1 use std::env;
2 use std::process::Command;
3 use std::str;
4
main()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(14) if libc_ci => println!("cargo:rustc-cfg=freebsd14"),
35 Some(_) | None => println!("cargo:rustc-cfg=freebsd11"),
36 }
37
38 // On CI: deny all warnings
39 if libc_ci {
40 println!("cargo:rustc-cfg=libc_deny_warnings");
41 }
42
43 // Rust >= 1.15 supports private module use:
44 if rustc_minor_ver >= 15 || rustc_dep_of_std {
45 println!("cargo:rustc-cfg=libc_priv_mod_use");
46 }
47
48 // Rust >= 1.19 supports unions:
49 if rustc_minor_ver >= 19 || rustc_dep_of_std {
50 println!("cargo:rustc-cfg=libc_union");
51 }
52
53 // Rust >= 1.24 supports const mem::size_of:
54 if rustc_minor_ver >= 24 || rustc_dep_of_std {
55 println!("cargo:rustc-cfg=libc_const_size_of");
56 }
57
58 // Rust >= 1.25 supports repr(align):
59 if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
60 println!("cargo:rustc-cfg=libc_align");
61 }
62
63 // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
64 // Otherwise, it defines an incompatible type to retaining
65 // backwards-compatibility.
66 if rustc_minor_ver >= 30 || rustc_dep_of_std {
67 println!("cargo:rustc-cfg=libc_core_cvoid");
68 }
69
70 // Rust >= 1.33 supports repr(packed(N)) and cfg(target_vendor).
71 if rustc_minor_ver >= 33 || rustc_dep_of_std {
72 println!("cargo:rustc-cfg=libc_packedN");
73 println!("cargo:rustc-cfg=libc_cfg_target_vendor");
74 }
75
76 // Rust >= 1.40 supports #[non_exhaustive].
77 if rustc_minor_ver >= 40 || rustc_dep_of_std {
78 println!("cargo:rustc-cfg=libc_non_exhaustive");
79 }
80
81 if rustc_minor_ver >= 51 || rustc_dep_of_std {
82 println!("cargo:rustc-cfg=libc_ptr_addr_of");
83 }
84
85 // #[thread_local] is currently unstable
86 if rustc_dep_of_std {
87 println!("cargo:rustc-cfg=libc_thread_local");
88 }
89
90 if const_extern_fn_cargo_feature {
91 if !is_nightly || rustc_minor_ver < 40 {
92 panic!("const-extern-fn requires a nightly compiler >= 1.40")
93 }
94 println!("cargo:rustc-cfg=libc_const_extern_fn");
95 }
96 }
97
rustc_minor_nightly() -> Option<(u32, bool)>98 fn rustc_minor_nightly() -> Option<(u32, bool)> {
99 macro_rules! otry {
100 ($e:expr) => {
101 match $e {
102 Some(e) => e,
103 None => return None,
104 }
105 };
106 }
107
108 let rustc = otry!(env::var_os("RUSTC"));
109 let output = otry!(Command::new(rustc).arg("--version").output().ok());
110 let version = otry!(str::from_utf8(&output.stdout).ok());
111 let mut pieces = version.split('.');
112
113 if pieces.next() != Some("rustc 1") {
114 return None;
115 }
116
117 let minor = pieces.next();
118
119 // If `rustc` was built from a tarball, its version string
120 // will have neither a git hash nor a commit date
121 // (e.g. "rustc 1.39.0"). Treat this case as non-nightly,
122 // since a nightly build should either come from CI
123 // or a git checkout
124 let nightly_raw = otry!(pieces.next()).split('-').nth(1);
125 let nightly = nightly_raw
126 .map(|raw| raw.starts_with("dev") || raw.starts_with("nightly"))
127 .unwrap_or(false);
128 let minor = otry!(otry!(minor).parse().ok());
129
130 Some((minor, nightly))
131 }
132
which_freebsd() -> Option<i32>133 fn which_freebsd() -> Option<i32> {
134 let output = std::process::Command::new("freebsd-version").output().ok();
135 if output.is_none() {
136 return None;
137 }
138 let output = output.unwrap();
139 if !output.status.success() {
140 return None;
141 }
142
143 let stdout = String::from_utf8(output.stdout).ok();
144 if stdout.is_none() {
145 return None;
146 }
147 let stdout = stdout.unwrap();
148
149 match &stdout {
150 s if s.starts_with("10") => Some(10),
151 s if s.starts_with("11") => Some(11),
152 s if s.starts_with("12") => Some(12),
153 s if s.starts_with("13") => Some(13),
154 s if s.starts_with("14") => Some(14),
155 _ => None,
156 }
157 }
158