chore: compat: remove unnecessary hardcoded platform check for some s…

…tubs

Signed-off-by: Ookiineko <[email protected]>

CMakeLists.compat.txt

@@ -26,6 +26,9 @@ elseif (EMSCRIPTEN)
     endif()
 
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -sALLOW_MEMORY_GROWTH -Wl,-u,ntohs -Wl,-u,htons -Wl,-u,htonl -Wl,--wrap=close")
+
+    # exists in musl but not in rust libc crate
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs_SYS_dup3")
 else()
     message(WARNING "
         New platform: ${CMAKE_SYSTEM_NAME}
@@ -43,14 +46,36 @@ endif()
 add_compile_definitions(_FILE_OFFSET_BITS=64 _LARGEFILE64_SOURCE)
 set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE")
 
+list(APPEND CMAKE_REQUIRED_INCLUDES "sys/types.h")
+include(CheckTypeSize)
+check_type_size(off64_t SIZEOF_off64_t)
+if(NOT HAVE_off64_t)
+    add_compile_definitions(off64_t=off_t)
+endif()
+
 include(CheckSymbolExists)
 check_symbol_exists(lseek64 "unistd.h" LSEEK64_EXISTS)
 if(NOT LSEEK64_EXISTS)
-    add_compile_definitions(off64_t=off_t)
     add_compile_definitions(lseek64=lseek)
+
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs_lseek64")
+endif()
+
+check_symbol_exists(lseek64 "unistd.h" FTRUNCATE64_EXISTS)
+if(NOT FTRUNCATE64_EXISTS)
     add_compile_definitions(ftruncate64=ftruncate)
 endif()
 
+check_symbol_exists(O_PATH "fcntl.h" HAVE_O_PATH)
+if(NOT HAVE_O_PATH)
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs_O_PATH")
+endif()
+
+check_symbol_exists(SYS_dup3 "sys/syscall.h" HAVE_SYS_dup3)
+if(NOT HAVE_SYS_dup3)
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs_SYS_dup3")
+endif()
+
 if (CMAKE_SYSTEM_NAME MATCHES "Android")
     message(STATUS "Fortify enabled")
     add_compile_options(-D_FORTIFY_SOURCE=2)
@@ -62,3 +87,13 @@ else()
 
     include(CMakeLists.android.txt)
 endif()
+
+check_symbol_exists(sendfile "sys/sendfile.h" HAVE_sendfile)
+if (NOT HAVE_sendfile)
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs_sendfile")
+endif()
+
+check_symbol_exists(__errno "errno.h" HAVE___errno)
+if(NOT HAVE___errno)
+    set(RUSTFLAGS "${RUSTFLAGS} --cfg mbb_stubs___errno")
+endif()

CMakeLists.stub.txt

@@ -12,7 +12,7 @@ add_library(platform_stubs STATIC
     libc-compat/placeholder.c)
 target_include_directories(platform_stubs PUBLIC libc-compat/include)
 
-if ((NOT CMAKE_SYSTEM_NAME STREQUAL "Linux") AND (NOT CMAKE_SYSTEM_NAME STREQUAL "Android"))
+if (NOT HAVE_sendfile)
     message(STATUS "Using generic sendfile replacement")
     target_sources(platform_stubs PRIVATE
         libc-compat/non-linux/sendfile_fallback.c)
@@ -24,6 +24,36 @@ if (NOT HAVE_STRLCPY)
         libc-compat/libbsd/str.c)
 endif()
 
+if(NOT HAVE___errno)
+    target_sources(platform_stubs PRIVATE
+        libc-compat/common/__errno.c)
+
+    # e.g Linux and Emscripten
+    check_symbol_exists(__errno_location "errno.h" HAVE___errno_location)
+    if (HAVE___errno_location)
+        set_source_files_properties(libc-compat/common/__errno.c PROPERTIES
+                                    COMPILE_FLAGS -DHAVE___errno_location)
+    else()
+        # e.g macOS
+        check_symbol_exists(__error "errno.h" HAVE___error)
+        if (HAVE___error)
+        set_source_files_properties(libc-compat/common/__errno.c PROPERTIES
+                                    COMPILE_FLAGS -DHAVE___error)
+        else()
+            # e.g MinGW
+            check_symbol_exists(_errno "errno.h" HAVE__errno)
+            if (HAVE__errno)
+                set_source_files_properties(libc-compat/common/__errno.c PROPERTIES
+                                            COMPILE_FLAGS -DHAVE__errno)
+            else()
+                message(FATAL_ERROR "Don't know errno implementation on this platform")
+            endif()
+        endif()
+    endif()
+
+    message(STATUS "Using __errno alias")
+endif()
+
 if (WIN32)
     message(STATUS "Using win32 libc-compat")
 

libc-compat/common/__errno.c

@@ -0,0 +1,13 @@
+#include <errno.h>
+
+int *__errno (void) {
+#ifdef HAVE___errno_location
+  return __errno_location();
+#elif defined(HAVE___error)
+  return __error();
+#elif defined(HAVE__errno)
+  return _errno();
+#else
+#  error "Unreachable"
+#endif
+}

libc-compat/rs/common/mod.rs

@@ -1,2 +1,7 @@
+#[macro_use]
 mod stubs;
+
 pub use stubs::*;
+
+#[macro_use]
+mod overrides;

libc-compat/rs/common/overrides.rs

@@ -0,0 +1,5 @@
+macro_rules! post_defs_overrides {
+    () => {
+        add_sendfile_stubs_if_needed!();
+    }
+}

