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//! Send data from a file to a socket, bypassing userland.
use cfg_if::cfg_if;
use std::os::unix::io::{AsFd, AsRawFd};
use std::ptr;
use libc::{self, off_t};
use crate::errno::Errno;
use crate::Result;
/// Copy up to `count` bytes to `out_fd` from `in_fd` starting at `offset`.
///
/// Returns a `Result` with the number of bytes written.
///
/// If `offset` is `None`, `sendfile` will begin reading at the current offset of `in_fd`and will
/// update the offset of `in_fd`. If `offset` is `Some`, `sendfile` will begin at the specified
/// offset and will not update the offset of `in_fd`. Instead, it will mutate `offset` to point to
/// the byte after the last byte copied.
///
/// `in_fd` must support `mmap`-like operations and therefore cannot be a socket.
///
/// For more information, see [the sendfile(2) man page.](https://man7.org/linux/man-pages/man2/sendfile.2.html) for Linux,
/// see [the sendfile(2) man page.](https://docs.oracle.com/cd/E88353_01/html/E37843/sendfile-3c.html) for Solaris.
#[cfg(any(linux_android, solarish))]
pub fn sendfile<F1: AsFd, F2: AsFd>(
out_fd: F1,
in_fd: F2,
offset: Option<&mut off_t>,
count: usize,
) -> Result<usize> {
let offset = offset
.map(|offset| offset as *mut _)
.unwrap_or(ptr::null_mut());
let ret = unsafe {
libc::sendfile(
out_fd.as_fd().as_raw_fd(),
in_fd.as_fd().as_raw_fd(),
offset,
count,
)
};
Errno::result(ret).map(|r| r as usize)
}
/// Copy up to `count` bytes to `out_fd` from `in_fd` starting at `offset`.
///
/// Returns a `Result` with the number of bytes written.
///
/// If `offset` is `None`, `sendfile` will begin reading at the current offset of `in_fd`and will
/// update the offset of `in_fd`. If `offset` is `Some`, `sendfile` will begin at the specified
/// offset and will not update the offset of `in_fd`. Instead, it will mutate `offset` to point to
/// the byte after the last byte copied.
///
/// `in_fd` must support `mmap`-like operations and therefore cannot be a socket.
///
/// For more information, see [the sendfile(2) man page.](https://man7.org/linux/man-pages/man2/sendfile.2.html)
#[cfg(target_os = "linux")]
pub fn sendfile64<F1: AsFd, F2: AsFd>(
out_fd: F1,
in_fd: F2,
offset: Option<&mut libc::off64_t>,
count: usize,
) -> Result<usize> {
let offset = offset
.map(|offset| offset as *mut _)
.unwrap_or(ptr::null_mut());
let ret = unsafe {
libc::sendfile64(
out_fd.as_fd().as_raw_fd(),
in_fd.as_fd().as_raw_fd(),
offset,
count,
)
};
Errno::result(ret).map(|r| r as usize)
}
cfg_if! {
if #[cfg(any(freebsdlike, apple_targets))] {
use std::io::IoSlice;
#[derive(Clone, Debug)]
struct SendfileHeaderTrailer<'a> {
raw: libc::sf_hdtr,
_headers: Option<Vec<IoSlice<'a>>>,
_trailers: Option<Vec<IoSlice<'a>>>,
}
impl<'a> SendfileHeaderTrailer<'a> {
fn new(
headers: Option<&'a [&'a [u8]]>,
trailers: Option<&'a [&'a [u8]]>
) -> SendfileHeaderTrailer<'a> {
let mut header_iovecs: Option<Vec<IoSlice<'_>>> =
headers.map(|s| s.iter().map(|b| IoSlice::new(b)).collect());
let mut trailer_iovecs: Option<Vec<IoSlice<'_>>> =
trailers.map(|s| s.iter().map(|b| IoSlice::new(b)).collect());
SendfileHeaderTrailer {
raw: libc::sf_hdtr {
headers: {
header_iovecs
.as_mut()
.map_or(ptr::null_mut(), |v| v.as_mut_ptr())
.cast()
},
hdr_cnt: header_iovecs.as_ref().map(|v| v.len()).unwrap_or(0) as i32,
trailers: {
trailer_iovecs
.as_mut()
.map_or(ptr::null_mut(), |v| v.as_mut_ptr())
.cast()
},
trl_cnt: trailer_iovecs.as_ref().map(|v| v.len()).unwrap_or(0) as i32
},
_headers: header_iovecs,
_trailers: trailer_iovecs,
}
}
}
} else if #[cfg(solarish)] {
use std::os::unix::io::BorrowedFd;
use std::marker::PhantomData;
#[derive(Debug, Copy, Clone)]
/// Mapping of the raw C sendfilevec_t struct
pub struct SendfileVec<'fd> {
raw: libc::sendfilevec_t,
phantom: PhantomData<BorrowedFd<'fd>>
}
impl<'fd> SendfileVec<'fd> {
/// initialises SendfileVec to send data directly from the process's address space
/// same in C with sfv_fd set to SFV_FD_SELF.
