1 use std::env; 2 use std::process::Command; 3 use std::str; 4 5 fn main() { 6 // Avoid unnecessary re-building. 7 println!("cargo:rerun-if-changed=build.rs"); 8 9 let (rustc_minor_ver, is_nightly) = rustc_minor_nightly().expect("Failed to get rustc version"); 10 let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok(); 11 let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok(); 12 let const_extern_fn_cargo_feature = env::var("CARGO_FEATURE_CONST_EXTERN_FN").is_ok(); 13 let libc_ci = env::var("LIBC_CI").is_ok(); 14 15 if env::var("CARGO_FEATURE_USE_STD").is_ok() { 16 println!( 17 "cargo:warning=\"libc's use_std cargo feature is deprecated since libc 0.2.55; \ 18 please consider using the `std` cargo feature instead\"" 19 ); 20 } 21 22 // The ABI of libc used by libstd is backward compatible with FreeBSD 10. 23 // The ABI of libc from crates.io is backward compatible with FreeBSD 11. 24 // 25 // On CI, we detect the actual FreeBSD version and match its ABI exactly, 26 // running tests to ensure that the ABI is correct. 27 match which_freebsd() { 28 Some(10) if libc_ci || rustc_dep_of_std => { 29 println!("cargo:rustc-cfg=freebsd10") 30 } 31 Some(11) if libc_ci => println!("cargo:rustc-cfg=freebsd11"), 32 Some(12) if libc_ci => println!("cargo:rustc-cfg=freebsd12"), 33 Some(13) if libc_ci => println!("cargo:rustc-cfg=freebsd13"), 34 Some(_) | None => println!("cargo:rustc-cfg=freebsd11"), 35 } 36 37 // On CI: deny all warnings 38 if libc_ci { 39 println!("cargo:rustc-cfg=libc_deny_warnings"); 40 } 41 42 // Rust >= 1.15 supports private module use: 43 if rustc_minor_ver >= 15 || rustc_dep_of_std { 44 println!("cargo:rustc-cfg=libc_priv_mod_use"); 45 } 46 47 // Rust >= 1.19 supports unions: 48 if rustc_minor_ver >= 19 || rustc_dep_of_std { 49 println!("cargo:rustc-cfg=libc_union"); 50 } 51 52 // Rust >= 1.24 supports const mem::size_of: 53 if rustc_minor_ver >= 24 || rustc_dep_of_std { 54 println!("cargo:rustc-cfg=libc_const_size_of"); 55 } 56 57 // Rust >= 1.25 supports repr(align): 58 if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature { 59 println!("cargo:rustc-cfg=libc_align"); 60 } 61 62 // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it. 63 // Otherwise, it defines an incompatible type to retaining 64 // backwards-compatibility. 65 if rustc_minor_ver >= 30 || rustc_dep_of_std { 66 println!("cargo:rustc-cfg=libc_core_cvoid"); 67 } 68 69 // Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor). 70 if rustc_minor_ver >= 33 || rustc_dep_of_std { 71 println!("cargo:rustc-cfg=libc_packedN"); 72 println!("cargo:rustc-cfg=libc_cfg_target_vendor"); 73 } 74 75 // #[thread_local] is currently unstable 76 if rustc_dep_of_std { 77 println!("cargo:rustc-cfg=libc_thread_local"); 78 } 79 80 if const_extern_fn_cargo_feature { 81 if !is_nightly || rustc_minor_ver < 40 { 82 panic!("const-extern-fn requires a nightly compiler >= 1.40") 83 } 84 println!("cargo:rustc-cfg=libc_const_extern_fn"); 85 } 86 } 87 88 fn rustc_minor_nightly() -> Option<(u32, bool)> { 89 macro_rules! otry { 90 ($e:expr) => { 91 match $e { 92 Some(e) => e, 93 None => return None, 94 } 95 }; 96 } 97 98 let rustc = otry!(env::var_os("RUSTC")); 99 let output = otry!(Command::new(rustc).arg("--version").output().ok()); 100 let version = otry!(str::from_utf8(&output.stdout).ok()); 101 let mut pieces = version.split('.'); 102 103 if pieces.next() != Some("rustc 1") { 104 return None; 105 } 106 107 let minor = pieces.next(); 108 109 // If `rustc` was built from a tarball, its version string 110 // will have neither a git hash nor a commit date 111 // (e.g. "rustc 1.39.0"). Treat this case as non-nightly, 112 // since a nightly build should either come from CI 113 // or a git checkout 114 let nightly_raw = otry!(pieces.next()).split('-').nth(1); 115 let nightly = nightly_raw 116 .map(|raw| raw.starts_with("dev") || raw.starts_with("nightly")) 117 .unwrap_or(false); 118 let minor = otry!(otry!(minor).parse().ok()); 119 120 Some((minor, nightly)) 121 } 122 123 fn which_freebsd() -> Option<i32> { 124 let output = std::process::Command::new("freebsd-version").output().ok(); 125 if output.is_none() { 126 return None; 127 } 128 let output = output.unwrap(); 129 if !output.status.success() { 130 return None; 131 } 132 133 let stdout = String::from_utf8(output.stdout).ok(); 134 if stdout.is_none() { 135 return None; 136 } 137 let stdout = stdout.unwrap(); 138 139 match &stdout { 140 s if s.starts_with("10") => Some(10), 141 s if s.starts_with("11") => Some(11), 142 s if s.starts_with("12") => Some(12), 143 s if s.starts_with("13") => Some(13), 144 _ => None, 145 } 146 } 147