1 files changed, 250 insertions, 0 deletions
diff --git a/vendor/rustix/build.rs b/vendor/rustix/build.rs
new file mode 100644
index 0000000..d95f9a9
--- /dev/null
+++ b/vendor/rustix/build.rs
@@ -0,0 +1,250 @@
+use std::env::var;
+use std::io::Write;
+
+/// The directory for inline asm.
+const ASM_PATH: &str = "src/backend/linux_raw/arch";
+
+fn main() {
+    // Don't rerun this on changes other than build.rs, as we only depend on
+    // the rustc version.
+    println!("cargo:rerun-if-changed=build.rs");
+
+    // Gather target information.
+    let arch = var("CARGO_CFG_TARGET_ARCH").unwrap();
+    let env = var("CARGO_CFG_TARGET_ENV").unwrap();
+    let inline_asm_name = format!("{}/{}.rs", ASM_PATH, arch);
+    let inline_asm_name_present = std::fs::metadata(inline_asm_name).is_ok();
+    let os = var("CARGO_CFG_TARGET_OS").unwrap();
+    let pointer_width = var("CARGO_CFG_TARGET_POINTER_WIDTH").unwrap();
+    let endian = var("CARGO_CFG_TARGET_ENDIAN").unwrap();
+
+    // Check for special target variants.
+    let is_x32 = arch == "x86_64" && pointer_width == "32";
+    let is_arm64_ilp32 = arch == "aarch64" && pointer_width == "32";
+    let is_powerpc64be = arch == "powerpc64" && endian == "big";
+    let is_mipseb = (arch == "mips" || arch == "mips32r6") && endian == "big";
+    let is_mips64eb = arch.contains("mips64") && endian == "big";
+    let is_unsupported_abi = is_x32 || is_arm64_ilp32 || is_powerpc64be || is_mipseb || is_mips64eb;
+
+    // Check for `--features=use-libc`. This allows crate users to enable the
+    // libc backend.
+    let feature_use_libc = var("CARGO_FEATURE_USE_LIBC").is_ok();
+
+    // Check for `RUSTFLAGS=--cfg=rustix_use_libc`. This allows end users to
+    // enable the libc backend even if rustix is depended on transitively.
+    let cfg_use_libc = var("CARGO_CFG_RUSTIX_USE_LIBC").is_ok();
+
+    // Check for `--features=rustc-dep-of-std`.
+    let rustc_dep_of_std = var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
+
+    // Check for eg. `RUSTFLAGS=--cfg=rustix_use_experimental_features`. This
+    // is a rustc flag rather than a cargo feature flag because it's
+    // experimental and not something we want accidentally enabled via
+    // `--all-features`.
+    let rustix_use_experimental_features =
+        var("CARGO_CFG_RUSTIX_USE_EXPERIMENTAL_FEATURES").is_ok();
+
+    // Check for eg. `RUSTFLAGS=--cfg=rustix_use_experimental_asm`. This is a
+    // rustc flag rather than a cargo feature flag because it's experimental
+    // and not something we want accidentally enabled via `--all-features`.
+    let rustix_use_experimental_asm = var("CARGO_CFG_RUSTIX_USE_EXPERIMENTAL_ASM").is_ok();
+
+    // Miri doesn't support inline asm, and has builtin support for recognizing
+    // libc FFI calls, so if we're running under miri, use the libc backend.
+    let miri = var("CARGO_CFG_MIRI").is_ok();
+
+    // If experimental features are enabled, auto-detect and use available
+    // features.
+    if rustc_dep_of_std {
+        use_feature("rustc_attrs");
+        use_feature("core_intrinsics");
+    } else if rustix_use_experimental_features {
+        use_feature_or_nothing("rustc_attrs");
+        use_feature_or_nothing("core_intrinsics");
+    }
+
+    // Features needed only in no-std configurations.
+    #[cfg(not(feature = "std"))]
+    {
+        use_feature_or_nothing("core_c_str");
+        use_feature_or_nothing("core_ffi_c");
+        use_feature_or_nothing("alloc_c_string");
+        use_feature_or_nothing("alloc_ffi");
+    }
+
+    // Feature needed for testing.
+    if use_static_assertions() {
+        use_feature("static_assertions");
+    }
+
+    // WASI support can utilize wasi_ext if present.
+    if os == "wasi" {
+        use_feature_or_nothing("wasi_ext");
+    }
+
+    // If the libc backend is requested, or if we're not on a platform for
+    // which we have linux_raw support, use the libc backend.
+    //
+    // For now Android uses the libc backend; in theory it could use the
+    // linux_raw backend, but to do that we'll need to figure out how to
+    // install the toolchain for it.
+    let libc = feature_use_libc
+        || cfg_use_libc
+        || os != "linux"
+        || !inline_asm_name_present
+        || is_unsupported_abi
+        || miri
+        || ((arch == "powerpc64" || arch.starts_with("mips")) && !rustix_use_experimental_asm);
+    if libc {
+        // Use the libc backend.
+        use_feature("libc");
+    } else {
+        // Use the linux_raw backend.
