try to convert to cfg var for uclibc time64

Author: Jonah Petri

.github/workflows/ci.yaml

@@ -225,6 +225,9 @@ jobs:
           - target: x86_64-unknown-linux-musl
             env: { RUST_LIBC_UNSTABLE_MUSL_V1_2_3: 1 }
             artifact-tag: new-musl
+          - target: armv7-unknown-linux-uclibceabihf
+          - target: armv7-unknown-linux-uclibceabihf
+            env: { TEST_UCLIBC_TIIME64: 1 }
           # FIXME: It seems some items in `src/unix/mod.rs` aren't defined on redox actually.
           # - target: x86_64-unknown-redox
 

build.rs

@@ -54,10 +54,6 @@ const CHECK_CFG_EXTRA: &[(&str, &[&str])] = &[
 /// Musl architectures that set `#define _REDIR_TIME64 1`.
 const MUSL_REDIR_TIME64_ARCHES: &[&str] = &["arm", "hexagon", "mips", "powerpc", "x86"];
 
-/// uclibc architectures that set `#define __UCLIBC_USE_TIME64__`,
-/// see UCLIBC_USE_TIME64 in uclibc-ng source: extra/Configs/Config.in
-const UCLIBC_TIME64_ARCHES: &[&str] = &["arm", "mips"];
-
 fn main() {
     // Avoid unnecessary re-building.
     println!("cargo:rerun-if-changed=build.rs");
@@ -127,11 +123,8 @@ fn main() {
         }
     }
 
-    let uclibc_use_time64 = env_flag("RUST_LIBC_UCLIBC_USE_TIME64");
-    println!("cargo:rerun-if-env-changed=RUST_LIBC_UCLIBC_USE_TIME64");
-    if target_env == "uclibc"
-        && uclibc_use_time64
-        && UCLIBC_TIME64_ARCHES.contains(&target_arch.as_str())
+    let uclibc_use_time64 = env_flag("CARGO_CFG_LIBC_UNSTABLE_UCLIBC_TIME64");
+    if target_env == "uclibc"&& uclibc_use_time64
     {
         set_cfg("linux_time_bits64");
     }

ci/docker/armv7-unknown-linux-uclibceabihf/Dockerfile

@@ -14,11 +14,9 @@ RUN sed -i -E 's/(archive|security)\.ubuntu\.com/old-releases.ubuntu.com/g' \
         qemu-user \
         xz-utils
 
-RUN mkdir /toolchain
-
-RUN curl --retry 5 -L https://toolchains.bootlin.com/downloads/releases/toolchains/armv7-eabihf/tarballs/armv7-eabihf--uclibc--bleeding-edge-2024.05-1.tar.xz | \
-    tar xjf - -C /toolchain --strip-components=1
-RUN /toolchain/relocate-sdk.sh
+ARG TEST_UCLIBC_TIIME64
+COPY install-uclibc.sh /
+RUN /install-uclibc.sh "$TEST_UCLIBC_TIIME64"
 
 ENV PATH=$PATH:/rust/bin:/toolchain/bin \
     STAGING_DIR=/toolchain/armv7-buildroot-linux-uclibceabihf/sysroot \

ci/install-uclibc.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/bash
+#
+# Installs the appropriate uclibc toolchain into /toolchain
+
+set -eux
+
+time64="$1"
+
+if [ "${time64:-0}" != "0" ]; then
+    version='bleeding-edge-2025.08-1'
+else
+    version='bleeding-edge-2024.05-1'  # last version with 32-bit time_t
+fi
+
+mkdir /toolchain
+
+curl --retry 5 -L "https://toolchains.bootlin.com/downloads/releases/toolchains/armv7-eabihf/tarballs/armv7-eabihf--uclibc--${version}.tar.xz" | \
+tar xjf - -C /toolchain --strip-components=1
+
+/toolchain/relocate-sdk.sh

ci/run-docker.sh

@@ -44,6 +44,13 @@ run() {
         fi
     fi
 
+    if [[ "$run_target" = *"uclibc"* ]]; then
+        if [ -n "${TEST_UCLIBC_TIIME64:-}" ]; then 
+            build_args+=("--build-arg=TEST_UCLIBC_TIIME64=1")
+            export RUSTFLAGS="$RUSTFLAGS --cfg=libc_unstable_uclibc_time64"
+        fi
+    fi
+
     # use -f so we can use ci/ as build context
     docker build "${build_args[@]}"
 

libc-test/build.rs

@@ -3731,11 +3731,10 @@ fn test_linux(target: &str) {
             cfg.cfg("linux_time_bits64", None);
         }
     }
-    let uclibc_use_time64 = env::var("RUST_LIBC_UCLIBC_USE_TIME64")
+    let uclibc_use_time64 = env::var("CARGO_CFG_LIBC_UNSTABLE_UCLIBC_TIME64")
         .map(|val| val != "0")
         .unwrap_or(false);
-    if uclibc && uclibc_use_time64 && (arm || mips) {
-        // see UCLIBC_TIME64_ARCHES in libc/build.rs
+    if uclibc && uclibc_use_time64 {
         cfg.cfg("linux_time_bits64", None);
     }
     cfg.define("_GNU_SOURCE", None)

src/unix/linux_like/linux/uclibc/arm/mod.rs

@@ -4,7 +4,7 @@ use crate::prelude::*;
 pub type wchar_t = c_uint;
 
 cfg_if! {
-    // See RUST_LIBC_UCLIBC_USE_TIME64 env var if your uclibc has 64-bit time
+    // Set cfg(libc_unstable_uclibc_time64) in rustflags if your uclibc has 64-bit time
     if #[cfg(linux_time_bits64)] {
         pub type time_t = c_longlong;
         pub type suseconds_t = c_longlong;