Auto merge of #2935 - bossmc:alias-lfs64-symbols-on-musl, r=Amanieu

Alias all LFS64 symbols to their non-LFS64 counterparts on musl

As per #2934 the LFS64 symbols on musl-libc are simply aliases to the non-LFS64 symbols.  Currently this is done both in the header files (as `#define` entries) and in the library (as aliasing symbols).  There is a desire in musl to drop the ABI compatibility shims (the symbol aliases) - currently the `libc` crate exports the LFS64 symbols by `extern`-ing the compatibility shims which will fail if musl removes them.

This changes the musl build of libc to replicate the aliasing that's in the C header files (with `pub use xxx as xxx64`) so the API from the `libc` crate is unchanged, but the crate is now compatible with the upcoming musl release.

I've also checked and all the LFS64 types (e.g. `off64_t`) are already the same as their non-LFS64 equivalents.

This is an annoying change to test, `libc-test` seems expect to build against `musl 1.1.24` (in fact, does Rust even support `musl 1.2`?  It's not obvious that it does... e.g. see https://github.com/rust-lang/libc/blob/d99c37d97c7a075ffc7f4260f2dd134d1ee3daaa/src/unix/linux_like/linux/musl/mod.rs#L288-L292)

libc-test/build.rs

@@ -3333,8 +3333,8 @@ fn test_linux(target: &str) {
             "Ioctl" if gnu => "unsigned long".to_string(),
             "Ioctl" => "int".to_string(),
 
-            // In MUSL `flock64` is a typedef to `flock`.
-            "flock64" if musl => format!("struct {}", ty),
+            // LFS64 types have been removed in musl 1.2.4+
+            "off64_t" if musl => "off_t".to_string(),
 
             // typedefs don't need any keywords
             t if t.ends_with("_t") => t.to_string(),
@@ -3399,7 +3399,14 @@ fn test_linux(target: &str) {
             "priority_t" if musl => true,
             "name_t" if musl => true,
 
-            _ => false,
+            t => {
+                if musl {
+                    // LFS64 types have been removed in musl 1.2.4+
+                    t.ends_with("64") || t.ends_with("64_t")
+                } else {
+                    false
+                }
+            }
         }
     });
 
@@ -3411,6 +3418,10 @@ fn test_linux(target: &str) {
         if musl && ty.starts_with("uinput_") {
             return true;
         }
+        // LFS64 types have been removed in musl 1.2.4+
+        if musl && (ty.ends_with("64") || ty.ends_with("64_t")) {
+            return true;
+        }
         // FIXME: sparc64 CI has old headers
         if sparc64 && (ty == "uinput_ff_erase" || ty == "uinput_abs_setup") {
             return true;
@@ -3528,6 +3539,10 @@ fn test_linux(target: &str) {
             {
                 return true;
             }
+            // LFS64 types have been removed in musl 1.2.4+
+            if name.starts_with("RLIM64") {
+                return true;
+            }
         }
         match name {
             // These constants are not available if gnu headers have been included

src/unix/linux_like/linux/mod.rs

@@ -61,11 +61,6 @@ impl ::Clone for fpos64_t {
 }
 
 s! {
-    pub struct rlimit64 {
-        pub rlim_cur: rlim64_t,
-        pub rlim_max: rlim64_t,
-    }
-
     pub struct glob_t {
         pub gl_pathc: ::size_t,
         pub gl_pathv: *mut *mut c_char,
@@ -685,6 +680,11 @@ s! {
     pub struct sctp_authinfo {
         pub auth_keynumber: ::__u16,
     }
+
+    pub struct rlimit64 {
+        pub rlim_cur: rlim64_t,
+        pub rlim_max: rlim64_t,
+    }
 }
 
 s_no_extra_traits! {
@@ -703,14 +703,6 @@ s_no_extra_traits! {
         pub d_name: [::c_char; 256],
     }
 
-    pub struct dirent64 {
-        pub d_ino: ::ino64_t,
-        pub d_off: ::off64_t,
-        pub d_reclen: ::c_ushort,
-        pub d_type: ::c_uchar,
-        pub d_name: [::c_char; 256],
-    }
-
     pub struct sockaddr_alg {
         pub salg_family: ::sa_family_t,
         pub salg_type: [::c_uchar; 14],
@@ -804,6 +796,14 @@ s_no_extra_traits! {
         pub tx_type: ::c_int,
         pub rx_filter: ::c_int,
     }
+
+    pub struct dirent64 {
+        pub d_ino: ::ino64_t,
+        pub d_off: ::off64_t,
+        pub d_reclen: ::c_ushort,
+        pub d_type: ::c_uchar,
+        pub d_name: [::c_char; 256],
+    }
 }
 
 s_no_extra_traits! {
@@ -4299,21 +4299,8 @@ extern "C" {
     pub fn mprotect(addr: *mut ::c_void, len: ::size_t, prot: ::c_int) -> ::c_int;
     pub fn __errno_location() -> *mut ::c_int;
 
