mmap addr

Author: JonathanWoollett-Light

src/sys/mman.rs

@@ -417,14 +417,19 @@ pub fn munlockall() -> Result<()> {
 ///
 /// [`mmap(2)`]: https://man7.org/linux/man-pages/man2/mmap.2.html
 pub unsafe fn mmap(
-    addr: *mut c_void,
+    addr: Option<size_t>,
     length: size_t,
     prot: ProtFlags,
     flags: MapFlags,
     fd: RawFd,
     offset: off_t,
 ) -> Result<*mut c_void> {
-    let ret = libc::mmap(addr, length, prot.bits(), flags.bits(), fd, offset);
+    let ptr = addr.map_or(
+        std::ptr::null_mut(),
+        |a| a as *mut c_void
+    );
+    
+    let ret = libc::mmap(ptr, length, prot.bits(), flags.bits(), fd, offset);
 
     if ret == libc::MAP_FAILED {
         Err(Errno::last())