Rollup merge of #113334 - fmease:revert-lexing-c-str-lits, r=compiler-errors

Revert the lexing of `c"…"` string literals

Fixes \[after beta-backport\] #113235.
Further progress is tracked in #113333.

This PR *manually* reverts parts of #108801 (since a git-revert would've been too coarse-grained & messy)
and git-reverts #111647.

CC `@fee1-dead` (#108801) `@klensy` (#111647)
r? `@compiler-errors`

`@rustbot` label F-c_str_literals beta-nominated

5 files changed, 19 insertions, 18 deletions

diff --git a/library/std/src/sys/unix/args.rs b/library/std/src/sys/unix/args.rs
index f8fa81e6ef1..eafd6821f54 100644
--- a/library/std/src/sys/unix/args.rs
+++ b/library/std/src/sys/unix/args.rs
@@ -242,15 +242,13 @@ mod imp {
         let mut res = Vec::new();
 
         unsafe {
-            let process_info_sel =
-                sel_registerName(c"processInfo".as_ptr() as *const libc::c_uchar);
-            let arguments_sel = sel_registerName(c"arguments".as_ptr() as *const libc::c_uchar);
-            let utf8_sel = sel_registerName(c"UTF8String".as_ptr() as *const libc::c_uchar);
-            let count_sel = sel_registerName(c"count".as_ptr() as *const libc::c_uchar);
-            let object_at_sel =
-                sel_registerName(c"objectAtIndex:".as_ptr() as *const libc::c_uchar);
-
-            let klass = objc_getClass(c"NSProcessInfo".as_ptr() as *const libc::c_uchar);
+            let process_info_sel = sel_registerName("processInfo\0".as_ptr());
+            let arguments_sel = sel_registerName("arguments\0".as_ptr());
+            let utf8_sel = sel_registerName("UTF8String\0".as_ptr());
+            let count_sel = sel_registerName("count\0".as_ptr());
+            let object_at_sel = sel_registerName("objectAtIndex:\0".as_ptr());
+
+            let klass = objc_getClass("NSProcessInfo\0".as_ptr());
             let info = objc_msgSend(klass, process_info_sel);
             let args = objc_msgSend(info, arguments_sel);
 
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index 9cf5cfcc8d5..fbc7f04ce9a 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -1097,7 +1097,7 @@ impl File {
         cfg_has_statx! {
             if let Some(ret) = unsafe { try_statx(
                 fd,
-                c"".as_ptr() as *const c_char,
+                b"\0" as *const _ as *const c_char,
                 libc::AT_EMPTY_PATH | libc::AT_STATX_SYNC_AS_STAT,
                 libc::STATX_ALL,
             ) } {
diff --git a/library/std/src/sys/unix/mod.rs b/library/std/src/sys/unix/mod.rs
index 1b72e21a832..326f1481e19 100644
--- a/library/std/src/sys/unix/mod.rs
+++ b/library/std/src/sys/unix/mod.rs
@@ -1,5 +1,6 @@
 #![allow(missing_docs, nonstandard_style)]
 
+use crate::ffi::CStr;
 use crate::io::ErrorKind;
 
 pub use self::rand::hashmap_random_keys;
@@ -74,7 +75,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     // thread-id for the main thread and so renaming the main thread will rename the
     // process and we only want to enable this on platforms we've tested.
     if cfg!(target_os = "macos") {
-        thread::Thread::set_name(&c"main");
+        thread::Thread::set_name(&CStr::from_bytes_with_nul_unchecked(b"main\0"));
     }
 
     unsafe fn sanitize_standard_fds() {
@@ -121,7 +122,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
                 if pfd.revents & libc::POLLNVAL == 0 {
                     continue;
                 }
-                if open64(c"/dev/null".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
@@ -151,7 +152,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
             use libc::open64;
             for fd in 0..3 {
                 if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
-                    if open64(c"/dev/null".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
diff --git a/library/std/src/sys/unix/process/process_common.rs b/library/std/src/sys/unix/process/process_common.rs
index 5f316b12b62..640648e8707 100644
--- a/library/std/src/sys/unix/process/process_common.rs
+++ b/library/std/src/sys/unix/process/process_common.rs
@@ -24,11 +24,11 @@ cfg_if::cfg_if! {
     if #[cfg(target_os = "fuchsia")] {
         // fuchsia doesn't have /dev/null
     } else if #[cfg(target_os = "redox")] {
-        const DEV_NULL: &CStr = c"null:";
+        const DEV_NULL: &str = "null:\0";
     } else if #[cfg(target_os = "vxworks")] {
-        const DEV_NULL: &CStr = c"/null";
+        const DEV_NULL: &str = "/null\0";
     } else {
-        const DEV_NULL: &CStr = c"/dev/null";
+        const DEV_NULL: &str = "/dev/null\0";
     }
 }
 
@@ -474,7 +474,8 @@ impl Stdio {
                 let mut opts = OpenOptions::new();
                 opts.read(readable);
                 opts.write(!readable);
-                let fd = File::open_c(DEV_NULL, &opts)?;
+                let path = unsafe { CStr::from_ptr(DEV_NULL.as_ptr() as *const _) };
+                let fd = File::open_c(&path, &opts)?;
                 Ok((ChildStdio::Owned(fd.into_inner()), None))
             }
 
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 893f8b8df3f..4f2d9cf3655 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -163,9 +163,10 @@ impl Thread {
     #[cfg(target_os = "netbsd")]
     pub fn set_name(name: &CStr) {
         unsafe {
+            let cname = CStr::from_bytes_with_nul_unchecked(b"%s\0".as_slice());
             let res = libc::pthread_setname_np(
                 libc::pthread_self(),
-                c"%s".as_ptr(),
+                cname.as_ptr(),
                 name.as_ptr() as *mut libc::c_void,
             );
             debug_assert_eq!(res, 0);