+        use_feature("linux_raw");
+        if rustix_use_experimental_asm {
+            use_feature("asm_experimental_arch");
+        }
+    }
+
+    // Detect whether the compiler requires us to use thumb mode on ARM.
+    if arch == "arm" && use_thumb_mode() {
+        use_feature("thumb_mode");
+    }
+
+    // Rust's libc crate groups some OS's together which have similar APIs;
+    // create similarly-named features to make `cfg` tests more concise.
+    let freebsdlike = os == "freebsd" || os == "dragonfly";
+    if freebsdlike {
+        use_feature("freebsdlike");
+    }
+    let netbsdlike = os == "openbsd" || os == "netbsd";
+    if netbsdlike {
+        use_feature("netbsdlike");
+    }
+    let apple = os == "macos" || os == "ios" || os == "tvos" || os == "watchos";
+    if apple {
+        use_feature("apple");
+    }
+    if os == "linux" || os == "l4re" || os == "android" || os == "emscripten" {
+        use_feature("linux_like");
+    }
+    if os == "solaris" || os == "illumos" {
+        use_feature("solarish");
+    }
+    if apple || freebsdlike || netbsdlike {
+        use_feature("bsd");
+    }
+
+    // Add some additional common target combinations.
+
+    // Android and "regular" Linux both use the Linux kernel.
+    if os == "android" || os == "linux" {
+        use_feature("linux_kernel");
+    }
+
+    // These platforms have a 32-bit `time_t`.
+    if libc
+        && (arch == "arm"
+            || arch == "mips"
+            || arch == "sparc"
+            || arch == "x86"
+            || (arch == "wasm32" && os == "emscripten"))
+        && (apple
+            || os == "android"
+            || os == "emscripten"
+            || os == "haiku"
+            || env == "gnu"
+            || (env == "musl" && arch == "x86"))
+    {
+        use_feature("fix_y2038");
+    }
+
+    println!("cargo:rerun-if-env-changed=CARGO_CFG_RUSTIX_USE_EXPERIMENTAL_ASM");
+    println!("cargo:rerun-if-env-changed=CARGO_CFG_RUSTIX_USE_LIBC");
+
+    // Rerun this script if any of our features or configuration flags change,
+    // or if the toolchain we used for feature detection changes.
+    println!("cargo:rerun-if-env-changed=CARGO_FEATURE_USE_LIBC");
+    println!("cargo:rerun-if-env-changed=CARGO_FEATURE_RUSTC_DEP_OF_STD");
+    println!("cargo:rerun-if-env-changed=CARGO_CFG_MIRI");
+}
+
+fn use_static_assertions() -> bool {
+    // `offset_from` was made const in Rust 1.65.
+    can_compile("const unsafe fn foo(p: *const u8) -> isize { p.offset_from(p) }")
+}
+
+fn use_thumb_mode() -> bool {
+    // In thumb mode, r7 is reserved.
+    !can_compile("pub unsafe fn f() { core::arch::asm!(\"udf #16\", in(\"r7\") 0); }")
+}
+
+fn use_feature_or_nothing(feature: &str) {
+    if has_feature(feature) {
+        use_feature(feature);
+    }
+}
+
+fn use_feature(feature: &str) {
+    println!("cargo:rustc-cfg={}", feature);
+}
+
+/// Test whether the rustc at `var("RUSTC")` supports the given feature.
+fn has_feature(feature: &str) -> bool {
+    can_compile(format!(
+        "#![allow(stable_features)]\n#![feature({})]",
+        feature
+    ))
+}
+
+/// Test whether the rustc at `var("RUSTC")` can compile the given code.
+fn can_compile<T: AsRef<str>>(test: T) -> bool {
+    use std::process::Stdio;
+
+    let out_dir = var("OUT_DIR").unwrap();
+    let rustc = var("RUSTC").unwrap();
+    let target = var("TARGET").unwrap();
+
+    // Use `RUSTC_WRAPPER` if it's set, unless it's set to an empty string, as
+    // documented [here].
+    // [here]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-reads
+    let wrapper = var("RUSTC_WRAPPER")
+        .ok()
+        .and_then(|w| if w.is_empty() { None } else { Some(w) });
+
+    let mut cmd = if let Some(wrapper) = wrapper {
+        let mut cmd = std::process::Command::new(wrapper);
+        // The wrapper's first argument is supposed to be the path to rustc.
+        cmd.arg(rustc);
+        cmd
+    } else {
+        std::process::Command::new(rustc)
+    };
+
+    cmd.arg("--crate-type=rlib") // Don't require `main`.
+        .arg("--emit=metadata") // Do as little as possible but still parse.
+        .arg("--target")
+        .arg(target)
+        .arg("--out-dir")
+        .arg(out_dir); // Put the output somewhere inconsequential.
+
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
+    }
+
+    let mut child = cmd
+        .arg("-") // Read from stdin.
+        .stdin(Stdio::piped()) // Stdin is a pipe.
+        .stderr(Stdio::null()) // Errors from feature detection aren't interesting and can be confusing.
+        .spawn()
+        .unwrap();
+
+    writeln!(child.stdin.take().unwrap(), "{}", test.as_ref()).unwrap();
+
+    child.wait().unwrap().success()
+}