pub fn newself(
off: off_t,
len: usize
) -> Self {
Self{raw: libc::sendfilevec_t{sfv_fd: libc::SFV_FD_SELF, sfv_flag: 0, sfv_off: off, sfv_len: len}, phantom: PhantomData}
}
/// initialises SendfileVec to send data from `fd`.
pub fn new(
fd: BorrowedFd<'fd>,
off: off_t,
len: usize
) -> SendfileVec<'fd> {
Self{raw: libc::sendfilevec_t{sfv_fd: fd.as_raw_fd(), sfv_flag: 0, sfv_off:off, sfv_len: len}, phantom: PhantomData}
}
}
impl From<SendfileVec<'_>> for libc::sendfilevec_t {
fn from<'fd>(vec: SendfileVec) -> libc::sendfilevec_t {
vec.raw
}
}
}
}
cfg_if! {
if #[cfg(target_os = "freebsd")] {
use libc::c_int;
libc_bitflags!{
/// Configuration options for [`sendfile`.](fn.sendfile.html)
pub struct SfFlags: c_int {
/// Causes `sendfile` to return EBUSY instead of blocking when attempting to read a
/// busy page.
SF_NODISKIO;
/// Causes `sendfile` to sleep until the network stack releases its reference to the
/// VM pages read. When `sendfile` returns, the data is not guaranteed to have been
/// sent, but it is safe to modify the file.
SF_SYNC;
/// Causes `sendfile` to cache exactly the number of pages specified in the
/// `readahead` parameter, disabling caching heuristics.
SF_USER_READAHEAD;
/// Causes `sendfile` not to cache the data read.
SF_NOCACHE;
}
}
/// Read up to `count` bytes from `in_fd` starting at `offset` and write to `out_sock`.
///
/// Returns a `Result` and a count of bytes written. Bytes written may be non-zero even if
/// an error occurs.
///
/// `in_fd` must describe a regular file or shared memory object. `out_sock` must describe a
/// stream socket.
///
/// If `offset` falls past the end of the file, the function returns success and zero bytes
/// written.
///
/// If `count` is `None` or 0, bytes will be read from `in_fd` until reaching the end of
/// file (EOF).
///
/// `headers` and `trailers` specify optional slices of byte slices to be sent before and
/// after the data read from `in_fd`, respectively. The length of headers and trailers sent
/// is included in the returned count of bytes written. The values of `offset` and `count`
/// do not apply to headers or trailers.
///
/// `readahead` specifies the minimum number of pages to cache in memory ahead of the page
/// currently being sent.
///
/// For more information, see
#[allow(clippy::too_many_arguments)]
pub fn sendfile<F1: AsFd, F2: AsFd>(
in_fd: F1,
out_sock: F2,
offset: off_t,
count: Option<usize>,
headers: Option<&[&[u8]]>,
trailers: Option<&[&[u8]]>,
flags: SfFlags,
readahead: u16
) -> (Result<()>, off_t) {
// Readahead goes in upper 16 bits
// Flags goes in lower 16 bits
// see `man 2 sendfile`
let ra32 = u32::from(readahead);
let flags: u32 = (ra32 << 16) | (flags.bits() as u32);
let mut bytes_sent: off_t = 0;
let hdtr = headers.or(trailers).map(|_| SendfileHeaderTrailer::new(headers, trailers));
let hdtr_ptr = hdtr.as_ref().map_or(ptr::null(), |s| &s.raw as *const libc::sf_hdtr);
let return_code = unsafe {
libc::sendfile(in_fd.as_fd().as_raw_fd(),
out_sock.as_fd().as_raw_fd(),
offset,
count.unwrap_or(0),
hdtr_ptr as *mut libc::sf_hdtr,
&mut bytes_sent as *mut off_t,
flags as c_int)
};
(Errno::result(return_code).and(Ok(())), bytes_sent)
}
} else if #[cfg(target_os = "dragonfly")] {
/// Read up to `count` bytes from `in_fd` starting at `offset` and write to `out_sock`.
///
/// Returns a `Result` and a count of bytes written. Bytes written may be non-zero even if
/// an error occurs.
