about summary refs log tree commit diff
path: root/library/std/src/sys/unix/fd.rs
diff options
context:
space:
mode:
authormark <markm@cs.wisc.edu>2020-06-11 21:31:49 -0500
committermark <markm@cs.wisc.edu>2020-07-27 19:51:13 -0500
commit2c31b45ae878b821975c4ebd94cc1e49f6073fd0 (patch)
tree14f64e683e3f64dcbcfb8c2c7cb45ac7592e6e09 /library/std/src/sys/unix/fd.rs
parent9be8ffcb0206fc1558069a7b4766090df7877659 (diff)
downloadrust-2c31b45ae878b821975c4ebd94cc1e49f6073fd0.tar.gz
rust-2c31b45ae878b821975c4ebd94cc1e49f6073fd0.zip
mv std libs to library/
Diffstat (limited to 'library/std/src/sys/unix/fd.rs')
-rw-r--r--library/std/src/sys/unix/fd.rs258
1 files changed, 258 insertions, 0 deletions
diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs
new file mode 100644
index 00000000000..84c4d662161
--- /dev/null
+++ b/library/std/src/sys/unix/fd.rs
@@ -0,0 +1,258 @@
+#![unstable(reason = "not public", issue = "none", feature = "fd")]
+
+use crate::cmp;
+use crate::io::{self, Initializer, IoSlice, IoSliceMut, Read};
+use crate::mem;
+use crate::sys::cvt;
+use crate::sys_common::AsInner;
+
+use libc::{c_int, c_void};
+
+#[derive(Debug)]
+pub struct FileDesc {
+    fd: c_int,
+}
+
+// The maximum read limit on most POSIX-like systems is `SSIZE_MAX`,
+// with the man page quoting that if the count of bytes to read is
+// greater than `SSIZE_MAX` the result is "unspecified".
+//
+// On macOS, however, apparently the 64-bit libc is either buggy or
+// intentionally showing odd behavior by rejecting any read with a size
+// larger than or equal to INT_MAX. To handle both of these the read
+// size is capped on both platforms.
+#[cfg(target_os = "macos")]
+const READ_LIMIT: usize = c_int::MAX as usize - 1;
+#[cfg(not(target_os = "macos"))]
+const READ_LIMIT: usize = libc::ssize_t::MAX as usize;
+
+impl FileDesc {
+    pub fn new(fd: c_int) -> FileDesc {
+        FileDesc { fd }
+    }
+
+    pub fn raw(&self) -> c_int {
+        self.fd
+    }
+
+    /// Extracts the actual file descriptor without closing it.
+    pub fn into_raw(self) -> c_int {
+        let fd = self.fd;
+        mem::forget(self);
+        fd
+    }
+
+    pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::read(self.fd, buf.as_mut_ptr() as *mut c_void, cmp::min(buf.len(), READ_LIMIT))
+        })?;
+        Ok(ret as usize)
+    }
+
+    pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::readv(
+                self.fd,
+                bufs.as_ptr() as *const libc::iovec,
+                cmp::min(bufs.len(), c_int::MAX as usize) as c_int,
+            )
+        })?;
+        Ok(ret as usize)
+    }
+
+    #[inline]
+    pub fn is_read_vectored(&self) -> bool {
+        true
+    }
+
+    pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        let mut me = self;
+        (&mut me).read_to_end(buf)
+    }
+
+    pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
+        #[cfg(target_os = "android")]
+        use super::android::cvt_pread64;
+
+        #[cfg(not(target_os = "android"))]
+        unsafe fn cvt_pread64(
+            fd: c_int,
+            buf: *mut c_void,
+            count: usize,
+            offset: i64,
+        ) -> io::Result<isize> {
+            #[cfg(not(target_os = "linux"))]
+            use libc::pread as pread64;
+            #[cfg(target_os = "linux")]
+            use libc::pread64;
+            cvt(pread64(fd, buf, count, offset))
+        }
+
+        unsafe {
+            cvt_pread64(
+                self.fd,
+                buf.as_mut_ptr() as *mut c_void,
+                cmp::min(buf.len(), READ_LIMIT),
+                offset as i64,
+            )
+            .map(|n| n as usize)
+        }
+    }
+
+    pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::write(self.fd, buf.as_ptr() as *const c_void, cmp::min(buf.len(), READ_LIMIT))
+        })?;
+        Ok(ret as usize)
+    }
+
+    pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        let ret = cvt(unsafe {
+            libc::writev(
+                self.fd,
+                bufs.as_ptr() as *const libc::iovec,
+                cmp::min(bufs.len(), c_int::MAX as usize) as c_int,
