| #![unstable(reason = "not public", issue = "none", feature = "fd")] |
| |
| #[cfg(test)] |
| mod tests; |
| |
| 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; |
| |
| #[cfg(any( |
| target_os = "dragonfly", |
| target_os = "freebsd", |
| target_os = "ios", |
| target_os = "macos", |
| target_os = "netbsd", |
| target_os = "openbsd", |
| ))] |
| const fn max_iov() -> usize { |
| libc::IOV_MAX as usize |
| } |
| |
| #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "linux"))] |
| const fn max_iov() -> usize { |
| libc::UIO_MAXIOV as usize |
| } |
| |
| #[cfg(not(any( |
| target_os = "android", |
| target_os = "dragonfly", |
| target_os = "emscripten", |
| target_os = "freebsd", |
| target_os = "ios", |
| target_os = "linux", |
| target_os = "macos", |
| target_os = "netbsd", |
| target_os = "openbsd", |
| )))] |
| const fn max_iov() -> usize { |
| 16 // The minimum value required by POSIX. |
| } |
| |
| 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(), max_iov()) 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(), max_iov()) 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", |
| target_os = "vxworks" |
| )))] |
| 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", |
| target_os = "vxworks" |
| ))] |
| 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) }; |
| } |
| } |
