From 0b3f97d8efad4768134110d1a366693e3ce193ca Mon Sep 17 00:00:00 2001
From: dybucc <149513579+dybucc@users.noreply.github.com>
Date: Sun, 31 May 2026 18:05:11 +0200
Subject: [PATCH] vxworks: gate `off64_t` behind cfg

VxWorks exposes a different bit width for `off64_t`. This will depend on
whether the program is a real-time-process. `off_t` will be 64-bits if
it is.

`off64_t` only exists when compiling kernels. `off_t` may then be
32-bits or 64-bits wide. This will depend on whether the target follows
LP64. `off64_t` is then 64-bits wide.

Two routines were removed. They were explicitly excluded from the
shipped SDK.
---
 build.rs           |  8 ++++++++
 libc-test/build.rs | 13 ++++++++++---
 src/vxworks/mod.rs | 18 ++++++++----------
 3 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/build.rs b/build.rs
index ee07f965228c..6c5545af8a36 100644
--- a/build.rs
+++ b/build.rs
@@ -35,6 +35,10 @@ const ALLOWED_CFGS: &[&str] = &[
     // Corresponds to `_REDIR_TIME64` in musl: symbol redirects to __*_time64
     "musl_redir_time64",
     "vxworks_lt_25_09",
+    // Corresponds with `__RTP__` in VxWorks. This feature test macro is exposed
+    // when compiling real-time-processes. Do not be set if compiling VxWorks
+    // kernels.
+    "vxworks_rtp",
 ];
 
 // Extra values to allow for check-cfg.
@@ -180,6 +184,10 @@ fn main() {
         }
     }
 
+    if target_os == "vxworks" && env_flag("CARGO_CFG_LIBC_UNSTABLE_VXWORKS_RTP") {
+        set_cfg("vxworks_rtp");
+    }
+
     // On CI: deny all warnings
     if libc_ci {
         set_cfg("libc_deny_warnings");
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 50c813e66576..210af820fa1f 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -3510,6 +3510,13 @@ fn test_vxworks(target: &str) {
         cfg.cfg("vxworks_lt_25_09", None);
     }
 
+    if env::var("CARGO_CFG_LIBC_UNSTABLE_VXWORKS_RTP")
+        .and_then(|val| val.parse::<usize>().map_err(|_| env::VarError::NotPresent))
+        .is_ok_and(|val| val != 0)
+    {
+        cfg.cfg("vxworks_rtp", None);
+    }
+
     headers!(
         cfg,
         "vxWorks.h",
@@ -3594,7 +3601,7 @@ fn test_vxworks(target: &str) {
         _ => false,
     });
     // FIXME(vxworks)
-    cfg.skip_alias(move |ty| match ty.ident() {
+    cfg.skip_alias(|ty| match ty.ident() {
         "stat64" | "sighandler_t" | "off64_t" => true,
         _ => false,
     });
@@ -4399,7 +4406,7 @@ fn test_linux(target: &str) {
                 | "SO_TXREHASH" => return true,
 
                 // requires linux 5.19
-                "SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV" 
+                "SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV"
                 | "NLM_F_BULK"
                 | "SO_RCVMARK"
                 | "TLS_INFO_ZC_RO_TX" => return true,
@@ -4505,7 +4512,7 @@ fn test_linux(target: &str) {
                 | "IPV6_PMTUDISC_OMIT"
                 | "IPV6_ROUTER_ALERT_ISOLATE"
                 // linux/elf.h
-                | "NT_PRFPREG" 
+                | "NT_PRFPREG"
                 // linux/sem.h
                 | "SEM_STAT_ANY"
                 // linux/shm.h
diff --git a/src/vxworks/mod.rs b/src/vxworks/mod.rs
index 536930467dde..84fe1114c2cb 100644
--- a/src/vxworks/mod.rs
+++ b/src/vxworks/mod.rs
@@ -57,8 +57,14 @@ pub type stat64 = crate::stat;
 pub type pthread_key_t = c_ulong;
 
 // From b_off_t.h
-pub type off_t = c_longlong;
-pub type off64_t = off_t;
+cfg_if! {
+    if #[cfg(vxworks_rtp)] {
+        pub type off_t = c_longlong;
+    } else {
+        pub type off_t = c_long;
+        pub type off64_t = c_longlong;
+    }
+}
 
 // From b_BOOL.h
 pub type BOOL = c_int;
@@ -2414,14 +2420,6 @@ safe_f! {
     }
 }
 
-pub unsafe fn pread(_fd: c_int, _buf: *mut c_void, _count: size_t, _offset: off64_t) -> ssize_t {
-    -1
-}
-
-pub unsafe fn pwrite(_fd: c_int, _buf: *const c_void, _count: size_t, _offset: off64_t) -> ssize_t {
-    -1
-}
-
 pub unsafe fn posix_memalign(memptr: *mut *mut c_void, align: size_t, size: size_t) -> c_int {
     // check to see if align is a power of 2 and if align is a multiple
     //  of sizeof(void *)