+            )
+        })?;
+        Ok(ret as usize)
+    }
+
+    #[inline]
+    pub fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
+        #[cfg(target_os = "android")]
+        use super::android::cvt_pwrite64;
+
+        #[cfg(not(target_os = "android"))]
+        unsafe fn cvt_pwrite64(
+            fd: c_int,
+            buf: *const c_void,
+            count: usize,
+            offset: i64,
+        ) -> io::Result<isize> {
+            #[cfg(not(target_os = "linux"))]
+            use libc::pwrite as pwrite64;
+            #[cfg(target_os = "linux")]
+            use libc::pwrite64;
+            cvt(pwrite64(fd, buf, count, offset))
+        }
+
+        unsafe {
+            cvt_pwrite64(
+                self.fd,
+                buf.as_ptr() as *const c_void,
+                cmp::min(buf.len(), READ_LIMIT),
+                offset as i64,
+            )
+            .map(|n| n as usize)
+        }
+    }
+
+    #[cfg(target_os = "linux")]
+    pub fn get_cloexec(&self) -> io::Result<bool> {
+        unsafe { Ok((cvt(libc::fcntl(self.fd, libc::F_GETFD))? & libc::FD_CLOEXEC) != 0) }
+    }
+
+    #[cfg(not(any(
+        target_env = "newlib",
+        target_os = "solaris",
+        target_os = "illumos",
+        target_os = "emscripten",
+        target_os = "fuchsia",
+        target_os = "l4re",
+        target_os = "linux",
+        target_os = "haiku",
+        target_os = "redox"
+    )))]
+    pub fn set_cloexec(&self) -> io::Result<()> {
+        unsafe {
+            cvt(libc::ioctl(self.fd, libc::FIOCLEX))?;
+            Ok(())
+        }
+    }
+    #[cfg(any(
+        target_env = "newlib",
+        target_os = "solaris",
+        target_os = "illumos",
+        target_os = "emscripten",
+        target_os = "fuchsia",
+        target_os = "l4re",
+        target_os = "linux",
+        target_os = "haiku",
+        target_os = "redox"
+    ))]
+    pub fn set_cloexec(&self) -> io::Result<()> {
+        unsafe {
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFD))?;
+            let new = previous | libc::FD_CLOEXEC;
+            if new != previous {
+                cvt(libc::fcntl(self.fd, libc::F_SETFD, new))?;
+            }
+            Ok(())
+        }
+    }
+
+    #[cfg(target_os = "linux")]
+    pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+        unsafe {
+            let v = nonblocking as c_int;
+            cvt(libc::ioctl(self.fd, libc::FIONBIO, &v))?;
+            Ok(())
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+        unsafe {
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFL))?;
+            let new = if nonblocking {
+                previous | libc::O_NONBLOCK
+            } else {
+                previous & !libc::O_NONBLOCK
+            };
+            if new != previous {
+                cvt(libc::fcntl(self.fd, libc::F_SETFL, new))?;
+            }
+            Ok(())
+        }
+    }
+
+    pub fn duplicate(&self) -> io::Result<FileDesc> {
+        // We want to atomically duplicate this file descriptor and set the
+        // CLOEXEC flag, and currently that's done via F_DUPFD_CLOEXEC. This
+        // is a POSIX flag that was added to Linux in 2.6.24.
+        let fd = cvt(unsafe { libc::fcntl(self.raw(), libc::F_DUPFD_CLOEXEC, 0) })?;
+        Ok(FileDesc::new(fd))
+    }
+}
+
+impl<'a> Read for &'a FileDesc {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    unsafe fn initializer(&self) -> Initializer {
+        Initializer::nop()
+    }
+}
+
+impl AsInner<c_int> for FileDesc {
+    fn as_inner(&self) -> &c_int {
+        &self.fd
+    }
+}
+
+impl Drop for FileDesc {
+    fn drop(&mut self) {
+        // Note that errors are ignored when closing a file descriptor. The
+        // reason for this is that if an error occurs we don't actually know if
+        // the file descriptor was closed or not, and if we retried (for
+        // something like EINTR), we might close another valid file descriptor
+        // opened after we closed ours.
+        let _ = unsafe { libc::close(self.fd) };
+    }
+}