Use more LFS functions.

On Linux, use mmap64, open64, openat64, and sendfile64 in place of their
non-LFS counterparts.

This is relevant to rust-lang#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 rust-lang#94173 is fixed. But I can't be sure if I've missed something
and maybe some non-LFS functions could sneak in somehow.

Author: Michael Benfield

library/std/src/sys/unix/fs.rs

@@ -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};
 

library/std/src/sys/unix/kernel_copy.rs

@@ -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)]
@@ -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)

library/std/src/sys/unix/mod.rs

@@ -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 },
@@ -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
@@ -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

library/std/src/sys/unix/stack_overflow.rs

@@ -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};
@@ -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());
         }

library/std/src/sys/unix/thread.rs

@@ -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;
@@ -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,