Preparing for merge from rustc

[rust.git] / library / std / src / sys / unix / thread.rs

diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index c1d30dd9d521b318ed83cdf225df4ee918da1fcc..d454a2a717c0639a326555d3dc8b21a60450b1dd 100644 (file)
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -136,7 +136,7 @@ pub fn set_name(name: &CStr) {
 
         unsafe {
             // Available since glibc 2.12, musl 1.1.16, and uClibc 1.0.20.
-            let name = truncate_cstr(name, TASK_COMM_LEN);
+            let name = truncate_cstr::<{ TASK_COMM_LEN }>(name);
             let res = libc::pthread_setname_np(libc::pthread_self(), name.as_ptr());
             // We have no good way of propagating errors here, but in debug-builds let's check that this actually worked.
             debug_assert_eq!(res, 0);
@@ -153,7 +153,7 @@ pub fn set_name(name: &CStr) {
     #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
     pub fn set_name(name: &CStr) {
         unsafe {
-            let name = truncate_cstr(name, libc::MAXTHREADNAMESIZE);
+            let name = truncate_cstr::<{ libc::MAXTHREADNAMESIZE }>(name);
             let res = libc::pthread_setname_np(name.as_ptr());
             // We have no good way of propagating errors here, but in debug-builds let's check that this actually worked.
             debug_assert_eq!(res, 0);
@@ -285,17 +285,12 @@ fn drop(&mut self) {
 }
 
 #[cfg(any(target_os = "linux", target_os = "macos", target_os = "ios", target_os = "watchos"))]
-fn truncate_cstr(cstr: &CStr, max_with_nul: usize) -> crate::borrow::Cow<'_, CStr> {
-    use crate::{borrow::Cow, ffi::CString};
-
-    if cstr.to_bytes_with_nul().len() > max_with_nul {
-        let bytes = cstr.to_bytes()[..max_with_nul - 1].to_vec();
-        // SAFETY: the non-nul bytes came straight from a CStr.
-        // (CString will add the terminating nul.)
-        Cow::Owned(unsafe { CString::from_vec_unchecked(bytes) })
-    } else {
-        Cow::Borrowed(cstr)
+fn truncate_cstr<const MAX_WITH_NUL: usize>(cstr: &CStr) -> [libc::c_char; MAX_WITH_NUL] {
+    let mut result = [0; MAX_WITH_NUL];
+    for (src, dst) in cstr.to_bytes().iter().zip(&mut result[..MAX_WITH_NUL - 1]) {
+        *dst = *src as libc::c_char;
     }
+    result
 }
 
 pub fn available_parallelism() -> io::Result<NonZeroUsize> {
@@ -658,7 +653,10 @@ pub unsafe fn init() -> Option<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 +806,7 @@ pub unsafe fn init() -> Option<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,