Fix (some?) 32 bit builds

Some 32 bit builds are broken, due to unnecessary specific casts, which
lead to integer mismatches. Fix them (and a few more...).

Fixes: #500

Author: d-e-s-o

libbpf-rs/CHANGELOG.md

@@ -1,3 +1,8 @@
+Unreleased
+----------
+- Fixed build failures on 32 bit x86 and aarch32
+
+
 0.21.0
 ------
 - Added `TcHook::get_handle` and `TcHook::get_priority` methods for restoring

libbpf-rs/src/map.rs

@@ -683,7 +683,7 @@ impl MapHandle {
         };
 
         let opts = libbpf_sys::bpf_map_batch_opts {
-            sz: mem::size_of::<libbpf_sys::bpf_map_batch_opts>() as u64,
+            sz: mem::size_of::<libbpf_sys::bpf_map_batch_opts>() as _,
             elem_flags: elem_flags.bits,
             flags: flags.bits,
         };

libbpf-rs/src/program.rs

@@ -59,7 +59,7 @@ impl From<UsdtOpts> for libbpf_sys::bpf_usdt_opts {
             _non_exhaustive,
         } = opts;
         libbpf_sys::bpf_usdt_opts {
-            sz: mem::size_of::<Self>() as u64,
+            sz: mem::size_of::<Self>() as _,
             usdt_cookie: cookie,
         }
     }
@@ -82,7 +82,7 @@ impl From<TracepointOpts> for libbpf_sys::bpf_tracepoint_opts {
         } = opts;
 
         libbpf_sys::bpf_tracepoint_opts {
-            sz: mem::size_of::<Self>() as u64,
+            sz: mem::size_of::<Self>() as _,
             bpf_cookie: cookie,
         }
     }
@@ -818,11 +818,11 @@ impl Program {
     pub fn attach_iter(&mut self, map_fd: BorrowedFd<'_>) -> Result<Link> {
         util::create_bpf_entity_checked(|| unsafe {
             let mut linkinfo = libbpf_sys::bpf_iter_link_info::default();
-            linkinfo.map.map_fd = map_fd.as_raw_fd() as u32;
+            linkinfo.map.map_fd = map_fd.as_raw_fd() as _;
             let attach_opt = libbpf_sys::bpf_iter_attach_opts {
                 link_info: &mut linkinfo as *mut libbpf_sys::bpf_iter_link_info,
-                link_info_len: std::mem::size_of::<libbpf_sys::bpf_iter_link_info>() as u32,
-                sz: std::mem::size_of::<libbpf_sys::bpf_iter_attach_opts>() as u64,
+                link_info_len: std::mem::size_of::<libbpf_sys::bpf_iter_link_info>() as _,
+                sz: std::mem::size_of::<libbpf_sys::bpf_iter_attach_opts>() as _,
                 ..Default::default()
             };