Remove the libc dependency for most platforms.

Cargo.toml

@@ -302,22 +302,28 @@ name = "ring"
 
 [dependencies]
 untrusted = { version = "0.7.0" }
-libc = { version = "0.2.48", default-features = false }
 
 [target.'cfg(all(any(target_arch = "aarch64", target_arch = "arm", target_arch = "x86", target_arch = "x86_64"), not(target_os = "ios")))'.dependencies]
 spin = { version = "0.5.0", default-features = false }
 
+
+[target.'cfg(any(target_os = "android", target_os = "linux"))'.dependencies]
+libc = { version = "0.2.48", default-features = false }
+
 [target.'cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux", target_os = "netbsd", target_os = "openbsd", target_os = "solaris"))'.dependencies]
 lazy_static = { version = "1.3", default-features = false, optional = true }
 
 [target.'cfg(all(target_arch = "wasm32", target_vendor = "unknown", target_os = "unknown", target_env = ""))'.dependencies]
 web-sys = { version = "0.3.25", default-features = false, features = ["Crypto", "Window"] }
 
+[target.'cfg(target_os = "windows")'.dependencies]
+winapi = { version = "0.3.7", default-features = false, features = ["ntsecapi", "wtypesbase"] }
+
 [target.'cfg(target_arch = "wasm32")'.dev-dependencies]
 wasm-bindgen-test = { version = "0.2.48", default-features = false }
 
-[target.'cfg(target_os = "windows")'.dependencies]
-winapi = { version = "0.3.7", default-features = false, features = ["ntsecapi", "wtypesbase"] }
+[target.'cfg(any(unix, windows))'.dev-dependencies]
+libc = { version = "0.2.48", default-features = false }
 
 # Keep this in sync with `[dependencies]` in pregenerate_asm/Cargo.toml.
 [build-dependencies]

crypto/internal.h

@@ -118,8 +118,6 @@
 #define ASSERT(x) ((void)0)
 #endif
 
-#include <GFp/type_check.h>
-
 #if defined(__GNUC__) && \
     (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40800
 // |alignas| and |alignof| were added in C11. GCC added support in version 4.8.

include/GFp/base.h

@@ -56,6 +56,8 @@
 
 // This file should be the first included by all BoringSSL headers.
 
+#include <GFp/type_check.h>
+
 #if defined(_MSC_VER)
 #pragma warning(push, 3)
 #endif
@@ -106,5 +108,12 @@
 // items.
 #define OPENSSL_EXPORT
 
+// `ring::c` would need to be customized on any platform where these assertions
+// fail. Keep in sync with `ring::c`.
+OPENSSL_STATIC_ASSERT(sizeof(int32_t) == sizeof(int), "int isn't 32 bits.");
+OPENSSL_STATIC_ASSERT(sizeof(uint32_t) == sizeof(unsigned int), "unsigned int isn't 32 bits.");
+OPENSSL_STATIC_ASSERT(sizeof(size_t) == sizeof(uintptr_t), "uintptr_t and size_t differ.");
+OPENSSL_STATIC_ASSERT(sizeof(size_t) <= sizeof(uint64_t), "size_t is larger than uint64_t.");
+OPENSSL_STATIC_ASSERT(sizeof(size_t) >= sizeof(uint32_t), "size_t is smaller than uint32_t.");
 
 #endif  // OPENSSL_HEADER_BASE_H

src/c.rs

@@ -14,25 +14,38 @@
 
 //! C types.
 //!
-//! The libc crate provide the C types for most, but not all, targets that
-//! *ring* supports.
+//! Avoid using the `libc` crate to get C types since `libc` doesn't support
+//! all the targets we need to support. It turns out that the few types we need
+//! are all uniformly defined on the platforms we care about. This will
+//! probably change if/when we support 16-bit platforms or platforms where
+//! `usize` and `uintptr_t` are different sizes.
 
-#[cfg(not(all(target_arch = "wasm32", target_env = "",)))]
-use ::libc;
+// Keep in sync with the checks in base.h that verify these assumptions.
 
-#[cfg(all(target_arch = "wasm32", target_env = ""))]
-mod libc {
-    //! The WASM32 ABI is described at
-    //! https://github.com/WebAssembly/tool-conventions/blob/master/BasicCABI.md#data-representation
+pub(crate) type int = i32;
+pub(crate) type uint = u32;
+pub(crate) type size_t = usize;
 
-    pub(crate) type c_int = i32;
-    pub(crate) type c_uint = u32;
+#[cfg(all(test, any(unix, windows)))]
+mod tests {
+    use crate::c;
 
-    // "The size_t type is defined as unsigned long."
-    // However, we must define it as an alias of `usize` for compatibility with `libc::size_t`.
-    pub(crate) type size_t = usize;
-}
+    #[test]
+    fn test_libc_compatible() {
+        {
+            let x: c::int = 1;
+            let _x: libc::c_int = x;
+        }
+
+        {
+            let x: c::uint = 1;
+            let _x: libc::c_uint = x;
+        }
 
-pub(crate) type size_t = self::libc::size_t;
-pub(crate) type int = self::libc::c_int;
-pub(crate) type uint = self::libc::c_uint;
+        {
+            let x: c::size_t = 1;
+            let _x: libc::size_t = x;
+            let _x: usize = x;
+        }
+    }
+}