add musl and glibc wrappers for getdents{,64}

libc-test/semver/linux-gnu.txt

@@ -604,6 +604,7 @@ fgetpwent_r
 fgetspent_r
 futimes
 getauxval
+getdents64
 getentropy
 getgrent_r
 getloadavg

libc-test/semver/linux-musl.txt

@@ -66,6 +66,8 @@ euidaccess
 explicit_bzero
 futimes
 getauxval
+getdents
+getdents64
 getloadavg
 getutxent
 getutxid

src/unix/linux_like/linux/gnu/mod.rs

@@ -1344,6 +1344,13 @@ extern "C" {
     pub fn mempcpy(dest: *mut c_void, src: *const c_void, n: size_t) -> *mut c_void;
 }
 
+extern "C" {
+    // There is no glibc wrapper for the getdents system call, and getdents64() is only available
+    // from 2.30 onwards.
+    /// `buffer` points to a buffer of [`crate::dirent64`] structs.
+    pub fn getdents64(fd: c_int, buffer: *mut c_void, nbytes: usize) -> isize;
+}
+
 cfg_if! {
     if #[cfg(any(
         target_arch = "x86",

src/unix/linux_like/linux/musl/lfs64.rs

@@ -198,6 +198,11 @@ pub unsafe extern "C" fn readdir64_r(
     crate::readdir_r(dirp, entry as *mut _, result as *mut _)
 }
 
+#[inline]
+pub unsafe extern "C" fn getdents64(fd: c_int, buf: *mut crate::dirent64, len: usize) -> c_int {
+    crate::getdents(fd, buf as *mut _, len)
+}
+
 #[inline]
 pub unsafe extern "C" fn sendfile64(
     out_fd: c_int,

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

@@ -974,6 +974,10 @@ extern "C" {
     pub fn utmpxname(file: *const c_char) -> c_int;
 }
 
+extern "C" {
+    pub fn getdents(fd: c_int, buf: *mut crate::dirent, len: usize) -> c_int;
+}
+
 // Alias <foo> to <foo>64 to mimic glibc's LFS64 support
 mod lfs64;
 pub use self::lfs64::*;