-    pub fn fopen64(filename: *const c_char, mode: *const c_char) -> *mut ::FILE;
-    pub fn freopen64(
-        filename: *const c_char,
-        mode: *const c_char,
-        file: *mut ::FILE,
-    ) -> *mut ::FILE;
-    pub fn tmpfile64() -> *mut ::FILE;
-    pub fn fgetpos64(stream: *mut ::FILE, ptr: *mut fpos64_t) -> ::c_int;
-    pub fn fsetpos64(stream: *mut ::FILE, ptr: *const fpos64_t) -> ::c_int;
-    pub fn fseeko64(stream: *mut ::FILE, offset: ::off64_t, whence: ::c_int) -> ::c_int;
-    pub fn ftello64(stream: *mut ::FILE) -> ::off64_t;
     pub fn fallocate(fd: ::c_int, mode: ::c_int, offset: ::off_t, len: ::off_t) -> ::c_int;
-    pub fn fallocate64(fd: ::c_int, mode: ::c_int, offset: ::off64_t, len: ::off64_t) -> ::c_int;
     pub fn posix_fallocate(fd: ::c_int, offset: ::off_t, len: ::off_t) -> ::c_int;
-    pub fn posix_fallocate64(fd: ::c_int, offset: ::off64_t, len: ::off64_t) -> ::c_int;
     pub fn readahead(fd: ::c_int, offset: ::off64_t, count: ::size_t) -> ::ssize_t;
     pub fn getxattr(
         path: *const c_char,
@@ -4614,12 +4601,6 @@ extern "C" {
         offset: *mut off_t,
         count: ::size_t,
     ) -> ::ssize_t;
-    pub fn sendfile64(
-        out_fd: ::c_int,
-        in_fd: ::c_int,
-        offset: *mut off64_t,
-        count: ::size_t,
-    ) -> ::ssize_t;
     pub fn sigsuspend(mask: *const ::sigset_t) -> ::c_int;
     pub fn getgrgid_r(
         gid: ::gid_t,
@@ -4871,6 +4852,40 @@ extern "C" {
     ) -> ::ssize_t;
 }
 
+// LFS64 extensions
+//
+// * musl has 64-bit versions only so aliases the LFS64 symbols to the standard ones
+cfg_if! {
+    if #[cfg(not(target_env = "musl"))] {
+        extern "C" {
+            pub fn fallocate64(
+                fd: ::c_int,
+                mode: ::c_int,
+                offset: ::off64_t,
+                len: ::off64_t
+            ) -> ::c_int;
+            pub fn fgetpos64(stream: *mut ::FILE, ptr: *mut fpos64_t) -> ::c_int;
+            pub fn fopen64(filename: *const c_char, mode: *const c_char) -> *mut ::FILE;
+            pub fn freopen64(
+                filename: *const c_char,
+                mode: *const c_char,
+                file: *mut ::FILE,
+            ) -> *mut ::FILE;
+            pub fn fseeko64(stream: *mut ::FILE, offset: ::off64_t, whence: ::c_int) -> ::c_int;
+            pub fn fsetpos64(stream: *mut ::FILE, ptr: *const fpos64_t) -> ::c_int;
+            pub fn ftello64(stream: *mut ::FILE) -> ::off64_t;
+            pub fn posix_fallocate64(fd: ::c_int, offset: ::off64_t, len: ::off64_t) -> ::c_int;
+            pub fn sendfile64(
+                out_fd: ::c_int,
+                in_fd: ::c_int,
+                offset: *mut off64_t,
+                count: ::size_t,
+            ) -> ::ssize_t;
+            pub fn tmpfile64() -> *mut ::FILE;
+        }
+    }
+}
+
 cfg_if! {
     if #[cfg(target_env = "uclibc")] {
         mod uclibc;

src/unix/linux_like/linux/musl/b32/riscv32/mod.rs

@@ -184,22 +184,6 @@ s! {
         __pad1: ::c_ulong,
         __pad2: ::c_ulong,
     }
-
-    pub struct flock {
-        pub l_type: ::c_short,
-        pub l_whence: ::c_short,
-        pub l_start: ::off_t,
-        pub l_len: ::off_t,
-        pub l_pid: ::pid_t,
-    }
-
-    pub struct flock64 {
-        pub l_type: ::c_short,
-        pub l_whence: ::c_short,
-        pub l_start: ::off64_t,
-        pub l_len: ::off64_t,
-        pub l_pid: ::pid_t,
-    }
 }
 
 //pub const RLIM_INFINITY: ::rlim_t = !0;

src/unix/linux_like/linux/musl/b64/riscv64/mod.rs

@@ -173,22 +173,6 @@ s! {
         __unused5: ::c_ulong,
         __unused6: ::c_ulong,
     }
-
-    pub struct flock {
-        pub l_type: ::c_short,
-        pub l_whence: ::c_short,
-        pub l_start: ::off_t,
-        pub l_len: ::off_t,
-        pub l_pid: ::pid_t,
-    }
-
-    pub struct flock64 {
-        pub l_type: ::c_short,
-        pub l_whence: ::c_short,
-        pub l_start: ::off64_t,
-        pub l_len: ::off64_t,
-        pub l_pid: ::pid_t,
-    }
 }
 
 pub const SYS_read: ::c_long = 63;