libc-compat/rs/common/stubs/errno.rs

@@ -1,19 +1,6 @@
 // android (bionic libc) errno
 
-#[cfg(any(target_os = "linux", target_os = "emscripten"))]
+#[cfg(mbb_stubs___errno)]
 extern "C" {
-    #[link_name = "__errno_location"]
-    pub fn __errno() -> *mut crate::c_int;
-}
-
-#[cfg(target_vendor = "apple")]
-extern "C" {
-    #[link_name = "__error"]
-    pub fn __errno() -> *mut crate::c_int;
-}
-
-#[cfg(target_os = "windows")]
-extern "cdecl" {
-    #[link_name = "_errno"]
     pub fn __errno() -> *mut crate::c_int;
 }

libc-compat/rs/common/stubs/fcntl.rs

@@ -1,3 +1,4 @@
 // for platform those doesn't have O_PATH
 
+#[cfg(mbb_stubs_O_PATH)]
 pub const O_PATH: crate::c_int = 0;  // no-op

libc-compat/rs/common/stubs/lfs64.rs

@@ -1,5 +1,6 @@
 // just aliases
 
+#[cfg(mbb_stubs_lseek64)]
 extern "C" {
     #[link_name = "lseek"]
     pub fn lseek64(fd: crate::c_int, offset: crate::off_t, whence: crate::c_int) -> crate::off_t;

libc-compat/rs/common/stubs/mod.rs

@@ -1,33 +1,14 @@
-#[cfg(not(any(target_os = "android", target_os = "cygwin")))]
 mod errno;
-
-#[cfg(not(any(target_os = "android", target_os = "cygwin")))]
 pub use errno::*;
 
-#[cfg(any(target_vendor = "apple", target_os = "windows"))]
 mod fcntl;
-
-#[cfg(any(target_vendor = "apple", target_os = "windows"))]
 pub use fcntl::*;
 
-#[cfg(any(target_os = "cygwin", target_vendor = "apple"))]
 mod lfs64;
-
-#[cfg(any(target_os = "cygwin", target_vendor = "apple"))]
 pub use lfs64::*;
 
-#[cfg(any(target_os = "cygwin", target_vendor = "apple",
-          target_os = "emscripten", target_os = "windows"))]
 mod sc_num;
-
-#[cfg(any(target_os = "cygwin", target_vendor = "apple",
-          target_os = "emscripten", target_os = "windows"))]
 pub use sc_num::*;
 
-#[cfg(any(target_os = "cygwin", target_os = "emscripten",
-          target_os = "windows"))]
+#[macro_use]
 mod sendfile;
-
-#[cfg(any(target_os = "cygwin", target_os = "emscripten",
-          target_os = "windows"))]
-pub use sendfile::*;

libc-compat/rs/common/stubs/sc_num.rs

@@ -1,3 +1,4 @@
 // no actually used, just for passing build
 
+#[cfg(mbb_stubs_SYS_dup3)]
 pub const SYS_dup3: crate::c_int = 0;  // stub

libc-compat/rs/common/stubs/sendfile.rs

@@ -1,26 +1,34 @@
 // defined in libc-compat/non-linux/sendfile_fallback.c
 
-extern "C" {
-    #[link_name = "__sendfile_stub"]
-    fn real_sendfile(
-        out_fd: crate::c_int,
-        in_fd: crate::c_int,
-        count: crate::size_t
-    );
-}
+macro_rules! add_sendfile_stubs_if_needed {
+    () => {
+        cfg_if::cfg_if! {
+            if #[cfg(mbb_stubs_sendfile)] {
+                extern "C" {
+                    #[link_name = "__sendfile_stub"]
+                    fn real_sendfile(
+                        out_fd: crate::c_int,
+                        in_fd: crate::c_int,
+                        count: crate::size_t
+                    );
+                }
 
-f! {
-    pub fn sendfile(
-        out_fd: crate::c_int,
-        in_fd: crate::c_int,
-        offset: *mut crate::off_t,
-        count: crate::size_t
-    ) -> crate::ssize_t {
-        if offset.is_null() {
-            real_sendfile(out_fd, in_fd, count);
-            0
-        } else {
-            panic!("unreachable code")
+                f! {
+                    pub fn sendfile(
+                        out_fd: crate::c_int,
+                        in_fd: crate::c_int,
+                        offset: *mut crate::off_t,
+                        count: crate::size_t
+                    ) -> crate::ssize_t {
+                        if offset.is_null() {
+                            real_sendfile(out_fd, in_fd, count);
+                            0
+                        } else {
+                            panic!("unreachable code")
+                        }
+                    }
+                }
+            }
         }
-    }
+    };
 }

libc-compat/rs/lib.rs

@@ -6,12 +6,7 @@
 mod macros;
 
 cfg_if::cfg_if! {
-    if #[cfg(target_vendor = "apple")] {
-        // on macos, we need to shadow some stuffs
-
-        mod darwin;
-        pub use darwin::*;
-    } else if #[cfg(target_os = "windows")] {
+    if #[cfg(target_os = "windows")] {
         // windows has some missing defs,
         // we also need to shadow add some extra stuffs
 
@@ -28,5 +23,9 @@ cfg_if::cfg_if! {
     }
 }
 
+#[macro_use]
 mod common;
+
+post_defs_overrides!();
+
 pub use common::*;