Skip to content

Commit

Permalink
Use more LFS functions.
Browse files Browse the repository at this point in the history
On Linux, use mmap64, open64, openat64, and sendfile64 in place of their
non-LFS counterparts.

This is relevant to #94173.

With these changes (together with rust-lang/backtrace-rs#501), the
simple binaries I produce with rustc seem to have no non-LFS functions,
so maybe #94173 is fixed. But I can't be sure if I've missed something
and maybe some non-LFS functions could sneak in somehow.
  • Loading branch information
Michael Benfield committed Dec 7, 2022
1 parent 01fbc5a commit 27011b4
Show file tree
Hide file tree
Showing 5 changed files with 31 additions and 8 deletions.
7 changes: 6 additions & 1 deletion library/std/src/sys/unix/fs.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1743,8 +1743,13 @@ mod remove_dir_impl {
use crate::sys::common::small_c_string::run_path_with_cstr;
use crate::sys::{cvt, cvt_r};

#[cfg(not(all(target_os = "macos", not(target_arch = "aarch64")),))]
#[cfg(not(any(
target_os = "linux",
all(target_os = "macos", not(target_arch = "aarch64"))
)))]
use libc::{fdopendir, openat, unlinkat};
#[cfg(target_os = "linux")]
use libc::{fdopendir, openat64 as openat, unlinkat};
#[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
use macos_weak::{fdopendir, openat, unlinkat};

Expand Down
6 changes: 5 additions & 1 deletion library/std/src/sys/unix/kernel_copy.rs
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,10 @@ use crate::ptr;
use crate::sync::atomic::{AtomicBool, AtomicU8, Ordering};
use crate::sys::cvt;
use crate::sys::weak::syscall;
#[cfg(not(target_os = "linux"))]
use libc::sendfile as sendfile64;
#[cfg(target_os = "linux")]
use libc::sendfile64;
use libc::{EBADF, EINVAL, ENOSYS, EOPNOTSUPP, EOVERFLOW, EPERM, EXDEV};

#[cfg(test)]
Expand Down Expand Up @@ -647,7 +651,7 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) ->

let result = match mode {
SpliceMode::Sendfile => {
cvt(unsafe { libc::sendfile(writer, reader, ptr::null_mut(), chunk_size) })
cvt(unsafe { sendfile64(writer, reader, ptr::null_mut(), chunk_size) })
}
SpliceMode::Splice => cvt(unsafe {
splice(reader, ptr::null_mut(), writer, ptr::null_mut(), chunk_size, 0)
Expand Down
12 changes: 10 additions & 2 deletions library/std/src/sys/unix/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,10 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
)))]
'poll: {
use crate::sys::os::errno;
#[cfg(not(target_os = "linux"))]
use libc::open as open64;
#[cfg(target_os = "linux")]
use libc::open64;
let pfds: &mut [_] = &mut [
libc::pollfd { fd: 0, events: 0, revents: 0 },
libc::pollfd { fd: 1, events: 0, revents: 0 },
Expand All @@ -116,7 +120,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
if pfd.revents & libc::POLLNVAL == 0 {
continue;
}
if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
// If the stream is closed but we failed to reopen it, abort the
// process. Otherwise we wouldn't preserve the safety of
// operations on the corresponding Rust object Stdin, Stdout, or
Expand All @@ -139,9 +143,13 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
)))]
{
use crate::sys::os::errno;
#[cfg(not(target_os = "linux"))]
use libc::open as open64;
#[cfg(target_os = "linux")]
use libc::open64;
for fd in 0..3 {
if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
// If the stream is closed but we failed to reopen it, abort the
// process. Otherwise we wouldn't preserve the safety of
// operations on the corresponding Rust object Stdin, Stdout, or
Expand Down
7 changes: 5 additions & 2 deletions library/std/src/sys/unix/stack_overflow.rs
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,10 @@ mod imp {
use crate::thread;

use libc::MAP_FAILED;
use libc::{mmap, munmap};
#[cfg(not(target_os = "linux"))]
use libc::{mmap as mmap64, munmap};
#[cfg(target_os = "linux")]
use libc::{mmap64, munmap};
use libc::{sigaction, sighandler_t, SA_ONSTACK, SA_SIGINFO, SIGBUS, SIG_DFL};
use libc::{sigaltstack, SIGSTKSZ, SS_DISABLE};
use libc::{MAP_ANON, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE, SIGSEGV};
Expand Down Expand Up @@ -135,7 +138,7 @@ mod imp {
#[cfg(not(any(target_os = "openbsd", target_os = "netbsd", target_os = "linux",)))]
let flags = MAP_PRIVATE | MAP_ANON;
let stackp =
mmap(ptr::null_mut(), SIGSTKSZ + page_size(), PROT_READ | PROT_WRITE, flags, -1, 0);
mmap64(ptr::null_mut(), SIGSTKSZ + page_size(), PROT_READ | PROT_WRITE, flags, -1, 0);
if stackp == MAP_FAILED {
panic!("failed to allocate an alternative stack: {}", io::Error::last_os_error());
}
Expand Down
7 changes: 5 additions & 2 deletions library/std/src/sys/unix/thread.rs
Original file line number Diff line number Diff line change
Expand Up @@ -658,7 +658,10 @@ pub mod guard {
))]
#[cfg_attr(test, allow(dead_code))]
pub mod guard {
use libc::{mmap, mprotect};
#[cfg(not(target_os = "linux"))]
use libc::{mmap as mmap64, mprotect};
#[cfg(target_os = "linux")]
use libc::{mmap64, mprotect};
use libc::{MAP_ANON, MAP_FAILED, MAP_FIXED, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE};

use crate::io;
Expand Down Expand Up @@ -808,7 +811,7 @@ pub mod guard {
// read/write permissions and only then mprotect() it to
// no permissions at all. See issue #50313.
let stackptr = get_stack_start_aligned()?;
let result = mmap(
let result = mmap64(
stackptr,
page_size,
PROT_READ | PROT_WRITE,
Expand Down

0 comments on commit 27011b4

Please sign in to comment.