bjoernager/rust
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Make sockaddr_un safe and use copy_nonoverlapping

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The creation of libc::sockaddr_un is a safe operation, no need for it to
be unsafe.

This also uses the more performant copy_nonoverlapping instead of an
iterator.
This commit is contained in:
Thomas de Zeeuw 2022-01-27 09:52:59 +01:00
parent c1cd200922
commit ca9a3c9a9f
1 changed files with 11 additions and 8 deletions
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19
library/std/src/os/unix/net/addr.rs
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@ -2,7 +2,7 @@ use crate::ffi::OsStr;
use crate::os::unix::ffi::OsStrExt; use crate::os::unix::ffi::OsStrExt;
use crate::path::Path; use crate::path::Path;
use crate::sys::cvt; use crate::sys::cvt;
use crate::{ascii, fmt, io, iter, mem, ptr}; use crate::{ascii, fmt, io, mem, ptr};
// FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here? // FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here?
#[cfg(not(unix))] #[cfg(not(unix))]
@ -22,8 +22,9 @@ fn sun_path_offset(addr: &libc::sockaddr_un) -> usize {
path - base path - base
} }
pub(super) unsafe fn sockaddr_un(path: &Path) -> io::Result<(libc::sockaddr_un, libc::socklen_t)> { pub(super) fn sockaddr_un(path: &Path) -> io::Result<(libc::sockaddr_un, libc::socklen_t)> {
let mut addr: libc::sockaddr_un = mem::zeroed(); // SAFETY: All zeros is a valid representation for `sockaddr_un`.
let mut addr: libc::sockaddr_un = unsafe { mem::zeroed() };
addr.sun_family = libc::AF_UNIX as libc::sa_family_t; addr.sun_family = libc::AF_UNIX as libc::sa_family_t;
let bytes = path.as_os_str().as_bytes(); let bytes = path.as_os_str().as_bytes();
@ -41,11 +42,13 @@ pub(super) unsafe fn sockaddr_un(path: &Path) -> io::Result<(libc::sockaddr_un,
&"path must be shorter than SUN_LEN", &"path must be shorter than SUN_LEN",
)); ));
} }
for (dst, src) in iter::zip(&mut addr.sun_path, bytes) { // SAFETY: `bytes` and `addr.sun_path` are not overlapping and
*dst = *src as libc::c_char; // both point to valid memory.
} // NOTE: We zeroed the memory above, so the path is already null
// null byte for pathname addresses is already there because we zeroed the // terminated.
// struct unsafe {
ptr::copy_nonoverlapping(bytes.as_ptr(), addr.sun_path.as_mut_ptr().cast(), bytes.len())
};
let mut len = sun_path_offset(&addr) + bytes.len(); let mut len = sun_path_offset(&addr) + bytes.len();
match bytes.get(0) { match bytes.get(0) {