///
/// `in_fd` must describe a regular file. `out_sock` must describe a stream socket.
///
/// If `offset` falls past the end of the file, the function returns success and zero bytes
/// written.
///
/// If `count` is `None` or 0, bytes will be read from `in_fd` until reaching the end of
/// file (EOF).
///
/// `headers` and `trailers` specify optional slices of byte slices to be sent before and
/// after the data read from `in_fd`, respectively. The length of headers and trailers sent
/// is included in the returned count of bytes written. The values of `offset` and `count`
/// do not apply to headers or trailers.
///
/// For more information, see
/// [the sendfile(2) man page.](https://leaf.dragonflybsd.org/cgi/web-man?command=sendfile§ion=2)
pub fn sendfile<F1: AsFd, F2: AsFd>(
in_fd: F1,
out_sock: F2,
offset: off_t,
count: Option<usize>,
headers: Option<&[&[u8]]>,
trailers: Option<&[&[u8]]>,
) -> (Result<()>, off_t) {
let mut bytes_sent: off_t = 0;
let hdtr = headers.or(trailers).map(|_| SendfileHeaderTrailer::new(headers, trailers));
let hdtr_ptr = hdtr.as_ref().map_or(ptr::null(), |s| &s.raw as *const libc::sf_hdtr);
let return_code = unsafe {
libc::sendfile(in_fd.as_fd().as_raw_fd(),
out_sock.as_fd().as_raw_fd(),
offset,
count.unwrap_or(0),
hdtr_ptr as *mut libc::sf_hdtr,
&mut bytes_sent as *mut off_t,
0)
};
(Errno::result(return_code).and(Ok(())), bytes_sent)
}
} else if #[cfg(apple_targets)] {
/// Read bytes from `in_fd` starting at `offset` and write up to `count` bytes to
/// `out_sock`.
///
/// Returns a `Result` and a count of bytes written. Bytes written may be non-zero even if
/// an error occurs.
///
/// `in_fd` must describe a regular file. `out_sock` must describe a stream socket.
///
/// If `offset` falls past the end of the file, the function returns success and zero bytes
/// written.
///
/// If `count` is `None` or 0, bytes will be read from `in_fd` until reaching the end of
/// file (EOF).
///
/// `hdtr` specifies an optional list of headers and trailers to be sent before and after
/// the data read from `in_fd`, respectively. The length of headers and trailers sent is
/// included in the returned count of bytes written. If any headers are specified and
/// `count` is non-zero, the length of the headers will be counted in the limit of total
/// bytes sent. Trailers do not count toward the limit of bytes sent and will always be sent
/// regardless. The value of `offset` does not affect headers or trailers.
///
/// For more information, see
/// [the sendfile(2) man page.](https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man2/sendfile.2.html)
pub fn sendfile<F1: AsFd, F2: AsFd>(
in_fd: F1,
out_sock: F2,
offset: off_t,
count: Option<off_t>,
headers: Option<&[&[u8]]>,
trailers: Option<&[&[u8]]>
) -> (Result<()>, off_t) {
let mut len = count.unwrap_or(0);
let hdtr = headers.or(trailers).map(|_| SendfileHeaderTrailer::new(headers, trailers));
let hdtr_ptr = hdtr.as_ref().map_or(ptr::null(), |s| &s.raw as *const libc::sf_hdtr);
let return_code = unsafe {
libc::sendfile(in_fd.as_fd().as_raw_fd(),
out_sock.as_fd().as_raw_fd(),
offset,
&mut len as *mut off_t,
hdtr_ptr as *mut libc::sf_hdtr,
0)
};
(Errno::result(return_code).and(Ok(())), len)
}
} else if #[cfg(solarish)] {
/// Write data from the vec arrays to `out_sock` and returns a `Result` and a
/// count of bytes written.
///
/// Each `SendfileVec` set needs to be instantiated either with `SendfileVec::new` or
/// `SendfileVec::newself`.
///
/// The former allows to send data from a file descriptor through `fd`,
/// from an offset `off` and for a given amount of data `len`.
///
/// The latter allows to send data from the process's address space, from an offset `off`
/// and for a given amount of data `len`.
///
/// For more information, see
pub fn sendfilev<F: AsFd>(
out_sock: F,
vec: &[SendfileVec]
) -> (Result<()>, usize) {
let mut len = 0usize;
let return_code = unsafe {
libc::sendfilev(out_sock.as_fd().as_raw_fd(), vec.as_ptr() as *const libc::sendfilevec_t, vec.len() as i32, &mut len)
};
(Errno::result(return_code).and(Ok(())), len)
}
}
}