as_mut()) {
+            if read_from_fd(fd, region.as_mut()).is_err() {
                 return None;
             }
         }
@@ -230,25 +229,19 @@ fn should_mmap() -> bool {
 
 /// Read from `fd` to fill `dest`, zeroing any unused space.
 // Return true on success, false on failure.
-fn read_from_fd(fd: RawFd, dest: &mut [u8]) -> bool {
-    let mut remaining = dest.len();
-    let mut nread = 0;
-    while remaining > 0 {
-        let amt =
-            unsafe { libc::read(fd, (&mut dest[nread]) as *mut u8 as *mut c_void, remaining) };
-        if amt < 0 {
-            if errno().0 != EINTR {
-                return false;
+fn read_from_fd(fd: RawFd, mut dest: &mut [u8]) -> nix::Result<()> {
+    while !dest.is_empty() {
+        match nix::unistd::read(fd, dest) {
+            Ok(0) => break,
+            Ok(amt) => {
+                dest = &mut dest[amt..];
             }
-        } else if amt == 0 {
-            break;
-        } else {
-            remaining -= amt as usize;
-            nread += amt as usize;
+            Err(nix::Error::EINTR) => continue,
+            Err(err) => return Err(err),
         }
     }
-    dest[nread..].fill(0u8);
-    true
+    dest.fill(0u8);
+    Ok(())
 }
 
 fn replace_all(s: &mut Vec<u8>, needle: &[u8], replacement: &[u8]) {

src/input_common.rs

@@ -294,7 +294,7 @@ fn readb(in_fd: RawFd) -> ReadbResult {
         // Check stdin.
         if fdset.test(in_fd) {
             let mut arr: [u8; 1] = [0];
-            if read_blocked(in_fd, &mut arr) != 1 {
+            if read_blocked(in_fd, &mut arr) != Ok(1) {
                 // The terminal has been closed.
                 return ReadbResult::Eof;
             }

src/reader.rs

@@ -13,9 +13,9 @@
 //! end of the list is reached, at which point regular searching will commence.
 
 use libc::{
-    c_char, c_int, c_void, EAGAIN, ECHO, EINTR, EIO, EISDIR, ENOTTY, EPERM, ESRCH, EWOULDBLOCK,
-    ICANON, ICRNL, IEXTEN, INLCR, IXOFF, IXON, ONLCR, OPOST, O_NONBLOCK, O_RDONLY, SIGINT, SIGTTIN,
-    STDIN_FILENO, STDOUT_FILENO, S_IFDIR, TCSANOW, VMIN, VQUIT, VSUSP, VTIME, _POSIX_VDISABLE,
+    c_char, c_int, ECHO, EINTR, EIO, EISDIR, ENOTTY, EPERM, ESRCH, ICANON, ICRNL, IEXTEN, INLCR,
+    IXOFF, IXON, ONLCR, OPOST, O_NONBLOCK, O_RDONLY, SIGINT, SIGTTIN, STDIN_FILENO, STDOUT_FILENO,
+    S_IFDIR, TCSANOW, VMIN, VQUIT, VSUSP, VTIME, _POSIX_VDISABLE,
 };
 use once_cell::sync::Lazy;
 use std::cell::UnsafeCell;
@@ -688,27 +688,31 @@ fn read_ni(parser: &Parser, fd: RawFd, io: &IoChain) -> i32 {
     let mut fd_contents = Vec::with_capacity(usize::try_from(buf.st_size).unwrap());
     loop {
         let mut buff = [0_u8; 4096];
-        let amt = unsafe { libc::read(fd, &mut buff[0] as *mut _ as *mut c_void, buff.len()) };
-        if amt > 0 {
-            fd_contents.extend_from_slice(&buff[..usize::try_from(amt).unwrap()]);
-        } else if amt == 0 {
-            // EOF.
-            break;
-        } else {
-            assert!(amt == -1);
-            let err = errno();
-            if err.0 == EINTR {
-                continue;
-            } else if err.0 == EAGAIN || err.0 == EWOULDBLOCK && make_fd_blocking(fd).is_ok() {
-                // We succeeded in making the fd blocking, keep going.
-                continue;
-            } else {
-                // Fatal error.
-                FLOG!(
-                    error,
-                    wgettext_fmt!("Unable to read input file: %s", err.to_string())
-                );
-                return 1;
+
+        match nix::unistd::read(fd, &mut buff) {
+            Ok(0) => {
+                // EOF.
+                break;
+            }
+            Ok(amt) => {
+                fd_contents.extend_from_slice(&buff[..amt]);
+            }
+            Err(err) => {
+                if err == nix::Error::EINTR {
+                    continue;
+                } else if err == nix::Error::EAGAIN
+                    || err == nix::Error::EWOULDBLOCK && make_fd_blocking(fd).is_ok()
+                {
+                    // We succeeded in making the fd blocking, keep going.
+                    continue;
+                } else {
+                    // Fatal error.
+                    FLOG!(
+                        error,
+                        wgettext_fmt!("Unable to read input file: %s", err.to_string())
+                    );
+                    return 1;
+                }
             }
         }
     }

src/tests/fd_monitor.rs

@@ -76,9 +76,8 @@ impl ItemMaker {
             }
             ItemWakeReason::Readable => {
                 let mut buf = [0u8; 1024];
-                let amt =
-                    unsafe { libc::read(fd.as_raw_fd(), buf.as_mut_ptr() as *mut _, buf.len()) };
-                assert_ne!(amt, -1, "read error!");
+                let res = nix::unistd::read(fd.as_raw_fd(), &mut buf);
+                let amt = res.expect("read error!");
                 self.length_read.fetch_add(amt as usize, Ordering::Relaxed);
                 was_closed = amt == 0;
             }

src/universal_notifier/notifyd.rs

@@ -114,16 +114,16 @@ impl UniversalNotifier for NotifydNotifier {
         let mut read_something = false;
         let mut buff: [u8; 64] = [0; 64];
         loop {
-            let amt_read = unsafe {
-                libc::read(
-                    self.notify_fd,
-                    buff.as_mut_ptr() as *mut libc::c_void,
-                    buff.len(),
-                )
-            };
-            read_something = read_something || amt_read > 0;
-            if amt_read != buff.len() as isize {
-                break;
+            let res = nix::unistd::read(self.notify_fd, &mut buff);
+
+            if let Ok(amt_read) = res {
+                read_something |= amt_read > 0;
+            }
+
+            match res {
+                Ok(amt_read) if amt_read != buff.len() => break,
+                Err(_) => break,
+                _ => continue,
             }
         }
         FLOGF!(

src/wutil/mod.rs

@@ -401,12 +401,8 @@ pub fn wrename(old_name: &wstr, new_name: &wstr) -> libc::c_int {
     unsafe { libc::rename(old_narrow.as_ptr(), new_narrow.as_ptr()) }
 }
 
-pub fn write_to_fd(input: &[u8], fd: RawFd) -> std::io::Result<usize> {
-    let mut file = unsafe { std::fs::File::from_raw_fd(fd) };
-    let amt = file.write(input);
-    // Ensure the file is not closed.
-    file.into_raw_fd();
-    amt
+pub fn write_to_fd(input: &[u8], fd: RawFd) -> nix::Result<usize> {
+    nix::unistd::write(fd, input)
 }
 
 /// Write a wide string to a file descriptor. This avoids doing any additional allocation.